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University of Nigeria Research Publications
UDOFIA_Ukpong_Sunny
Aut
hor
PG/Ph.D/00/31288
Title
Effect of Traditional Processing Techniques on Leafy Vegetables and Starchy Staples Consumed In Akwa
Ibom State, Nigeria
Facu
lty
Agriculture
Dep
artm
ent
Home Science
Dat
e
August, 2005
Sign
atur
e
EFFECT OF TRADITIONAL PROCESSING TECHNIQUES ON LEAFY VEGETABLES AND STARCHY STAPLES
CONSUMED IN AKWA IBOM STATE, NIGERIA
UDOFIA, UKPONG SUNNY PG/Ph.D/00/32188
DEPARTMENT OF HOME SCIENCE, NUTRITION AND DIETETICS
UNIVERSITY OF NIGERIA, NSUKKA
AUGUST, 2005
TITLE PAGE
EFFECT OF TRADITIONAL PROCESSING TECHNIQUES ON LEAFY VEGETABLES AND STARCHY STAPLES CONSUMED IN AKWA IBOM
STATE, NIGERIA
A THESIS
SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY (Ph.D) IN HUMAN
NUTRITION
UDOFIA, UKPONG SUNNY PGIPh.D100132188
AUGUST, 2005
APPROVAL PAGE
THIS THESIS HAS BEEN APPROVED FOR THE DEPARTMENT OF
HOME SCIENCE, NUTRITION AND DIETETICS
PROFESSOR (MRS.) HJ N. ENE-OBONG HEAD OF DEPARTMENT
CERTIFICATION
UDOFIA, UKPONG SUNNY, a postgraduate student in the
Department of Home Science, Nutrition and Dietetics with registration
number PG/Ph.D/00/32188 has satisfactorily completed the requirements
for the research work for the degree of Doctor of Philosophy in Human
Nutrition.
The work embodied in this thesis is original and has not been
submitted in part or in full or any degree of this or any other University.
------------------- PROFESSOR
SUPERVISOR (HEAD OF DEPARTMENT)
DEDICATION
This work is dedicated to:
ALMIGHTY GOD WHO WITH HIS SPECIAL GRACE AND FAVOUR HAS GOTTEN THIS WORK TO A SUCCESSFUL END.
ACKNOWLEDGEMENT
I, Udofia, Ukpong Sunny do sincerely express my profound gratitude
to my supervisor Prof. I. C. Obizoba who is specially designed by Almighty
God to be my mentor in this programme. He is an academic father who has
taken painful time and energy to guide me throughout this work critically
and constructively. May Almighty God, maker of the universe, grant him all
his heart desires, above all long life (for his harvests are near). I say a big
thank you to Mrs. M. I. Obizoba for her motherly care and words of
encouragement when my spirit was low.
My sincere appreciation goes to all my lecturers, especially Prof.
(Mrs.) E. C. Okeke, Prof. (Mrs.) H. N. Ene-Obong, Dr. (Mrs.) N. M. Nnam
and Dr. (Mrs.) E. K. Ngwu for their thoughtful and constructive criticisms. I
am grateful to Mr. Umeh for his technical assistance for analysing of the
samples.
I thank the management of the University of Uyo for releasing me to
improve my academic work in this great institution. Special thanks goes to
the Registrar of the University of Uyo, Mr. P. J. Effiong for his fatherly
encouragement and support.
Behind my success are missiles of prayers from great men of God
(Bishop Mike Okonkwo, Rev. Korakpe, Rev. J. Asekeme, Rev. E. Joshua,
Pastor Kelvin, Pastor Etokudo and Hon. lyet).
To my sweet, caring, loving and patient husband, I say remain bless
for your financial support and encouragement. To my sweet and patient
children, Samuel, Mfon-Obonb, Edidiong-Obong, Emem-Obong and
Edinam-Abasi, I say thanks for your prayers and understanding year in year
out throughout my sojourn in Nsukka. My gratitude goes to my brothers, Mr.
Ekpeyong E. Bassey and Mr. Ema E. Bassey for their prayers,
vii
encouragement and taking special care of my mother (Mrs. Arit E. Bassey)
when I was away. I must thank my sister and husband, Mr. and Mrs. Agnes
J. Effiom, for their encouragement. I thank my numerous friends, sisters
and brothers who have in one way or the other encouraged me in this
academic endeavour.
UDOFIA, UKPONG SUNNY
TABLE OF CONTENTS
Title Page ---- -- -- -- Approval Page-- -- -- -- Certification -: -- -- -- Dedication -- -- -- -- Acknowledgement -- -- -- Table of Contents-- -- -- List of Tables -- -- - -- List of Figures-- -- -- -- Abstract -- -- -- -- --
CHAPTER ONE 1.0 Introduction-- -- -- 1 .I Statement of Problem-- -- 1.2 General Objective-- -- 1.3 Specific Objective-- -- 1.4 Significance of Study-- --
CHAPTER TWO 2.0 Background Information--- 2.1 Vegetable-- -- -- -- 2. I. 1 Composition and nutritional quality of vegetables-- 2.1.2 Uses of vegetables -- -- -- -- -- -- 2.1.3 Processing of vegetables-- -- -- -- -- 2.2 Green leafy vegetables-- -- -- -- -- 2.2.1 Production and utilization-- -- -- -- -- 2.2.2 Leaves of annual and shrubs-- -- -- -- -- 2.2.2a Amaranths (Amaranthus spp)---- -- -- 2.2.2b Celosia (Celosia argentea) local name-- -- 2 .2 .2~ Basella (B rubra and B.alba)---- -- -- -- 2.2.2d Crassocephalum (C. biafrae and C. crepidiodes)--- 2.2.2e Corchonis spp (C. capsu1aris)---- -- -- -- 2.2.2f Bitter leaf veronia sp (V. amygdalina)-- -- -- - 2.2.2g Wild lettus (Laurea taraxicifo1ia)-- -- -- -- 2.2.2h Water bitter leaf (Struhium sparganophora)-- -- 2.2.21 Talinum spp (7. triangulare and 7. panicu1atum)-- -- - 2.2.2j The sorrel (Hibiscus sabdariffa)- -- -- -- - 2.2.2k The fluted pum kin (Telfaria accidentalis)--- -- -- - 2.2.3 Leaves of trees-- -- -- -- -- -- -- -- 2.2.4 Nutrient composition of green leafy vegetables -- -- - 2.2.4.1 Moisture content-- -- -- -- -- -- - 2.2.4.2 Energy and nutrient content-- -- -- -- -- 2.2.4.3 Protein-- -- -- -- -- -- -- -
I I
iii iv v vi viii xiii xv xvi
1 2 3 3 4
5 5 5 6 6 7 8 9 9 10 10 11 11 11 12 12 12 12 12 13 14 15 15 15
2.2.4.4 . Ether extract-- -- -- -- -- -- 2.2.4.5 Mineralcomposition-- -- -- -- -- 2.2.4.6 Vitamin composition-- -- -- -- -- 2.2.4.7 Anti-nutrient content-- -- -- -- -- 2.2.4.8 Effect of food processing on nutrient content of
green leafy vegetables-- -- -- -- .4.9 Blanching and cooking-- -- -- -- .5 Cassava leaves---- -- -- -- --
2.2.5.1 Nutrient content-- -- -- -- -- 2.2.5.2 Food toxicant content-- -- -- -- 2.3 Banana and plantain (Musa spp)---- -- 2.3.2 Utilization--- -- -- -- -- -- 2.3.3 Chemical composition and nutrient value of
plantain and banana (Musa spp)-- -- -- 2.3.4 Toxic substances and anti-nutritional factors-- 2.4 Roots and tubers crops- -- -- -- 2.4.1 Origin-- -- -- -- -- -- -- 2.4.2 Roots and tuber crops-- -- -- -- -- 2.4.3 Nutritional values and uses-- . -- -- -- 2.4.4 Effect of processing and nutritional value-- -- 2.4.4.1 Cassava (Manihot spp)-- -- -- -- 2.4.4.1 . I Origin-- -- -- -- -- -- -- 2.4.4.1.2 Production-- -- -- -- -- -- 2.4.4.1.3 Crop status--- -- -- -- -- -- 2.4.4.1.4 Harvesting-- -- -- -- -- -- 2.4.4.1.5 Processing -- -- -- -- -- -- 2.4.4.1.6 Chemical composition and nutritional value of
cassava roots---- -- -- -- -- -- 2.4.4.1.7 Toxic components of cassava roots--- -- -- 2.4.4.2 Cocoyam-- -- -- -- -- -- - 2.4.4.2.1 Kind of edible aroids-- -- -- -- -- 2.4.4.2.2 Origin-- -- -- -- -- -- -- -- 2.4.4.2.3 Advantages of cocoyam over other roots--- -- 2.4.4.2.4 Utilization of taro cocoyam (C. escu1enta)-- -- 2.4.4.2.5 Utilization of tannia cocoyam (Xanthosoma S.)-- 2.4.4.2.6 Toxicity---- -- -- -- -- -- -- 2.4.4.2.7 Nutritive value--- -- -- -- -- -- 2.5 Nutritive value of Nigerian foods-- -- -- -- 2.6 Food availability and affordability -- -- -- -- 2.7 Food processing, safety and quality--- -- --
CHAPTER THREE 3.0 Materials and Methods-- -- -- -- -- -- 3. I .a Purchase of fresh green leafy vegetables -- -- --
3.1 .b Purchase of roots, tuber, plantain and banana-- -- -- 43 3.2 Processing of green leafy vegetables (Figures 1 - 7
depict the processing of various vegetable)-- -- -- . 43 3.2.1 Processing of cassava, cocoyam, unripe
plantain and banana-- -- -- -- -- -- -- 44 3.3 Confirmatory study-- -- -- -- -- -- -- 53 3.3.1 Abak atama soup (Hensia crinata)-- -- -- -- -- 53 3.3.2 Efere "editan" (Lasianthera africana) (soup meal)--- -- 55 3.3.3 Preparation of dishes-- -- -- -- -- -- -- 57 3.3.3.1 lwukukom (unripe green plantain pottage)
(Musa paradisca)-- -- -- -- - -- 57 3.3.3.2 "Otomboro" (Banana porridge) (Musa sapienturn)---- 59 3.3.3.3 Atitin kop (cassava pacels) (Manihot escu1enta)-- --- 60 3.4.0 Analytical procedure-- -- -- -- -- -- -- 62 3.4.1 The proximate composition of processed green leafy vegetables
and their controls and processed starchy staples.-- --- 62 3.4.2 The minerals, vitamins and anti-nutrients concentration
of the samples-- -- -- -- -- -- -- -- 62 3.5.0 Statistical analysis-- -- -- -- -- -- ---- 63 3.5.1 The data-- -- -- -- -- -- -- -- -- 63
CHAPTER FOUR Results -- -- -- -- -- -- -- -- -- 64 The nutrient composition of processed and unprocessed green leafy vegetables--- -- -- -- 64 Effect of processing on the proximate composition of three green leafy vegetables (%)- -- -- -- -- 66 Some minerals and vitamins content of processed and unprocessing green leafy vegetables -- -- -- -- 69 Effect of processing on minerals and vitamins content of Green leafy vegetables -- - -- -- -- ---- 7 1 Antinutrient on food toxicant levels in processed green leafy vegetables-- -- -- -- -- -- -- -- 75 Effect of processing on some antinutrient and food toxicants content of green leafy vegetables--- -- -- 77 Proximate composition of processed and unprocessed cassava and its products, cocoyam, unripe green plantain and banana products---- -- -- -- -- 80 Effect of processing on the proximate composition of cassava and its products, cocoyam, unripe green plantain and banana -- -- -- -- -- -- -- 82
4.1 0 some minerals and vitamins content of processed and unprocessed cassava and products, cocoyam, unripe green plantain and banana-- -- -- -- -- -- 84
~ f f e c t of processing on some minerals and vitamins content of cassava and its products, cocoyam, unripe green plantain and banana - -- -- -- -- -- Antinutrient and food toxicant composition of processed and unprocessed cassava and its products, cocoyam and unripe green plantain and banana-- -- -- Effect of processing on antinutrients and food toxicants on cassava and its products, cocoyam, unripe green plantain and banana-- -- -- -- -- -- - Proximate composition on two soup meals and the accompaniments-- -- -- -- -- -- -- Some minerals and vitamins content of two soup meals and their accompaniments-- -- -- -- -- Proximate composition of three - one pot meals ("lwukukom", "otomboro" and "atitinkopll)-- -- -- -- Some minerals and vitamins content of three - one pot meals ("lwukukom", "otomboro" and "atitinkopn)-- -- --
CHAPTER FIVE Discussion --- -- -- -- -- -- -- -- Proximate composition of processed and unprocessed three leafy vegetables based on residual moisture against (Table I)--- -- -- -- -- -- -- Some minerals and vitamins content of processed and unprocessed green leafy vegetables---- -- -- -- Anti-nutrients and food toxicant of processed and unprocessed green leafy vegetables-- -- -- ---- Proximate composition of processed and unprocessed cassava and its products, cocoyam, unripe green plantain and banana based on residual moisture -- -- Some minerals and vitamins content of processed and unprocessed cassava and its products, cocoyam, unripe green plantain and banana -- -- -- -- -- Anti-nutrients and food toxicants of processed and unprocessed cassava and its products, cocoyam, unripe green plantain and banana --- -- -- -- --- Proximate composition of two soup meals and accompaniments -- -- -- -- -- --- - Some minerals and vitamins content of two soup meals and accompaniments-- -- -- -- -- -- Proximate composition of three-one pot meals-- -- ---
5.10 Some minerals and vitamins content of three - one pot meals-- -- -- - -- -- --
~ondusion-- -- -- -- -- -- -- -- -- 117 Recommendations-- -- -- -- -- -- --- -- 117 Further research work-- -- -- -- -- -- -- -- 118 References-- -- -- -- -- -- -- -- -- 119 Appendices '
I . Proximate composition determination using standard methods of AOAC ( I 995)--- -- -- -- -- 135
2. Determination of p-carotene and folate-- -- -- -- 139 3. Determination of antinutrients and food toxicants-- -- 141 4. Statistical procedure-- -- -- -- -- --- 144
Tables
LIST OF TABLES
Page
Proximate composition of processed and unprocessed green leafy vegetables -- -- -- -- -- -- -- --
Effect of processing on the proximate composition of three green leafy vegetables -- -- -- -- -- --
Some minerals and vitamins content of processed and unprocessed green leafy vegetables -- -- -- --
Effect of processing on some minerals and vitamins content of green leafy vegetables -- -- -- -- --
Antinutrients and food toxicants composition of processed and unprocessed green leafy vegetables-- -- -- --
Effect of processing on some antinutrients and food toxicants content of green leafy vegetables-- -- --
Proximate composition of processed and unprocessed cassava and its products, cocoyam, unripe green plantain and banana-- -- -- -- -- -- --
Effect of processing on the proximate composition of cassava and its products, cocoyam, unripe green plantain and banana-- -- -- -- -- -- --
Some minerals and vitamins content of processed and unprocessed cassava and products, cocoyam, unripe green plantain and banana-- -- -- -- --
Effect of processing on some minerals and vitamins content of cassava and its products, cocoyam, unripe green plantain and banana-- -- -- -- -- --
Antinutrients and food toxicants composition of processed and unprocessed cassava and its products, cocoyam, unripe green plantain and banana-- -- -- -- --
xiv
12. Effect of processing on some antinutrients and food toxicants content of cassava and its products, cocoyam, unripe green plantain and banana-- -- -- -- -- 93
13. Proxim'ate composition of two soup mealslaccompaniments-- 95
14. Some minerals and vitamins content of two soup mealslaccompaniments-- -- -- -- -- -- . 99
15. Proximate composition of iwukukom, otomboro and atitinkop - one pot meal (dishes)-- -- -- -- -- 102
16. Some minerals and vitamins content of "iwukukom" (Musa paradisca), "otomboro" (Musa sapientum), and "atitinkop" (Manihot escu1enta)-- -- -- -- -- 105
LISTS OF FIGURES
Figures
1. "Atama" (Heinsia crinata) processing-- -- -- --
2. "Editan" (Lasianthera africana) processing -- -- --
3. Waterleaf (Talinum triangulare) processing -- -- --
4. Cassava (Manihot esculenta) processing-- -- -- --
5. Cocoyam (Xanthosoma sagittifolium) processing---- --
6. Unripe green plantain (Musa paradisiaca) processing -- --
7. Unripe green banana (Musa sapienturn) processing-- --
Page
46
47
48
49
50
5 1
52
xvi
ABSTRACT
The work identified the green leafy vegetables and starchy food
staples used. to prepare popular traditional soup meals and dishes
consumed in Akwa lbom State, Nigeria. The vegetables include "atama"
(Heinsia crinata), "editan" (Lasianthera africana) and waterleaf (Talinum
triangulare), while starchy staples included; cassava (Manihot esculenta)
and its products (fufu and gari), cocoyam (Xanthosoma sagittifolium) and
unripe plantain (Musa paradisiaca) and banana (Musa sapientum). The
vegetables were washed and divided into three equal portions, fresh
(control) and the rest (2) were sun and shade dried. The fresh and the
treated vegetables were used for soup preparations. Cassava was
fermented (24h), an aliquot was sun dried and the rest were drained and
fried as gari. Cocoyam was peeled, sliced, cooked, a portion was sun dried
and hammermilled all for preparation of pounded cocoyam. The unripe
plantain and banana were peeled, sliced, cooked, an aliquot sun dried.
Banana was hammermilled for "otomboro" and unmilled plantain for
"iwukukom" preparation. The cassava flour was used to prepare "atitinkop".
All the samples prepared as described were chemically analysed to
determined the effects of the treatments on their nutrients, antinutrients and
food toxicants contents. Sun and shade drying reduced moisture and
increased dry matter of the 3 vegetables. Shade drying increase nutrients in
vegetables more than sun drying and sun drying alone increased nutrients
in starchy foods. Shade drying increased minerals and vitamins more than
sun drying in green leafy vegetables. Sun drying drastically reduced
antinutrients in both vegetables and starch food staples more than shade
drying. Shade drying increased macro and micronutrient contents of soup
more than sun drying. Both sun and shade drying reduced moisture and
increased dry matter. Sun drying reduced moisture in pot meals and
increased the nutrients. Shade drying is highly recommended over sun
xvii
drying as a'traditional food processing technique for seasonal green leafy
vegetables. Sun drying and fermentation are good processing techniques
for starchy food staples.
CHAPTER ONE
INTRODUCTION
It is known that about 30% of the population in developing
countries suffer currently from one or more of the multiple forms of
nutritional deficiencies, especially micronutrients (WHO, 2000). The
major nutritional problems in these countries are (a) insufficient food
intake, which is related to food insecurity, disease and lack of care and
(b) excessive or unbalanced food intake andlor particular dietary
constituent (Latham, 1997). Energy and some micronutrients
deficiencies in some cases are attributed to traditional methods of
harvesting, processing and preparation of food into dishes (Obizoba,
1 998).
Traditional dishes are as diverse as the localities (Oguntona,
1998). Social factor and cultural practices in most communities greatly
influence what the people consume, how they prepare their food, their
feeding practices and energy of the food (Latham, 1997). However, it
is true that some traditional food practices in some societies contribute
to nutritional deficiencies among particular group of the population.
The method of preparing traditional soup meals and dishes in
Nigeria has been passed on from one generation to the other. The
major traditional soup meals and dishes are incomplete without
plentiful green leafy vegetables. In Akwa lbom state, especially in Uyo
Local Government Area (L.G.A.), many traditional soup meals and
dishes contain a lot of green leafy vegetables. However, there is
paucity of information on the effect of processing on these green leafy
vegetables and the nutritional quality of soup meals and dishes. based
on them. The nutrient contribution of these soup meals and dishes to
the diets of the populace is very scanty in Nigeria literature. Many
Nigerians scramble for traditional soup meals and dishes from both
Cross River and Akwa lbom states, known as "Calabar food" - "edikafi
ikofi", "ukwoho afaA1' and "ekpaA-nkukwo" are among delicious soup
meals and dishes. Most of these soup meals and dishes have not been
investigated for nutritional adequacy mostly micronutrients (vitamin A,
zinc, iron, iodine, copper and folate).
Latham (1997) reported that the traditional soup meals and
dishes of most societies are good and only minor changes are needed
for them to meet the nutrient requirements of all members of a family.
The quantity of food consumed is a more common problem than the
quality. The foodstuffs used for preparation of traditional soap meals
and dishes in Uyo for instance are seasonal. Seasonal variations are
known to affect production, availability, quantity and quality of what is
consumed in localities.
1 .I Statement of Problem
Plant foods are the most important dietary sources to meet the
nutritional needs of the majority in Akwa lbom state. This may be the
cause of set back in nutritional status of the people due to the
presence of food toxicants and antinutrients which precipitate the
unavailability of nutrients to the body cells (Oyeleke, 1984).
The possibility of malnutrition in the presence of apparently
adequate food supply might be attributed to factors other than
availability. lgbedioh (1990) observed that improper food processing
and preparation could be the possible causes of malnutrition among
population groups. The paucity of information on the nutrient
composition of some traditional soup meals and dishes and their
nutrients contribution to the diet of Uyo communities, Akwa lbom state,
need to be investigated and documented.
The prevention of malnutrition is greatly assisted if the people
affected have accurate information on what constitutes a balance diet.
They need to know how best to meet their nutritional needs. The
nutrient composition of some traditional soup meals and dishes is very
important. The accurate information on nutritional quality of soup meals
and dishes would help to address the increasing trends of chronic
diseases or life style in some segments of Uyo.
With these information at hand, it is imperative that the
indigenous food crops used to prepare traditional dishes in Uyo Local
Government Area be investigated. The investigation would focus on
whether or not processing these food crops would stem off seasonality,
increase all year availability, densitication of nutrients and affordability
to all classes of people in Uyo Local Government Area.
1.2 General objective
The general objective of the study was to identify the food crops used
to prepare some popular traditional soup meals and dishes consumed
in Akwa lbom state and effects of some food processing techniques on
the nutrients and antinutrients.
1.2.a
0)
(ii)
Specific objectives are
to determine the effects of traditional processing techniques on
the nutrients and antinutrients composition of some leafy
vegetables and starchy staples used for preparing some popular
traditional soup meals and dishes in Akwa lbom State.
to prepare traditionally consumed soup meals, accompaniments
and dishes in Akwa lbom State.
1.3 Significance of the study
There is paucity of information on the effect of processing
techniques on identified food crops used to prepare traditional soup
meals and dishes. Such information are lacking in both national and
local government records such as Uyo L.G.A. in Akwa lbom state. This
work serves as a bench mark for future research on all this important
topic.
Information on the chemical changes in food crops for preparing
soup meals and dishes due to processing and the nutritional quality of
traditional soup meals and dishes are important. The results of such
research is bound to sensitize and mobilize the policy and decision
makers to pay much more attention to food security and improvement
of the nutritional status of their communities. The results could be the
basis for making better choices for food materials used in traditional
soup meals and dishes.
CHAPTER TWO
2.0 BACKGROUND INFORMATION
2.1 Vegetable
Vegetables are edible parts of plant which are usually cooked or
salted prior to consumption with other foods. These include, leaves,
stems, roots, flowers, seeds, fruits, bulbs, tubers and fungi. There are
thousands of plants used as vegetables. These plants belong to
different botanical classes. They may be cultivated or wild, may be
trees, herbs, shrubs, climbers, or erect plants that cut across the plant
kingdom. Certain fruits such as tomatoes, egg plant and beans are
used as vegetables (Enwere, 1998).
2.1 . I Composition and nutrional quality of vegetables
Vegetables contain non-volatile acids, organic acids, mineral
salts, volatile sulphur compound and tannins which impart flavour in
diets.
The colour of vegetables depends on the pigments they contain.
Anthocyanin imparts blue, purple and red colours to vegetables such
as raddish and red cabbage. Chlorophyll colours vegetable green,
especially leafy ones, green peas and cucumber while carotenoids are
responsible for the yellow colour of ripe tomatoes, carrots, sweet
potatoes and maize (Uwaegbute, 1989).
The carbohydrate in vegetables consists mainly of indigestible
fibrous materials such as cellulose, hemicellulose and lignin. These
are in addition to small quantities of sugars such as glucose, fructose
and sucrose. However, the proportion of fibre in the vegetables
depends on the stage of maturity. The turgidity or rigidity of vegetables
depends on the water content. It might sometimes be between 75%
and 95% (Uwaegbute, 1989; lfon and Bassir, 1979; Yamrong and
Shenquan, 1986; Woox-lseun and Flores, 1961 ).
Vegetables are low in energy, contribute fairly moderate
quantities of protein and are rich sources of vitamins. They contribute
roughage to the diet when the solid matter is considered. Vegetables
are low in fat, however, fat soluble vitamins (A, E and K) present in
vegetables are soluble. The dietary fibre in vegetables increases bulk
and reduces food transit time in the gastrointestinal tract and the
incidence of constipation and other related diseases (Enwere, 1998;
Purseglove, 1991; lfon and Bassir, 1979; Pearson, 1976; Martin and
Ruberte, 1975).
Vegetables are important sources of minerals and vitamins,
other nutrients, add colour, flavour and appeal to meals (Smith, 1982).
2.1.2 Uses of vegetables
The use to which vegetables are put in the diet depends on the
purpose to be achieved. They may be used as major or minor
ingredients in soups, sauces, stews, pottage, porridge and salads to;
(a) enhance the flavours of foods (b) to garnish prepared dish so as to
enhance eye appeal (c) as fillings for sandwiches, pies and Indian egg
rolls and (d) as a critical part of the ingredients in the preparation of
certain dishes such as vegetable soups, vegetable pottage, vegetable
porridge, vegetable parcles and salads (Enwere, 1998).
2.1.3 Processing of vegetables
Any method selected for processing vegetables should be such
that it does not adversely affect colour, texture, flavour and nutritional
value, especially the vitamins and minerals. The processing of
vegetables involves such unit operations as cleaning, sorting, grinding,
peeling (for cassava and related vegetables), trimming, size reduction
(slicing or dicing or shredding or pulping) blanching, filling into cans
(where it is to be canned), sealing, sterilizing, cooling, labelling, storing
and distributing. Processed vegetables may also be frozen or dried
(Enwere, 1998).
Vegetables, which are eaten raw, do not go beyond the slicing
stage. Sliced vegetables are added into stew, soups, sauces and
pottage, while shredded, sliced, or diced vegetable used for vegetable
salads are eaten raw. Potatoes used for salad are cooked, sliced and
diced.
The processing method used for vegetables depends on the end
product desired and storage facilities available (Gruess, 1958),
2.2 Green leafy vegetables
Green leafy vegetable constitute an indispensable constituent of
human diet in Africa, generally and West Africa in particular (Oguntona,
1986). Generally they are consumed as cooked complements of major
staples like cassava, cocoyam, guinea corn, maize, millet, rice, unripe
plantain and banana. Indeed most of the meals based on these staples
are considered incomplete without a generous serving of cooked
vegetables.
The variety of green leafy vegetables utilized are as diverse as
both the staples they are consumed with and the localities. There are
over sixty species of green leafy vegetables that are used in Nigeria
alone (Okoli et al., 1988). These range from leaves of annual and
shrubs of the families (Amaranthecea, Compositae, Portulaceaae and
Solanacea) to leaves of trees e.g. baobab. Many of these leafy
vegetables (e.g. Amaranth) are common in all parts of Nigeria.
However, some (e.g. baobab) are restricted to their natural distribution
and mostly found in northern Nigeria. The seasonal variation affects
the availability of these green leafy vegetables. These vegetables grow
abundantly in rainy season when they are much more readily available
than in the dry season. This is particularly true of the annuals.
Seasonal variation in production and availability naturally decide the
quantities to be consumed by the local consumers. Despite this,
relatively large quantities of these vegetables are consumed. Fafunso
and Bassir (1977) had estimated per capita daily consumption of fresh
vegetables in Nigeria to be 65g and some more recent survey
(Oguntona et a/., 1989) reported consumption to be as high as 360g
daily. Nutritionist and Food Scientists had ignored the importance of
vegetables as a complement of diets in Nigeria. They stressed much
more on the role and contribution of other dietary components to the
nutrition of Nigerians (Oguntona, 1998).
2.2.1 Production and utilization
There are an immense number of plants both wild and cultivated
in Nigeria. The leaves of these can be consumed either raw, however,
most are cooked prior to consumption. Information on production of
these vegetables are very scanty. Most reference works identify areas
where specific vegetables are grown in significant quantities. On the
other hand, there is no statistical data provided for levels of production
(Oguntona, 1998). Due to the wide variation in environment within
Nigeria, level and scope of production of the different vegetables
depend naturally on the major factor affecting plant growth.
