OUMH1303

Table of Contents

1.0 Introduction to fruit jam.........................................................................................................3

1.1 Health benefit of fruit jam.....................................................................................................3

2.0 Introduction to food jam manufacturing...............................................................................4

2.1 Fruit Preparation...................................................................................................................5

2.2 Pasteurizing .........................................................................................................................5

2.3 Cooking and boiling ............................................................................................................6

2.4 Filling .............................................................................................................................6&7

2.5 Labeling and packaging.......................................................................................................7

3.0 Raw materials...........................................................................................................................8

3.1 Pectin....................................................................................................................................8

3.2 Sugar ..............................................................................................................................8&9

3.3 Citric acid ............................................................................................................................9

3.4 Preservatives and other addictives ...............................................................................9&10

4.0 Quality control and hygiene..................................................................................................10

5.0 Summary.........................................................................................................................10&11

References

Page 1 of 11

OUMH1303

INTRODUCTION

1.0 Introduction to Fruit Jam

In general, fruit jam is a type of fruit spread made by boiling fruit with sugar to make an

unfiltered jelly. Jam is often spread on bread and is suitable for everyone to consume at

anytime during breakfast and tea time. Besides, it can also act as a culinary sweetener in other

food product such like yogurt.

Fruit jam may made from practically all varieties of fruits and consumer can choose from the

more conventional types such as apple jam, orange jam, or other more exotic types like

blackberry jam and passion fruit jam.

Fruit jam is increasing importance in many countries, especially in wealthy urban areas. The

suitability for small-scale production offer entrepreneurs a promising business.

1.1 Health Benefits of Fruit Jam

There are a lot of people who love eating gourmet jams. The jam taste superbly awesome and

also contain many nutritional health benefits.

Undoubtedly, fruit is cholesterol-free and naturally low in sodium and calories. It is a vital

source of many nutrients, including Vitamin C, folic acid, dietary fiber and potassium. In

addition, fruit also has a positive effect on our brains at which it can stimulate our memory

and quick boosts of energy for our body.

The other advantages of consuming fruit jams are listed as below:

1. Improve the health of hair, skin and finger nails.

2. Reduce one’s chance of developing type 2 diabetes

3. Promote healthy growth and repair of all body tissues.

4. Reduce the risk of kidney stones.

5. Keep teeth and gums healthy.

6. Help the body form red blood cells

7. Slow down aging process.

Page 2 of 11

OUMH1303

2.0 Introduction to Fruit Jam Manufacturing

Nowadays, most of the manufacture of jams and jellies is largely commercial. There are a

number of important steps in jam processing which will be discussed in the following

sections. First of all, the fruits are prepared according to the desired type of product. Next, the

fruits undergo pasteurizing technique. This is followed by cooking and boiling of fruits,

which are considered as the most important processes in jam processing. Subsequently, the

fruit jam is being cooled and filled. Last but not least, the fruit jam products are being sent for

labeling and packaging.

Figure 1: Flowchart of Jam Processing

Page 3 of 11

Raw Material Preparation

Pasteurization of Fruits

Cooking and Boiling

Cooling

Filling

Labeling and Packaging

Sugar and Additives

Water

OUMH1303

2.1 Fruits Preparation

The first step in fruit jam processing is to prepare the fruits, based on the type and quantity of

final product. Fruits for jam making should be fully mature, possess a rich flavor and be of

the most desirable texture.

Firstly, the fruits are inspected for quality when they arrive at manufacturing plant, by using

color, ripeness, and taste as guides. The fruits that go through inspection process are then

loaded into a funnel-shaped hopper that carries the fruit into pipes for cleaning and crushing

process. They are then being washed thoroughly in clean water to remove any adhering dirt.

In case of fruit that has been sprayed with lead or arsenical sprays, it should be washed in a

warm solution of 1% hydrochloric acid and then rinsed in water (Isabel D.W, 2009).

For berries jam, all berries must be carefully sorted and washed. For instance, strawberries

must be stemmed; peaches, apples, pears and other fruits with heavy skin must be peeled,

whereas stone fruits such as apricots and fresh prunes can be pitted by machine. They require

a very heavy pulping screen because of abrasive action of the pits. Berries should not be

softened by boiling before the addition of sugar, but need only to be crushed (Janne Clarke,

2008).

