FOOD COMMODITIES  

NTD 201 (3 UNITS)

Course requirements:

CAT: 30% Exam: 70%

Class attendance compulsory

*Contact Lecturer ahead of time if any cogent reason will keep you away from lectures.

Present medical reports if absence from lectures/CAT was due to ill health.

Sanni, S. A. , PhDDepartment of Nutrition & Dietetics

University of AgricultureAbeokuta

SynopsisFood ClassificationMarket SurveysFood Selection & purchasingUses of FoodsFoods and Food tablesCereals, Starches & starchy foods, Sugars, Pulses, nut and seedsVegetables and fruitMeat, fish etc.Infective agents in foodNatural food toxins

Food DefinedFood is any substance that is consumed to

provide nutritional support for the body, possibly to the point of excess.

It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals.

The substance is ingested by an organism and assimilated by the organism's cells in an effort to produce energy, maintain life, and/or stimulate growth.

Food Classification

Food Selection & purchasing The types of food you select depends on: the money you have your nutritional needs and the effect of advertisements Now let us examine each of these factors and see how they influence our selection

or choice of food! Nutritional needs Your food choice will also depend on your need for food. Everyone has a biological

need for food. It is essential for life without food one becomes weak and ill. People vary in the amount of food they need for reasons like health, age and activity.

Your choice of food will therefore depend on each of these factors. Your nutrition knowledge helps you to choose food that provides the necessary nutrients to meet your needs.

Food Purchasing Food purchasing can be a boring or interesting adventure depending on one’s

approach to it. To make food purchasing interesting you have to know much about the market place and ways in which you can make the most out of your food budget.

Now let us look at some of the things you can do to avoid waste of your time and money when purchasing food.

First of all you need to know the factors that determine the cost of the things you want to purchase.

Foods and Food tables-------------------Carbohydrates------------------- Fats Proteids

Foods Rich in

Mineral SaltsChocolate Honey Vegetables - Butter Cheese Vegetables -

Fruits - Nuts - Asparagus Cheese Eggs Asparagus

Dates Chestnuts Bananas Chocolate Fish Beet-tops

Figs Peanuts Beets Cream Legumes - Cabbage

Grapes Pignolia or Cabbage Nuts - Beans - dried Carrots

Persimmons pine nuts Carrots Almonds Lentils - dried . Celery

Raisins Sirups Celery Brazil-nuts Peas - dried Dandelion

Grains - Sugar Lettuce Cocoanuts Milk Green peas

Barley Tapioca Onions Hickory- Nuts - Lettuce

Corn Parsnips nuts Peanuts Onions

Oats Potatoes - Peanuts Pignolia or Radish-tops

Rice sweet Pecans pine nuts Romaine

Rye Potatoes - Pignolia or Poultry Spinach

Wheat white pine nuts Vegetables - String beans

Pumpkin Walnuts Cabbage Turnip-tops

Spinach Oils - Lettuce Watercress

Squash Cottonseed Onions Wheat bran

Turnips Nut-oil Spinach

Olive-oil Turnips

Wheat bran

CEREALS

Cereals are the edible seeds or grains of the grass

family.

There are many different types of cereal grains, each

having unique properties.

Most cereals are processed to form other foods or

ingredients. Cereals and cereal products are an

important source of energy, carbohydrate, protein

and fibre. They also contain a range of

micronutrients such as vitamin E, some of the B

vitamins, sodium, magnesium and zinc. Wheat and

rice are the most important cereal crops world-wide

as they account for over 50% of the world’s cereal

production.

TYPES OF CEREALS

Wheat: is usually ground to flour which is used to produce a

wide range of products. The type of flour produced differs

according to the rate of extraction. Couscous and cracked

wheat or bulgur is also made from wheat. Wheat can be

fermented to make beer.

Maize: (or corn) may be processed to make many different

ingredients (e.g. high fructose corn syrup which can be used as

an alternative to sucrose derived from sugar cane and sugar

beet) and food products. It may be milled in a similar process to

wheat. Its germ is rich in oil, and can be refined to produce

corn oil.