Temperature, water, soil and pest conditions influence growth of
plants. Over the last few years, most of these vegetables have been
cultivated for home consumption and market. This is true for the leaf
crop that grows rapidly and is harvested within a few weeks. Apart from
these, a good percentage of vegetables are still gathered in the wild
(Oguntona, 1998).
2.2.2 Leaves of annuals and shrubs:
Although accurate statistics on the production of these leaves
are unavailable, data from several food intake studies (Oguntona et a/.,
1989; Addo and Eka, 1982) indicate that leaves of annuals and shrubs
constitute the bulk of green leafy vegetables consumed in Nigeria. In
general, however, these are cultivated plants that grow fairly rapidly
and are harvested within weeks of cultivation.
The leaves and sometimes stems used frequently as boiled
vegetables are added to soups and stews that usually contain pepper,
tomatoes, oil, salt and crushed seeds. The common ones are:
2.2.2.a Amaranths (Amaranthus spp)
Common local names include "Aliefo" (Hausa), "Tete" (Yoruba),
"lnine" (Igbo). The Amaranths refer to member of the .genus
Amaranthus and the family Amaranthaceae. There are about sixty
species of Amaranths. However, only a few are used as food crops.
Among these are amaranths, which are most important for the cereal
like grain (seed) crop.
Members of the amranthus spp. that are of food and nutritional
importance in Nigeria belong to the vegetable amaranths and include
(Caudatus, hybridus and tricolour). Apart from these fairly established
species, it is possible that many local hybrids between species and
varieties as well as strains exist. The amaranths constitute perhaps the
green leafy vegetables mostly consumed in Nigeria today. This is partly
due to the fact that it is short-lived annuals, high yielding and tolerant of
high temperature.
2.2.2.b Celosia (Celosia argentea)
Sokoyokota or Soko. This is another short-lived annual leaf
belonging to the Amaranthacea family but not generally called an
amaranth. It is also smaller, slow growing and more drought resistant
than amaranths. Two cultivars (green and red) are common in Nigeria.
They are similar in many respects; the red form is generally taller and
has a higher yield. Celosia argentea (or cock's comb) appears to be
popular mostly in the South Western part of the country where the
vegetable is prepared in the same way as amaranth.
2.2.2.c Basella (B.rubra and B.alba)
This is the so-called Indian Spinach. In Africa, it is referred to in
some areas as Gambian spinach, Malbar spinach or Malabar
nightshade. In Nigeria, it is called 'Amunututu'. The plant belongs to
the family of Basellecea but some authors classify it under
chenopodiaceae.
Basella has thick leaf, thick stem short-lived perenial with
tendency to climb. The flowers are small and developed in groups in
the leafy axis. When mature, the trilobbed fruits are round and
succulent containing only one seed in the middle. Two varieties of
Basella are usually identified in Nigeria (i) Basella alba or the group
type which has white flowers, (ii) Basella rubra or the red Indian
spinach which has red (dark purple) stems, petioles and leaves and
pale pink flowers. Both varieties are tolerant to heavy rainfall and are
common in the southern part of the country. Both varieties have high
water content.
2.2.2.d Crassocephalum (C. biafrae and Cxrepidiodes)
The perenial plant is also called Sierra Leone bologni. A member
of compositae family, it is a shade tolerant plant common in certain
forest areas of West Africa. The cylindrical climbing stem bears
succulent leaves. C.biafrae is not as common as Amaranth or the
other leafy vegetables in Nigeria. Its use appears to be restricted to
the forest zones of Western and Eastern Nigeria (Oguntona, 1998).
2.2.2.e Corchorus spp. (C.capsularis)
The plant is a member of the family Taliaceae. The other
common names include long-fruited jute, Jew's marrow, bush okra and
West African sorrel. Local names include 'Krim-krim', 'Ewedu', 'Oyo',
'Eyo', 'Lalo'.
The two main types of Corchorus are common in Nigeria, one
with fairly serrate leaves called "Amughadu" and the other generally
shorter but coarsely serrate broad leaves are called "Oniyaya"
(Epenhuijsen, 1 974).
The plant is cultivated as a vegetable in many Nigerian farms,
especially as it is tolerant to many soil conditions. Among many
communities the leaves are valued as a cooked vegetable mostly
because of the high proportion of mucilage they contain.
2.2.2.f Bitter leaf (Vernonia amygdalina)
The common English name of this perennial plant is bitter-leaf.
Its other local name is "Ewuro." It belongs to the family compositae. As
the name implies, it contains a bitter pigment necessitating much
squeeze washing prior to cooking and consumption. Unlike many other
vegetables, bitter leaf is cherished in Nigeria for the distinctive flavour it
imparts in the dish of which it is a component.
2.2.2.g Wild lettus (Laurea taraxicifolia)
This is a member of compositae, an annual plant, equally bitter
as Veronica spp. In Nigeria, it is called "Yanrin."
2.2.2.h Water bitter leaf (Struchium sparganophora)
This is an aquatic plant of the compositae family. In Nigeria, it is
called "Ewuru Odo."
2.2.2.i Talinum spp. ( TJriangulare and T.paniculatum)
Talinum belong to the family Partulaceae. The common name is
Waterleaf but locally, it is called "gbure" or "gure". As the common
name implies, it is high in moisture and thrives better in high moisture
area: It is very invasive and constitutes a common feature of farms
under fallow in these areas.
2.2.2.j The sorrel (Hibiscus sabdariffa)
This is a member of the Malvaceae family. The local names in
Nigeria include "lsapa", "Aukan" and "Yakwa". It is a woody annual that
often survives on relatively poor soils.
There are two varieties (a) the green and (b) the red varieties.
The leaves and flowers of both varieties are used as cooked
vegetables. In some parts of Western Nigeria, the dried flowers are
cooked with melon paste. In many communities, local drinks are
produced from the red sorrel e.g. yakwa drink in Borno (Oguntona,
1 998).
2.2.2. k The fluted pumpkin (Telfaria accidentalis)
The leaves of this crop are important food vegetables for many
people, especially in the mid-western and eastern parts of Nigeria. The
local names include "Ugu" (Igbo) and "lroko" (Yoruba). The crop is a
member of Cucurbitaceae family. It is a perennial vine. Its stem is as
long as 10 meters. The male plants produce leaves that are similar to
the female plants. It has been estimated that approximately 0.5 kg
leaves and shoots are obtained from one plant per harvest (Tindall,
1983) and up to 15 harvests are obtained between 3 - 4 months. The
leaves are highly cherished as cooked vegetables and the seeds are
used in soups, etc.
2.2.3 Leaves of trees
If the statistics on production and utilization of leaves of annuals
and shrubs are scarce, those on use of tree leaves as vegetables are
much more scarce (Oguntona, 1998). This is because trees are
generally considered important only as source of fruits rather than
leaves for human consumption.
Several communities in Nigeria utilize the leaves of many shrubs
and trees. They constitute the group usually referred to as "Lesser
known" (Temple, 1998). In Nigeria perhaps the best known trees that
provide leaves for use as vegetables for human consumption are the
zogale and baobab (Oguntona, 1998; Oguntona and Oguntona, 1986).
Baobab (Adansomia digitata L.) leaf is one of such vegetables.
Baobab leaves, fruits and seeds are used as articles of food in the
northern states of Nigeria where it grows extensively. However, the
leaves are not consumed in the southern states. Baobab plant is a
deciduous tree and a member of the family Bombaceae. Flowers,
fruits and leaves develop in the tree during rainy season. The leaves
fall and the fruits mature in dry season. The tree may live for hundreds
of years. The baobab tree grows extensively in semi-arid Africa, from
Senegal east to Kenya and throughout southern Africa and
Madagascar. As the baobab has many uses, young trees are kept alive
and encouraged to grow in and around village sites (Scheuring et a/.,
1999).
The leaf of baobab tree has rich nutrient potentials. FA0 (1990)
reported its protein value as 12.3%, 3.1% fiber, 9.6% ash, 11.8%
moisture, 221 mg calcium, 24mg iron, 275mg phosphorus and traces of
ascorbate. The leaf has been identified as a rich source of beta-
carotene, the precusor of vitamin A (156.5pglg) (Scheuring et a/.,
1999). The baobab leaf provides macro and micronutrients to the diets
of its consumers. The leaf is used as a vegetable in soups either in
fresh, dried or powdered form. The powder, known as "kuka" in
northerm Nigeria is used to thicken soups called "miyan kuka" (Addy,
1978). This is because the pulverized baobab leaf has a high mucilage
content like lrvingia gabonensis seed (bush mango) (FAO, 1988).
2.2.4 Nutrient composition of green leafy vegetables:
Green leafy vegetables are good sources of micronutrients
(Raiyalakshms, 2001; FAO, 1997). There are a lot of green leafy
vegetables in Nigeria ecosystem. These could provide adequate
quantities of micronutrients in the diet when properly processed and
utilized. In spite of this, Nigerians still suffer from micronutrient
deficiencies (OMNI and USAID, 1993; NDHS, 1990). This is partly
because of lack of knowledge of its processing, nutrient composition
and utilization of many and varied leafy vegetables indigenous to
Nigeria (Nnam and Nwofor, 2001)
Green leafy vegetables consumed in Nigeria have been the
subject of many analytical studies, especially during the 1960's and
1970's (Oke, 1967; Oke, 1968; Fafunso and Bassir, 1977; lfon and
Bassir, 1979). Since the nutrient composition of tropical green leafy
vegetables and other groups of tropical foods are available, an
excellent compilation (West et a/., 1988) exists for food commonly
consumed in East Africa, however, information on green leafy
vegetables is not extensive. Oguntona (1998) reported that the wide
variation in nutrient content of leafy vegetables are due to (a) a
problem of taxonomy or proper identification of the samples, especially
given the ever increasing range of strains and hybrids available, (b)
variation in the nutrient and fertilizer status of the soil in which the crop
is grown, sample preparation procedures prior to analysis cause
considerable problem and (c) analytical procedures vary in techniques
and quality (Oguntona, 1998).
2.2.4.1 Moisture content
As expected fresh green leafy vegetables are high in moisture
that ranges from 72% in cassava leaves to 92-93% in Indian spinach
and waterleaf. The amount in individual sample of course, depends on
several factors including (a) age (b) agronomic practices prevailing
during cultivation and (c) freshness (Oguntona, 1998). Freshness is a
function of time lag between harvest and analysis as well as the
condition under which the samples are kept during the time lag. The
moisture content of the sun-dried vegetables are understandably
variable depending on the local environmental condition and storage.
2.2.4.2 Energy and nutrient content
Green leafy vegetables are not good sources of dietary energy. This is
a reflection of the low dry matter (DM) content of many of these leaves
(Oguntona, 1998).
2.2.4.3 Protein:
Overall fresh green leafy vegetables have crude protein content
ranging for 1.5 to 1.7%. However, some workers (Aletor and Adeogun,
1995) reported a mean of 4.2% for seventeen of such vegetables.
When dried samples were used, crude protein ranged from 15.0 to
30%. However, the mean is usually around 20% (Aletor and Adeogun,
1995). Schmidt (1971) indicated that 75% of total nitrogen in most
vegetables is protein nitrogen. Many reports indicate that green leafy
vegetable are low in sulphur amino acids (Oguntona, 1998).
2.2.4.4 Ether extract
Leafy vegetables are known to be poor sources of fat. Among the
proximate components, fat content is the lowest. The levels of ether
extract scarcely exceeds 1.0% in fresh leafy vegetable. The dry
samples range from 1-30%. An important considerate in the evaluation
of ether extracts of these materials is that many other ether soluble
materials are extracted with the true fat (Oguntona, 1998).
2.2.4.5 Mineral composition
The mineral composition of green leafy vegetables is influenced
by soil fertility or type and quality of fertilizer used is perhaps the most
considerations (Schmidt, 1971). This is the reason for the reported
wide variation in some of the published data for green leafy vegetables
(Oguntona, 1998). In a study of twelve Nigerian vegetables, Latande
Dada (1 990) reported that the total iron content differed significantly. It
ranged from 29.4 to 92mglkg.
Most of the earlier studies (Oke, 1968; Oyenuga, 1968) showed
that Nigerian green leafy vegetables contain appreciable amounts of
minerals. This was confirmed by more recent studies (Ifon and Bassir,
1979; Faboya, 1983; Aletor and Adeogun, 1995). Specifically, green
leafy vegetables are low in sodium (Ifon and Bassir, 1979). Smith
(1983) reported that they are high in potassium. The report by lfon and
Bassir (1977) suggested that some of the green leafy vegetables
contain comparatively high levels of sulfur.
2.2.4.6 Vitamin composition
As with other nutrients many factors influence the composition of
vitamins in green leafy vegetables. Cultivar and maturity are important
factors as well as light. It is known that crops that mature during
autumn contain higher pro-vitamin A (precusor) than those that mature
in poorer light of winter (Selman, 1994). The richest vegetable sources
of thiamin are green leafy vegetables. This vitamin is retained at high
levels in the leaves prior to transferring to the seed or root at maturity.
Green leafy vegetables contain some quantity of riboflavin. However,
niacin and folate are found in reasonable amounts in green leafy
vegetables (Oguntona, 1998). Green leafy vegetables are good
sources of ascorbate. The component of Nigerian green leafy
vegetables had received considerable attention. Some recent studies
on the vitamin content of Nigerian green leafy vegetable are those of
lfon and Bassir (1 979) and Aletor and Adeogun (1 995).
2.2.4.7 Anti-nutrient content
The major antinutrients commonly found in green leafy
vegetables are phytic and oxalic acids. These are important because
of their significant adverse effect on the nutritional value of these
vegetables. High levels of either phytate and oxalate inhibit the
absorption and utilization of minerals in animals and man (Talyor,
1975). Despite the high levels of antinutrients in spine green leafy
vegetables (e.g cassava leaves contain 5 to 20 times high cyanogenic
glycosides than the roots). Green leafy vegetables when processed
and cooked are free of food toxicants (Bokanga, 1994 ).
2.2.4.8 Effect of food processing on nutrient content of green
leafy vegetables
Green leafy vegetables like other foodstuffs used in Nigeria are
subjected to quite a variety of processing procedures in the preparation
for consumption. These procedures include rinsing, cutting, chopping
and lacerating, washing, squeeze washings, drying, blanching, boilding
and combination of some of these. For dried vegetables, cleaning may
include stone and debris picking or even willowing. These processes,
cause tissue damage and losses of some nutrients. Some aspects of
these losses were reviewed for European vegetables (Rutledge, 1991).
In Nigeria the degree of success of the cleaning and washing
processes is a function of water quality. Another aspect of the general
preparation of green leafy vegetables is cutting, chopping and
laceration. The main objective is to reduce the size of the vegetables.
These processes leach nutrients from the vegetables, especially when
these processes include washing (Oguntona, 1998).
Squeeze washing is a popular procedure among Nigerians in the
preparation of certain green leafy vegetables. Keshinro and Ketitku
(1979) reported that the objective of these processes were to eliminate
most of the associated "bitter taste" in these tough vegetables. This
procedure is quite severe and losses of nutrients are considerable
(Keshinro and Ketitku, 1979; Latunde-Dada, 1990).
2.2.4.9 Blanching and cooking
Blanching is a well-known procedure in vegetable processing.
The temperature is between 75-95 '~ for a period of time. The time
ranges between 1 to 10 minutes, depending on product reqirement.
There are various types of blanching operation (Selma, 1994). The
most common with green leafy vegetables in Nigeria is water
blanching.
Blanching has several advantages. It removes foreign materials,
improves product colour, inactivation of enzymes that would otherwise
cause undesirable changes in physio-chemical properties and
improvement in texture (Okoli et a/., 1988). Under industrial conditions,
blanching aids in filling of can.
Over the years a numbers of studies on the effect of blanching
on nutrient status of several Nigerian green leafy vegetables have
been reported (Fafunso and Bassir, 1977; Akpapunam, 1984; Okoli et
a/., 1988; Latunde-Dada, 1990). However, as these reports are, some
of them had a considerable lack of control over key parameters that
affect nutrient losses (Oguntona, 1998). Some of these parameters
include cultivar differences, harvesting procedure, maturity, index, leaf
size, initial nutrient content, the analytical method employed, blanching
procedure, equipment and product of water ratio used (Selman, 1994).
Nutrient losses from green leafy vegetables due to water
blanching increase with contact time, especially for water-soluble
nutrients. Fat-soluble nutrients are relatively unaffected (Oguntona,
1998).
Studies on the effect of cooking on nutrient content of Nigerian
green leafy vegetables showed greater losses of nutrients than
reported for blanching (Faboja, 1985; Oguntona and Oguntona, 1985;
Ajaji et a/., 1980; Keshinro and Ketiku, 1979; Fafunso and Bassir,
1977).
Vitamin losses are the greatest concern during blanching and
cooking of vegetables (Ajaji et al., 1980; Keshinro and Ketiku, 1979;
Fafunso and Bassir, ' 1977). Vitamin losses during cooking range from
20-70% in green vegetables (Paul and Southgate, 1978). Fafunso and
Bassir (1977) found that ascorbic acid content of freshly harvested
green leafy vegetable was lower by cooking for 5 minutes in a 2-to-10
volume of water by 15 to 16%. Increase in cooking time or volume of
cooking water led to increased loss of ascorbate (Latunde-Dada,
1990; Oguntona and Oguntona, 1985; Akpapunam, 1984; Keshinro
and Ketiku, 1979). Cooking for a long time destroys vitamins e.g
ascorbate in green leafy vegetables (Latunde-Dada, 1990). Nigerian
soup meals are generally rich in mineral nutrients and provitamin A.
The presence of antinutritive factors may not significantly reduce their
bioavailability (Ene-Obong and Madukwe, 2001; Nnam and Nwofor,
2001 ; Akpanabiatu et a/. , 1998).
2.2.5 Cassava leaves
There are indications from food intake survey (Oguntona et a/.,
1987) that cassava leaves are being increasingly utilised for food by
Nigerians. This is already the practice in much of the so-called
cassava belt of Africa, stretching from Senegal in the West to
Mozambique in Southern Africa (Bokanga, 1994). There is absolutely
no data on the quantities of cassava leaves so utilised, an omission
from FA0 production statistics properly highlighted by Bokanga (1994).
The increased use in Nigeria could possibly be in response to
deteriorating economic conditions or other reasons. Whatever be the
reasons, however, continued increased consumption promises has
both economic and nutritional consequences. The economic
implications for cassava root-based economics would become
important with uncontrolled harvesting of cassava leaves for food.
It is known that harvesting the leaves more than once a month
could significantly reduce root yield of the cassava plant (Bokanga,
1 994).
2.2.5.1 Nutrient content
The nutritive value of cassava leaves has been the subject of
some early studies by Nigerian scientists. Oke (1968) examined the
nutritional and non-nutritional value of the leaves. More recently,
Lancaster and Brooks (1983) and Bokanga (1994) had reviewed the
status of cassava leaves for human consumption. Awoyinka et a/.,
(1995) reported the nutrient content of young cassava leaves and
assessed their acceptance as a green vegetable in Nigeria.
Most studies put the protein content at between 5.58% for fresh
leaves. This is higher than in most leaves. Some reports indicate that
cassava leaf protein is low in sulphur containing amino acid (Gomez et
a/., 1985; Oyenuga, 1968). However, more recent data (West et a/.,
1988) showed the amino acid pattern to be well balanced and indeed
superior to the standard FAOIWHO (1 973) reference pattern.
In the review by Lancaster and Brooks (1983) cassava leaf
protein digestibility is given as 80% for younger leaves and 67% for
older leaves and the protein utilization (NPU) was below 40%.
2.2.5.2 Food toxicant
The cassava root is well known for its content of cyanogenic
glycosides. The level of these glycosides in the leaves however, can
be 5 to 20 times higher than in the root. It is also known that the
leaves contain the enzyme linamarase that is capable of breaking
down linamarin and lotaustralin. The presence of this enzyme coupled
with the processing procedures of pounding or chopping the leaves
(leading to the extensive mechanical damage), the washing and the
cooking guarantee the detoxification of such cooked cassava leaves
and virtual removal of toxicity. Bokanga (1994) has reported that
cassava leaf so treated and cooked for 15 minutes lost 99% of the
initial level of cyanogenic glycosides.
Cassava leaves are also known to contain tannins, oxalic acid
and phytic acid. These are anti-nutritional factors which are known to
affect the complete absorption of many minerals.
2.3 Banana and plantain (Musa spp.)
2.3.1 Banana is believed to have originated in southern Asia. It was
cultivated in south India around 500 B.C from where it was distributed
to Malaya through Madagascar and then moved eastl~ards around
pacific to Japan and Samoa in mid Pacific at about AD 1000. -It was
probably introduced to West Africa by AD 1400. It was introduced in
the Caribbean and Latin America soon after AD 1500 (Simmonds,
1962; 1966; 1976). By the end of the eleventh century, banana had
spread widely throughout the tropics. Banana was probably taken to
East Coast of Africa from Indonesia (FAO, 1990). Plantain arrived
much later. Plantain and banana are cultivated in all parts of the
tropics including Nigeria. The fruits are mutants of two wild species
namely "Musa Acuminate" and "Musa Balbisiona" (Vickery and Vickery,
1 979).
2.3.2 Utilization
Banana (Musa sapienturn) and plantain (Musa paradisiaca) form
the staple food for several African countries and the world. In many
parts of Africa cooking banana is prepared by boiling or steaming,
mashing, baking, drying or pounding to fufu. In Cameroon, green
banana is boiled and served in a source of palm oil with fish, cooked
meat, green beans, haricot beans and seasoning. In Uganda, where it
is a staple, it is boiled with other ingredients including beans. Ghee is
added together with pepper, salt and onions. This dish is called
"akatogo". "Omuwumbo" is prepared by wrapping the pulp in banana
leaves and steaming for about an hour. It is then pressed in the hands
to a firm mass and eaten. The green form of banana is dried and
stored, known as "mutere", it may be used for cooking after grinding
into flour (Goode, 1974) but it is mainly used in Gabon, Cameroon,
South and Central America and in the West lndies (Fawcet, 1921).
A soup called "sancocho" is made in Colombia by boiling slices
of green banana with cassava and other vegetables, while in the West
lndies boiled green banana is served with salted fish and meat.
Banana is fermented in pits in the Pacific. The fermented
product is formed into leaves and baked, known as "masi", it keeps for
over years while buried in the pit, baked "masi" stored in air-tight
baskets in a deep hole may last for generations (Cox, 1980). The
starch peseudo-stem and corm of the false banana, or " ensete"; is
prepared by similar methods in Ethoipia. The fermented product, called
"kocho" is used to prepare flat, baked bread. Ripe banana is
preserved by sun drying known as banana figs, they are eaten as
sweetmeats. This product keeps for months or even years.
In West Africa, banana are parboiled before drying. The dried
product is then bound tightly in leaves and stored until it is needed
(Massal and Barrau, 1956).
In Burundi where banana occupies about 25% of the arable land, it is
mainly used for the production of beer. It has been estimated that local
beer is consumed at a rate of 1.21lcaputlday. Making beer from
banana is common in East Africa. Green banana is buried in pits
covered with leaves to ripen for about a week, at which stage it also
starts to ferment. The peels are removed, the pulp is mixed with grass
in a trough and the juice is squeezed out. The residue is washed and
added to the bulk of the juice. Roasted sorghum flour or millet is
added and the mass is fermented for one to two days, covered with
fresh banana leaves. In modifications of the process, honey is.added
to the fermented banana pulp (FA0,I 990).
In Nigeria banana is most familiar to consumers than plantain. It
is generally consumed fresh. The cooking types are often referred to
as plantain. Fresh unripe green plantain pulp can be consumed boiled,
fried in chips, prepared into porridge, sundried and milled into amala.
Ripe peeled plantain can also be consumed directly or sliced and fried
in vegetable oil to produce "dodo" (Umoh, 1998; Ogazi, 1989; Ketiku,
1973). In other parts of the world and most especially in Africa in
particular Ghana, roasted plantain is consumed with groundnut and
puree (Akoma et a/., 1987; Ketiku, 1973). In Africa large quantities of
beer are brewed from Musa species because of its low alcoholic
content (Umoh, 1998).
Plantain is used as an antidote against diarrhea and gonorrhea.
The skin of the pulp form valuable fodder for ruminants, especially
sheep and goats. It can be used in the manufacture of soap tenderizer
(Ogazi, 1989; Ndubuizu, 1979).
2.3.3. Chemical composition and nutrient value of plantain and
banana (Musa spp.)
The chiemical composition of green plantain (unripe) was
reported (Ladele et a/., 1984; Ndubuizu, 1979) as follows: 50%
moisture, 50% dry matter, 1.9% ash, 1 .O% crude fibre, 2.9% protein,
0.58% fat, 46.62% nitrogen free extract, 1.3% sugars and 89% starch
(dry weight basis). The ripe plantain on the other hand had 51%
moisture, 49% dry matter, 0.96% ash, 1 .I O/O crude fibre, 3.0% protein,
0.74% fat, 43.2% nitrogen-free extract, 15% sugar and 47% starch.
Plantains are high-energy food. They have high concentration of
carbohydrate (unripe) and sugar when ripe. They are rich in ascorbate,
Beta-carotene, iron; calcium, potassium, magnessium and dietary
carbohydrate (Ogazi, 1989; Gwanfogbe et a/., 1980; Ndubuizu, 1979).
The pulp of ripe banana (Musa sapienturn) contains about 70%
moisture, the rest is carbohydrate. There is a little quantity of fat and
protein. It is a fairly good source of provitamins A, 62 and C. The
sodium content is low about 1.2 mg1100g edible fruit portion (Ladele et
a/., 1984; Platt, 1962).
Plantain protein is relatively rich in arginine, aspartic acid,
glutamic acid, lysine, histidine, proline and phenylalanine than other
amino acids. Alanine, threonine, tryptophan, methionine, cystine and
isoleucine are at low concentrations (Ketiku, 1973; Oyenuga, 1968).
2.3.4 Toxic substances and anti-nutritional factors
Banana and plantain do not contain significant level of any toxic
principles. They contain high levels of serotonin, dopamine and other
biogenic animes. Dopamine is responsible for enzymic browning of
sliced banana. Serotonin intake at high levels from plantain was
implicated in the aetiology of endomyocardial fibrosis (EMF) (Foy and
Parratt, 1960). However, Ojo (1 969) has shown that serotonin is rapidly
removed from circulating plasma and does not contribute to elevated
levels of biogenic amines in healthy Nigerian. Shaper (1967)
confirmed that there is insufficient evidence for regarding its level in
plantain as a factor in the aetiology of EMF.
2.4 Roots and tubers
2.4.1 Origin
Roots and tubers were dispersed by the Portuguese during the
voyages for slaves, by both Portuguese and Spaniards in their
missionary journeys and the Arab traders.
2.4.2 Roots and tuber crops:
Roots and tubers are thickened underground starch storage
organ of some plants. Some plants can propagate vegetatively from
the underground stems. Some roots and tuber crops are usually
propagated from stem cuttings. The edible roots and tubers belong to
several families. They are formed by both monocotyledons (yam and
cocoyams) and dicotycledons (Cassava, potatoes and sweet
potatoes). Cocoyam differs from yam in that they are corms. Tubers
are thickened fleshy parts of underground stems; corms are short
fleshy, vertical underground stems (Vickery and Vickery, 1979).
The root and tuber crops are grown over a range of climate and
altitudes on a variety of soils. Cassava (Manihot spp.), yam,
(Dioscorea spp.), and sweet potatoes (Ipomoea batatas) are grown
from rainfall to semi-arid parts of Nigeria because they tolerate drought
and thrive in wide range of soils. Cocoyam (xanfhosoma spp.) on the
other hand, is well adopted to wet and flooded areas and tolerant to
shade. The Irish potato (Solanum tubersum) is a temperate crop.
However, it grows well in high altitudes of Nigeria plateau (Osagie,
1992; Eka, 1 989).
Some root and tuber crops, e.g. sweet potato and cassava
require little attention after cultivation. Cassava may be left in the
ground until they are needed for consumption or sale. One
disadvantage of root and tuber crops is that, except for yam, they
cannot be stored for long after harvest. This is because they
deteriorate rapidly and their transportation to market is rather difficult.
The presence of toxic substances such as cyanide in cassava, acridity
factors, trypsin and chymotrypsin inhibitors, as well as oxalates in
aroids and poisonous steriods and in alkaloids in yam and lrish
potatoes are disadvantages (Bradbury and Holloway, 1988).