After fruit preparation is done, accurate scales are needed to ensure that the correct amounts

of ingredients are used. Normally two sets of scales are needed; one with a large capacity for

sugar and fruit and another smaller set for pectin and citric acid.

2.2 Pasteurizing

Subsequently, the fruits will pass through another set of pipes to cooking vats. Here, they are

heated to just below the boiling point (100°C) and then immediately chilled to just below

freezing (0°C). This process is known as pasteurization technique. With the use of ultrahigh

pressurization pasteurization, the pressure treatment destroys the cellular integrity of

microorganisms without detrimentally affecting heat labile flavor compounds, vitamins and

other essential compounds (Hui Y. H, 2006).

The advantage of pasteurization of fruits is that it slows down microbial growth within fruit

products. As a result, it has a longer shelf life and can be kept without refrigeration. The

incidence of disease such as E Coli infection, gastroenteritis, listeria infection which can

cause miscarriage can be reduced through pasteurization process too.

Page 4 of 11

OUMH1303

2.3 Cooking and Boiling

Cooking and boiling are the most vital steps in the jam making process, as it dissolves the

sugar and causes union of the sugar, acid, and pectin to form the desired product.

Here, pre-measured amounts of fruits, sugar and pectin are blended in industrial cooking

kettles, usually open steam jacketed stainless steel kettles. The mixtures are usually cooked

and cooled three times. If additional flavorings are to be included, they are added at this

point. When the mixture reaches the predetermined thickness and sweetness, it is pumped to

filling machines.

The principal purpose of boiling is to increase the concentration of the sugar to the point

where gelling occurs (Ashish Kumar, 1988). The boiling operation, while normally being a

necessary step in jelly making, should be as short as possible. Prolonged boiling results in

loss of flavor, change in color, and hydrolysis of the pectin; this situation will lead to jam

failure.

During boiling, the juice or pulp should be skimmed, if necessary, to remove coagulated

material and should be stirred to cause thorough mixing. The boiling is continued until on

cooling, the product will form a jam or jelly of the desired consistency.

2.4 Filling

Next, the finishing of jams usually comprises of three major steps, namely pre-cooling prior

to filling, filling process and cooling after filling process.

Prolonged heating affects the appearance and the keeping quality of the finished product. As

the inversion of sugar is greatly influenced by the temperature, it is obvious that an efficient

cooling system is necessary to control and check the process. Difficulties are also

experienced in filling, as some fruit varieties show a tendency to float, the most susceptible

being strawberry, cherry, black currant, and stone fruit jams. These jams should be cooled

until they are near setting point, but great care must be taken not to exceed the limit,

otherwise the set will break and the jam curdles, more so in the case of jellies (Rauch G.H,

1965).

Nowadays, the manufacturers usually fill up the jam into pre-sterilize jars by using roller

conveyor. After being filled, jam in jars must not be cooled too quickly.

Page 5 of 11

OUMH1303

Then, the cans are being passed through a water bath. Glass jars and large containers have to

be cooled by slowly through a tunnel fitted with an air blast or keeping them in a cooling

room constructed on the same principle until the jam is well set. Automatic filling machines

that measure a definite volume of jelly into each container are in general used in large

factories to reduce the cost of filling as compared to that of hand filling.

Sterilization of jars, lids and filling equipment can be done in a 225ºF oven for 10 minutes or

by boiling water for 15 minutes. The sterilized jars are then kept in the oven until needed,

with heat turned off, so they stay warm.

2.5 Labeling and Packaging

The final stages of the production process are labeling and packaging. The sealed jars are

conveyed to a machine that affixes pre-printed labels. According to law, these labels must list

all detailed and truthful information about the product contents and printed expiry date.

Sample label printed on fruit jam products is depicted in Figure 2 and Figure 3. Lastly, the

jars are then packed into cartons for shipment.

Figure 2: Sample Labeling of Fruit Jam

Figure 3: Sample Labeling of Fruit Jam

Page 6 of 11

OUMH1303

3.0 Raw Materials

In jam processing, there are a few fundamental raw materials that are required. First and

foremost, jams are made from a variety of fruits. The fruits can be chosen in combination or

in single type, depending on the desired flavor of final product. Most of the fruits are

harvested in the fall. Basically, the level of ripeness for the fruits varies. For example, it is

best to pick strawberries, apricots, peaches and rasberries when they are slight under-ripe.

Meanwhile, cherries and plums are best if picked when they are just ripe.