Barley: is mainly sold as pearl barley, which is the whole grain

with its husk removed. It is also used in bread (as flour) and

ground as porridge in some countries.

Rice: brown rice has its outer husk removed, and white rice is

milled and polished further to remove the bran and germ. There

are many different types of rice, categorized by size, shape and

the region where they are grown. Rice can be ground to make

flour and is used to make Japanese rice wine (saké).

Rye: contains little gluten, so produces breads with low volume

and a dense texture, although in Russia, Poland, Germany and

Scandinavian countries it is the major bread grain. Rye is also

used to produce crisp bread and alcohol.

Oats: are rolled rather than crushed during processing.

Coarse, medium and fine grades of oatmeal are available and

are used for porridge and oatcakes, while rolled oats are used

for porridge, and oat flour is used for baby foods and for ready-

to-eat (RTE) breakfast cereals.

Millet: is the name used for a number of different small-

grained cereal grasses, e.g. pearl, finger (or ragi), proso and

foxtail millet. These crops are important in parts of Africa and

Asia.

Sorghum: (also known as great millet, guinea corn, kafir corn,

jowar and kaoling in different parts of the world) is a staple

food in many parts of Africa, Asia and parts of the Middle East.

It is also used as animal feed in many other countries.

NUTRITIONAL VALUE OF CEREALS AND CEREAL PRODUCTS

Cereals and cereal products are an important source of energy,

carbohydrate, protein and fibre.

They also contain a range of micronutrients such as vitamin E, some of

the B vitamins, sodium, magnesium and zinc. Because of the

fortification of some cereal products they also contribute significant

amounts of calcium and iron.

There is evidence to suggest that regular consumption of cereals,

specifically whole grains, may have a role in the prevention of chronic

diseases. The strength of evidence varies and although cause and

effect has not currently been established, people who consume diets

rich in whole grain cereals seem to have a lower incidence of many

chronic diseases, e.g. coronary heart disease and type 2 diabetes.

It remains to be established whether this is a direct effect, or whether

whole grain consumption is merely a marker of a healthy lifestyle or

some other factor.

   

Structure of the maize kernel (caryopsis)

Essential Amino Acid Content of Cereal ProteinsEssential Amino Acids

Percentage content

Rice Corn Wheat

Arginine 8.40 9.36 24.06

Histidine 2.60 0.75 7.89

Isoleucine 4.50 0.80 0.00

Leucine 8.40 31.22 33.91

Lysine 3.50 6.71 5.88

Methionine 2.50 2.35 4.84

Phenylalanine 4.50 9.34 8.40

Threonine 3.90 2.90 2.00

Tryptophan 1.20 2.07 8.14

Valine 6.50 1.88 3.85

ROOTS AND TUBERS

Roots are plant materials which edible portions grows under the soil

but the stem serve as planting materials, while tubers are thick parts

or swollen parts of an underground stem bearing small buds from

which new plants can be formed. Roots and tubers belong to the class

of foods that basically provide energy in the human diet in the form of

carbohydrates. The principal root and tuber crops of the tropics are

cassava (Manihot esculenta Crantz), yam (Dioscorea spp.), sweet

potato (Ipomoea batatas L.), potato (Solanum spp.) and edible aroids

(Colocasia spp. and Xanthosoma sagittifolium). They are widely grown

and consumed as subsistence staples in many parts of Africa, Latin

America, the Pacific Islands and Asia. The increased use of major roots

and tubers – cassava, potato, sweet potato, and yam, for food and

livestock feed in developing countries will have wide-ranging effects on

global public- and private-sector policies and investments. Roots and

tubers will continue to play a significant role in developing-country

food systems because they:

a. contribute to the energy and nutrition requirements of

more than 2 billion people;

b. are produced and consumed by many of the world’s

poorest households;

c. are an important source of employment and income in

rural, and often marginal, areas, especially for women,

and

d. d.adapt to a wide range of uses, from food-security crops

to cash crops, raw material for industrial uses, and from

fresh to high-end processed products.