2.4.3 Nutritional value and uses
The roots and tubers are estimated to contribute 15.1% of the
total calories and 8.0% of the total protein in the daily diet of the
average Nigerian (Olayide et a/., 1979; Ogunmodede, 1983). The
edible green leaves of sweet potatoes, cocoyam and cassava are good
sources of protein, vitamins and minerals. They are often used to
augment diets in local communities and as feed for live-stock (Norman
et a/.; 1984; Cobley and Steele, 1976; Coursey, 1976; Oyenuga, 1968).
Root and tuber crops are used in Nigeria for production of
various local dishes, flours and their composites and starch. They
serve as sources of fermentable sugars required in the production of
alcoholic beverages. They are used as raw materials for various
industrial fermentation including the manufacture of pharmaceuticals,
industrial enzymes, organic solvents and cosmetics (Osagie, 1992;
Okigbo, 1986; Eka, 1986; 1985).
2.4.4 Effect o f processing on nutritional value
Root crops are not easily digested in their natural state and
should be cooked prior to consumption. Cooking improves their
digestibility, promotes palatability and improves their keeping quality as
well as making the roots safer to eat. The heat used during cooking
can be dry heat as in baking in an oven or over an open fire or wet
heat as when boiling, steaming or frying. Heat sterilizes the food by
killing harmful bacteria and other microorganisms. It increases the
availability of nutrients. Protein is denatured by heat, for easy
digestion by proteolytic enzymes. Cellulosic cell walls that cannot be
broken down by monogastic animals are broken down by heat. Some
anti-nutritional factors such as enzyme inhibitors are inactivated.
However, processing may reduce the nutritional value of some root
crops as a result of losses and changes in major nutrients, including
protein, carbohydrates, minerals and vitamins (FAO, 1990).
Nutrients may be lost during cooking by degradation, which can
occur by destruction or by other chemical changes such as oxidation,
and by leaching into the cooking medium. Vitamins are susceptible to
both processes and minerals are often lost by leaching. The
percentage loss depends partly on the cooking temperature and on
whether the food is prepared by boiling, baking or roasting (Ajayi,
1 980).
The first step in processing any root crop is usually peeling. This
may remove nutrients if it is not done carefully. Cooking losses can be
reduced by retaining the skin to minimize leaching and to protect the
nutrients. It is sometimes advisable to peel after boiling and use the
cooking water in order to conserve water-soluble nutrients (FAO,
1 990).
2.4.4.1 Cassava (Manihot spp.)
Cassava is known as manioc or tapioca root. It is
dicotyledonous plant. It is about 1-3 metre in height when fully grown.
It belongs to the family Euphorbiaceae and the genus Manihot
esculenta. It represents a whole complex of cultivars of cassava that
Taxonomists have from time to time tried to separate into distinct
species with little success. Thus, M. utilissina, M. dulcis, M. palmata
and other proposed species are regarded as synonyms of M, esculenta
(Janick et a/., 1974).
2.4.4.1 .I Origin
Cassava originated in tropical America but the precise area of its
origin is unknown. The two probable areas suggested are the Mexican
and central American areas of south America. It was first introduced
into Congo basin as early as 1558 by the Portuguese. It then spread
rapidly through Angola, Zaire, Congo and Garbon and later to West
Africa. At present, cassava is grown throughout tropical and subtropical
areas approximately 30' and 30's of the equator and up to altitude of
1500 meters (FAO, 1990). It is widely spread throughout tropical
Africa, Asia and South America. It is particularly important in Nigeria,
Brazil, Zaire, Indonesia and Thailand (FAO, 1985).
2.4.4.1.2 Production
Cassava is planted using 7-30cm portions of the mature stem as
propagules. The selection of healthy, disease-free and pest-free
propagules is essential. The stem cutting are sometimes referred to as
"stakes." In areas where freezing temperatures are possible, the
cuttings are planted as soon as danger of frost has past. The cuttings
are planted by hand in moist prepared soil, burying the lower half.
When soil are too shallow to plant the cutting in an upright or slanted
position, the cutting are laid flat and covered with 2-3cm soil.
Mechanical planters have been developed in Brazil to reduce labour
inputs. Observing the polarity of the cutting is essential in successful
establishment of the cutting. The top of the cutting must be placed up.
Typical plant spacing is I m by Im . Cutting produce roots within few
days and new shoots soon appear at old leaf petiole axes on the stem.
Early growth is relatively slow, thus weeds must be controlled
during the first few months. It produces a crop with minimal inputs,
optimal yields are recorded from fields with average soil fertility levels
for food crop production and regular moisture availability. Optimal
growth and productivity of the plant is related to its harvest index, root
weight divided by total plant weight. The desirable index ranges from
0.5 to 0.7. Response to macronutrients vary. Cassava responds most
to P and K fertilization. Vasicular-arbuscular (VA) mycorrhizae benefit
cassava by scavenging for phosphorus and supplying it to the roots.
Fertilizer is only applied during the first few months of growth. There is
no mature stage for cassava. The plants are ready for harvest as soon
as there are storage roots large enough to meet the requirements of
the consumer. Under the most favourable conditions, yields of fresh
roots can reach 90 tonnelhectre and average world yields from mostly
subsistence agricultural system are 9.8 tonneslhectre. Typically
harvesting can begin as soon as eight months after planting. In the
tropics, plant can remain unharvested for more than one growing
season, allowing the storage roots to enlarge further. However, as the
roots age, the central portion becomes woody and inedible (OIHair,
1995; FAO, 1990).
Cassava varieties in Nigeria are hardy, drought resistant crop
that can give acceptable yeilds on low fertility soil. Cassava thrives
successfully from sea level to low altitudes. The root deteriorates after
1-3 days exposure to air. The plant is unique in that its roots are not
organs of dormancy. It has no natural function in the preservation of
the plant through an adverse season. The plant does not withstant
much heat and prolonged cold. These cause it to shed leaves and
produce soft poor quality roots (Coursey, 1983). The poor storage
quality of cassava roots presents a major problem (Richard, 1985;
Richard and Coursey, 1981).
2.4.4.1.3 Crop status
Cassava is a perennial woody shrub, grown as an annual.
Cassava is a major source of low cost carbohydrate for populations in
humid tropics. The largest producer of cassava is Brazil, followed by
Thailand, Nigeria, Zaire and Indonesia. Production in Africa and Asia
continues to increase and that in Latin America has remained relatively
high level over the past 30years. Thailand is the main exporter of
cassava with most of it going to Europe. The world market for cassava
starch and meal is limited, due to the abundance of substitutes.
FA0 (2001) reported that 172 million tonnes of cassava was
produced worldwide in 2000. Africa accounted for 54%, Asia 28% and
Latin America and the Caribbean 19% of the total world production. In
1999, Nigeria produced 33 million tonnes making it the world's largest
producer then (Balogun et al., 2003).
2.4.4.1.4 Harvesting
Most cassava is harvested by hand, lifting the lower part of the
stem and pulling the roots out of the ground, then removing them from
the base of the plant by hand. The upper parts of the stems with the
leaves are removed prior to harvest. Levers and ropes can be used to
assist harvesting. Care must be taken during the harvesting process to
minimize damage to the roots, as this generally reduces shelf life.
During the harvesting the cutting for the next crop are selected. These
must be kept in a protected location to prevent desiccation.
2.4.4.1.5 Processing
Although raw cassava is occasionally eaten in Congo region,
Tanzania and West Africa, cassava is not generally consumed raw.
After harvest, cassava roots are processed to stop physiological and
microbial spoilage, reduce the cyanogenic glucoside content (Asiedu,
1989) and convert the roots to other products which are more
acceptable. A large variety of processing techniques have been
developed in different parts of the world resulting in a wide variety of
products. Many such processes as soaking and fermenting have been
designed specifically to detoxify the root. Boiling and roasting are
designed to make cassava products more palatable. The degree of
reduction of cyanide in the final product varies greatly with the type of
processing techniques used (FAO, 1 990).
The shelf life of cassava is only a few days unless the roots
receive special treatment. Removing the leaves two weeks before
harvest lengthens the shelf life to two weeks. Dipping the roots in
paraffin or a wax or storing them in plastic bags reduces the incidence
of vascular streaking and extends the shelf life to three or four weeks.
Roots can be peeled and frozen. Traditional methods include packing
the roots in moist mulch to extend shelf life (O'Hair, 1995).
Cassava is a cheap source of carbohydrate for human and
livestock in the tropical parts of the world. The whole root may be
boiled and consumed with oil or local sauces. It may be shredded,
heated and dried to make a meal of "farina" consumed alone or mixed
with other foods and sauces (Enwere, 1998). The roots may be
sectioned dried in the sun and later ground into flour for preparation of
various types of local dishes. Peeled roots are grated, soaked in water
for several days, kneaded, strained, dried and heated to partly
hydrolyze the starch to sugar and gel particles for production of
tapioca. In Nigeria and other West African countries the roots
fermented or unfermented, are usually boiled and pounded into a thick
paste called fufu (Obizoba, 1998). The roots can be cooked and eaten
with oil sauces. In most cases, the roots are grated, fermented and
fried into gari. This is the form in which it is most commonly consumed
in Nigeria. In some parts of Nigeria, cassava roots are sectioned, dried
in the sun and ground into flour for preparation of paste consumed with
soups and sauces. The flour is at times mixed with other flours for
preparation of a paste called "danwake" (Eka, 1986; 1984; Eka and
Hobbs, 1987). Alcoholic beverages are made by fermentation of the
root. Cassava root is a good source of industrial starch used in
laundry. It is used to produce gums, adhesives, pharmaceutical and
alcohol (Norman et a/. , 1984).
The young leaves of sweet cassava are used as green leafy
vegetables. The leaves are more wholesome than the roots because
they contain high amounts of protein. The leaves are valuable food for
livestock, particularly goats.
The cassava roots comprises the peel (10-20%) and the edible
fleshy portion (80-90%). For human consumption, cassava root is
peeled to obtain the fleshy portion which is used for food or industrial
applications. However, the peel from which the cyanogenic glucocide
was removed is consumed by humans after a careful processing. The
peel was consumed by hungry populace in Biafra during the Nigeria
Civil war after boiling, soaking overnight, discarding the soak water and
washing. Although it was not harmful yet it is not palatable (Enwere,
1998).
2.4.4.1.6 Chemical composition and nutritional value of
cassava roots
The fleshy portion of the cassava root contains about 62%
moisture, 1-2% fibre, 1% ash, 35% carbohydrate of which 20-25% is
starch, 1% protein, 0.3% fat and cyanogenic glycoside (Purseglove,
1991 ; Meuser and Smolink, 1980). The protein content of cassava root
is low, however, it is rich in arginine and low in the essential amino
acids methionine, lysine, tryptophan and phenylalanine (Onyenuga,
1 968).
The carbohydrate of cassava root comprises starch in addition to
small quantities of dietary fibre, sucrose, glucose and fructose. With
the exception of starch and dietary fibre, all the other carbohydrates
are soluble sugars which are lost during processing operations that
involve dewatering of cassava pulp, soaking and boiling of cassava
roots and fermentation, thus they may contribute much to the nutrient
in cassava (Enwere, 1998).
The fat content of the cassava root is so low that it is seldom of
any nutritional significance. In addition to other minerals in cassava
root, calcium, phosphorus and iron predominate. The roots are rich in
vitamin C to the level of 35mgl100g fresh weight. It contains small
amount of niacin, vitamins A, B, and B2 (Purseglove, 1991;Asiedu,
1989; Onwueme, 1978).
2.4.4.1.7 Toxic components of cassava roots
The cassava roots contain two cyanogenic glucosides-linamarin
and lotaustralin. They are highly soluble in water. They tend to
decompose when heated to temperature above 1 5 0 ' ~ or under the
influence of the enzyme, linamarase, which is present in the cassava
root. The glycosides are hydrolyzed to produce hydrocyanic acid or
hydrogen cyanide (prussic acid) which is toxic to man and animal
(Asiedu, 1989). The rate of hydrolysis is accelerated by soaking the
roots in water, cutting or raising the temperature up to 75'~. Above
7 5 ' ~ the enzyme is denatured. Peeling, pulping, grating, fermentation
and denaturing significantly reduce the hydrogen cyanide level in
cassava flesh root. Purseglove (1 991 ) reported that the hydrogen
cyanide level (HCN) in cassava root varies between 10 and 370mglkg
fresh weight less than 50mg is not poisonous, and over 100mg is
highly poisonous.
2.4.4.2 Cocoyam
2.4.4.2.1 Kind of edible aroids
The monocotyledonous family Araceae (the aroids) contain
several plants which are cultivated and used for food in various parts of
the tropics. They are best adapted to wet and flooded area and
tolerant to shade. They are grouped as follows:
Colocasia esculenta (L,) schott (taro, old cocoyam, eddoe,
dasheen)
Xanthosoma spp. (tannia, new cocoyam) of which X.sogittiflolium
is the most important and X.atrovirens, X.violaceum and
X.caracu are of lesser importance.
Alocasia spp (giant taro) includes A.macrorrhiza, as the main
cultivated species with A.. indica, A. fornicata and A. cucullatu as
minor species.
Cyrtosperm chamissonia (swamp taro).
Amorphophallus companulatus (elephant yam) A. uncophyllus,
A.. variable and A. rivieri are edible.
Alocasia, cyrtosperma and Amorphous phallus are cultivated
globally to a very limited extent. By far more important and extensive in
the cultivation, are colocasia and xanthosoma. Colocasia and
xanthosoma are together called cocoyams in many parts of the world,
especially Africa (Onwueme, 1978).
2.4.4.2.2 Origin:
Xanthosoma, or new cocoyam, had its origin in South America
and the Caribbean. The Spanish and Portuguese introduced it in
Europe and were responsible for spreading it to Asia. It moved from
the Caribbean in the late nineteenth century, first to Sierra Leone and
then to Ghana, in West Africa xanthosoma is more important than
colocasia, being popular for its corm, cormels, leaves and young stems
(FAO, 1990; Cable, 1984).
Colocasia originated in Indian and Southern Asia. About 2000
years ago it spread to Eygpt and thence to Europe (Wang,. 1983,
Pluckett et a/., 1970). Subsequently, it was taken from Spain to
tropical America and then to West Africa. It was used in feeding slaves
and was transferred to the West lndies with the slave trade (Coursey,
1968). In order to distinguish it from the newer species, xanthosoma,
colocasia was referred to as "old yam" in West Africa whereas
xanthosoma is called "new yam". Colocasia and xanthosoma tolerate
shade conditions and are often planted under permanent plantations
as plantain, banana, coconut, citrus, oil palm and cocoa. They are
collectively referred to as cocoyam.
There are two major varieties of cocoyam in Nigeria viz: taro
cocoyam (Colocasia esculentus) and the tannia cocoyam (Xanthosoma
sagittifolium). They are the most edible and are members of the family
Araceae (Chandra, 1984; Pluckett, 1983).
Taro cocoyam (C. esculentus) needs fertile soil and a rainfall of
at least 2000mm per annum (Onwueme, 1978). It grows in the tropics
from sea levels up to 2700 metres (Bourke, 1982), with reduction of
yield and increased time of maturity at higher altitudes. It has a low
tolerance to frost. Time .for maturity is usually 7 to 9 months at sea
level. On the other hand, it maybe as short as 4 months and up to 18
months at high altitudes (Bourke, 1982). Corm yields are variable, the
average yield worldwide as 5.6 tonnes per hectare (FAO, 1985).
2.4.4.2.3 Advantages of cocoyam over other roots
The protein content of cocoyam is comparatively higher than
those of other root crops. It has a high score for total essential amino
acid and sulphur containing amino acids than other roots. Vitamin and
mineral contents of cocoyam are higher, especially thiamin, riboflavin,
niacin, calcium and phosphorus (Arene and Ene, 1987). The starch
granules of cocoyam are small in size and are easily digested than
other root crops (Kochhar, 1986). It is used as nurse crops in providing
shades for tender seedling of cocoa or coffee in West Africa. The
leaves contain about 20% protein and sometimes used to wrap cooked
foods such as mio-mio and pottage. The leaf is rich source of calcium,
iron, vitamin C, thiamin, riboflavin and niacin. All vegetative parts of
cocoyam are used as food in one form or the other (Inyang, 1987).
Cocoyam has been used to reclaim saline soil on which very few crops
could grow.
2.4.4.2.4 Utilization of taro cocoyam (C. esculenta)
The corms and cormels of taro cocoyam usually contain good quality
carbohydrate. They are of great value as food for man and animals.
The cormels rather than corms are much more commonly used for
human consumption. The young leaves of cocoyam are eaten in parts
of Nigeria as vegetables. They are valuable in livestock feed. The
peels of the corms and cormels of taro cocoyam (C. esculenta) are
valuable for ruminants, particularly sheep and goats (Onwueme, 1978).
The leaves and corms of certain cultivars of taro cocoyam are acrid.
The leaves and stems of non-acrid varieties are used widely as green
leafy vegetables and in salad and traditional dishes. The leaves and
corms of the acrid varieties are boiled prior to human consumption and
livestock feed because the acrid substances are removed by boiling
(Bassir and Umoh, 1976).
2.4.4.2.5 Utilization of tannia cocoyam (Xanthosoma s.)
The main corm of tannia cocoyam is usually not eaten. This is
because of its acridity. It is used for planting setts and fed to animals
(Wijmeerschran, 1986; Bourke, 1982). Tannia plant produces cormels
that are eaten and yields are normally higher than taro cocoyam. The
flour from cormel are higher than taro cocoyam. The boiled cormels are
usually pounded and made into fufu in some parts of Nigeria and West
Africa. The cormels are commonly grated and portions tied with young
leaves and cooked into special dishes in Nigeria known as "Ekpang
Nkukwo" (Agboola, 1987;Umoh and Bassir, 1980). Many use it as
salad, as green vegetables as well as the stems. The corms, cormels
and leaves are fed to livestock. The cormel tends to store better than
those of taro cocoyam. The starch grains of tannia cocoyam are larger
than those of taro cocoyam. The starch is extracted from the peeled
tuber for industrial purposes (Uguru, 1996). The flours from cormels
are mixed composite with that from cereals in baking industriy
(Bradbury and Holloway, 1988).
2.4.4.2.6 Toxicity
The greatest problem in cocoyam utilization is its acridity nature.
Acridity of cocoyam causes a sharp irritation and burning of the throat
and mouth on ingestion of improperly cooked or uncooked material.
Acridity is greater if the root crop experiences adverse growing
condition such as drought or poor soil. Swamp taro (C.esculenta) is
more acrid, particularly its thick skin, and giant taro. The oxalate
compound of cocoyam tends to precipitate calcium, makes it
unavailable for use by the body. The role of oxalate in nutrition include
the possibility of oxalaurea and kidney stones which lead to death
(Oke, 1967).
The acridity of high oxalate cultivars of cocoyam can be reduced
by peeling,, grating, soaking and fermentation processes. The slightly
acrid taste of the corm is due to presence of calcium oxalate crystal
which are fortunately removed after boiling for 15 minutes with water to
which a pinch of baking soda is added (Kochhar, 1986).
2.4.4.2.7 Nutritive value:
Cocoyam (Xanthosoma, sagittifolium): Its nutritive valve is
important. It contains 80% moisture and some quantities of ascorbate,
thiamin, p-carotene, niacin and riboflavin. It contains some traces of
minerals (Purseglove, 1991 ; Udealor et a/., 1987; Akomas et a/., 1987;
Cobley and Steele, 1976).
The corms and cormels of the cocoyam contain small and
digestible starch granules ideal for making baby food and special diets
for invalids (Onwueme, 1978). The Xanthosoma sagittifolium (tannia)
has a hard and highly starchy nature. The granules are larger than
those of colocasia esculenta. They are however, smaller and more
digestible than those of cassava, yam and potatoes (FAO, 1994; Egbe
and Treche, 1987; Okorie, 1986; Onwueme, 1978). The essential
amino acid profile is deficient in histidine and lysine (Oyenuga, 1968).
2.5 Nutritive value of Nigerian foods.
The widespread use of locally available foods in Nigeria is limited
due to poor nutrition education. The nutritive value of any diet
prepared; for human consumption is influenced by a number of
inherent factors viz: food preparation, the quantity and quanlity of
protein, the level of vitamins and minerals and the amount of food
consumed. The nutritional value of Nigerian foods were evaluated
using chemical composition and animal experiments.
Malik (1 967) evaluated some traditional dishes of the Yoruba of
western Nigeria. His work showed that many of the foods had protein
of high biological value and high utilization. Basically, the diet of the
Nigeria peasants as in other tropical and sub-tropical countries of
Africa are starchy with little or no supplementation.
Obizoba and Okeke (1 986) studied the nutritive values of five all-
vegetable diets based on sorghum, maize, brown bean, white' bean,
bambara groundnut, rice and cowpea in rats. Combination of rice and
bambara groundnut in the ratio 80:20 produced increase in food and
nitrotgen (N) intakes, weight gain, digested and retained N, biological
value (BV) and net protein utilization (NPU) higher than for those of
other diets. The result showed that popular traditional method of
consuming combination of rice and beans met protein and caloric
requirements by consumption of a cheaper and more nutritious blends
of bambara groundnut and rice
Eka (1982) evaluated the nutritive value of traditional rice meal
(tuwo Shinkafa damiyan tushe). The proximate and amino acid
composition of the foods were high, however the protein quality was
poor. The meal is deficient in most of the essential amino acids when
compared to standard hen's egg protein.
In Nigeria, fresh fruits are reliable sources of ascorbate.
However, the vegetables are subjected to various food processing
including heat treatment that could possibly destroy vitamin C.
Vegetables such as hibiscus esculenta (Okra) and vernonia (bitter leaf)
have ascorbate level ranging from 203mg1100g to 30.95mgl100g when
fresh, respectively. However, after cooking the ascorbate loss in these
vegetables ranged from 73.54% in Talinum triangulare (Gbura) to
100% in selenium gito raddi (spinach) and vernonia amygdalina (bitter
leaf).
Vegetables supply abundant vitamin C when fresh. They cannot
be relied on as the major source of the nutrient because it is destroyed
during heat treatment. Fruits which are not heat treated remain the
source of ascorbate of most Nigerians when cultivated in large
quantities to be available all year round. Addo and Eka (1982), studied
the ascorbate and proximate composition of five stored Nigeria
vegetable soups. The protein content of these soups ranged from 4.37
to 20.07%. All soups except the stew had high crude fibre content
(9.35 - 14.79%).
2.6 Food availability and affordability
Households are food secure when they have year-round access
to the quantity and variety of foods their members need to live active
and healthy lives. At the household level, food security refers to the
ability of the household to secure either from its own production or
through purchases, adequate food for meeting the dietary needs of all
its members at affordable prices. The nutritional status of each
member depends on several conditions, the food available must be
shared according to individual needs, the food must be of sufficient
variety, quality, safety and each household member must have a good
health status in order to benefit from the food consumed (Maziya-Dixon
et al., 2003).
2.7 Food processing, safety and quality
Food processing aims at ensuring microbiological and chemical
safety of foods, adequate nutrient content, bioavailability and
acceptability to the consumers and caregivers with regards to sensory
properties and ease of preparation (WHOINUT, 1998). Different
processing methods may have either beneficial or harmful effects on
different properties of food. For example, heat treatment at low or
moderate temperature, such as blanching, pasteurization and the most
of cooking techniques, generally lead to improved digestibility and
inactivation of some anti-nutritional factors. By contrast, the most
severe condition of high temperature or extreme pH may lead to
nutritional losses and induce formation of toxic derivation in food. So
these should be taken into account in the design and preparation of
soup meals and dishes. The safety of soup meals and dishes can be
defined as the set of condition and practices during the production,
storage, distribution, preparation and (domicallary) storage of soup
meals and dishes that are necessary to protect them from pathogenic
micro-organisms, exogenous chemical contaminants, naturally
occurring toxic substances and newly formed toxic compounds
produced during food storage, processing or preparation (Motarjemi et
a/., 1993). In other words, it is the certainty that food(s) would not be
harmful to members of the family when prepared.
The food quality assessed in terms of its nutritional value,
nutrient bioavailability, functional properties and ease of preparation. In
each case, food-processing techniques may influence these aspects of
food quality. Throughout history, a number of techniques have been
developed to improve the safety, nutritional value and functional
properties of foods (WHO, 1996).
CHAPTER THREE
3.0 Materials and methods
3.1 .a Purchase of fresh green leafy vegetables
Urua Uyo main market was where green leafy vegetables were
identified and purchased before they were processed to prepare soup
meals and dishes. The green leafy vegetables identified and
purchased include, "atama" (Heinsia crinata), "editan" (Lasianthera
africana), waterleaf (Talinum triangulare), "nkukwo" (Colocasia
esculenta).
3.1.b Purchase of roots, tubers, plantain and banana:
Some quantities of fresh cassava (Manihot esculenta), cocoyam
(Xanthosoma sagittifolium), unripe green banana and plaintain (Musa
sapienturn and Musa paradisiaca) were purchased from the same
market for the same purpose as the green leafy vegetables.
3.2 Processing of green leafy vegetables and the starchy
staples (Figures 1 - 7)
3.2.1 Green leafy vegetables
The various green leafy vegetables were purchased in bulk
(IOkg), the leaves were removed from their stalks and divided into
three equal portions. One portion of each of these vegetables served
as control were washed, chopped to acceptable sizes for immediate
soup preparation to avoid spoilage. One of the other two portions was
sundried to 1.05 and 1.04% dry matter for "atama" (Heinsia crinata)
and waterleaf (Talinum triangulare), respectively. The third portion was
shade dried to 1.06 and 1.05% dry matter for "atama" (Heinsia crinata)
and waterleaf (Talinum triangulare), respectively. These two dried
samples were packaged, name labelled and stored safely in cool dry
place for use when desired. However, "editan" ("Lasianthera africana")
was chopped, boiled in water containing sodium bicarbonate for 30 min
and drained to remove slimmy solution. After draining, it was divided
into 3 equal portions. The first portion (control) was ready for
immediate soup preparation - "efere editan". The second portion was
sun dried to 1.04% dry matter and the third sample was shade dried to
1.04% dry matter. The separately dry samples were packaged, name
labelled and stored for later use.
3.2.2. Processing of casssava (Manihot esculenta), tannia cocoyam
(Xanthosoma sagittifolium), unripe (green) plantain and banana (Musa
paradisiaca and Musa sapientum). These food crops were purchased
in bulk (15kg). Each food sample was divided in 3 equal portions after
peeling and washing. Cassava (Manihot esculenta) was processed into
gari, fufu and composite flour (Fig. 4). Cassava was peeled, washed
and divided in 3 equal portions. One portion was fermented for 48hrs
and milled. The paste was further fermented for 24hrsl washed,
decanted and divided into 2 equal portions. One portion was cooked
into fresh cassava fufu. The other portion was sun dried to 1.15% dry
matter based on value for residual moisture, milled, packaged, name
labelled and stored unitil needed for preparation of fufu. The second
portion was milled, decanted for 24hrs, sieved, divided into two equal
aliquots. The first portion was fried into fresh gari and the other porition
was sun dried to 1.13% dried matter based on residual moisture,
packaged, name labelled and stored as sun dried gari. The third
portion was sliced and put in a container half filled with common salt
solution (NaCI), sun dried to 1.06O/0 dry matter based on residual
moisture, hammermilled, packaged, name labelled and stored.
Tannia cocoyam (Xanthosoma sagittifolium) was divided into 2
equal portions and processed as shown in Figure 5, unripe (green)
plantain (Musa paradisiaca) was divided into 2 equal portions and
processed as shown in Figure 6. Unripe (green) banana (Musa
sapienturn) was divided into 2 equal portions and processed as shown
in Figure 7.
"Atama" (Heinsia crinata)
Leaves remov I!! d from stalk
I Washed
Dr ined (for 20 minu es)
// 1 ('"''. Shade dried to I .06%* dry matter
1 Packaged
Na e labelled
1 Stored
Chopped
1 Sun dried to 1.05°/~* dry matter
Pounded (ready for immediate soup
preparation) (control) I
Packaged
* Name labelled
1 Stored
Fig. I"Ataman processing. *Based on residual moisture
"Ed itan" (Lasianthera africana)
+ Leaves removed from stalk
(30 minutes in water containing sodium \
Shade dried to 1.04%* dry matter
+ Packaged
1
Name labelled
1 Stored
i Boiled at 6 0 ' ~
(30 minutes in water containing sodium
bicarbonate)
Drained (ready for soup
preparation)
bicarbonate)
Sun dried to 1.04%* dry matter
I 4
Drained i
Packaged (ready for soup preparation) (control)
1 Name labelled
* Stored
i Boiled at 6 0 ' ~
(30 minutes in water containing sodium
bicarbonate)
1 Drained (ready for soup preparation)
Fig. 2:"EditanV processing. *Based on residual moisture
Waterleaf (Tulinum ~ricmgzilurc)
.t Leaves removed from stalk ..