Usually for commercial jam processing, the fruits are purchased from the farmers. Most jam

manufacturers maintain close relationships with the farmers in order to ensure the freshness

and good quality of fruits. The production plants are normally built close to the fruit farms so

that the time elapsed between harvest and preparation is between 12 to 24 hours.

3.1 Pectin

In general, pectin is known as a natural fiber found in plant cell walls and most concentrated

in the skin of fruits. It is water-soluble and binds with sugar and fruit acid to form a gel.

Adding pectin in jam processing shortens the cooking time and resulting in a fresher fruit

flavor. Using pectin can eliminate the long boil method at which it has the extra benefit of

yielding up to 50% more jam from a certain amount of fruit.

Commercial pectin is usually made from apple and citrus fruit waste. The amount of pectin

varies from fruit to fruit. Besides, it depends on the stage of ripeness and the growing season

weather as well. Normally little pectin is used for fruits that are more ripe, such as pears,

peaches, strawberries, sweet cherries and overripe fruit.

Pectin can be used to achieve the desired gelled structure of jams, jellies and marmalades.

The gelling effect depends on the degree of etherification of the applied pectin. Furthermore,

pectin is a harmless additive and its use for jams and jellies is not restricted.

3.2 Sugar

As the acid groups are relatively weak, the changes in the acidity of pH will alter the amount

of charge on the pectin chains. Pectins which can link together under acid conditions have

Page 7 of 11

OUMH1303

enough charge at lower acidity (or higher pH) to repel each other. Therefore, it requires both

sugar and acid in order to produce fruit jam.

Typically, sugar and high fructose corn syrup are added to the fruit. In fact, sugar does a lot

more than just sweeten your jams. Its main function is to work with the pectin and fruit acids

to form the gel structure that is known as jam. Moreover, adding sugar in jam processing can

prevent the degrading of vitamin C and flavorings too. The other functions of sugar in jams

including strengthening the flavor of fruits alongside increasing the gloss of jams.

Sugar also acts as a preservative that helps maintain the beautiful color of the fruit and

inhibits mould growth. Cane sugar chips are the ideal type of sugar used for preserving fruit.

The exact amount of sugar is important in jam processing. Reducing the amount of sugar will

upset the balance of fruit, sugar and pectin needed to ensure the jam or jelly sets.

3.3 Citric Acid

Citric acid is used in jam processing in order to provide tartness and to control the product pH

for optimum gelatin. On the whole, citric acid appears as an odorless white crystalline

granule with a strong acidic taste. It is very soluble in water, freely soluble in alcohol and

slightly soluble in ether (Hui Y.H, 2006).

Generally, citric acid is a constituent of fruit and soft drinks and other food products. Its main

uses include flavor enhancement, bacterial inhabitant, anti-oxidant as well as pH adjustment.

Citric acid is considered necessary to correct the balance which is needed in jam and jelly

production. Lime and lemon juice are high in citric acid therefore they can be used as a

replacement of citric acid in jam manufacture.

3.4 Preservatives and Other Addictives

Preservatives are added to prolong the shelf-life of final products by protecting them against

deterioration caused by microorganisms, such as bacteria, moulds and yeasts. Owing to the

use of preservatives, unopened products can even be kept in room temperature, and they keep

better even after opening. Meanwhile, additives are substances added intentionally to

foodstuffs to perform certain technological functions. The number of additives permitted in

jam products is limited. 

Emulsifiers (gelling agents), stabilizers and thickeners are additives used in jam processing

which might affect the structure of final products. Gelling agents produce a firm structure

whereas thickeners give a thicker consistence to liquid products. On the other hand, Page 8 of 11

OUMH1303

stabilizers soothe the structure of the product. These additives can be used in amounts

required for the desired result.

Color can be defined as one of the most important characteristics of food from consumers’

point of view. No coloring is required for jams produced from fresh fruit, provided the

boiling time is short and the heat not excessive. However, the natural color of the fruit is

always affected by process of boiling. This necessitates the addition of artificial color in order

to restore the original natural appearance. Only permitted edible food colors should be used.

4.0 Quality Control and Hygiene

In the United States, food processing regulations require than jams and jellies are made with

45 parts fruit or juice to 55 parts sugar. The federal Food and Drug Administration (FDA)

mandates that all heat-processed canned foods must be free of live microorganisms. Hence,

processing plants keep detailed lists of cooking times and temperatures, which are checked

periodically by the FDA.