Roots and tubers together constitute a significant share of the

total volume and value of horticultural crops worldwide. These

commodities are particularly important as a source of food,

employment, and income in developing countries where the

bulk of the world's producers, processors, and consumers

reside. In this new millennium, roots and tubers will play

Cereals and oil seeds Roots and tubers

1.Low moisture content, typically 10% to 15%

High moisture content, typically 70% to 80%

2. Small unit size, typically less than 1 gram

Large unit size, typically 100 grams to 15 kg

3. Very low respiration rate with very low generation of heat. Heat production is typically 0.05 megajoule/ton/day for dry grain

High respiration rate. Heat production is typically 0.5 to 10 megajoules/ton/day at 0°C to 5 to 70 megajoules/ton/day at 20ºC

4. Hard texture Soft texture, easily bruised

5. Stable, natural shelf life is several years

Perishable, natural shelf life is a few days to few months

6. Losses usually caused by moulds, insects and rodents

Losses usually caused by rotting (bacteria and fungi), senescence, sprouting and bruising

Chemical Composition of some Tropical Roots and TubersCommodity

Dry Crude Ether Total Energy Ascorbic Calcium Phosphorus Fe Matters Protein extract ash acid (g) (g) (g) (g) (cals) (mg) (mg) (mg) (mg)

Cassava

31.94

2.71 0.53 2.66 390.0 35.0 10.0 35.0 0.50

Yam 26.17

5.87 0.46 4.30 385.9 17.0 18.9 40.7 0.48

Cocoyam(Taro)

26.52

8.66 0.71 4.83 376.4 14.0 24.0 53.6 0.72

Cocoyam(Tannia)

24.89

7.85 0.70 5.22 382.6 10.0 6.0 360.0 0.70

Sweet Potato

28.08

5.36 0.33 3.15 391.0 26.2 16.6 31.0 0.83

Pulses (Legumes)Legumes are widely distributed world- wide and generally referred to as pulses. Every zone of

the world has some legumes peculiar to them.

For example, in France, groundnuts are found, in South America, lima and runner beans, in the United States, soya beans and in Africa, cowpeas, bambara nut, broad beans, in India, lentils and chick peas etc.

The fruit is a pod containing seeds ranging generally from 2-10 seeds. There are two main types of legumes, viz :

I. Those containing high protein and high oil content.

II. Those containing moderate protein and low oil content.

Examples of the first group include soya bean, groundnut, lupin and winged beans. The protein content is as high as 35% while oil content vary from 15 - 45%.

Examples of the second group include cowpea, gram, pea, bambara groundnut, lentil and the different varieties of the phaseolus group. The protein content is in the range of 25- 30% while the oil content is less than 5%.

Legumes are generally high in B vitamins but low in sulphur containing amino acids, methionine and cystine. They have high content of lysine which makes legumes a good complement to cereals (cereals are low in lysine but high in methionine).

Legumes have some nutritional disadvantages apart from being deficient in methionine and cystine. These are of low digestibility and the consumption of high proportion of legumes in the diet can cause flatulence. Some legumes contain toxic substances which interfere with normal enzymic reactions.

Composition of some LegumesLegumes Moisture Energy Protein Fat Total

(g) (KJ) (g) (g) Carbohydrates(g)

Bambara groundnut

10 1550 20 6 60

Black eye Beans(raw)

13 1360 23 1.5 58

(Decorticated) 30 1080 20 1.2 44

(Moi- moi) 70 500 7 2 20

(Akara) 60 920 9 15 14

Black gram (Urad dahl)

10 1450 24 1.5 60

Chick pea (Bengal gram)

11 1360 20 5.6 60

Humous (Chick pea paste)

60 770 8 13 11

Groundnut (Dry) 5 2570 26 48 20

Lentil (Masar dahl

12 1300 20 0.6 65

Lima (Butter) Bean

12 1162 20 1.5 58

Mung Bean 12 980 22 1.0 35

(Sprouts) 90 146 3.8 0.2 6

Pea 78 280 5.8 0.4 11

Soya Bean 10 1700 40 20 20

Winged Bean 10 1700 33 17 37

Composition of some FruitsCommodity

Water(%)