Washed
J Sliced (ready for
immediate soup Shade dried to 1.05%* preparation dry matter (control)
+ Packaged
+ Name labelled
1 Stored
\r Sun dried to 1.04%"
dry matter
1 . Packaged
I Name labelled
I Stored
Fig. 3: Waterleaf processing. *Based on residual moisture
Cassava (Mnnihof esculenm) f
Peeled + Washed
Fermented Sliced into in water solution of
for 24 hrs
I Sun dried to 1 .Oh%*
1 Sieved
dry matter gari
I (control)
ed / dry matter J
Grated and squeezed to
Wrapped with Hamnier young cocoyam milled leaves (ready for
immediate preparation +
Package "Atitinkop" dish (control) I
1 f
Fermented for 24 hrs. Name labelled
Packaged 4
Washed
i 4 Name labelled Decanted
4 Stored
Stored Cooked into Cassava foofoo Sun dried to 1.15%* dry
matter (c ntrol) S $.
Milled I +
Packaged
Name t abelled I +
Stored
Fig. 4: Cassava processing. *Based on residual moisture
Cocoyam (Xanthoso a sagittifolium) r +
Washed
Sliced into solution of common salt (NaCI)
(with addition of some tablets of piritone)
Drained
I Pounded into cocoyam foofoo (control)
I Packaged
1 Name labeled
1 Stored
Fig. 5: Cocoyam processing. *Based on residual moisture
Unripe plantain (Musa paradisiaca)
1 Sliced into a solution of
dry matter
Packaged
1 Name labeled
4 Stored
\ Coo ed (iwu ku kom) (control)
Fig. 6: Unripe green plantatin processing. *Based on residual moisutre
Unripe green banana (Musa sapienturn)
* Washed
Sliced i t to common salt solution (NaCI)
Grated un dried to 1.07%* dry matter 0
Cooked 1
Ha mer-milled (otomboro) (control) 1
P ckaged
9 Name labelled
1 Stored
Fig. 7: Unripe green banana processing. *Based on residual moisture
3.3 Confirmatory study
Traditional soup preparation and their accompaniments: Traditionally in
Uyo local government area of Akwa lbom state, soup meals are served with
starchy pounded fufu as full dishes. "Abak atama1' and "efere editan" were
the soup meals to accompany the starchy foods.
3.3.1 "Aba k atama" (Heinsia crinata) (soup meal)
"Abak atama" is special soup meal often consumed by Akwa lbom
people at family meals, during special occasions such as funerals, naming
ceremonies and similar other events. "Atamall leaf (Heinsia crinata) is used
in soup preparation as thickener and flavour enhancer. The soup meal's
special ingredients are palm fruit juice and atama leaf. The soup is served
with gari, cassava fufu, pounded yam and rice.
Recipe 1. Recipe for preparation of "Abak atama"
Ingredients Metric measurements(g) Local measurements
Palm fruit juice 250 2 milk tins
Chopped "atama" leaves 50 1/2 Milk tin
Ground crayfish 3 0 2 table spoon
Ground fresh pepper 20 1 teaspoon
Dressed smoked fish 100 1 small
Beef 100 4 pieces
Dressed periwinkle 80 1 tomato tin
Water 180 1% milk tin
Salt 5 ?4 teaspoon
0 kro 3 0 2 small fingers
Stock fish head 50 1 small
"lkpa" ("kanda") 50 4 pieces
Onions 3 0 1 small
Maggi cubs 10 1 cube
source: ~ b o h (2000)
Method
Remove "atama" from the stock and wash with cold water:
Shred it finely.
Boil palm fruits until cooked and soft.
Remove from the pot, put into a mortar and pound to dehull to
obtain the oil.
Add water to the palm fruit hull and mix well.
Sieve the liquid to remove the hull.
Put the filtrate into the pot and bring to boil.
Add dressed smoked fish, ground crayfish and pepper, salt,
boiled meat and stock fish head dressed periwinkle and chopped
onions and "ikpa."
9. Add the prepared "atama" leaves and cook for 15 minutes.
Sun dried "atama" leaf soup meal: Sun dried vegetable instead of
fresh is the slight modification of Eboh's (2000) recipe.
Sun dried "atama" leaves are used in place of fresh atama leaves with
the same quantities of ingredients and method of cooking.
Shade dried "atama" leaf soup meal: Shade dried vegetable instead
of fresh is the slight modification of Eboh's (2000) recipe.
Shade dried "atama" leaves were used in place of fresh ones with the
same quantities of ingredients and method of cooking.
3.3.2 "Efere" "editan" (Lasianthera africana) (soup meal)
"Editan" leaf is from "editan" plant. The leaves are very bitter. It
is parboiled and washed prior to the soup preparation. Some people
like it partially bitter. In the village "editan" sticks are used for fencing
the compounds.
Recipe 2. Recipe for preparation of "Efere editan"
Ingredients Metric measurements(g) Local
measurements
Chopped "editan" leaves
1 small dressed smoked fish
Beef
Ground crayfish
Dressed periwinkle
Palm oil
Ground pepper
"lkpa" ("kanda")
Stock fish head
Water
Maggi cube
Waters Leaves
Onions
Salt
Soda bicarbonate
1 milk tin
I small
'4 medium pieces
2 table spoons
1 tomatoes tin
1 tomatoe
1 teaspoon
4 medium pieces
.I small
1% milk tin
1 cube
1 Milk tin
1 small
% teaspoon
1 teaspoon
Source: Eboh (2000)
Method:
1. Cook meat till tender.
2. Collect "editan" leaves enough for soup.
3. Pick, wash and drain.
4. Chop "editan" leaves into fine pieces.
5. Parboil in soda bicarbonate solution, wash and drain.
6. Boil water, add cooked meat, "ikpa" and dressed periwinkle.
7. Add chopped water leaves.
8. Add dressed smoked fish, ground crayfish, pepper, chopped
onions and cook for 10 minutes.
9. Add palm oil, "editan" and cook for 10 minutes. Serve soup meal
with gari or cassava or fufu and or pounded cocoyam.
Sun dried "editan" soup meal: Sun dried vegetable instead of fresh
is the slight modification of Eboh's (2000) recipe.
Sun dried "editan" and waterleaves were used in place of fresh
"editan" and waterleaves with the same quantities of ingredients and
method of cooking.
Shade dried "editan" soup meal: Shade dried vegetable instead of
fresh is the slight modification of Eboh's (2000) recipe.
Shade dried "editan" and water leaves were used in place of the
fresh leaves with the same quantities of ingredients and method of
cooking.
3.3.3 Preparation of dishes:
Some selected traditional dishes consumed in Akwa lbom state
chosen for the study were "iwukukom", "atitiFikopn and "otomboro".
3.3.3.1 lwu ku kom (u ripe green plantain pottage) (Musa
paradisiaca)
lwukukom is a traditional dish of Akwaibomites. It is normally
consumed as a family dish, during traditional festivals such as
traditional marriages. Lactating mothers are fed the pottage in Akwa
lbom state.
Recipe 3. Recipe for preparation of "lwukukom"
Ingredients . Metric measurements(g) Local
measurement
Unripe (green) plantain 200 2 medium
Flutted pumkin leaves 100 I small bundle
Dressed smoked fish 8 0 I small
Ground crayfish 3 8 2% table spoons
Ground fresh pepper 20 1 teaspoon
Palm oil 75 1 112 tomato tin
Onions 30 I small
Ntong 20 I tablespoon
Salt 10 I tablespoon
Maggi cube 10 l cube
Water 240 2 milk tin
Source: Eboh, (2000)
Method
1. Peel, wash and chop the unripe (green) plantain into small cubes
and scrape some portions of plantain into the pot.
2. Add palm oil, dressed smoked fish, ground crayfish, pepper,
chopped onions and maggi cube.
3. Cook for 20 minutes, stirring at frequent intervals to avoid
scorching.
4. Add chopped fluted pumpkin leaves and ntong leaves. Cook for
5 minutes and serve.
Sun dried pottage
Sun dried unripe sliced plantain instead of fresh is the slight
modification of Eboh's (2000) recipe.
Sun dried sliced unripe green plantain was used in place of the
fresh plantain with the same quantities of ingredients and method of
cooking.
3.3.3.2 "Otomboro" (Banana porridge) (Musa sapientum)
"Otomboro is the traditional dish of the Ibibios, in Akwa lbom
state. The main ingredient is unripe (green) banana. It is a dish
served to family members, infants, lactating mothers, convalescents
and invalids. It can be served hot or cold.
Recipe 4: Recipe for preparation of "Otomboro"
Ingredients Metric measurements(g) Local measurements
Unripe (green) banana 200
Dressed smoked fish 80
Ground crayfish 38
Ground fresh pepper 2 0
Palm oil 7 5
Dressed periwinkle (with shell)
Ntong 20
Fluted pumkin leaves 100
Maggi 10
Onion 30
Salt 10
Water 180
-
4 medium
1 small
2% table spoons
1 teaspoon
1 % tomato tin
1 tomato tin
1 tablespoon
1 small bundle
1 cube
1 small
1 tea spoon
1% milk tins
Source: Eboh (2000)
Method
1. Peel the banana and wash it with warm water.
2. Dress the periwinkle, wash it thoroughly and add little quantity of
salt.
Grate the banana.
Add a, pinch of salt to the grated banana and mix.
Add oil to the grated banana and mix.
Wash pot and add water.
Add ground crayfish and pepper, dressed smoke fish, chopped
onion and maggi, allow to boil for 10 minutes.
Add palm oil.
Drop the grated banana and stir.
Add chopped vegetable and cook for five minutes.
Serve hot or cold.
Sun dried unripe green banana porridge: Sun dried unripe banana
flour instead of fresh unripe paste is the slight modification of EbohJs
(2000) recipe.
Sun dried sliced unripe green banana was used in place of fresh
one with the same quantities of ingredients and method of cooking.
3.3.3.3. Atiti ii kop (Cassava parcles) (Manihot esculanta)
Atitifikop is a delicious meal in Akwa lbom state, especially eaten
by the Ibibios. It is prepared from fresh sweet cassava. It can be
served at traditional marriage ceremonies, in fattening room, for
lactating mothers and served as family meals.
It is a balanced diet and suitable for youth and elderly. It is consumed
at lunch or dinner either hot or cold.
Recipe 5: Recipe for preparation of "atitinkop"
Ingredients Metric measurements(g) Local measurements
Cassava tuber 200 I medium
Dressed smoked fish 8 0 I small
Ground crayfish 30 2 table spoons
Ground fresh pepper 2 0 l teaspoon
Dressed periwinkle (with shell) 100 I tomato tin
Palm oil 75 1% tomato tin
Salt 10 l teaspoon
Fluted pumpkin leaves 100 I small bundle
immature cocoyam leaves 100 I small bundle
Maggi cube 20 2 cubes
"Odusa leaves' 20 I tablespoon
Water 240 2 milk tin
Source: Eboh (2000)
Method:
Peel cassava and wash.
Grate cassava and squeeze to dewater.
Wrap the squeezed cassava paste with immature young
shredded cocoyam leaves into pot lined with dressed shelled
periwinkle and small quatity of palm oil.
Put the pot on the fire for 2 minutes and add boiling water.
Add ground crayfish and peppers, dressed smoked fish, maggi,
salt and chopped onions.
Cook for 30 minutes.
Add palm oil, chopped fluted pumpkin leaves and 'adusa leaves.
Simmer for 5 minutes and serve hot or cold.
Sun dried cassava porridge: Sun dried cassava flour instead of fresh
cassava paste is the slight modification of Eboh's (2000) recipe.
Sun dried cassava flour turn into paste was used in place of
fresh cassava paste with the same quantities of ingredients and
method of cooking.
3.4.0 Analytical procedure
3.4.1 The proximate composition of processed green leafy vegetables
and their controls, processed cassava (gari, fufu), cocoyam, unripe
green banana and plantain, soup meals alone, accompaniments alone
and dishes (one pot meals) were determined using standard methods
of AOAC (1 995). See Appendix I.
3.4.2 The minerals, vitamins and antinutrients concentration of the
fresh, sun and shade dried vegetables, processed cassava, cocoyam,
unripe green banana and plantain, soup meals alone, accompaniments
alone and dishes (blends of soup meals and accompaniments, one pot
meals), iron and copper were estimated by polarized atomic absorption
spectrophtometry. Zinc concentration was determined in conjunction
with the mineral standard for Unicam Ltd (UK) and iodine was
estimated by titration.
Vitamin A (RE) and folate were determined by the AOAC (1995)
method. Provitamin A was determined using the method adapted from
IVACG (1982). The vitamin A activity, as retinol equivalent (RE) was
calculated based on the in vivo concentration factor (WHO, 1982). For
details, see Appendix 2.
Antinutrient content of samples were determined. Tannins were
determined by the modified vanilla-HCL method of Price and Buttler
(1977). Phytate was determined by the method of Latta and Eskin
(1 980). Cyanide was determined using an enzyme extraction
procedure of lkediobi et a/. (1984). Trypsin inhibitors were determined
by the standard assay procedure of AOAC (1995). Oxalate was
determined by the modified procedure of Fatoki and Ekwenchi (1996).
See details in Appendix 3
3.5.0 Statistical analysis
3.5.1 The data obtained at the end of the study were analyzed using
the statistical procedure of Steel and Torrie (1960). See detail in
Appendix 4.
CHAPTER FOUR
4.0 RESULTS
4.1 Nutrient composition of processed and unprocessed green
leafy vegetables
Table 1 presents the nutrient composition of processed and
unprocessed green leafy vegetables. Fresh "atama", sun and shade
dried samples had 63.24, 5.33 and 6.53% moisture, respectively.
Fresh "editan", sun and shade dried "editan" vegetable had 74.43, 4.2
and 4.6% moisture, respectively. There were losses in moisture due
to sun and shade drying. As expected fresh waterleaf had 89.33%
moisture. Sun and shade dried samples had 4.3 and 4.9% moisture,
respectively.
The protein content of the 3 vegetables increased after sun and
shade drying. The protein content of " fresh, sun and shade atama"
samples were 3.97, 4.8 and 8.779'0, respectively. Fresh and sun dried
"editan" samples had 4.33, 4.5%, respectively. The increase in "editan"
protein after the shade drying was much higher than fresh and sun
dried samples (1 0.1 Vs 4.33 and 4.5%, respectively). The increase in
waterleaf protein after sun and shade drying was much higher than
those of "atama" and "editan" samples. The fresh waterleaf had 2.47%
protein, the sun and shade dried samples had 13.75 and 20.g0/0,
respectively.
The ash content of the 3 vegetables increased after sun and
shade drying. The ash content of fresh, sun and shade dried "atama"
samples had 1.3 for the fresh, 8.47 and 8.87%, respectively. The
increase in "editan" ash after shade and sun drying were the same
(8.8 and 8.9% respectively).
Tab
le I. Pro
ximate co
mp
ositio
n o
f pro
cessed an
d u
np
rocessed
green
leafy vegetab
les (%).
Fo
od
materials
Mo
isture
Pro
tein
Ash
Fat
Fib
re C
HO
Atam
a 63.2420.49
Heinsia crinata C
Atam
a SU
D
5.3320.15 H
einsia crinata SU
D
Atam
a SH
D
6.5320.36 H
einsia crinata SH
D
Editan C
74.4350.58
Lasianthera africana C
Editan S
UD
4.2720. 15
Lasianthera africana SU
D
Editan S
HD
4.620.28
Lasianthera africana SH
D
Waterleaf C
89.3320.46
Talinum
triangulare C
Water leaf S
UD
4.3020.09
Talinum
triangulare SUD
Water leaf S
HD
4.9020.07
20.920.45 12.87+0.11
3.720.19 3.5320.1 8
54.1 T
alinum triangulare S
HD
Me
an
2 S
D o
f thre
e determ
inations C
=
control (fresh) ; SU
D = su
n dried; S
D =
shade dried
The increase in waterleaf ash after sun and shade drying was higher than
those of "atama" and "editan" samples. The fresh waterleaf had 1.7% ash,
the sun and shade dried samples had 12.7 and 12.9%, respectively. The
ash contents of sun and shade dried samples increased to 11.0 and
11.2%, respectively.
There were increases in fat for all the green leafy vegetables. Sun
and shade dried "atama" had 3.27 and 3.33% fat contents compared to
1.0% for fresh sample. The increases in fat for "editan1' after sun and
shade drying were 3.4 and 4.2%, respectively. The highest increase in fat
due to treatment occurred in waterleaf. The increases were 2.23 and
3.23% for the sun and shade drying, respectively.
There appeared to be slight increases in both fibre and carbohydrate
after sun and shade drying. Sun and shade dried "atama" differ in fibre
slightly (4.73 and 4.80%, respectively). The difference was only 0.07%.
The fibre values for sun and shade dried "editan" were 3.63 and 3.8O0/0,
respectively. As expected, the fresh waterleaf had low fibre (0.1 %). Sun
and shade dried samples had 3.43 and 3.53% fibre, respectively.
Sun and shade drying increased carbohydrate in "atama" from 2 to 3
folds. The values for sun and shade dried samples were 73.4 and 67.7%'
respectively, and that of fresh was 29.12%. Fresh "editan" had 16.88%
carbohydrate and those of sun and shade dried samples were 75.4% and
68.48%, respectively. The fresh waterleaf contained 5.93% carbohydrate,
sun and shade dried samples had 63.12 and 54.1%, respectively.
4.3 Effect of processing on the proximate composition of three
green leafy vegetables
Table 2 presents the effects of processing on the proximate
composition of three green leafy vegetables. The values were based on
residual moisture calculated from Table 1. Surprisingly, the three fresh
leafy vegetables had higher protein and other nutrients than sun and
shade dried samples when the values were based on residual moisture as
against values in Table 1. Fresh (control) "atama" (Heinsia crinata) had
higher protein than sun and shade dried samples (10.80Vs 5.10 and
9.30%, respectively). In the other hand shade dried "atama" had higher
protein than sun dried sample (9.30 Vs 5.10%). Fresh (control) "editan"
(Lasianthera africana) as well as waterleaf (Talinum triangulare) had
higher protein than those of sun and shade dried samples, respectively.
Fresh (control) "atama" and "editan" had lower ash than sun and
shade dried samples (3.50 and 4.46 Vs 8.90°h, 9.40 and 9.15 Vs .9.25%,
respectively). On the other hand fresh waterleaf had higher ash than either
sun or shade dried samples. However shade dried waterleaf had higher
ash than sun dried. The difference was only 0.17% (1 3-51 - 13.34%).
The fat values differed. Sun and shade dried "atama" had higher fat
than the control (fresh). Fresh (control) "editan" had higher values than sun
and shade dried (7.82 Vs 3.53 and 4.36%, respectively). Sun dried
waterleaf had lower values for fat than both control (fresh) as well as
shade dried (2.84 Vs 4.42 and 4.10%). Shade dried value for fat for
waterleaf was also lower than that of the control (fresh) (4.1 0 Vs 4.42%).
The fibre content of all fresh (control) samples were lower than those
of sun and shade dried samples (3.53, 3.75 and 0.94%) for "atama",
"editan" waterleaf, respectively. Sun and shade dried "editan" CHO
samples were higher than their controls (fresh) (66.03 Vs 78.47 and
71.94%). However, the values for waterleaf samples were (55.44 Vs 65.78
and 56.67%) (Table 2). Sun and shade dried "atama" CHO samples were
lower than control (77.61 and 72.67 Vs 79.23%).
Table 2. Effect of processing on the proximate composition of the three green leafy vegetables (%)*
Food Materials Protein Ash Fat Fibre CHO
Atama C (Heinsin crinata C) 10.80 3.53 2.91 3.53 79.23
Atama SUD (Heinsin crinata SUD) 5.10 8.90 3.43 4.96 77.61
Atama SHD) (Heinsin crinata SHD) 9.30 9.40 3.53 5.10 72.67
Editan C (Lasianthera africana C) 16.93 5.46 7.82 3.75 66.03
Editan SUD (Lasianthera africana SUD) 4.68 9.15 3.53 3.77 78.47
Editan SHD (Lasianthera africana SHD) 10.58 9.25 4.36 3.95 71.94
Waterleaf C (Talinum triangulares C) 22.14 15.98 4.42 0.94 55.44
Waterleaf SUD (Talinum trangulare SUD) 14.36 13.34 2.84 3.60 65.78
Waterleaf SHD (Talinum trangulare SHD) 22.01 13.51 4.10 3.71 56.67
C - - Control (fresh) SUD - - Sun dried SHD - - Shade dried * Based on residual moisture
4.4 Some minerals and vitamin contents of processed and
unprocessed green leafy vegetables.
Table 3 presents Iron (Fe), iodine (I2), copper (Cu), zinc (Zn), vitamin
A (Retinol-RE) and folic acid of processed and unprocessed green leafy
vegetables.
The iron content of the 3 vegetables were affected by treatments. There
were increases in iron for vegetables after sun drying. The increases in
iron after shade drying were much higher than sun drying. Sun dried
"atamal' had 29.0 yg iron and that of shade dried was 38.0 yg. The
increase in iron after shade drying in "editan" was 4.0pg. The increase in
iron after sun and shade drying were 8.0 and 12.0pg1 respectively. The
increases in iron after sun and shade drying were higher in waterleaf than
in the other 2 vegetables. The increase due to sun drying was 7.0 yg while
for shade drying it was 10.0kg.
The iodine (I2) values for the 3 vegetables were affected by sun and
shade drying. The increases in iodine values for sun and shade drying
were 28.3 and 52.01.19 while that of fresh sample was 205 yg. The
increases after shade drying were almost 2 folds of both fresh and sun
dried samples. The differences were 68.7 and 64.4 pg for fresh and sun
dried samples, respectively. The increases in iodine for waterleaf after sun
and shade drying had the same pattern as those of "editan." The increase
for sun-dried waterleaf sample was 34.3 yg and that of the shade drying
was 121.7pg.
Tab
le 3
. S
om
e m
iner
als
and
vit
amin
s co
nte
nt
of
pro
cess
ed a
nd
un
pro
cess
ed g
reen
leaf
y ve
get
able
s.
Foo
d m
ate
ria
ls
Fe(
pg11
00g)
I2
(pg
/1 00
9)
Cu(
pg11
00g)
Zn(
pg11
00g)
P
-car
oten
e (p
gll
OO
g)
Fol
ate
(pg1
100g
)
"Ata
ma"
C
28
.0k0
.71
20
5.0k
1 .47
tr
ace
9.0
k0.7
1
11 5.
029.
2 16
.20k
0.07
-
Hei
nsia
crin
ata
C
"Ata
ma"
SU
D
29.0
k1.4
1 23
3.3k
3.53
tr
ace
1 O.O
kO.0
12
4.3k
1 .I 5
16
.50k
0.11
H
eins
ia c
rinat
a SUD
"Ata
ma"
SH
D
38.0
k0.7
1 25
7.0k
21 .6
0 41
.0+
0.71
1 0
.3kO
.41
2984
.6k2
.43
27.6
k0.7
1 H
eins
ia c
rinat
a SHD
"Edi
tan"
C
20.0
k0.7
1 66
.0k1
.41
trac
e 11
.Ok0
.71
21 8.
OkO
.71
trac
e La
sian
ther
a af
rican
a C
"Edi
tan"
SU
D
28.0
.kO
.71
70.3
k1.0
8 73
.020
.71
12.0
k0.7
1 10
68.0
k0.7
1 13
.6k0
.53
Lasi
anth
era
afric
ana
SU
D
"Edi
tan"
SH
D
32
.0k0
.71
13
4.7k
1 .I2
7
5.0
k0.7
1
18.0
k3.0
8 29
44.3
k21.
8 18
.5k0
.25
r- - n
Lasi
anth
era
afric
ana
SH
D
Wat
er le
af C
11
.Ok0
.71
1 06.
0k2.
6 tr
ace
10.0
k0.7
1 7.
0k0.
71
13.4
0k0.
07
Tal
inum
tria
ngul
are
C
Wat
er le
af S
UD
18
.0k0
.71
140.
30k1
.I2
tr
ace
11.0
k0.7
1 12
6.0k
0.71
18
.40k
O. 1
5 T
alin
um tr
iang
ular
e S U D
Wat
er le
af S
HD
21
.0k0
.71
227.
70k9
.65
7O.3
kl .O
8 l9
.OkO
.71
820.
0k4.
24
35.4
0k0.
96
Tal
inum
tria
ngul
are
S H
D
Mea
ns +
SD
of t
hree
det
erm
inat
ions
C
- C
ontr
ol (
fres
h);
SU
D
= S
un d
ried;
S
HD
=
S
hade
drie
d
Fresh "atama ", "editan" and waterleaf and sun dried "atama" and
waterleaf had trace amounts of copper (Cu). Sun drying resulted in 73.0
pg copper for "editan". Shade drying resulted in 41.0, 75.0 and 70.30 pg
copper for "atama", "editan" and waterleaf, respectively.
There were varied increases in zinc (Zn) after sun and shade drying
of the 3 green leafy vegetables. There were 1.0 and 1.3 pg. increases for
the sun and shade dried "atama" samples, respectively. Sun and shade
dried "editan" samples had 1.0 and 7.0 pg increases, respectively.
The P-carotene concentrations of the 3 green leafy vegetables were
a function of sun and shade drying. Sun and shade drying increased P- carotene in all the 3 vegetables. Shade drying had much more advantage
over the sun drying in the 3 vegetables. The highest increases of P-
carotene after shade drying occurred in "atama" and "editan" vegetables
(2984.6 and 2944.3pg1 respectively). The increase in P-carotene after
shade drying in waterleaf was 820.0pg.
They were increases in folate values after sun and shade drying for
all the three leafy vegetables. Sun drying increased folate only by 0.3pg1
and shade drying by 11.4pg in "atama". Fresh "editan" had traces of
folate. Sun and shade dried "editan" had l3.6pg and 1 8.5pg1 respectively.
Fresh waterleaf had 13.4pg folate and sun and shade dried samples had
18.4 and 35 .4~9 , respectively.
4.5 Effect of processing on some minerals and vitamins content of
green leafy vegetables
Table 4 presents the effect of processing on some mineral and
vitamin contents of 3 seasonal green leafy vegetables based on residual
moisture as against values in Table 3. The values for the 3 fresh leafy
vegetables were higher for iron (Fe) than theose of sun an shade dried
samples. The values for "atama" were 76.16 Vs 30.45 and 40.28p.g.
"Editan" had 78.20 Vs 29.12 and 33.28pg. On the other hand, waterleaf
had 103.07 Vs 18.72 and 22.05pg. Shade dried samples of the 3 leafy
vegetables were higher than those of sun dried samples.
There appears to be a trend towards decreases in iodine (I2) values
for Fe (Table 4). Control (fresh) l2 values were 557.6, 258.06 and 993.22pg
for "atama", "editan" and waterleaf, respectively. Sun and shade dried
values for the 3 vegetables were 244.96 and 272.42~9 for "atama"; 73.1 1
and 140.08pg for "editan" and 145.91 and 239.08pg for waterleaf. Shade
dried samples for the 3 leafy vegetables were higher than those of sun
dried. The values for l2 for "atama" were 272.42 Vs 244.96pg; 140.08 Vs
73.1 1 pg for "editan" and 239.08 Vs 145.91 pg for waterleaf.
The values for copper (Cu) varied. Fresh (control) and sun dried
"atama" had traces of the nutrient (Cu). On the other hand shade dried
"atama" had 43.46pg. Fresh (control) "editan" had traces of Cu. Sun and
shade drying increased copper. However, shade drying caused much
more increase than sun drying (78.0 Vs 75.92pg, respectively). Both
control (fresh) and sun dried waterleaf had traces of Cu. Shade dried
sample, however, had 73.81pg.
Sun and shade drying decreased zinc (Zn) values for the 3 leafy
vegetables against their controls. Sun and shade dried values for "atama"
were 10.5 and 10.91 Vs 24.48pg; and 12.48 and 18.12 Vs 43.04 pg for
"editan" and 11.44 and 19.95 Vs 93.70pg for waterleaf.