Fruit jam manufacturer has to draw up a self supervision plan when starting the operation.

Typically, the self supervision plan consists of a hygiene program, a cleansing program and

an assessment of critical control points and plan concerning the supervision. Then, a self

supervision license can be granted by a local sanitary inspector. The most critical aspects in

fruit jam processing requiring strict supervision are fruit quality, canning and cleanliness of

jars and lids.

5.0 Summary

Fruit jam, which remains popular in the world, is usually made from pulp and juice of a

single or mix combination of fruits. It possesses a number of health benefits to our human

body and can be consumed by everyone. Fruit jams can be in numerous types, such as apple

jam, strawberry jam, apricot jam and so forth. Typically, the fruit content of a jam must be at

least 40% while the total sugar content must be no less than 68%.

In jam manufacturing process, there are a number of methods involved. First and foremost,

the manufacturers will prepare the fruits based on to the desired variety of product.

Subsequently, the fruits undergo pasteurizing technique and then followed by cooking and

boiling of fruits. Cooking and boiling processes are considered as the most important

processes in jam processing as they dissolve the sugar and causes union of the sugar, acid,

and pectin to form the desired product. Next, the fruit jam is being cooled and filled. Lastly,

Page 9 of 11

OUMH1303

the fruit jam products are being sent for labeling and packaging. Other than fruits, a few types

of raw materials that involved in jam processing are pectin, citric acid, sugar, preservatives

and so forth. Each of them has its own function in jam making process.

Besides, there is a number of parameter that affect the rheological behavior of fruit jams,

including pH, temperature, composition alongside the technology applied for jam

manufacturing process. As the final products are being sold to consumers, fruit jam

manufacturers must ensure their quality before shipping process is done with self supervision

plan which consists of hygiene and cleansing program as well as an assessment of critical

control points concerning their supervision.

To sum up, fruit jams can be produced in many countries around the world. Fruit jam

manufacturing remains as a strong field in food industry as it enjoys substantial shelf life and

can be made available round the year.

2670 words

Page 10 of 11

OUMH1303

References:

Ashish Kumar (1988) The effect of ingredient on the quality of confectionery jellies.

CFTRI, Mysore. Page 1-22.

Barbara H. Ingham (2008) Making jams, jellies and preserves. Retrieved June 29, 2011 from

http://www.foodsafety.wisc.edu/assets/preservation/B2909_Jams_2008.pdf

Barrett and Somogyi (2005) Processing Fruits. CRC Press UK, Page 67-79.

Cancela M.A (2005) Effects of temperature and concentration on carboxymethycellulose

with sugar rheology. Journal of Food Engineering Vol. 71, Page 419-424.

Diana Bauman (2010) Types of Pectin. Retrieved July 3, 2001 from

http://indianapublicmedia.org/eartheats/pectin-naturally-sweetening-jam-jelly/

Fishman L and Jen J (1986) Chemistry and functions of pectins. ACS Symposium Series 310,

Washington DC, Page 321-332.

Fugel et al. (2005) Quantity and authenticity control of fruit puree, fruit preparation and jams.

Food Technology International, Europe, Page 35-36.

Guerrero S.N and Alzamora S.M (1998) Effect of pH, temperature and glucose addition on

flow behaviour of fruit purees. Journal of Food Engineering Vol. 33, Page 239-256.

Holm K. et al. (2009) Sweetness and texture perceptions in structured gelatine gels with

embedded sugar rich domains. Food Hydrocolloids Vol.23, Page 2388-2393.

Hui Y.H (2006) Handbook of Fruits and Fruit Processing. Blackwell Publishing, USA.

Isabel D.W (2009) Fruit preparation methods. Retrieved June 29, 2011 from

http://www.extension.umn.edu/distribution/nutrition/dj1088.html

Janne Clarke (2008) Benefits of fruit jam. Retrieved July 9, 2011 from

http://www.articlesbase.com/nutrition-articles/fruits-jam-makes-your-breakfast-healthier-

622632.html

Nindo C.I et al. (2007) Rheological Properties of Blueberry Puree for Processing

Applications. Food Science and Technology Vol. 40, Page 292-299.

Pelegrine D.H et al. (2002) Rheological Behavior of Pineapple and Mango Pulps. LWT Vol.

35, Page 645-648.

Rauch G.H (1965) Jam Manufacture. Leonard Hill Books, London

Page 11 of 11