Energy(cal)

Protein (%)

Fat(%)

Carbohydrate (%)

Ascorbic acid (%)

Calcium (%)

Phosphorus (mg)

Vit. A (i.u)

Fruits

Banana

75 86 1.1 0.2 24 10 8 26 190

Pineapple

85 65 0.4 0.4 15 110 20 11 30

Mango

83 63 0.6 0.1 15 30 10 10 180

Guava 80 58 1.0 0.4 13 200 15 33 200

Orange

86 49 1.0 0.2 12 50 41 20 200

Lemon

85 58 1.0 0.9 11 43 40 22 -

Cashew apple

85 - 0.7 - 13 250 10 - 150

Pawpaw-ripe

81 40 0.5 0.6 10 110 16 8 2200

Commodity

Water(%)

Energy(cal)

Protein (%)

Fat(%)

Carbohydrate (%)

Ascorbic acid (%)

Calcium (%)

Phosphorus (mg)

Vit. A (i.u)

Onions

89 38 1.5 0.1 9 10 27 56 40

Carrot 88 42 1.1 0.2 10 51 37 36 11000

Spinach

91 26 3.2 0.3 5 51 93 51 8100

Cabbage

92 24 1.3 0.2 4 47 49 29 130

Pepper

92 22 1.2 0.2 4 125 9 22 420

Tomato

93 22 1.1 0.2 5 30 13 27 190

Composition of some Vegetables

Composition of Meat and Meat ProductsType % Composition of Edible Portion

Water Protein Fat Ash Carbohydrate

Beef (medium fat) 60.0 17.5 22.0 0.9 -

Veal (medium fat) 66.0 18.8 14.0 1.0 -

Pork (medium fat) 42.0 11.9 45.0 0.6 -

Lamb (medium fat)

56.0 15.7 27.7 0.8 -

Chicken 66.0 20.2 12.6 1.0 -

Duck 52.8 16.2 30.0 1.0 -

Turkey 58.3 20.1 20.2 1.0 -

Fish (fillet non fat) 81.8 16.4 0.5 1.3 -

Fatty fish fillet 68.8 20.0 10.0 1.4 -

Crustaceans 79.3 14.6 1.7 1.8 2.6

Dried fish 4.0 60.0 21.0 15.0 -

Milk (cow) 87.3 3.5 3.5 0.7 5.0

Cheese (hard) 37.0 25.0 31.0 5.0 2.0

% Composition of Raw Fish FleshLean Fatty

Water 80 60-80

Protein 16-18 16-18

Lipids 0.5-2.0 5-20

Extractives(salts glycogen, amino acids

0.5-2.0 0.5-2.0

Mineral content 1.0-1.5 1.0-1.5

Lean: cod, haddock, whiting, rockfish, sole

Fatty: Salmon, mackerel, trout, butterfish

Infective and Toxic Agents in FoodsThere are more than 200 known diseases that

can be transmitted through food, however, and the known causes of food poisoning include infective agents and toxic agents.

Infective agents include viruses, bacteria, and parasites.

Toxic agents include poisonous mushrooms, improperly prepared exotic foods (such as barracuda), or pesticides on fruits and vegetables.

Sources of Food ContaminationFood usually becomes contaminated with

these agents from poor sanitation or preparation. Food handlers who do not wash their hands after using the bathroom or have infections themselves often cause contamination.

Improperly packaged food stored at the wrong temperature also promotes contamination.

Three of the most important causes of food poisoning are the salmonella, clostridium botulinum and staphylococcal organisms.

Further ReadingsCollingham, E. M. The Taste of War: World War

Two and the Battle for Food (2011)Marion Nestle: Food Politics: How the Food

Industry Influences Nutrition and Health, University Presses of California, revised and expanded edition 2007, ISBN 0520254031

Katz, Solomon. The Encyclopedia of Food and Culture, (Scribner, 2003)

http://en.wikipedia.org/wiki/Foodhttp://www.healthscout.com/ency/68/676/

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