There were tremendous increases in p-carotene in "atama" and
"editan" due to shade drying when compared with control (fresh) and sun
dried samples. Shade dried "editan" had 3163.67pg against 312.80 and
130.51 pg for fresh and sun dried samples. Shade dried "editan" had also
higher p-carotene (3062.07pg) than the control (fresh) and sun dried
samples (852.38 and 11 10.72yg). On the other hand sun dried waterleaf
had higher value than shade dried (131.04 Vs 86.0pg). However, the
shade dried sample increased p-carotene in waterleaf (86.0 Vs 65.59~9).
There were general decreases in sun and shade dried folate for the
3 leafy vegetables. However, the highest decreased occurred in waterleaf
(125.55 Vs 19.1 3 and 37.1 7pg). Fresh (control) "editan" had trace of folate.
Both sun and shade drying increased folate levels in "editan" but the
increase was much more in shade dried sample (19.24 Vs 14.14pg).
Shade drying also increased folate much more than sun drying in "atama"
(29.25 Vs 17.32pg). However, control (fresh) had more folate than sun and
shade dried samples (44.06 Vs 17.32 and 29.25pg, respectively).
Tab
le 4
: E
ffec
t of
pro
cess
ing
on
so
me
min
eral
s an
d v
itam
ins
con
ten
t o
f g
reen
lea
fy v
eget
able
s*
Foo
d m
ater
ials
F
e (p
g110
0g)
12 (p
g110
0g)
Cu
(pg/
lOO
g)
Zn
(pg1
100g
) p-
caro
tene
(pg/
lOO
g)
Fol
ate
(pg1
100g
) --
--
"Ata
ma"
C (
Hei
nsia
cri
nata
C)
76.1
6 55
7.60
tr
ace
24.4
8 3
12.8
0 44
.06
"Ata
ma"
SU
D (H
eins
ia c
rina
ta S
UD
) 30
.45
244.
96
trac
e 10
.50
130.
5 1
17.3
2
-'Ata
ma"
SH
D (H
eins
ia c
rina
ta S
HD
) 40
.28
272.
42
43.4
6 10
.9 1
3 16
3.67
29
.25
"Edi
tan"
C (
Las
iant
hera
afr
ican
a C
) 78
.20
258.
06
trac
e 43
.O 1
85
2.38
tr
ace
"Edi
tan"
SU
D (L
asia
nthe
ra a
fric
ana
SUD
) 29
.12
73.1
1
75.9
2 12
.48
1 1 10
.72
14.1
4
"Edi
tan"
SH
D (L
asia
nthe
ra a
fric
ana
SH
D)
33.2
8 14
0.08
78
.0
18.7
2 30
62.0
7 19
.24
Wat
erle
af C
(T
alin
um tr
iang
ular
e C
) 10
3.07
99
3.22
tr
ace
93.7
0 65
.59
125.
55
Wat
erle
af S
UD
(Tal
inum
tria
ngul
are
SU
D)
18.7
2 14
5.91
tr
ace
1 1.4
4 13
1 .04
19
.13
Wat
erle
af S
HD
(T
alin
um tr
iang
ular
e S
HD
) 22
.05
239.
08
73.8
1 19
.95
86.0
1 37
.17
C =
Con
trol
(fr
esh)
SUD
= S
un d
ried
SH
D =
Sha
de d
ried
* Bas
ed o
n re
sidu
al m
oist
ure
4.6 Antinutrient and food toxicant levels in processed green leafy
Table 5 presents antinutrient and food toxicant levels in processed
green leafy vegetables.
Sun and shade drying reduced saponin levels drastically in all the
three green leafy vegetables. Sun drying was much more effective in
reducing saponin in all the three vegetables. In "atama" sun drying
reduced saponin by 114.7mg (124.0 to 9.3mg). Shade drying reduced
saponin to 91.2mg. The unprocessed "editan" had 18.897mg saponin, sun
dried sample had 12.7mg and shade dry had 17.0mg. Fresh waterleaf had
35.73mg1 sun and shade dried samples had 3.9 and 6.5mg, respectively.
The oxalate levels in 3 fresh green leafy vegetable samples were
reduced by sun and shade drying. Sun drying reduced oxalate much
more than shade drying of the 3 vegetables. The "atama" sun dried value
was 9.2 while the shade dried was 34.3mg. For "editan" it was 33.3mg
and shade drying was 35.5mg. Waterleaf values were 4.2 and 5.22mg for
sun and shade drying, respectively. When differences in reduction of
oxalate by sun and shade drying in waterleaf were compared with "atama",
the difference was 25.lmg. The difference of oxalate in "editan" between
sun and shade drying was 1.07mg. The largest difference in oxalate was
25.lmg in "atama" as compared with 2.2mg and 1.07mg for "editan" and
waterleaf, respectively.
The cyanide levels followed the same trend as the oxalate and the
tannins. In "atama", the level of cyanide due to sun drying was 0.67mg.
Shade drying reduced cyanide from 12.43 to 6.56mg in "atama". Sun dried
"editan" reduced cyanide from 47.0 to 1 .9mg, shade drying
Table 5. Antinutrients and food toxicants composition of processed and unprocessed green leafy vegetables.
Food materials Saponin Oxalate Cyanide Tannins (mgll OOg) (mgll OOg) (mgl100g) (mg1100g)
Atama C Heinsia crinata C
Atama SUD Heinsia crinata SU D
Atama SHD Heinsia crinata SH D
Editan C Lasianthera africana C
Editan SUD Lasianthera africana SUD
Editan SHD Lasianthera africana SHD
Waterleaf C Talinum triangulare C
Waterleaf SUD Talinum triangulare S U D
Water leaf SHD Talinum triangulare SH D
Means +SD of three determinations
C - control (fresh)
SUD- sun dried
SHD- shade dried
reduced it from 47.0mg to 2.0mg. The cyanide was low in fresh waterleaf
(6.88mg). This value was reduced to 0.22 and 0.90mg by sun and shade
drying, respectively. The difference in cyanide between sun and shade
dried samples was 0.68mg.
Fresh "editan" had the highest tannins followed by "atama" and
waterleaf (1 03.53, 45.17 and 22.30mgl respectively). As observed before,
sun drying reduced tannins much more than shade drying.
4.7 Effect of processing on some antinutrients and food toxicants
content of green leafy vegetables.
Sun drying caused reduction in saponin in "atama" from 337.28mg
(control) to 9.48mg (Table 6). On the other hand shade drying reduced
saponin in "atama" from 337.28 (control) to 34.76mg. In "editan" sun drying
reduced saponin from 74.17mg (control) to 13.20mg and shade drying
reduced it from 74.17 to 17.71mg. In fresh (control) waterleaf, sun and
shade drying reduced saponin, respectively.
Sun and shade drying caused decreases in oxalate in the 3 leafy
vegetables as compared with controls (fresh) (320.41, 404.68 and
959.20mg for "atama", "editan" and waterleaf, respectively).
Cyanide content of the 3 leafy vegetable were reduced by sun and
shade drying. However, sun drying was much more drastic than shade
drying when compared with controls (fresh). In "atama" sun drying reduced
cyanide to 0.70mg and shade drying to 6.95mg as compared with control
(fresh) (33.80mg). The reductions in "editan" were 1.98 and 2.08mg for sun
and shade drying, respectively as compared with the control (183.77mg).
The reductions in cyanide waterleaf due to sun and shade drying were
0.22 and 0.94mg, respectively as compared with control (64.46mg).
Tannins was reduced in the 3 leafy vegetables. The reduction in
tannins varied depending on the vegetable. In "atama" the reductions were
0.13 and 0.45mg for sun and shade drying, respectively as against the
control 122.86mg. Sun and shade drying caused reductions in tannins in
"editan". The reductions were 0.12 and 0.18mg for sun and shade drying,
respectively as against the control 404.80mg. Sun and shade drying
reduced tannins in waterleaf. The reductions were 0.34 and 0.48mg as
against the control 208. 95mg.
Table 6: Effect of processing on some antinutrients and food
toxicants content of green leafy vegetables *
Food materials Saponin Oxalate Cyanide Tannins Cm~/_1_OO~L.Smm~lo~~~~~~L~~!IO_O_o~g)g)g)@~/100~1111
"Atama" C (Heinsia crinata C) 337.28 320.41 33.80 122.86
"Atama" SUD (Heinsia crinata SUD) 9.48 9.66 0.70 0.13
"Atama" SI-ID (Heinsia crinata SHD) 34.76 36.35 6.95 0.45
"Editan" C (Lasianthera africana C) 74.17 404.68 183.77 404.80
"Editan" SUD (Lasianthera africana SUD) 13.20 34.62 1.98 0.12
"Editan" SHD (Lasianthera africana SHD) 17.71 36.92 2.08 0.48
Waterleaf C (Talinum triangulare C) 334.90 959.20 64.46 208.95
Waterleaf SUD (Talinum triangulare SUD) 4.05 4.36 0.22 0.34
Waterleaf SHD (Talinum triangulare SHD) 6.82 5.53 0.94 0.48
C = Control (fresh)
SUD = Sun dried
SHD = Shade dried
* Based on residual moisture
4.8 Proximate composition of processed and unprocessed
cassava and its products, cocoyam, unripe green plantain and
banana products
Table 7 presents the proximate composition of processed and
unprocessed cassava, cocoyam, unripe green plantain and banana
products. Fresh samples for cassava and its products as well as cocoyam
contained the following moisture levels 13.73% for gari, 56.57% for
cassava paste, 70.30% for cassava fufu and 67.6% for cocoyam. The
moisture content of the fresh unripe green plantain and banana was 62.8
and 75.5%, respectively. Sun drying drastically reduced moisture in
cassava and its products, cocoyam, unripe green plantain and banana.
The decreases and increases in protein due to sun drying followed
the same trend as those of moisture. The cassava paste (fresh) had 0.4
increase in protein (0.9 Vs 0.5%). The protein of cassava fufu increased
from 1.30 to 2.18% while gari increased from 1.30 to 1.73%. The protein of
cocoyam increased from 2.00 to 3.83%, unripe green plantain from 0.87 to
1.40% and unripe green banana from 1.40 to 2.27% (Table.4).
There were increases in ash due to sun drying for all the food
materials. The increase in ash for cassava paste was 0.55% (1.45 Vs
0.9%), cassava fufu had only 0.10% increase, gari had 0.01 %, cocoyam
had 0.65%, unripe green plantain had 0.6% and unripe green banana had
0.8% increase.
The fat values also increased in all the food materials due to drying.
Cassava paste had the highest increase when compared with other
starchy food materials (Table 7). The increase was 1.2%. Those of
cassava fufu and gari were 0.07 and 0.05%, respectively. The increase in
cocoyam was 0.10% and those of unripe green plantain and banana were
0.5 and 0.6%, respectively.
Tab
le 7
. P
roxi
mat
e co
mp
osi
tio
n o
f p
roce
ssed
an
d u
np
roce
ssed
cas
sava
an
d i
ts p
rod
uct
s, c
oco
yam
, u
nri
pe
gre
en p
lan
tain
an
d b
anan
a (%
).
Food
mat
eria
ls
Moi
stur
e P
rote
in
Ash
Fa
t Fi
bre
CH
O
.. -
- . . ....
--
Cas
sava
C
56
.57
2 0
.4 I
0.52
0.07
0.
220.
07
0.23
+0.0
0 40
.33
Man
ihot
esc
ulen
ta C
Cas
sava
SU
D
Man
ihot
esc
ulen
ta S
U D
Cas
sava
fufu
C
Man
ihot
esc
ulen
ta (
fufu
) C
Cas
sava
fufu
SU
D
Man
ihot
esc
ulen
ta (
fufu
) S
UD
Gar
i C
Man
ihot
esc
ulen
ta (
gari)
C
Gar
i SU
D
Man
ihot
esc
ulen
ta (
gari)
SU
D
Coc
oyam
C
Xan
thos
oma
sagi
ttifo
lium
C
Coc
oyam
SU
D
Xan
thos
oma
sagi
ttifo
lium
SU
D
Unr
ipe
gree
n pl
anta
in C
M
usa
para
disi
aca
C
Unr
ipe
gree
n pl
anta
in S
UD
M
usa
para
disi
aca
SU
D
Unr
ipe
gree
n ba
nana
C
Mus
a sa
pien
tum
C
Unr
ipe
gree
n ba
nana
SU
D
.
- M
usa
sapi
entu
m S
UD
M
ea
ns
2 S
D o
f tw
o d
ete
rmin
atio
ns;
C
=
con
tro
l (fr
esh
);
SU
D
= su
n d
rie
d
The fibre and carbohydrate values for the food materials increased
after sun drying. The cassava paste had 1.27 and 49.99% increase in fibre
and carbohydrate contents, respectively. The cassava fufu had 3.,07 and
52.45% increase in fibre and carbohydrate, respectively. The gari had 0.05
and 1.19% increase in fibre and carbohydrate. Cocoyam had the highest
increase in fibre (3.13%). Its fibre had 3.13% and carbohydrate had
51 -09% increase. The unripe green plantain had 0.3% and 57.6% increase
in both fibre and carbohydrate. The increases in fibre and carbohydrate for
banana were 0.2 and 68.1 7%.
The ash contents of fresh (raw) cassava and sun dried samples
were 0.9 and 1.45% respectively. The ash content for fresh cassava fufu
and sun dried samples were 0.33 and 0.43%. The ash content of gari and
sun-dried samples were 0.44 and 0.45%. The ash content of fresh
cocoyam and sun dried samples were 0.35 and 1.0%. The ash content of
fresh unripe green plantain and sun dried samples were 0.9 and 1.5%. Ash
content of fresh unripe green banana and its sun-dried sample were 1.1
and 1.9%.
4.9 Effect of processing on the promixate composition of cassava and its products, cocoyam, unripe green plantain and banana.
The decreases of protein of all the sun dried cassava, cassava fufu
except sun dried gari, cocoyam, unripe plantain and banana based on
residual moisture (Table 8) indicates that sun drying had no advantage
over non-treated samples.
The slight increase in ash (0.12%) in sun dried samples appears to
be food specific. The decreases might be attributed to loses during sun
drying.
The increase in fat for sun dried cassava (1 -4 Vs 0.46) and 0.7%
(0.72 - 0.54%) of sun dried and undried plantain might be also nutrient
specific.
Table 8. Effect of processing on the proximate composition of cassava and its products, cocoyam, unripe green plantain and banana ( O h ) *
Food materials Protein Ash Fat Fibre CHC Cassava (Manihot esculenta C) 1.15 2.07 0.46 0.53 95.7!
Cassava (Manihot esculenta SUD)
Cassava fufu (Manihot esculenta C)
Cassava fufu SUD (Manihot esculenta C)
Gari C (Manihot esculenta gari C)
Gari SUD (Manihot esculenta gar; SUD)
Cocoyam C (Xanthosoma sagittifoli~~m C)
Cocoyam SUD (Xanthosoma sagittifolium SUD)
Unripe plantain C (Musa paradisiaca C)
Unripe plantain SUD (Musa paradisiaca SUD)
Unripe banana C (Musa sapientum C)
Unripe banana SUD (Musa sapientum SUD)
C - - Control (fresh) SUD = Sun dried SHD = Shade dried * Based on residual moisture.
4.10 Some minerals and vitamins content processed and unprocessed
cassava and its products, cocoyam, unripe green plantain and
banana
Table 9 presents iron (Fe), iodine (I), copper (Cu), zinc (Zn) p-carotene
(RE) and folate of processed and unprocessed cassava and products,
cocoyam, unripe green plantain and banana.
Sun drying produced varied increases in iron (Fe) concentrations in
cassava and its products. It had 14.0 pg increase in cassava paste (29.0 Vs
15.0) in cassava fufu (54.0 Vs 42.6pg) and in gari 0.0 pg. There was 1.0 pg
increase in Fe of cocoyam after sun drying. There were increases in Fe in both
plantain and banana after sun drying. There was an increase in Fe of 12.0pg
due to sun drying in unripe green plantain and 17.0 pg in unripe green banana.
Cassava fufu contained 0.5pg 1, per 100 sample. Sun drying increased
the 1, to 2.0pg. Sun dried cocoyam contained 0.9pg 1,. All the other samples
contained trace amounts of I,.
The copper (Cu) values were affected by sun drying. Sun drying caused
varied increases in Cu in all food materials. It increased Cu in cassava paste
by 74.67, 10.9 and 0.10 pg for the sun dried cassava, cassava fufu and gari
(Table 9), respectively. Sun drying increased Cu by 1.77 pg in cocoyam, 38.67
and 48.97pg in plantain and banana, respectively.
Sun drying caused 0.4mg increase in zinc (Zn) of cassava paste (0.9 Vs
0.5mg). Zn was not detected in cassava fufu and gari. There were increases
of 2.63, 8.0 and I l.Omg after sun drying of cocoyam, plantain and banana,
respectively.
Tab
le 9
: S
om
e m
iner
als
and
vit
amin
s co
nte
nt
of
pro
cess
edan
d
un
pro
cess
ed c
assa
va
and
its
p
rod
uct
s,
coco
yam
, u
nri
pe
gre
en p
lan
tain
an
d b
anan
a.
Foo
d m
ate
rils
Ir
on
(Fe
) lo
din
e(1
2))
C
op
pe
r(C
u)
Zin
c(Z
n)
p-ca
rote
ne
Fol
ate
(yg
ll O
Og)
(p
gll
oog
(yg
ll O
Og)
(m
gll
OO
g)
Cas
sava
C
15.0
+ 0.
71
trac
e 28
.0k1
.41
0.5k
0.4
1 M
anih
ot e
scul
enta
C
Cas
sava
SU
D
29.0
( 0.7
1 tr
ace
1 02.
67k
1.8
0.9k
0.7
1 M
anih
ot e
scul
enta
SU
D
Cas
sava
Fuf
u C
42
.60k
1.83
0.
5k0.
01
37.3
3k 0
.40
trac
e M
anih
ot e
scul
enta
(fu
fu)
C
Cas
sava
Fuf
u S
UD
54
.00k
0.52
2.
0k0.
00
44.2
3k 0
.12
trac
e M
anih
ot e
scul
enta
(fu
fu)
SU
D
Gar
i C
24.8
3k0.
06
trac
e 31
.10k
0.5
6 tr
ace
Man
ihot
esc
ulen
ta (
gari)
C
Ga
ri S
UD
24
.84k
0.06
tr
ace
31.2
0+ 0
.56
trac
e M
anih
ot e
scul
enta
(ga
ri) S
UD
Coc
oyam
C
24.4
7k0.
35
trac
e 35
.93k
0.2
1 4.
00k0
.00
Xan
thos
oma
sagi
ttifo
lium
C
Coc
oyam
SU
D
25.4
7k 0
.57
0.9k
O.1
0 37
.70+
0.8
5 6.
63k0
.06
Xan
thos
oma
sagi
ttifo
lium
S
UD
Unr
ipe
gree
n P
lant
ain
C
17.0
k0.7
1 tr
ace
65.0
k1.7
3 13
.OkO
.71
Mus
a pa
radi
siac
a C
Unr
ipe
gree
n P
lant
ain
SU
D
29.0
k0.7
1 tr
ace
1 03.
67+
1 .0
8
21 .O
kO.7
1 M
usa
para
disi
aca
SU
D
Unr
ipe
gree
n ba
nana
C
13.0
+0.
71
trac
e 72
.03+
0.0
6 10
.0k0
.71
Mus
a sa
pien
tum
C
Unr
ipe
gree
n ba
nana
SU
D
30.0
+0.
71
trac
e 12
1 .O
+ 0.
71
21.0
+0.
71
Mus
a sa
pien
tum
SU
D
Me
an
s +
SD
of t
wo
de
term
ina
tio
ns;
C
=
con
tro
l (fr
esh
);
SU
D
=
sun
dri
ed
(yg1
1 oog
(y
gll
OO
g)
trac
e tr
ace
trac
e
O.O
5+_O
. 10
O.O
8+O
. 10
O.5
kO. 1
0
O.8
+O. 1
0
0.01
+0.
20
0.03
+0.
20
478.
0+0.
07
734.
0k 0
.71
trac
e
trac
e
trac
e
trac
e
trac
e
trac
e
trac
e
trac
e
15.1
kO.8
9
Cassava paste had traces of p-carotene. There were small increases in p-
carotene for cassava fufu, gari and cocoyam samples. Sun drying caused
0.03 1-19 increase in p-carotene of cassava fufu, 0.3pg in gari and 0.02yg in
cocoyam, respectively. Sun drying caused increases in p-carotene of
plantain and banana samples. The increase in plantain was 256.0 pg and
378.0 pg in banana samples.
There were traces of folate in all the fresh samples except for sun
dried plantain and banana samples. Sun drying increased folate in banana
by 16.6mg and 15. I mg in plantain samples.
4.11 Effect of processing on some minerals and vitamins content of
cassava and its products, cocoyam, unripe green plantain and
banana.
Sun drying had adverse effect on iron content of all the food crops
(cassava and its products, cocoyam, unripe green plantain and banana) (Table
10) based on residual moisture.
Sun drying increased iodine (I2) only in cassava fufu and cocoyam
(1.68 Vs 2.30 and I .OO Vs 0.0pg). The other food crops had traces of the
nutrient (Table 1 0).
Sun drying caused increase in copper (Cu) only in cassava flour but
not its products. The increase was from 64.40 to 108.83119. The other food
crops had various decreases when compared with controls.
Sun drying caused reductions in zinc (Zn) in cassava, cocoyam,
unripe plantain and banana. Cassava products that had no zinc prior to
sun drying that had traces of sun drying that had traces of the nutrient after
drying.
Sun drying increased p-carotene only in gari. The increase was from
0.57 to 0.90pg. The greatest decrease occurred in unripe plantain and
banana. The decrease in unripe plantain was from 1281.04 to 756.02pg
and 920.25 to 645.21 pg in unripe banana.
Sun drying decrease folic acid in all the food crops except unripe
plantain. The increase in unripe plantain was from 0.0 to 15.55pg.
Tab
le 1
0: E
ffec
t of
pro
cess
ing
on s
ome
min
eral
s an
d vi
tam
ins
cont
ent
of c
assa
va a
nd it
s pr
oduc
ts, c
ocoy
am, u
nrip
e gr
een
plan
tain
and
ba
nana
* F
ood
mat
eria
ls
Fe
(pg/
lOO
g)
I? (p
gI10
0g)
Cu
(pg/
100g
) Z
n (p
gI10
0g)
P-c
arot
ene
Fol
ate
(pgl
l OOg
) (P
~J
~O
O~
) C
assa
va C
(M
anih
ot e
scul
enta
C)
34.5
0 tr
ace
64.4
0 1.
15
trac
e tr
ace
Cas
sava
SU
D (M
anih
ot e
scul
enta
SU
D)
30.7
4 tr
ace
108.
83
0.95
tr
ace
trac
e
Cas
sava
Fu
h C
(M
anih
ot e
scul
enta
(fu
fu)
C)
143.
13
1.68
12
5.42
tr
ace
0.16
tr
ace
Cas
sava
Fuf
u S
UD
(Man
ihot
esc
ulen
ta (
hfu
) S
UD
) 62
.10
2.30
50
.86
trac
e 0.
09
trac
e
Gar
i C
(M
anih
ot e
scul
enta
(ga
ri)
C)
28.5
5 tr
ace
35.7
6 tr
ace
0.57
tr
ace
Gar
i S
UD
(M
anih
ot e
scul
enta
(ga
ri)
SU
D)
28.0
6 tr
ace
35.2
5 tr
ace
0.90
tr
ace
Coc
yam
C (
Xan
thos
oma
sagi
ttif
oliu
m C
) 75
.36
trac
e 1 1
0.66
12
.32
0.03
tr
ace
Coc
yam
SU
D (X
anth
osom
a sa
gitt
ifol
ium
SU
D)
28.5
2 1 .
OO
42.2
2 7.
42
0.03
tr
ace
Unr
ipe
gree
n pl
anta
in C
(M
usa
para
disi
aca
C)
45.5
6 tr
ace
174.
20
34.8
4 12
81.0
4 tr
ace
Unr
ipe
gree
n pl
anta
in S
UD
(M
usa
para
disi
aca
SU
D)
29.8
7 tr
ace
106.
78
21.6
3 75
6.02
15
.55
Unr
ipe
gree
n ba
nana
C (
Mus
a sa
pien
turn
C)
53.1
7 tr
ace
264.
60
40.9
0 92
0.25
36
.40
Unr
ipe
gree
n ba
nana
SU
D (
Mus
a sa
pien
turn
SU
D)
32.1
0 tr
ace
129.
47
22.4
7 64
5.21
27
.28
C =
Con
trol
(fr
esh)
SU
D =
Sun
dri
ed
* Bas
ed o
n re
sidu
al m
oist
ure
4.12 Antinutrient and food toxicant composition of processed and
unprocessed cassava and its products, cocoyam and unripe
green plantain and banana.
Table 11 presents the antinutrient and food toxicant composition of
processed and unprocessed cassava and products, cocoyam, and unripe
green plantain and banana.
Saponin was not present in cassava and its products as well as
cocoyam regardless of treatment. There was no saponin in the sun dried
unripe green plantain. Fresh unripe green plantain had 12.7mg as well as
the fresh unripe green banana. Sun drying reduced saponin in banana by
1 O.03mg.
Sun drying reduced oxalate in cassava paste by 75.63mg (201 . I Vs
125.47mg). Cassava fufu and gari had no oxalate regardless of treatment.
Sun drying reduced oxalate in cocoyam, unripe green plantain and
banana. The reduction after sun drying in cocoyam was 212.53mg. In
unripe green plantain the reduction was 1154.94mg oxalate. The oxalate in
unripe green banana was the least (123.80mg). Sun drying of unripe green
banana caused 1 15.73mg reduction in oxalate.
Cyanide was reduced from 5.75 to 0.41mg in cassava paste (5.75
Vs 0.41%). The cassava products and sun dried cocoyam had traces of
cyanide. The fresh cocoyam had 1.04 and 0.60mg cyanide and tannins,
respectively. The fresh cassava paste had 11 7.7mg tannins, and the value
for sun dried cassava was only 0.14mg reduction after sun drying. The
cyanide content of the unripe green plantain was 6.33mg and that of the
sun dried was 3.30mg. The percentage reduction was 48.1%. The fresh
unripe green banana had 1.27mg cyanide while the sun dried sample had
0.86mg.
The fresh unripe green plantain and banana had 122.5 and 78.46mg
tannins, respectively. The value after sun drying was 0.13 and 0.40mg for
plaintain and banana. The unripe green plantain had more tannins than the
unripe green banana.
Tab
le 1
1: A
nti
nu
trie
nts
an
d f
oo
d t
oxi
can
ts c
om
po
siti
on
of
pro
cess
ed a
nd
un
pro
cess
ed c
assa
va a
nd
its
p
rod
uct
s, c
oco
yam
, un
rip
e g
reen
pla
nta
in a
nd
ban
ana
Fo
od
ma
teri
als
S
ap
on
in
Oxa
late
C
yan
ide
T
an
nin
s (m
gll
OO
g)
(mg
ll O
Og)
(r
ng
ll 0
0)
(mg
ll0
0g
) C
assa
va C
tr
ace
201.
1+1.
08
5.75
k0.0
1 1
1 7.
5+0.
79
Man
ihot
esc
ulen
ta C
Cas
sava
SU
D
trac
e 12
5.47
k1.0
8 0.
41 kO
.007
0.
14k0
.01
Man
ihot
esc
ulen
ta S
UD
Cas
sava
fuf
u C
tr
ace
trac
e M
anih
ot e
scul
enta
(fu
fu)
C
Cas
sava
fufu
SU
D
trac
e tr
ace
Man
ihot
esc
ulen
ta (
fufu
) S
UD
Gar
i C
trac
e tr
ace
Man
ihot
esc
ulen
ta (
gari)
C
trac
e tr
ace
trac
e tr
ace
trac
e tr
ace
Gar
i SU
D
trac
e tr
ace
trac
e tr
ace
Man
ihot
esc
ulen
ta (
gari)
SU
D
Coc
oyam
C
trac
e 3
35
.53
k0.0
6
1.04
k0.0
1 0.
60k0
.001
X
anth
osom
a sa
gitt
ifoliu
m C
Coc
oyam
SU
D
trac
e 12
3.O
OkO
. 10
trac
e tr
ace
Xan
thos
oma
sagi
ttifo
lium
SU
D
Unr
ipe
gree
n pl
anta
in C
1
2.7
k0.0
7
11 76
.67_
+0.
01
6.33
k0.0
07
122.
5k1.
50
Mus
a pa
radi
siac
a C
Unr
ipe
gree
n pl
anta
in S
UD
tr
ace
21.7
3+0.
17
3.30
k0.0
3 0.
13_+
0.00
1 M
usa
para
disi
aca
SU
D
Unr
ipe
gree
n ba
nana
C
12.7
_+0.
07
123.
8k0.
47
1.27
k0.0
07
78.4
6kO
. 15
Mus
a sa
pien
tum
C
Unr
ipe
gree
n ba
nana
SU
D
2.67
_+1 .5
8.
07+
0. 1
6 0.
86*0
.00
0.40
_+0.
001
Mu
sa s
apie
ntum
SU
D
Mea
ns +
SD
of t
wo
dete
rmin
atio
ns;
C
=
cont
rol (
fres
h);
SU
D
= su
n dr
ied
4.13 Effect of processing on antinutrients and food toxicants on
cassava and its products, cocoyam, unripe green plantain and
banana.
Table 12 base on residual moisture presents some antinutrients and
food toxicants content in cassava and its products, cocoyam, unripe
plantain and banana, cassava and its products had traces of saponin. Sun
drying reduced saponin in plantain to traces (trace Vs 34.03mg). In unripe
banana the reduction was from 59.94 to 2.85mg.
Sun drying reduced oxalate in cassava. The decrease was from
462.53 to 132.99mg. Cassava products (fufu and gari) had traces of
oxalate. Sun drying caused tremendous decreases in cocoyam, unripe
plantain and banana. The highest decrease was in unripe plantain. The
decrease was from 3153.47 to 1.44mg in unripe plantain. In unripe banana
it was from 506.32 to 8.63mg and in cocoyam it was from 1033.43 to
137.76mg.
The decreases in cyanide due to sun drying followed the same trend
as in oxalate. In cassava cyanide decreased from 13.22 to 0.42mg.
Cassava, fufu and gari had traces of cyanide even after sun drying.
Cyanide decreased in cocoyam from 3.20mg to traces. Unripe plantain and
banana had decreases in cyanide due to sun drying. In unripe plantain the
decrease was from 16.96 to 3.39mg and in banana it was 5.19 to 0.92mg.
Sun drying caused decreases in tannins content of the food crops. In
cassava the decrease was from 270.25 to 0.14mg. All the cassava products
had traces of tannins regardless of processing. Cocoyam had trace tannins
after sun drying (1.84 to traces). In unripe plantain and banana the
decreases were from 328.3 to 0.1 3mg and 320.90 to 0.42mg.
Tab
le 12: Effect o
f pro
cessing
on
som
e antin
utrien
ts and
foo
d to
xicants co
nten
t of cassava an
d its p
rod
ucts,
Food m
aterials Saponin
Oxalate
Cyanide
Tannins
(mg-) (m
gl100g) (m
g/100g) C
assava C (M
anihot esculenta C)
trace 462.53
13.22 270.25
Cassava S
UD
(Manihot esculenta S
UD
) trace
132.99 0.42
0.14
Cassava Fufu C
(Manihot esculenta (fu
h) C
) trace
trace trace
trace
Cassava Fufu S
UD
(Manihot esculenta (fufu) SU
D)
trace trace
trace trace
Gari C
(Manihot esculenta (gari) C
) trace
trace trace
trace
Gari S
UD
(Manihot esculenta (gari) S
UD
) trace
trace trace
trace
Cocyam
C (X
anthosoma sagittifolium
C)
trace 1033.43
3.20 1.84
Cocyam
SU
D (X
anthosoma sagittifolium
SU
D)
trace 137.76
trace trace
Unripe green plantain C
(Musa paradisiaca C
) 34.03
3 153.47 16.96
328.3
Unripe green plantain S
UD
(Musa paradisiaca S
UD
) trace
1.44 3.39
0.13
Unripe green banana C
(Musa sapientum
C)
51.94 506.32
5.19 320.90
Unripe green banana S
UD
(Musa sapientum
SU
D)
2.85 8.63
0.92 0.42
C =
Control (fresh)
SU
D =
Sun dried
* Based on residual m
oisture
Tab
le 12: Effect o
f pro
cessing
on
som
e antin
utrien
ts and
foo
d to
xicants co
nten
t of cassava an
d its p
rod
ucts,
coco
yam, u
nrip
e green
plan
tain an
d b
anan
a* F
ood m
aterials S
apon
in
Oxalate
Cyanide
Tannins
(mg/100g)
(mg/100g)
(mgl100g)
(mg/lO
Og)
Cassava C
(Manihot esculenta C
) trace
462.53 13.22
270.25
Cassava S
UD
(Manihot esculenta S
UD
) trace
132.99 0.42
0.14
Cassava Fufu C
(Manihot esculenta (fufu) C
) trace
trace trace
trace
Cassava Fufu S
UD
(Manihot esculenta (fufu) S
UD
) trace
trace trace
trace
Gari C
(Manihot esculenta (gari) C
) trace
trace trace
trace
Gari S
UD
(Manihot esculenta (gari) S
UD
)
Cocyam
C (X
anthosoma sagittifolium
C)
Cocyam
SU
D (X
anthosoma sagittifolium
SU
D)
Unripe green plantain C
(Musa paradisiaca C
)
trace trace
trace trace
trace 1033.43
3.20 1.84
trace 137.76
trace trace
34.03 3153.47
16.96 328.3
Unripe green plantain S
UD
(Musa paradisiaca S
UD
) trace
1.44 3.39
0.13
Unripe green banana C
(Musa sapienturn C
) 51.94
506.32 5.19
320.90
Unripe green banana S
UD
(Musa sapienturn S
UD
) 2.85
8.63 0.92
0.42
C =
Control (fresh)
SU
D =
Sun dried
* Based on residual m
oisture
4.14 Proximate composition of two soup meals and the
accompaniments
Table 13 presents the proximate composition of two soup meals alone
and the accompaniments alone.
The moisture content of soups prepared with fresh, sun and shade
dried "atama" vegetables varied. It ranged from 64.86 to 76.73% for sun
dried and fresh samples, respectively. The shade dried sample had a
moisture value of 67.04%. The moisture for the soups prepared with fresh,
sun and shade dried "editan" vegetables were 74.63,57.19 and 58.44%,
respectively. Cooked fresh pounded cocoyam had 76.20% moisture, and
sun dried sample had 43.70%. Fresh cassava fufu and gari had 78.33 and
51.80% moisture, respectively. Sun dried cassava fufu and gari had 52.53
and 50.0% moisture contents, respectively.
The protein values for the six soups and six accompaniments differ
after treatments. There were increases in protein in "atama" soups made
from sun and shade dried samples. The soup containing fresh "atama" had
2.20% protein, that of sun dried was 3.30°h1 and that of shade dried was
7.83% protein. Sun dried "atama" soup had 0.83% protein more than fresh
"atama" soup (3.03 Vs 2.20%). The soup made from shade dried "atama"
had 4.8% protein more than sun dried "atama soup (7.83 Vs 3.03%). This
observation was true for "editan" soups. Fresh "editan" soup had 0.17%
protein lower than that of sun dried "editan" soup (3.10 Vs 2.93%). Sun
dried "editan" soup had 5.77% protein lower than that of shade dried (8.87
Vs 3.1 0%). Cooked fresh pounded cocoyam had 1.10% protein and sun
dried pounded cocoyam had 1.23%. The difference in protein between the
two was only 0.13%.
Fresh cassava fufu had 0.27% protein less than sun dried cassava fufu
(0.50 Vs 0.23). Sun dried gari had 0.17% protein more than gari alone
(0.40% Vs 0.23%).
Tab
le 1
3: P
roxi
mat
e co
mp
osi
tio
n o
f tw
o s
ou
p m
eals
lacc
om
pan
imen
ts (O
h).
Fo
od
mat
eria
ls
Mo
istu
re
Pro
tein
A
sh
Fat
F
ibre
CHO
Ata
ma
soup
C
76.7
3k0.
23
2.20
k0.1
0 1
.70
k0.1
0
5.70
k0.1
0 H
eins
ia c
rinat
a (s
oup)
C
Ata
ma
soup
SU
D
64.8
6kO
. 10
Hei
nsia
crin
ata
(sou
p) S
UD
Ata
ma
soup
SH
D
67.0
4k0.
10
Hei
nsia
crin
ata
(sou
p) S
HD
Edi
tan
soup
C
74.6
3k0.
25
Lasi
nthe
ra a
fric
ana
(sou
p) C
Edi
tan
soup
SU
D
57.1
9kO
. 10
La
sint
hera
afr
ican
a (s
oup)
S U
D
Edi
tan
soup
SH
D
58.4
4k0.
20
Lasi
nthe
ra a
fric
ana
(sou
p) S
HD
Pou
nded
coc
oyam
C
76
.20
k0.4
4
Pou
nded
(X
anth
osom
a sa
gitti
foliu
m) C
Pou
nded
coc
oyam
SU
D
43.7
0k1
.OO
P
ound
ed (
Xan
thos
oma
sagi
ttifo
lium
) S U
D
Cas
sava
fufu
C
78.3
3k0.
49
Man
ihot
esc
ulen
ta (
fufu
) C
Cas
sava
fufu
SU
D
52.5
3k1.
10
M
anih
ot e
scul
enta
(fu
fu) S
UD
Gar
i C
51.8
0k0.
85
Man
ihot
esc
ulen
ta (
gari)
C
Gar
i SU
D
50.0
0k0.
10
Man
ihot
esc
ulen
ta (
gari)
SU
D
Me
an
k S
D o
f tw
o a
nd
th
ree
de
term
ina
tion
s;
C =
co
ntr
ol (
fre
sh);
S
UD
=
sun
dri
ed
; S
HD
=
sha
de
dri
ed
The ash content of the soups and accompaniments varied. Fresh
"atarna" soup had 1.7% ash. Sun dried "atama" soup had 5.53% and
shade dried had 5.93%. The soup containing sun dried "atama" had 3.83%
ash more than the soup containing fresh "atama" vegetable. Equally, the
soup containing shade dried "atama" had 0.40% ash more than sun dried
"atama" soup. The soup containing fresh "editan" vegetable had 5.7% ash
less than sun dried "editan" soup, while sun dried "atama" had 0.1 1% ash
less than shade dried soup. Sun dried cooked pounded cocoyam had
0.4% ash more than fresh cooked pounded cocoyam (3.53 Vs 3.13%). In
the same vein, dried cassava fufu had 0.93% ash more than the undried
sample (4.50 Vs 3.57%). The difference in ash between the undried and
dried gari was 0.27% (4.67 Vs 4.40%). There appears to be slight
increases of fat in both soups and their accompaniments after sun and
shade drying.
Soup containing fresh "atama" had 2.2% fat lower than the soup
containing the dried "atama" (7.90 Vs 5.70%). On the other hand, soup
containing sun dried "atama" had 0.06% fat lower than that of shade dried
(7.96 Vs 7.90%). Fresh "editan" soup had 1.8% fat lower than sun dried
"editan" soup, and sun dried "editan" soup had 0.9% fat lower than soup
containing shade dried "editan" (7.9 Vs 6.1 and 8.8 Vs 7.g0h, respectively).
Sun dried pounded cocoyam had 0.13% fat for sun dried cassava fufu.
Sun dried gari had 0.030hA higher fat than the undried sample (0.49 Vs 0.
46%).
Sun and shade drying produced varied increases in fibre for both
soup and their accopanimants. Soup containing sun dried "atama" had
3.4% fibre more than soup containing fresh "atama" (5.33 Vs 1.93%).
Soup containing shade dried "atama had 0.07% fibre more than soup
containing sun dried "atama". Soup containing sun dried "editan" had
4.74% fibre more than soup containing fresh "editan". Soup containing
shade dried "editan" had only 0.17% fibre more than soup containing sun
dried "editan". Fresh cooked pounded cocoyam had 1.23% fibre less than
the sun dried pounded cocoyam (0.53 Vs 1.30%). Sun dried cassava fufu
had 0.4% fibre more than undried cassava fufu. Sun dried gari had 0.01%
fibre more than its fresh counterpart (2.08 Vs 2.07%). The carbohydrate
(CHO) composition of both soups and their accompaniments varied. The
variations were a function of treatments and moisture. Sun dried "atama"
soup with lower moisture (64.36%) had 1.61% CHO more than the fresh
"atama" soup with higher moisture (76.73%). Shade dried "atama" soup
had 7.51% CHO lower than that of sun dried sample (13.35 Vs 5.84%).
Fresh "editan" soup with high moisture (74.63%) had 5.03% CHO lower
than soup containing sun dried "editan". Equally, soup containing shade
dried editan had 8.2% CHO lower than soup containing sun dried "editan".
Cooked (fresh) pounded cocoyam had 30.61% CHO lower than sun dried
pounded cocoyam (48.58 Vs 17. 97%). Sun dried cassava fufu had
24.07% CHO more than fresh cassava fufu (40.34 Vs 16.27%). There was
only 1.32% difference in carbohydrate between sun dried gari and undried
gari.
4.15 Some minerals and vitamins content of two soup meals and
their accompaniments.
Table 14 presents iron (Fe), iodine (I2), copper (Cu), zinc (Zn), vit. A
(RE) and folic acid content of two soup meals alone and their
accompaniments alone.
The iron (Fe) content of the six soup meals and their six
accompaniments varied. It ranged from 3.17 to 34.53mg. The values were
20.36 and 24.47mg for the fresh "atama" and "editan" soups, respectively.
The two fresh soups and their accompaniments had lower Fe when
compared with either sun or shade dried samples. Sun dried samples had
21.48 and 34.53 mg for "atama", and "editan" soups, respectively. Shade
dried "atama" and "editan" soups had 29.23 and 39.15 mg. The values,
3.5, 5.9 and 3.17mg were for fresh pounded cocoyam, cassava fufu and
gari, respectively. Sun dried soups and their accompaniments had lower
Fe values when compared with those of shade dried samples. Sun dried
pounded cocoyam had 6.57mg Fe content, sun dried cassava fufu had
6.17mg and sun dried gari had 3.20mg.
The iodine (I2) content of soups and their accompaniments followed
the same trend as iron, except for trace values for fresh pounded
cocoyam, gari and sun dried gari. Fresh "atama" and "editan" soups had
40.00 and 23.67pg 12, respectively. These values were lower than those of
sun dried samples of the same soups (68.3 vs 40.00 and 63.1 5 vs 23.67
1-19, respectively). Shade dried "atama" and "editan" soups had much
higher l2 values than those of fresh and sun dried samples (92.0 Vs 68.30
or 40.00 pg) for "atama" and (101 .O7 vs 68.15 or 23.67 pg) for "editan",
respectively. Both pounded cocoyam and gari had traces of 12. Sun dried
cassava fufu had higher l2 than fresh sample (4.33 Vs 1.33 pg).
Fo
od
mat
eria
ls
Fe
(mg
ll0
0g
) l2
(pg
ll0
0g
) C
u (p
g11
00g
) Z
n (
pg
1100
g)
Tab
le 1
4.
So
me
min
eral
s an
d v
itam
ins
con
ten
t of
two
so
up
mea
Is/a
cco
mp
anim
ents
.
-
"Ata
ma"
sou
p C
20
.36k
0.20
H
eins
ia c
rinat
a (s
oup)
C
"Ata
ma"
sou
p S
UD
21
.48k
0.03
H
eins
ia c
rinat
a (s
oup)
SU
D
"Ata
ma"
sou
p S
HD
2
9.2
3k0
.06
H
eins
ia c
rinat
a (s
oup)
SH
D
"Edi
tan"
sou
p C
24
.47k
0.3
5 La
sian
ther
a af
rican
a (s
oup)
C
"Edi
tan"
sou
p S
UD
34
.53k
0.5
1 La
sian
ther
a af
rican
a (s
oup)
SU
D
"Edi
tan"
sou
p S
HD
39
.15k
0.67
La
sian
ther
a af
rican
a (s
oup)
SH
D
Pou
nded
coc
oyam
C
3.50
kO. 1
0 P
ound
ed (
Xan
thos
oma
sagi
ttifo
lium
) C
Pou
nded
coc
oyam
SU
D
6.5
7k1
.I 0
Pou
nded
(X
anth
osom
a sa
gitti
foliu
m)
SU
D
Cas
sava
fufu
C
5.9O
fO.1
0 M
anih
ot e
scul
enta
(fu
fu)
C
Cas
sava
fufu
SU
D
6.17
k0.2
5 M
anih
ot e
scul
enta
(fu
fu)
SU
D
Gar
i C
3.1
7f0
.15
M
anih
ot e
scul
enta
(ga
ri) C
Gar
i SS
D
3.2O
kO. 1
0
68.3
0k0.
06
41
.43
k 0.4
9
92.0
0+0.
00
82
.43
k0.5
0
23.6
7k0.
58
52.9
0k0.
26
63.1
550
.58
67.6
02 0.
30
101 .
O7+
0.58
90
.6O
k 0.5
9
trac
e 4.
OO
fO.1
0
2.3
3f 0
.58
8.23
k 0.3
5
1.33
k0.5
8 1.
73k0
.06
4.33
20.5
8 3.
03k0
.15
trac
e 5
.13
k 0.0
6
trac
e 5
.15
k 0.0
6
27.O
Of 0
.00
28
.30
f0.0
0
35.0
0k0.
00
37.0
0k0.
00
48.0
0+0.
00
3.33
k0.0
6
5.91
f 0.
10
trac
e
trac
e
trac
e
trac
e
6-ca
rote
ne
Fo
late
-0O
g)
O.O
7f 0
.001
0.02
k0.0
06
0.05
f0.0
02
0.08
k0.0
01
trac
e
trac
e
trac
e
trac
e
trac
e
trac
e U
M
anih
ot e
scul
enta
(ga
ri) S
U D
M
ean
k S
D o
f thr
ee d
eter
min
atio
ns
C
- - co
ntro
l (fr
esh)
; S
UD
=
su
n dr
ied;
S
HD
=
shad
e dr
ied
There appears to be increases in copper (Cu) after sun and shade
drying. Fresh "atama" and "editan" soups had 39.43 and 52.90~9 Cu,
respectively. Sun dried "atama" and "editan" soups had 41.43 and 67.60pg
Cu, respectively. Shade dried "atama" and "editan" soups had higher Cu
than fresh and sun dried samples (82.43 Vs 41.43 or 39.43 pg) for "atama"
soups and (90.60 Vs 67.60 or 52.90 pg) for "editan" soups, respectively.
Fresh pounded cocoyam had 4.0 pg , fresh cassava fufu had 1.73 pg and
value for gari was 5.1 3 pg. Sun dried pounded cocoyam had 4.23 pg more
than fresh sample (8.23 Vs 4.00 pg), cassava fufu had 1.3 pg more than
fresh cassava fufu (3.03 Vs 1.73 1-19, respectively).
Both fresh and sun dried cassava products had traces of zinc (Zn).
Fresh "atama" and "editan" soups had 26.0 and 35.0 mg, respectively.
Fresh pounded cocoyam had 3.33 mg. There were little or no increases
between sun dried "atama" and "editan" soups and their controls (only 1.0
mg for the dried "atama" and 2.0 mg for dried "editan" soups). The
differences in Zn between shade dried "atama" and "editan" soups were
1.30 and 11.00 mg for "atama" and "editan" soups, respectively. Sun
dried pounded cocoyam had 2.58 mg more than fresh sample (5.91 Vs
3.33 mg).
There were increases in p-carotene for both soups and their
accompaniments. Fresh "atama" and "editan" soups had 214.0 and 191.33
pg p-carotene. Sun dried samples of these soups had 9.3 and 369.4 pg
more than their fresh samples. Shade dried "atama" and "editan" soups
had more than 100 fold increase in p-carotene when compared with the
fresh and sun dried values. The differences in p-carotene of shade and
sun dried "atama" and "editan" soups were 2851.0 pg for "atama" soup
and 1701.26 pg for "editan" soup. Shade dried "atama" soup had much
higher p-carotene than "editan" soup (2851.0 vs 1701.26 pg, respectively).
Fresh cocoyam and cassava products had 13.33 pg p-carotene for fresh
pounded cocoyam, 22.00 pg for cassava fufu and 29.33 pg for gari. There
were increases in p-carotene due to sun drying of cocoyam and cassava
products. The increase for gari was 0.67, 1.33 for cassava fufu and I . I pg
for pounded cocoyam.
There was no folate value for pounded cocoyam, cassava fufu and
gari. Fresh "atama" and "editan" soups had each 0.02 pg folate content.
Their sun dried samples had 0.03 and 0.05 pg for "atama" and "editan"
soups, respectively. Shade drying had equal increase in folate in both
soups when compared with sun dried value (0.07 Vs 0.03 pg) for "atama"
soup and (0.08 Vs 0.05 pg) for "editan" soup.
Tab
le 15. P
roxim
ate
com
po
sition
of iw
uku
kom
, oto
mb
oro
an
d a
titinko
p - o
ne p
ot m
eal (d
ishe
s)(%).
-- - -
-
Dish
M
oistu
re
Pro
tein
A
sh
Fa
t F
ibre
CHO
lwukukom
C
81.50k0.10 0.4320.06
1.13k0.06 4.60k0.10
2.03k0.06 10.31
- M
usa paradisca (pottage) C
lwukukom
SU
D
31
.97
ko.1
0
0.96k0.10 1.73k0.06
5.10k0.10 2.33k0.06
57.91 M
usa paradisca (pottage) SU
D
Otohom
boro C
80.00k0.00 0.43k0.06
1 .13+0.06
6.83k0.10 2.01k0.10
10.01 M
usa sapientum (porriage) C
Otohom
boro SU
D
26.59kO. 1
0
1.30kO. 10
1.93k0.06 7.43k0.06
2.20k0.10 60.55
Musa sapientum
(porriage) SU
D
Atitinkop C
81 .O
OkO
.OO
0.43k0.06
1.63k0.06 5.6O
kO.10
1.23*0.06 10.1 1
Manihot esculenta (dish) C
Atitinkop S
UD
40.23k0.06
0.83kO.15
2.1
8k0.10 6.70k0.10
2.50k0.10 47.56
Manihot esculenta (dish) S
UD
Mean k
SD
of two determ
inations
C
- controls (fresh unripe green plantain and banana and fresh cassava paste)
SU
D
- sun dried (unripe green plantain and banana and cassava flour)
4.16 Proximate composition of three - one pot meals - ("lwukukom",
"otornboro" and "atitinkop").
Table 15 presents the proximate composition for three - one pot
meals - ("lwukukom", "otomboro" and "atitinkop").
Moisture content of fresh (control) dishes ranged from 80.00% for
"otomboro" to 81.5% for "iwukukom" and 81 .OOOh for "atitinkop." Sun drying
drastically reduced moisture in these three - one pot meals. The values
were 31.97% for sun dried "iwukukom", 26.59% for sun dried "otomboro",
and 40.23% for sun dried "atitinkop."
There were increases in protein after sun drying. Sun dried
"iwukukom" had 0.53% protein more than fresh "iwukukom" (0.96 Vs
0.43%). Sun dried "otomboro" had 0.87% protein more than fresh sample
(1.3 vs 0.43%). Sun dried atitinkop had the least increase in protein
(0.40%).
There appears to be a trend towards increases in ash after sun
drying in all the three - one pot meals. Sun dried "iwukukom" had 0.6%
increase in ash, for "otomboro" 6.80% and for "atitinkop" 0.55%.
Fresh "iwukukom", "otomboro" and "atitinkop" had 4.60, 6.83 and
5.60% fat. The increases in fat were different due to the source of meals.
The increases in values were as follows, 0.5% for "iwukukorn", 0.55% for
"otomboro" and 1.1 % for "atitinkop." The increase in fat was much more
for "atitin kop" ( I . I %).
Fibre content of the three - pot meals were 2.03, 2.01 and 1.23%.
There were slight increases in fibre after sun drying. Sun dried "iwukukom"
had 0.3O0hl 0.19% for "otomboro" and 1.27% for "atitinkop." Again the
increase after sun drying was much higher in "atitinkop" (1.27%) when
compared with those of its counterparts.
The increase in CHO was very high for all three - one pot meals
after sun drying. "lwukukom" had 47.6% increase, "otomboro" had 50.54%
and "atitinkop" had 37.45% as compared with their fresh samples,
respectively
4.17 Some minerals and vitamins content of three - one pot meals
("iwukukom", "otomboro", and "atitinkop").
Table 16 presents iron (Fe), iodine (I2), copper (Cu), zinc (Zn), vit A
(RE) and folate content of three - one pot meals ("iwukukorn", "otornboro",
and "atitinkop").
There were increases in Fe of the three - one pot meals after sun
drying. It increased from 20.77 to 32.77mg in "iwukukom", 20.13 to
37.13mg in "otomboro" and 20.70 to 34.70mg in "atitinkop". The highest
increase occurred in "otomboro" (17mg1 followed by 12.0 and 14.0mg Fe
for "iwukukom" and "atitinkop" , respectively).
The l2 content of the three - one pot meals is revealing. Prior to
addition of periwinkle, crayfish and green leafy vegetables these pot meals
contained traces of the element. "lwukukom", "otomboro" and
'"'atitinkop"regardless of treatment had comparable values. "lwukukom"
had 6.67~9, "otomboro" 0.33yg and atitinkop 8.67~9.
The Cu content of "iwukukom" increased from 31.10 to 69.77ygl
"otomboro" 28.77 to 77.74 and "atitinkop" from 49.73 to 124.4~9 after sun
drying. The increases were 38.67, 48.97 and 74.67~9 for "iwukukom",
"otomboro" and "atitinkop", respectively. The increases were much higher
in "atitin kop" (74.67 yg) followed by "otomboro" and "iwukukom."
There were increases also in Zn after sun drying. "lwukukom" had
8.0mg increase (25.63 Vs 1 7.63mg), "otomboro" had l3.Omg (26.63 Vs
13.63mg) and atitinkop had 0.04mg (9.26 Vs 9.22mg). "Atitinkop" had the
least increase (0.04mg) and "otomboro" had the highest (13.0mg) follwed
by "iwukukom" (12.0mg).
"lwukukom" and "otomboro" pot meals had increases in both p-
carotene and folate. Sun drying had no effect on p-carotene and folate
content of "atitinkop." The increases in both 0-carotene and folate in
"iwukukom" were 256.0 and 15.1 yg, respectively. The increases in both P- carotene and folate in "otomboro" were 378.0 and 16.6yg1 respectively.
CHAPTER FIVE
5.0 DISCUSSION
5.1 Proximate composition of processed and unprocessed three leafy
vegetables based on residual moisture against (Table 1)
The higher protein and other nutrients except carbohydrate for
shade dried samples as against sun dried (Table 2) indicates that shade
drying is a better processing method to increase and preserve nutrients in
seasonal green leafy vegetables (Ruel, 2001 ; Oguntona, 1998; FAO, 1997;
Osagie, 1992). The slight differences in ash, fat, fibre and carbohydrate
(Table 2) between shade and sun dried samples meant that either process
could be used to preserve and supply macronutrients rich foods in time of
scarcity (dry season).
5.2 Some minerals and vitamins content of processed and
unprocessed leafy vegetables
The higher iron (Fe) (Table 3) for shade dried vegetables as
compared with sun dried samples suggests that the superiority of shade
over sun drying to increase and preserve iron in green leafy vegetables-a
commonly observed phenomenon (Latande - Dada, 1990; Ifon, 1977).
They were much increases in iron for shade dried "editan" (12.Opg) (32.0 -
20.0~9) as against those of "atama" and waterleaf (21.0 and 1 I.Opg),
respectively.
The high iodine (I,) for shade dried samples regardless of the type
of vegetable shows that it is better than other food processing techniques
tested to preserve and retain iodine in seasonal perishable vegetables.
Shade dried waterleaf that had the highest iodine appears to suggest that
it is a good source of the nutrient. This observation confirms those of
many workers (Aletor and Adeogun, 1995; Tindall, 1983; lfon and Bassir,
1979).
The traces of copper in fresh and sun dried "atama" and waterleaf
showed that copper content of the vegetables is utilizable when shade
dried. This observation is in accord with those of many workers (Osagie
and Onigbinde, 1998; WHO, 1995; Hardenburg et a/., 1986).
The slight differences in zinc (Zn) (1.0 and 1.3pg) among fresh, sun
and shade dried "atama" suggest that either form of the vegetables could
supply the nutrients. However, the higher values 7.0 and 9.Opg for shade
dried "editan" and waterleaf (1 8.0 - I I .Opg and 19.0 - 10.Opg) as against
sun dried value indicates that shade drying is a better processing
technique to preserve zinc in these vegetables.
The tremendous increases in beta-carotene of shade dried "atama"
and "editan" as against those of sun dried samples demonstrates the edge
shade has over sun drying. The lower beta-carotene of shade dried
waterleaf (820.0p.g) as compared with its counterparts ("atama" and
"editan") suggests that it is not a good source of beta-carotene.
The traces of folate in fresh "editan" might be attributed to poor
analytical technique or the quantity of the fresh sample was small as such
the equipment was not sensitive enough to detect it. This confirms the
same observation by others (Oguntona, 1998; FAO, 1995; WHO, 1995).
The much more concentrations of folate in shade dried samples was an
indicative of its superiority over sun drying as a method of processing
vegetables for the nutrient (Ruel, 2001; Osagie and Onigbinde, 1998).
5.3 Antinutrients and food toxicants of processed and unprocessed
green leafy vegetable
The consistently much more decreases in saponin, oxalate, cyanide
and tannins in sun dried samples of the three vegetables (Table 5) is
revealing. It showed that sun has an advantage over shade drying in
reducing antinutrients and food toxicant to safe levels in vegetables
(Osagie, 1998; Udosen and Ukpanah, 1993; Cheeke, 1989; Birk and Peri,
1980; Munro and Bassir, 1969).
5.4 Proximate composition of processed and unprocessed cassava
and its products, cocoyam, unripe green plantain and banana
based on residual moisture
The increases in fibre for sun dried cassava, cassava fufu and
cocoyam might be due to loss in moisture that concentrates dry matter of
which fibre is one (Table 6) (Eka, 1998; Comb et a/., 1996; Ladeji, 1995).
5.5 Some minerals and vitamins content of processed and
unprocessed cassava and its products, cocoyam, unripe green
plantain and bannana
The variations in micronutrient levels of processed and unprocessed
cassava and products, cocoyam, unripe green plantain and banana (Table
9) were due to varied structure of the food and soil levels of the
micronutrients (Eka, 1998; FAO, 1997; FAO, 1990; Okigbo, 1986; Eka,
1985; Olayide et a/., 1979; Ogunmodele, 1983).
The higher iron for sun dried cassava fufu (54.00 pg) appears to
indicate that it has advantage over other cassava products as source of
iron (Table 9). The slight difference in iron (1.0 1-19) between sun dried and
its non-sun dried cocoyam (25.47 Vs 24.47vg) suggests that the extra
effort to sun dry was not cost effective. The high concentration of iron in
sun dried unripe green plantain and banana (29.0 and 39.0 Vs 19.0 and
13.0, respectively) was similar to those reported in literature (Ruel, 2001;
Baiyeri, 2000; FAO, 1997; Robinson, 1996; FAO, 1990; Swennen, 1990;
Ogazi, 1985).
The traces of iodine in cassava and its products except for sun dried
cassava fufu (2.0 pg) suggests that sun dried cassava fufu is a better
source of iron, iodine and copper (44.23pg). The higher copper levels for
sun dried products (Table 9) appears to suggest that sun drying is a good
food processing technique to increase the nutrients (Ruel, 2001; FAO,
1997; Osagie, 1992; FAO, 1990; lhekoronye and Ngoddy, 1985).
The traces of zinc for all cassava products might be due to analytical
error and loss during processing. The observation in the present work
agrees with those of many that some food processing techniques cause
loss of some nutrients (Enwere, 1998; Osagie and Onigbinde, 1998;
Obizoba, 1998; FAO, 1997; FAO, 1990; Oyewole and Odunfa, 1989;
Hesseltine and Wang, 1980). The increases in zinc of the dried cocoyam
and unripe green plantain and banana suggest that sun drying is an
effective domestic processing technique to improve Zn levels in these
foods.
The lower values and traces for p-carotene and folate levels in
cassava and its products and cocoyam (tubers) was not a surprise.
Tubers are not good sources of the nutrients (Eka, 1998; Enwere, 1998;
Purseglore, 1992; Hahn et a/., 1992; Osagie, 1992; Purseglove, 1991;
FAO, 1990; Burton, 1989; Bradbury and Hollaway, 1988; lhekoronye and
Ngoddy, 1985; Ologbobo, 1985; Eka, 1984; Ekpeyong, 1984; Egbe and
Treche, 1984). However, orange flesh tubers e.g. orange flesh potato
recently developed in East Africa (Uganda and Kenya) (IITA, 2004) is a
fairly good source of beta-carotene. The one to two fold increases in beta-
carotene in unripe green plantain and banana is very interesting. This is
because many workers had earlier observed the same phenomenum
(Baiyeri, 2004; Umoh, 1998). It means that many communities that are Vit.
A deficient but can produce plantain and banana and consume them can
prevent or reduce Vit. A deficiency. These communities would be advised
to sun dry and consume more of the products rather than sell them and not
use the cash to purchase Vit. A supplements. This would improve Vit. A
source and consumption.
The traces of folate in cassava and its products, cocoyam and unripe
green plantain except for sun dried samples (15.lmg) showed that these
foods are poor sources of the nutrient. The three fold increase in folate due
to sun drying suggest its beneficial effects (FAO, 1997; FAO, 1990;
lhekoronye and Ngoddy, 1985).
5.6 Antinutrients and food toxicants of processed and unprocessed
cassava and its products, cocoyam, unripe green plantain and
bannana
The traces of saponin (Table 11) in cassava and products and
cocoyam might be attributed to (a) low levels of the food toxicant and (b)
poor analytical technique. The reduction of saponin to traces in unripe
green plantain is indicative of beneficial effect of the treatment. On the
other hand, the reduction of saponin in unripe banana was not as low as
that of unripe green plantain. The differences might be attributed to the
type of food or much more lower levels in banana than in plantain (Osagie,
1998; Osagie, et a/., 1996; FAO, 1990; Oakenful and Sidhu (1 989); Birk
and Peri, 1980; Manro and Bassir, 1969).
The decreased levels of oxalate in cassava from 201.1 to l25.47mg
might be due to evaporation after high heat of the sun. The traces of
oxalate in cassava products might be attributed to treatment (fermentation
and drying). It is known that during fermentation microflora enzymes
hydrolyze bond between oxalate protein-enzymes. The hydrolysed oxalate
is lost after drying of the product (Osagie, 1998; FAO, 1997; Aworth, 1993;
Udoessien and Ifon, 1990; FAO, 1990; Oke, 1969; Munro and Bassir,
1969). The lower oxalate of sun dried cocoyam (1 23.00mg) might be solely
attributed to heat of the sun. Oxalate is volatile and evaporates at high
temperature. This observation is similar to those of many researchers
(Osagie, 1998; Osagie et a/., 1996; Osagie et a/., 1992; Libert and
Franceschi, 1987; Eka, 1977). The reduced levels of oxalate in both
unripe green plantain and banana is very interesting. The reduction in
plantain from 1176.67 to 21.73mg suggests that sun drying is an effective
food processing technique to lower oxalate in foods (FAO, 1997). The
lower levels in banana than in plantain suggest that oxalate is much more
firmly bound in banana and less harmful to consumers.
The reduction in cyanide in cassava from 5.75 to 0.4mg might be
solely attributed to sun drying. The traces of cyanide in the other cassava
products might be due to synergistic effect of combination of fermentation
and sun drying (Obizoba, 1998; Obizoba and Atii, 1994; Nnam, 1994;
Obizoba and Atii, 1991). The reduction of cyanide in cocoyam from 1.04 to
traces might be (a) that cocoyam contains low concentration of cyanide
(Osagie, 1998) (b) the low concentration was easily reduced to traces by
sun drying (FAO, 1997). The much more reduced cyanide in unripe green
plantain (1.27 to 0.86mg) appears to suggest that cyanide is labile in
unripe green plantain. The reduction in banana from 6.33 to 3.30 indicates
that cyanide is firmly bound in banana and less harmful to consumers
(FAO, 1990).
The reduction in tannins from 117.5 to 0.14mg in cassava tubers
indicates that sun drying is an effective domestic method to reduce the
antinutrient to safe levels in cassava. However, the traces of tannins in
other cassava products might be due to combination of the food
processing techniques (Obizoba, 1998; Osagie, 1998; Osagie et a/., 1996;
FAO, 1997; FAO, 1990). The reduced cyanide in sum dried cassava and
cocoyam demonstrates the efficacy of sun drying in reduction of cyanide in
both cassava and cocoyam. The 0.60mg tannins content of the untreated
cocoyam indicates its low levels in the food. The lower tannins in plantain
might be due to sun drying as compared to that of banana (0.13 Vs
0.40mg), which suggests that the antinutrient is loosely bound in plantain
than in banana. The untreated plantain and banana had 122.5 and
78.46mg tannins, respectively. Sun drying caused much more reduction in
plantain that had higher levels of the antinutrient (122.5mg) than in banana
(78.46mg).
5.7 Proximate composition of two soup meals and
accompaniments
The lower moisture (Table 13) of sun dried "atama" soup (64.86%)
as against (67.04%) for shade dried "atama" soup indicates that sun drying
had an edge over shade drying. The higher moisture content for shade
dried "editan" soup (58.44%) as compared with sun dried samples
suggests that shade drying is not beneficial and vice versa. The reduction
in moisture from 76.2 to 43.70% in fresh pounded cocoyam suggests that
sun drying could be a good domestic technique to reduce moisture in fresh
pounded cocoyam. The lower moisutre for sun dried gari (50.00%) as
compared with the control (51.8%) suggests that the extra effort to reduce
moisture by sun drying had no advantages over frying.
The higher protein levels in two soups containing shade dried
"atama" and "editan" (7.83 and 8.87%, respectively) were not surprising
when one considers the effect of high heat generated by sun over that of
shade drying. Direct sun drying could reduced moisture and indirect shade
drying would have the opposite effect (FAO, 1995; Osagie, 1992). The
higher protein for sun dried pounded cocoyam and cassava products
indicates the beneficial effect of the treatment.
There appears to be a trend towards increases in ash as in protein
for soups containing shade dried "atama" and "editan" vegetables than
those of the sun dried samples. The increases in ash in both pounded
cocoyam and cassava products was due to loss of moisture by drying and
concentration'of ash in these tubers.
The higher fat content of soup containing shade dried "editan" and
"atama" might be attributed to the source of oil in the soups. Shade dried
"editan" soup was prepared with red palm oil and "atama" soup was
prepared with palm fruit juice. This suggests that red palm oil has much
more fat concentration than palm fruit juice. Palm fruit juice had an
advantage over red palm oil in the diets of those who require less fat in
their foods for health reasons (Ene-Obong, 2001). The increases in the fat
content of gari whether sun dried or not might be due to palm oil added
during processing (Eboh, 2000; Enwere, 1998; Obizoba, 1998; FAO,
1 990).
The increases in fibre for all the foods whether sun or shade dried
might be attributed to lost in moisture and increase in dry matter in which
fibre is one of them.
The increase in CHO for all the foods whether sun or shade dried
might be attributed to lost in moisture and increased concentration of dry
matter (CHO) - a commonly observed phenomenon. The variations in
CHO levels of the 2 soups might be attributed to the type of vegetable and
its moisture composition.
5.8 Some minerals and vitamins content of two soup meals and
accompaniments
The increases in iron in 2 soup meals (Table 14) were attributed to
sun and shade drying of the vegetables prior to use as compared with their
controls that contained fresh vegetables. Shade drying, had an edge over
sun drying for increases in iron content of soups (29.23 Vs 21.48mg for
"atama" soup meal and 39.15 Vs 34.53mg for "editan" soup meal). Dried
pounded cocoyam and dried gari combined with shade dried "editan" soup
meal (7.87 and 10.46 pg, respectively) was due to the source of nutrient.
The only accompaniment of shade dried "editan" soup meal that had
advantage in folate concentration as compared with the other dishes was
that of shade dried "editan" and sun dried pounded cocoyam (0.64 Vs
0. I pg, respectively).
5.9 Proximate composition of three-one pot meals
The lower moisture content (Table 15) of all the 3-one pot meals
(31.97, 26.59 and 40.33OI0) as against the undried (81.5, 80.00 and
81.00%) was not surprising. The major staples fresh unripe green plantain
and banana and fresh cassava slices were dried before use. They lost
moisutre, which caused increased concentration of dry matter.
The increases in protein, ash, fat, fibre and carbohydrate (Table 15)
were due to drying that caused loss of moisture. The lower moisture of the
3-one-pot meals due to drying suggests that the 3 meals would have
increased nutrients and longer shelf life of the staples (cassava. unripe
green plantain and banana).
5.10 Some minerals and vitamins content of three - one pot meals
The increases in iron, copper and zinc except for p-carotene and
folate in atitinkop dish (Table 16) were solely due to loss in moisture and
increased nutrient density. There was no advantage in iodine
concentration for sun drying of the 3 one-pot meals.
Conclusion
The work has provided a baseline information on the effects of sun
and shade drying on the nutritional quality of some seasonal green leafy
vegetables, starchy staples used for preparation of traditional soup meals
and dishes consumed in Akwa lbom state. Shade drying was the best
traditional food processing technique to increase nutrient density in
seasonal green leafy vegetables particularly p-carotene. Sun drying and
fermentation are good food processing techniques since it increased the
nutrient density, shelf life and extended diversification of food use of
cassava, starchy staples.
Shade drying has a potential of giving nutrient density. Sun dried
starchy staples contained reduced moisture and increased nutrient
concentration. Sun and shade drying as well as fermentation are good
traditional food processing techniques to increase and preserve nutrients
in seasonal foods, diversify their uses, availability and consumption all year
round.
Recommendation
1. Women should be advised to dry their green leafy vegetable in
the shade and sun dried their starchy stapes to retain more
nutrients.
2. Shade dried vegetables could be pulverized, dried cocoyam
could be hammermilled and blended with pulverised vegetables,
packaged and used as complementary food for children,
especially those that do not like vegetables and starchy foods.
I ""*PI A=-, Further research work -
1. Organoleptic attributes of the dishes are necessary in the
subsequent research thrust.
2. Contribution of these food processing techniques on food safety,
quality control and nutrient bioavailability is also necessary for
further research work.
REFERENCES
Adeniji, T.A. aqd Tenkouano, A. (2002). Important of plantain and banana and their hybrid in human diet. IITA. Ibadan, Nigeria, 10.
Addo, A.A. and Eka, O.U. (1982). Ascorbic acid retention of stored Nigerian vegetable soups. Nig. J. Nutr. Sci. 3; 129.
Addy, E.O.H. (1978). Studies on the nutritive values of leaves and fruits of the baobab tree (Adansonia digitata). M.Sc. (Biochemistry Thesis - ABU, Zaria, 82.
Agboola, S.D. (1987). Cocoyam storage and the potentials for food sufficiency and future economic recovery of Nigeria. In Arene, O.B., Ene, L.S.O., Odunukwa, S.O. and Eze, N.O.A. (eds). A monograph in cocoyam in Nigeria. Co-sponsored by national root crop research institutes, national root centre, and federal dept. of Agric. Umudike, Nigeria, 20.
Ajayi, S.O., Oderinde, S.F. and Osibanjo 0. (1980). Vitamin C losses in cooked fresh leafy vegetable. Fd. Chem. 5: 247.
Akomas, G.E.C., Mbanaso, E.N.A. and Akomas, O.E.U. (1987). Food forms of cocoyamfor home and commercial use. In Arene, O.B., Enel- L.S.O., Odunukwe, S.O., Eze, N.O.A. (eds), Cocoyam in Nigeria. National root crop centre and Federal dept.of Agric. Sci. 34.
Akpanabiatu, M.I., Bassey, N.B., Udosen, E.O. and Eyong, E.U. (1998). Evaluation of some minerals and toxicants in some Nigerian soup meals, J. Fd. Composition and analysis. 11: 297.
Akpapunam, M.A. (1 984). Effects of wilting, blanching and storage temperatures on ascorbic acid and total carotenoids content of some Nigerian fresh vegetables. PL. Fd. Hum. Nutr. 34:180.
Aletor, M.V. and Adeogun, O.A. (1995). Nutrient and antinutrient compositions of some tropical leafy vegetables, Fd. Chem. 53: 379.
Amah, C.A.K. (1992). Chemical and nutritional evaluation of some wild fruits and vegetables eaten by the Ututu community of Abia State of Nigeria, M.Sc. Thesis, University of Calabar, Calabar, 54.
Antai, S.P. and Obong, U.S. (1992). The effect of fermentation on the nutrient status of some toxic components of plants. PL. Fd. Hum. Nutr. 42:224.
AOAC (1995). Official methods of analysis, Association of official analytical chemistry. Washington D.C.
Asiedu, J. J. (1 989). Processing tropical crops. A technological approach London. MacMillian press Ltd. 280.
Arene, O.B. and Ene, L.S. (1987). Advance in cocoyam research. In Arene, O.B. and Ene, L.S.O., Oduzukwe, S.O. and Eze, N.O.A. (eds). Cocoyam in Nigeria, Co- sponsored by national root crop research institute, National root crop centre and Federal dept. of Agric. Umudike, Nigeria. 74.
Aworth, O.C. (1993). Exploration and exploitation of indigenous technology for the growth of food and beverage industry. An overview in a paper presented on the 17Ih annual conference of the Nigerian institute of Fd. Sci. Tech. llorin 25.
Awoyinka, A.F., Abegunde, V.O. and Adewusi, R.A. (1995). Nutrient content of young cassava leaves and assessment of their acceptance as a green vegetable in Nigeria. PL. Fd. Hum. Nutr. 47: 28.
Baiyeri, K.P. (2000). Effect of nitrogen fertilization on mineral concentration in plantain (Musa AAB) fruit peel and pulp at unripe and ripe stages. Plant product R. J. 5:43.
Balogun, S.A. Bodin, J.B., Bikangi, N., Rafiqul, I. and Jarlebring, 1. (2003). Cassava. The ultimate future crop, IITA, Ibadan. 28.
Barquar, S.R. and ;Oke, O.L. (1976). Protein in Nigerian yams (Dioscorea Spp) Nutr. Rep. Intl. 14: 248.
Becker H.C. (1940). The method for determination of non-protein N in soybean meal. Cereal Chem. 17: 457.
Birk, Y. and Peri, 1 . (1980). Saponin, In toxic constituent of plant foodstuffs C.R.C. critical review in Fd. Sci. Nutr. 26: 135.
Bokanga, M. (1994). Processing of cassava leaves for human consumption. Acta Horticulture. 375: 207.
Bollard, J. (1970). In Plant Biochemistry. Academic Press, N.Y. 68.
Bourke, R.M. (1982). Root crops in papua New Guinea. In Bourke, R.M. and Kasavan, V. (eds). Processings of the 2"d Papua New Guinea food crops conference, Port Morestry, Dept. of primary industry, 63.
Bradbury, J.H. (1 988). The chemical composition of tropical root crops. ASEAN Fd. J., 4:31.
Bradbury, J.H. and Holloway, W.D. (1988). Chemistry of tropical root crops. Significance for nutrition and agriculture in the pacifics. ACIAR, Monograph 6: 201.
Cable, W.J. (1984). The spread of taro (Colocasia spp.) in the Pacific. In Chandra, S. (ed). Edible aroids. Oxford. Clarenton press. 33.
Chandra, S. (1986). Tropical root crops and their potential for food in the less developed countries. Fd. Rev. Intl. 2: 169.
Chandra, S. (1984). Edible aroids. Oxford. Clarendon press. 33.
Charkraborty, R.E. and Eka, O.U. (1978). Studies on hydrocyanic, oxalic and phytic acid content of foodstuffs. W. Afr. J. Biol. Appl. Chem. 21:59.
Cheeke, P.R (1989). ED. Toxicants of plant origin. Florida, U.S.A. CRS press 4: 148.
Cobley,. L.S. and Steele, W.M. (1976). An introduction to botany of tropical crops. London. znd edn., 371.
Combs, G.E., Welch, R.M.T., Duxbury, J.M., Uphoff, N. T. and Mesheim, M.C. (eds) (1996). Food base approach to prevent malnutrition, on international research agenda. Summary approach of an international workshop. lthaca N.Y. U.S.A. Cornell 50.
Cooke, R.C,., Richard, J.D. and Thompson, J.K. (1 988). The storage of tropical roots and tuber crops - cassava, yam, edible aroids. Ex. Agric. 24: 270.
Coursey, D.G. (1983). In Chan, H.T. (ed). Hand book of tropical foods. New York, N.Y. Dekker. 601.
Coursey, D.G. (1976). The origin and domestication of yams in Africa. In Harlan, J.R. and Stember, A.B. (eds). Origins of African plant domestication, Mouton. The Hague. 408.
Coursey, D.G. (1 968). The edible aroids. World crops 24: 30.
Cox, P.A. (1980). Two Samoan technologies for breadfruit and banana preservation, Econ. Bot. 34: 185.
Eboh, LO. (2000). 21'' century Akwa lbom state cuisine. Uyo, Etofia media services Ltd. 20.
Egbe, T.A. and Treche, S. (1984). Variability in chemical composition of yams grown in Cameroon. In Terry, E. R. Doku, E.V., Arene, O.B. and Mahungu N.M. (ed). Tropical root crops. Production and uses in Africa, Duala C'ameroon, IDRC. 156.
Eka, O.U. (1998). Roots and tubers. In Osagie, A.U. and Eka, O.U. (eds). Quality of plant foods, Nigeria, Post harvest research unit. 31.
Eka, O.U. (1989). Towards self-sufficiency and self reliance in food and nutrient requirements; in Nigeria by the year 2000. A challenge to food and nutrition scientists. An inaugural lecture, University of Calabar, 43.
Eka, O.U. and Hobbs C. (1987). Effect of cooking on nutrient status of tubers. Nig. J. Nutr. Sci. 12: 325.
Eka, O.U. (1 986), Studies on the fermentation of cassava. Some enzymes and microorganisms in the fermentation of liqours and the effect of fermentation on nutrient status of cassava products. W. Afr. J. Biol. Appl. Chem. 31: 12.
Eka, O.U. (1985). The chemical composition of tubers. Advances in yam research. The biochemisty and technology of yam tubers. Eung, Nigeria, Published by Biochem. Soc., Nig. J. collaboration with ASUTECH
Eka, O.U. (1984). A review of studies of changes in nutrient composition during fermentation of food. Nig. J. Nutr. Sci. 5: 21.
Eka, O.U. (1982). Nutritive value of tuwo shinkafa Dauiyan Tushe. A traditional rice meal of Hausa in Northern Nigeria. Nig. J. Nutr. Sci. 3:90.
Ekpenyong, T.E. (1984). Composition of some tropical tuberous foods. Fd. Chem. 15:36.
Eleje, 1 . (187). Cocoyam a major national carbohydrate staple for the future in Nigeria, Cocoyam in Nigeria, Co-sponsored by national root crop research institute. National root crop centre, and Federal Dept. of Agric. Umudike. 35.
Ene-Obong, H.N. and Madukwe, E.U. (2001). Bioavailability of trace elements in Southern Nigeria meals and the effect of dietary components, Nig. J. Nutr. Sci. 22: ' I l .
Ene-Obong, H. N. (2001). Eating right (A nutritional guide). University of Calabar Press, Calabar. 49.
Enwere, N.J. (1998). Foods of plant origin. Nigeria, Afro-Orbis public. Ltd. 293.
Ephenhuijsen, S.W. (1974). Crowing native gegetables in Nigeria. FAO, Rome. 49.
Faboya, O.O.P. (1985). Chlorophyl changes in some green leafy vegetables during cooking, J. Sci. Fd. Agric. 36: 760.
Faboya, O.O.P. (1983). Mineral content of some green leafy vegetables commonly food in the Western part of Nigeria. Fd. Chem. 12: 216.
Fafunso, Yand Bassir, 0. (1977). Variation in the loss of vitamins in leafy vegetables with various method of food preparation. Fd. Chem. 2:55.
FAO, (2001), Cassava, World statistic on cassava production, FA0 technical series, Rome, 15.
FAO, (1997). Preventing micronutrient malnutrition. A guide to food-based approaches. A manual for policy makers and programme planners. Food and agricultural organization of United Nations and International life science institute. Washington D.C. 19.
FAO, (1995). Fruit and vegetables processing by Dauthy, M.E., FAO, agricultural services bulletin, Rome, 1 19: 437.
FAO, (1994). Tropical root and tuber crops production perspective and future prospects FA0 plant production and protection, Rome. 126: 205.
FAO, (1990). Roots, tubers, plantain and banana in human nutrition, Rome, Fd. Nutr. Series. 24 : l l .
FAO, (1989). Utilization of tropical foods. Roots ;and tubers. Fd. Nutr. Paper, 47:117
FAO, (1988). Traditional food plants Food and agricultural organization of the United Nations FAO, Fd. Nutr. Paper 42:67.
FAO, (1985). Rep. Workshop on processing technologies for cassava and other tropical roots, tubers and plantains in Africa, Kinshasa, Zaire. Rome, 50.
FAOANHO (1973). Energy and protein requirements, Report of a joint FAOANHO ad hoc. Expert committee WHO Technical Report series, 522: 11 8.
Fatoki, O.S. and Ekwenchi, M.M. (1996). The determination of oxalate content of some common Nigerian vegetables Nig. J. Nutr. Sci. 11 :I 1.
Fawcet, W. (1921). The banana. Its cultivation, distribution and commercial uses. 2". Edn. London. Duckwoorth 56.
Forsyth, W.G.C. (1980). Banana and plantain. In Nagy, S. and Shaw, P.E. (eds). Tropical and subtropical fruits composition, properties and uses, Westport. Conn. Avi. 278.
Foy, J.M. and Parratt, J.R. (1960). A note on the presence of noradrenaline and 5-hydroxytriptamine in plantain. J. Pharm. Pharmacol. 12: 364.
Gomez, G.A. and Valdivieso, M. (1985). Cassava foliage, chemical composition, cyanide content and effect of drying an cyanide elimination. J.Sci. Fd. Agric. 36:441.
Goode, P.M. (1974). Some local vegetables and fruits of Uganda. Enteble. Uganda, Dept. of Agric. 66.
Gruess, ,W.V. (1 958). Commercial fruits and vegetables products. 4th edn. New York McGraw Hill book company, 244.
Gwanfogbe, P.N., Cherry, J.P., Simmonds, J.G. and James, C. (1980). Dehydration and nutritional content of plantain flour. Tropical Sci. 28:482.
Hahn, S.K., Reynolds, L. and Egbunike, G.N. (1992). Cassava as livestock feed in Africa. Ibadan, Nigeria, 45.
Hahn, S.K. and Keyser, J. (1985). Cassava. A basic food of Africa. Outlook on Agric. 14:99.
Hardenburg, R.E. and Wang, C. (1986). The commercial storage of fruits, vegetables and florist and nursery stocks. Agricultural handbook of the United States Department of Agric. 66: 130.
Hesseltine, C.W. and Wang, L.H. (1980). The importance of traditional fermented foods. Bio. Sci. 30:48.
Idowu, M.A., Oni, A. and Amusa, B.M. (1996). Bread and biscuit making potentials of some Nigerian cocoyam cultivars. Nig. Fd. J. 14:12.
Ifon, E.T. and Bassir, 0 . (1979). The nutritive value of some Nigerian leafy vegetables. Part 1 vitamin and mineral contents. Fd. Chem. 4:267.
Ifon, E.T. (1977). The nutrient composition of some Nigerian leafy green vegetables and physiological availability of their iron content. Phrol. Thesis, Dept. of Biochemistry University of Ibadan, Nigeria, 120.
Igbedioh, O.S. (1 990). Causes and prevention of malnutrition in Nigeria. Papers presented to F.D.A. Lagos, Nutr. PL.
Ihekoronye, A.I. and Ngoddy, P.O. (1985). lntergrated food science and technology for the tropics. London, MacMillan publishers Ltd. 368.
Ikediobi, C.O., Onyia, G.O.C., and Eluwah, C.E. (1984). A rapid and inexpensive enzymatic assay of total cyanide. J. Agric. Chem. 17: 2810.
IITA, (2004). Potatoes. Production and utilization in Kenya and Uganda.lbadan, Nigeria, 10.
ILS, (1997). Preventing micronutrient malnutrition. A guide to food-based approaches. A manual for policy makers and programme players. Washington D.C FAO, Rome 25.
Inyang, E. (1987). Cocoyam. A major national carbohydrate staple for the future Address presented at the 1'' National workshop on cocoyam, 15.
IVACA, (1982). Reprints of selected methods for the analysis of vitamins. A and carotenoids in nutrition surveys. Washington D.C. The nutrition foundation.
Janick, J. Scherry, R.W., Woods, A.W. and Ruthan, VM. (1994). Plant Science. An introduction to would crops. U.S.A 2"d, edn. W.H. Freeman and company.
Keshinro, 0.0. (1983). Free and total folate activity in some common available tropical fruits and vegetables. Fd. Chem. 1 1 :93.
Keshinro, 0 . 0 . and Ketiku, A.O. (1 979). Effect of traditional cooking method on the ascorbic acid content of some Nigerian leafy and fruit vegetables. Fd. Chem. 4: 310.
Ketiku, A.O. (1973). Chemical composition of unripe (green) and ripe banana and plantain, J. Fd. Sci. Tech. 24:96.
Ketiku, A.O. and Olusanya, J.O. (1986). Nutrient composition of multimixes for us, as weaning foods in Nigeria. Fd. Chem.. 21 : 56.
Ketiku, A.O. (1973). Chemical composition of unripe (green) and ripe plantain (Musa paradissiaca), J. Sci. Fd. Agric. 24:707.
Kochhar, S.L. (1986). Tropical crops (A textbook of economic botany) MacMillian publishers, 560.
Ladele, O.A., ~akan ju , 0.0, and Olaofe, 0. (1984). Chemical composition of plantain (Musa paradisiacal) Nig. J. Nutr. Sci. 5:39.
Ladeji, O.O., Okoye, Z.S.C.; and Ojobe, T. (1995). Chemical evaluation of the nutritive value of leaf fluted pumkin (Telferia occidentatis). Fd. Chem. 53:355
Lancaster, P.A. and Brooks, J.E. (1983). Cassava leaves as human food. Eco. Bot. 37: 348.
Latham, M.G. (1997). Human nutrition in developing World. Rome, Fd. Nutr. Series, 315.
Latta, M. C. and Eskin, M.A. (1980). Simple and rapid calorimetric method for phytate determination J. Agric. Fd. Chem. 28:Ig.
Latande-Dada, G.O. (1990). Effects of processing on iron levels in and availability from some Nigerian vegetables. J. Sci. Fd. Agric. 53:361.
Liener, I.E. (1983). Toxic constituents of plant foodstuff. New York, Academic press 472.
Libert, B. and Franceschi, V.R. (1987). Oxalate in crop plants, J. Agric. Fd. Chem. 35:938.
Linehan, M. (1994). Assessment of food preservation activities for vitamin A nutrition. Vit. A field support programme. (VITAL). U.S.A. International life Science and technology institute. 30:25.
Marfo, E.K. Simpson, B.K., ldowu J.J., and Oke, O.L. (1 990). Effect of local food processing on phytate and oxalate levels in cassava, cocoyam, yam, maize, sorghum, rice, cowpea and soybean. J. Agric. Fd. Chem. 38:1583.
Malik, Z.R. (1967). Nutrient changes in some Nigerian foods during preparation and their effect on mammalian body, Ph.D. thesis.
Martin, F.W. and Ruberte, R.M. (1975). Edible leaves of the tropics. Mayagiiez Puerto Rico. Antillium college press. 360.
Massal, E. and Barrau, J. (1956). Banana. In Food plants of South Sea islands. Noumea, South Pacific Commission. Technical paper. 94: 18.
Maziya - Dikon, B., Akinyele, I.O., Oguntona, E.B., Nokoe, S., Sanusi, R.A., and Harris, E. (2003). Nigerian food consumption and nutrition survey. IITA. lbadan ' ~ i ~ e r i a . 49.
Meuser, F. and Smolink, H.D. (1980). Processing of cassava to gari and other foodstuffs. Starchlstarke 32: 122.
Motarjemi, V., Kaferstain, F., Moy, G. and Quevodo, F. (1993). Contaminated weaning foods. A major risk factor to diarrhoea and associated malnutrition. Bull. WHO 71: 79.
Munro, A. and Bassir, 0. (1969). Oxalate in Nigerian vegetables. W. Afr. J. Biol. Appl Chem.12:18.
NHDS (1 990). Nigerian health and demographic survey, UNICEF public. series, 25:60.
Ndubuizu, T.O.C. (1 979), Production problems and prospects. West African farming and food processing 26.Nnam, N.M. and Nwofor M.G (2001), Evaluation of the nutrient and orgenoleptic properties of pulverized baobab leaf (Adansonia Digitatal) soup. J. of Tropical Agric. Fd. Environment and Extension 2:41.
Nnam, N.M. (2000). Chemical evaluation of multimixes formulates from some local staples for use as complementary foods in Nigeria. PL. Fd. Hum. Nutr. 55: 263.
Nnam, N.M. (1994). Nutritional and orgenoleptic evaluation of fermented products and composite flours developed ;from plant foods. Ph.D. thesis, Dept. of Home Science and Nutrition, Univ. of Nig. Nsukka.
Nnam, N. M. and Nwafor, M. G. (2001). Evaluation of the nutrients and organoleptic properties of pulverized baobab leaf (Adansonia digitatal) soup. J. of tropical Agric, Fd. Environment and extension, 2: 41.
Norman, M. J. T., Pearson, C. J, and Searle, P. G. E. (1984). The ecology of tropical root crops. Cambridge University Press.
Nowordu, 1.1. (1989). Cereal - tuber composition flour in fufu formulation. Thesis, University of Nigeria, Nsukka. 50.
Oakenful, D. and Sidhu, G.S. (1 989). Saponin. In Cheeke, P.R. (ed). Toxicants of plants origin. New York. Acad. Press, 2:113.
Obiekwe, L.N. (1998). Acceptability of Maize, cocoyam, soybean and amylace rice flour (ARF) enriched weaning food and snacks. Thesis, University of Nigeria, ksukka, Nsukka. 18.
Obizoba, I.C. (1998). Fermented foods. In Osagie A.U. and Eka, O.U. (eds). Nutritional quality of plant foods, Nigeria. Post Harvest research unit. 198.
Obizoba, I.C. and Atii J.V. (1994). Evaluation of the effect of processing techniques the nutrient and antinutrient pearl millet (Pennkelum glaucum) seeds. PL. Fd. Hum. Nutr. 45:24.
Obizoba, I.C. and Egbuna, H.I. (1992). Effect of germination and fermentation on the nutritional quality of bambara nut (Vaandzeia subterranean T. Thauars) and its product (milk). PL. Fd. Hum. Nutr. 42:23.
Obizoba, I.C. and Atii, J.V. (1991). Effect of soaking, sprouting, fermentation and cooking on the nutrient composition and some antinutrient factors of sorghum (Guinesia) seeds. PI. Fd. Hum. Nutr. 41: 23.
Obizoba, I.C. and Okeke, E.C. (1986). Nutritive value of all vegetable protein diets base on legume, cereal, and tuber in weaning rat. PI. Fd. Hum. Nutr 36:2l3.
Odigbo, E.U. (1 983). Cassava, Production, processing and utilization. In chan, H.T. (ed). Handbook of tropical foods. New York, Marcel Dekkar, 200.
Odunfa, S.A. (1985). African fermented foods. From art to science. Proceeding of the IFSIUNN workshop held in Duala, Cameroon, 33.
Ogazi, P.O. (1989). Plantain utilization. In Mbah, M. and Nnanyelugo, D.O. (eds). Food crops production, utilization and nutrition. Ibadan. Dotam Publi. Ltd.
Ogazi, P.O. (1995). Plantain storage and processing, Proceedings of a post harvest conference Accra, Ghana, 11 9.
Ogbonna, C.E. (1991). Functional characteristics and chemical composition of indigenous wild herbs species, fruits and leafy vegetables used as food. M. Phil. Thesis, Rivers state University of Science and Technology. Port Harcourt, Nigeria 100.
Ogunmodede, B.K. (1983). Demand and availability of food in Nigeria. In Atinmo, T. and Akinyele, L. (eds). Nutrition and food policy in Nigeria. Nigeria. , Published by national institute for policy and strategic studies. 447.
Oguntona, T. (1998). Green leafy vegetables. In Osagie, A.U. and Eka, O.U. (eds). Nutritional quality of plant foods. Nigeria. Post Harvest research unit 133.
Oguntona, T., Oguntona, C. R. B. and Williams, L. (1989). Survey of food and nutrient intake of Kanuri of Borno, Nigeria. Savanna 10: 91.
Oguntona, T. and Oguntona, C.RB. (1986). Proximate composition of three leafy vegetables commonly consumed in Northeastern Nigeria. Paper Presented at 1'' National workshop of Food composition. University of Ibadan, Nigeria.
Oguntona, T. (1985). Loss of thiamine in some Nigerian vegetables. Paper presented at the 1'' International conference on food and health. Italy, Salsamaggiore Parma, 20.
0 ' Hair, S.K. (1995). Cassava. Tropical research and education center, University of Florida, U.S.A
Okafor, P.N. and Abara, C.N. (2003). The cyanogic potentials of some foodstuffs used as intervention for cassava cyanogens in Nigeria, Nig. J. Nutr. Sci. 24:34.
Oke, O.L. (1983). Processing and detoxification of cassava. In Delange, F. and Aliuwalia, R. (eds). Cassava toxicity and thyroid research and public health issues. IDRC, Ottawa, Canada 133.
Oke, O.L. (1969). Oxalic acid in plants and in nutrition World Rev. Nutr. Diet 1 O:3O3.
Oke, O.L. (1968). Composition of some Nigerian leafy vegetables. J. Am. Diet. Assoc. 53: 132.
Oke, O.L. (1968). Cassava as food in Nig. Rev. Nutr. Diet. 9227.
Oke, O.L. (1967). The ascorbic content of Nigerian vegetables. J. Fd. Sci. 32: 86.
Okigbo, B.N. (1986). Processing and industrial utilization of local raw material with emphasis on IlTA mandated crops. Paper presented at a meeting of manufacturers association of Nigeria. Oyo State branch of IITA. 30.
Okoh, P.N. (1993). Biochemical studies on traditional prepared foods of Northern Nigeria. M.Sc. Thesis, Ahmadu Bello University, Zaria.
Okoli, E.C.; Nmorka, 0.0. and Unaegbu, A. (1988). Blanching and storage of some Nigerian vegetables. Int. J. Fd. Sci. Tech. 23: 641.
Okorie, F.U. (1986). The study of the properties and characteristics of some tropical tuber starches. B.Sc. Thesis, Dept. of Food Science and Technology, University of Nigeria, Nsukka. 40.
Ojo, G.O. (1 969). Plantain meals and serum 5-hydroxytryptamine in healthy Nigerians. W. Afr. Med. J. 18:174.
Olayide, S.O., Emeka, J.A. and Bello Osagie, V.E. (1979). Food production in Nigeria, (Report of the agricultural statistics working party). University of Ibadan, Nigeria. 31 5.
Ologbobo, A.D. (1985). Biochemical assessment tubers of Nigeria dioscorea species. Tropical Agric. (Trinidad). 62:l68.
OMNl and USAID (1993). National micronutrient survey, Atinmo T., Department of Human Nutrition, University of Ibadan, Nigeria.
Onwueme I.C. (1978). The tropical tuber crops, yam, cassava, sweet potatoes and cocoyam, Chichester. John Wiley.
Ortiz, R.R., Ferris, S.B. and Vere, D. (1995). Banana and plantain breeding. In Gowen, S. (ed). Banana and plantain. London, Chapman and Hall, 116.
Osagie, A.U. and Onigbinde, A.O. (1998). Effect of growth, maturation and storage on the composition of plant foods. In Osagie, A U. and Eka, O.U. (eds). Nutritional quality of plant foods. Nigeria. Post Harvest Research unit. 220.
Osagie, A.U.; Muzquiz, M.; Burbano; C.O.; Cuadrado, C.; Ayet, G. and Castana, A. (1 996). Some antinutritional constituents in ten staple food items grown in Nigeria, U.K. Trop Sci. 36:115.
Osagie, A.U. (1992). The yam tuber in storage. Post Harvest Research Unit. Benin, University of Benin, Nigeria 247.
Osagie A.U. and Bafor, M.E. (1990) Triacylglycerols of oil palm (Elaeis guineensis) var, Dura mesocarp during fruit maturation. Biochem, cell Biol. 68: 313.
Oyeleke, O.A. (1984). Outline of food analysis. Dept. of Biochemistry, Zaria, Ahmadu Bello University (unpublished). 45.
Oyenuga, V.A. (1968). Nigerian food and feeding stuffs, their chemistry and nutritive value. 3rd edn. University of Ibadan, Nigeria.
Oyewole, 0.6. and Odunfa, S.A. (1989). Effect of fermentation on the carbohydrate, mineral and protein content of cassava during fufu production, J. Fd. Comp and Analy. 2: 176.
Paul, A.A. and Southgate, D.A.T. (1978). M'Cance and Widdowson's. The composition of foods, (4th edn). Ministry of agriculture, fishenes and food, HMSO, London, U.K. 420.
Pearson D. (1 976). Chemical analysis of foods. Edinburgh, J.Sc. Fd. Agric. 26: 207.
Pena, R.S. de la and Pardales, J.R., (1984). Evidence of proteolytic enzyme activity in taro, Colocasia esculenta. Symp. Int. Soc. Lima international potatoe Center Root Crops. 6:120.
Platt, B.S. (1962). Table of representive values of foods commonly used in tropical countries. Special representative service Medical research council, London, HMSO 302: 240.
Pluckett, D.L., Pena, R.S. de la and Obrero, F. (1970). Taro (Colocasia esculenta). Field crop, Abstr. 23:426.
Price, M. I. and Buttler, L. G. (1977). Detoxification of high tannins sorghum grain. Nutr. Rept. Intl. 17: 229.
Purseglove, J.W. (1991). Tropical crops. Dicotyledons. Longman scientific and Technical, U.S.A. John Wiley and Sons. 199.
Rajyalakshmi, K.; Venkatxmi, K.; Venkatalakshmamna, Y.; Jyothsna, K.; Devil, B., and Suneeth, V. (2001). Total carotenoid and beta-carotene contents of forest green- leafy vegetables consumed by tribals of South India. PI. Fd. Hum. Nutr. 5: 238.
Rice, R.P.; Rice, I.W. and Tindall, H.H. (1992). In fruit and vegetable production in Africa. London, MacMillan publishers Ltd. 85.
Richard, J.E. (1 985). Agric. 36: 176.
Physiological deterioration of cassava roots. J. Sci. Fd.
Richard, J.E. a d COI Jrsey, D.G. (1981). Cassava Storage. Trop Sci. 23:31.
Robinson, J.C. (1996). Banana and plantain. CAB International, U.K. 238.
Rodriguez-Amaya, D.B. (1 997). Carotenoids and food preparation. The retension of provitamin A, carotenoids in prepared, processed and stored foods., Opportunities for micronutrient intervention project. U.S.A. John Snow Inc. 94.
Ruel, M.T. (2001). Can food based strategies help reduce vitamin A and iron deficiency, A review of recent evidence, Washington D.C. IFPRI. 63.
Rutledge, P. (1991). Preparation procedures, In Arty, V.D. and Dennis, C. (eds). Vegetables processing. U.K. Blackie, Glasgow. 68.
Samson, J.A. (1980). In Tropical fruits. lSt edn. London Longman publishers. 86.
Scheuring, J.F.; Sidibe, M. and Frigg, M. (1999). Malian agronomic research identifies local baobab tree as source of vitamin A and vitamin C. Sight and Newsletter. 1 :38.
Schmidt, D.T. (1971). Comparative yield and composition of eight tropical leafy vegetables grown at two different fertility levels. Agron. J. 63: 550.
Selman, J.D. (1994). Vitamin retention during blanching of vegetables. Fd. Chem. 49:147.
Shaper, A.G. (1967). Plantain diets serotonin and encomyocardial fibrosis. Am. Heart J. 73:432.
Sheila, B. (1978). In Better health through good eating. Gorgi Books, 151.
Simmonds, N.W. (1976). Banana. In Simmonds, N.W. (ed). Evolution of crop plants. London, Longman 21 5.
Simmonds, N.W. (1966). Banana 2"d ed. London, Longman, 56.
Simmonds, N.W. (1962). The evolution of banana. London, Longman. 112.
Smith, I.F. (1983). Use of Nigerian leafy vegetables for diets modified in sodium and potassium. Nig. J. Nutr. Sci. 4: 27.
Smith, I.F. (1 982). Leafy vegetables as sources of minerals in southern Nigerian diets. Nutr. Rept. Intl. 26:688.
Sodipo. O.A. and Arinze, H.U. (1985). Saponin content of some Nigerian foods. J. Sci. Fd. Agric. 36: 408.
Standel, B.R. (1983). Nutritive value. In Wang, J.J. (ed). Taro a review of colocasia esculenta and its potentials. Honololo. University of Hawaii press. 147.
Steel, R.G. and Torrie J.H. (1960). Principal of procedure of statistics with special reference to biological science. New York. McGraw hill 890.
Swennen, R. (1990). Plantain cultivation under West African condition. A reference manual for international institute for Tropical agriculture. Ibadan, Nigeria. 24.
Taylor, T.G. (1975). Perspective in mineral nutrition. Proc. Nutr. Soc. 34:41.
Tang, C. and Sakai, W.W. (1983). Acridity in Taro and related plants in Aracea. In Want, J.J. (ed). Taro a review of colocasia esculenta and its potentials. Honolulu, University of Hawaii press. 164.
Temple, V.J. (1998). Lesser known plant foods. In Osagie, A.U. and Eka, O.U. (eds). Nutritional quality of plant foods. Post Harvest Research Unit 274.
Tindall, H.D (1 983). Vegetables in the tropics. London McMillan press, 86.
Tindall, H.D. and Florence, A.S. (1983). Fruits and vegetables in West Africa. FA0 plant production and protection Series. 4:12.
Udealor, A.E.; Ezulike, T.O. and Umana, R.P.A. (1987). Cocoyam in the farming systems of southeastern Nigeria. In Arena, 0. B. (ed). Cocoyams in Nigeria, production, storage, processing and utilization. Umudike, Nigeria. NRCRI, NRCC, FAD public.
Udoessien, E.I. and Ifon, E.T. (1990). Chemical evaluation of some antinutritional constituents in fair species of cocoyam. Trop. Sci. 321 19.
Udosen, E.O. and Ukpanah, U.M. (1993). The toxicants and phorosphorus content of some Nigerian vegetables. PL. Fd. Hum. Nutr. 44275.
Uguru, M.I. (1996). Crop production tools techniques and practice. Nsukka, Nigeria. Fulldu public Coy, 15.
Umoh, L.B. (1998). Commonly used fruits in Nigeria. In Osagie, A.U. and Eka, O.U. (eds) Nutritional quality of plant foods. Post Harvest research unit, Nigeria. University of Benin, 11 9.
Uwaegbute, A.C. (1 989). Vegetables, nutrition and utilization. In Mbah, B.N. and Nnanyelugo (eds). Food crops production, utilization and nutrition. Ibadan, Dotan public. Ltd. 175.
Vickery, M.1. and ;Vickery B. (1979). Plant products of Tropical Africa. London, MacMillian press Ltd. 50.
Wang, J.K. (1983). Taro, A review of colocasia esculenta and its potentials. Honolulu, University of Hawaii press, 124.
West, C.E.; Pepping, F, and Temalilwa, C.R. (1988). The composition of foods commonly eaten in East Africa. Wageningn Agricultural University, The Netherlands.
WHO (2000). Iron improves life. The micronutrient initiatives, World Health Organization Geneva. 15.
WHOINUTII 998). Complementary feeding of young children in developing countries: a review of current scientific knowledge. Geneva 42.
WHO (1996). Fermentation, assessment and research report of a FAOIWHO workshop on fermentation as a household technology to improve food safety. Pretoria South Africa. WHOlFNUIFOSlGeneva, 38.
WHO (1995). Trace elements in human nutrition and health. Geneva. 127,
WHO (1 982). Control of vitamin A deficiency and xerophthalmia Report of a Joint WHOIUNICEF Technical report services, 672:467.
Wijmeerschran, P. (1986). Root crops production in Tanga. FA0 in association with South Pacific commission, Suva, Fiji, Field document, 13:80.
Woox-lseum and Flores (1961). Food composition for use in Latin America, 30.
Yanrong, W. and Shenquan, Y. (1986). Chinese cooking. Zhaohua Publi. House, Beijing. 50.
APPENDICES
Detailed procedure for analysis; all analysis were in triplicate.
APPENDIX 1
Crude protein determination:
The micro-Kjeldahl method (AOAC, 1995) that involved digestion
distillation and titration was used in determining the crude protein content of the
samples.
Digestion:
I g of each sample was weighed into a 100ml kjeldahl flask
2.5g anhydrous sodium sulphate, 0.5g copper sulphate (catalyst) and 5ml
of concentrated sulphate acid were added.
The flask was then placed on a heater in a fume chamber and heated
gently initially until the solution turn black, the heat was increased to get a
clear solution.
This was then cooled, washed and transferred into a 250 volumetric flask and
rinsed down with distilled water.
Distillation:
A combination of boric acid and methyl red indicator was poured into a
conical flask and placed under a condenser in such a way that the
condenser's tip was under the liquid.
5ml of the digest plus 10ml of 60% concentrated sodium hydroxide were
put in a Markham Distillation Apparatus.
Steam were let down through the distillation apparatus for 5mins.
Ammonia was evolved which changed the colour of the indicator from
purple to green, characteristics of alkaline gas.
Titration:
The distillate was titrated with a 0.1 hydrochloric acid (HCL) until a neutral
point was reached (weight purple).
Titre value (T) = final biuret reading - initial biuret reading.
% crude protein (14.01 x 0 . 1 ~ 100 x 6.25) x T
1000mg
where 14.01 = atomic wt. Of nitrogen crude protein determination
0.1 = molarity of acid
100 = percent
6.25 = conversion factor of nitrogen to protein
T = titre value
Fat determination:
Fat was estimated by the Soxhlet extraction procedure (AOAC, 1995).
Two (2) gm of sample were weighed into dry soxhlet thimble.
The thimble was suspended in a beaker and dried to a constant weight in
an oven and placed in a soxhlet condenser containing ether.
A reflux condenser was attached to the extraction tube and heated, the
ether returned to the flask with fat when the thimble was full.
The extraction continued for about 6 hours at 120°C
The flask and fat were dried in air to vaporize the ether, and weighed to a
constant weight
Fat was washed off with a fat solvent, the flask was dried and weighed
again.
% fat = XI - X Z x 100 W 1
Where x2 - - final weight of flask
x1 - - initial weight of flask
W = weight of sample
Moisture determination:
This was done by hot air oven method (Pearson, 1976).
Two (2) gm of sample were weighed into an empty aluminium dish with a
known weight.
The dish and sample were dried in an air oven at 100°C for 24 hours and
cooled in a dessicator and then re-weighed.
This process was repeated until a constant weight was obtained.
% moisture (y - Z)gm x 100
(Y - x)gm 1
Where X = weight of empty dish
Y = initial weight of dish + weight of sample
Z = final weight of dish weight of sample
Ash determination:
The ash content of the samples were determined by AOAC (1995)
method.
One (1) gm of sample was placed ;in a clean crucible of known weight.
One crucible was then placed in a muffle furnace (600°C) over night (or
24 h).
The crucible and content were cooled in a dessicator and weighed again.
Where X = weight of crucible
Z = weight of crucible and ash
Crude fibre determination:
The crude fibre content of the samples were determined by AOAC (1995)
method.
Two (2) gm of the sample was put in a 250ml beaker, boiled for 30
minutes with 100ml 0.12M H2S04 and filtered through a funnel.
The filtrate was washed with boiling water until the washing was no longer
acidic.
The solution was boiled for another 30 minutes with 100ml of 0.0120M
sodium hydroxide solution, filtered with hot water and methylated spirit
three times.
The residue was transferred into a crucible and dried in the oven for I h.
The crucible with its content was coded in a dessicator then weighed (W2).
This was taken to a furnace for ashing at 600°C for I h.
The ashed sample was removed from the furnace after the temperature
had cooled and put into a dessicator and later weighed (W3)
The crude fibre content was obtained between the weight before and after
incineration. The percentage of crude fibre was calculated thus:
APPENDIX 2
CAROTENIODS (RS) (U-V-SPECTROPHOTOMETRIC METHOD)
Regents
cyclohexane
Caroteniods (RS).
Principle
The principle is based on the use of u-v-spectrophotometric method after
washing with cyclohexane.
Method
Dissolve the sample or a prepared portion in cyclohexane such that it
contains 9-15 units per ml and obtain the wavelength of maximum absorption.
Measure the extinctions at the wavelengths and calculate as fractions relative to
that at 328nm.
Calculate the E'" I c m figure at 328nm if the wavelength of maximum absorbtion
is 326-329nm and the observed relative extinctions are within 0.02.
Calculation:
Potency (unitslg) = 1900 x El" I c m at 328nm
The ollowing correction can be applied, if the maximum lies in the same range
but the relative extinctions are not within 0.02. E238 (corrected) = 3.52(2E328 -
E316 - E340).
Folate determination:
The determination of folic acid was done using the method described by
Pearson (1 976).
Two (2)mg of the sample were dissolved with 50ml of 3% potassium
phosphate.
(K2 Po4) of pH 6.8.
The solution was allowed to stand for 30 mins and centrifuged at 10,000
pm for 15mins.
The sample was diluted to an eluted concentration with k2 PO4 and
absorbency read at 256nm
Folate (mg) = absorbency x dilution x volume Extinction co-efficient (580)
APPENDIX 3
Determination of antinutrients and food toxicants:
Saponin determination:
O.lg of the sample was boiled with 50ml diluted water for 15 minutes and filtered
with Whatman No.1 5ml of the titrate was pipetted into a test tube and 2ml of
olive oil was added. The solution was shaken vigorously for 30 seconds and
read at 620nm against a blank.
Calculation
Saponin = reading from curve x dilution factor x 100(m~/1'00qZ Weight of the sample x 10
Oxalate determination:
Two (2)g of the sample was put into 300ml flask. 20ml of 30% HCL was
added and allowed to stand for 20 minutes. 4.0g of ammonium sulphate was
added and the solution was filtered into 250ml volumetric flask and made up to
the mark with 25ml 30% HCL.
10ml of the filtrate was transferred in 100ml centrifuge tube, 30ml of
diethyl ether was added and pH was adjusted to 7.0 with either NH40H
(ammonium hydroxide) or CH3CooH (acetic acid). It was centrifuged at 10,000
rpm for 15 mins. The supernatant was decanted into 250ml flask and was
titrated with O.lm potassium tetraoxomanganat (KMn04) and volume was
recorded.
Calculation
Oxalate - - Titre x molk Mn04 x dilution factor x 100 Weight of ihe sample
Cyanide determination:
Five (5) gm of sample was introduced into 300ml volumetric flask. 160ml
of 0.1M orthophosphoric acid and homogenize for 15 minutes at low speed and
made up the mark. The solution was centrifuged at 10,000 rpm (revolution per
minute) for 30 minutes. The supernatant was transferred into a screw cap bottle
and stored at 40°C.
5ml 'aliquot of the extract was transferred into quick fit stoppered test tube
containing 0.4ml of 0.2m phosphate buffer pH7.0. 10ml of diluted linamarase
enzyme.was added. The tube was incubated at 30°C for 15 minutes and the
reaction was stopped by addition of 0.2M NaOH (0.6ml). The absorbance of the
solution was measured using suitasce spectrophotometer at 450nm against
blank.
Calculation:
Cyanide = absorbance x dilution factor x 100 (mg1100g) Extinction coefficient
Extinction coefficient (r 11450) = 2550.
Tannin determination
Reagents
0.1 M Fech2 in O.IN HCL
0.008M. K3Fe(CN)6
Tannic acid standard solution
Tannic acid standard solution was made by dissolving O.lg tannic acid in
100ml water.
Standard curve: Serial dilution was made in the test tubes a follows; 0.01, 0.02,
0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.011, 0.012, Blank was also made
to zero the spectrophotometer. 3ml of 0.008m K3Fe(CN)6 were added to the
serial dilution solution.
Sample reading: 10ml of 2M HCL methanol was added to 0.5g sample in a
conical flask and shaken for 5 minutes. The content was quantitatively
transferred into 50ml volumetric flask and made up to the mark filtered. 5ml of
the filtrate was transferred into test tube, 3ml of 0.1M FeCI3 in O.IN HCI and 30MI
of 0.008M potassium ferrocyanide (K3 Fe (CN)6) were added to it. It was allowed
to stand for 3 minutes and read within 10 minutes at 500nm against blank.
Read the concentration of tannin from the calibration curve.
Calculation:
Tannin = reading from the curve x dilution factor x 100(mg/100g) Original weight x l o 6
APPENDIX 4
Statistical procedure of Steel and Torrie (1 960).
Where C x * = 0 (mean) Squared and all added together
(CX)~/N = Multiply Cx (Sum of values) by itself then divided by the
number
Ex = Sum of values (Square)
0 = mean
N = number
S = Standard error
SD = Mean + standard error