Preparation of Fruit Jam

 Aim:   Preparation of Fruit Jam

 

Raw materials, equipment and apparatus

1. Fruit/vegetable, sugar

2. Peeler

3. Pulper

4. Filter cloth / sieve

5. Pans of suitable size

6. Heaters

7. Volumetric flask

8. Weighing balance

Chemicals and reagents

1. Citric acid / ascorbic acid
2. Potassium metabisulphite (KMS)
3. Sodium benzoate

Theory:

Jam: Jam is prepared by boiling whole fruit pulp with cane sugar (sucrose) to a moderately thick consistency with out retaining the shape of the fruit.

Or

            Jam is a product with reasonably thick consistency, firm enough to hold the fruit tissues in position, and is made by boiling fruit pulp with sufficient sugar.

            Jams may be made from all varieties of fruits. Good, fully matured fruits are selected, washed, peeled. Thin skinned fruits do not require peeling such as Apricots, plums etc but stone can be removed by machine. Fruits should be boiled in a small quantity of water and steamed and passed through pulper and finisher to get the desired texture pulp.Most jam should be concentrated to boiling temperature of 103 to 1050C. The end points of jams boiling vary with fruit varieties, amount of sugar and some other factors. As per FPO specification 45 parts of fruit to each 55 parts of sugar and contain 0.5-0.6% acid and invert sugar should not be more than 40%. is used for preparation of jam.

Preparation of jam

1. Selection of fruit: - This is the first step in the preparation of jam. In this step ripe and deep color fruits are chosen from a lot by shorting and grading
2. Washing: - After selection of fruits the fruits are washed with clean or plane running water.
3. Peeled: - After washing the fruit is peeled by using hot water and mechanical pilling.
4. Pulping: - After pilling the pulping of fruit is done with the help of pulpier in which the seeds and core are removed.
5. Addition of Sugar: - 0.80 kg of sugar is added in 1kg of pulp. 150 of water may be added if necessary.
6. Boiling: - Pulp and sugar concentrate is boiled with continues stirring.
7. Addition of citric acid: - 2.5 gm of citric acid in 1kg of pulp.
8. Judging of end point: - By further cooking up to 105 C or 68-70% T.S.S.
9. Filling: - Jam is filled into sterilized bottle.
10. Cooling: - After filling then cooling is done 1 to 5 Degree C.
11. Sealing: - After waxing the bottle are sealed with the help of sealing machine.
12. Storage: - After sealing the last step is storing. The jam is stored at ambient temperature 25 to 30 degree C

Observations

Determine TSS, acidity, pectin

Result

Acidity of the given jam, jelly, preserve = % (w/v)

TSS of the given jam, jelly, preserve = %

PRECAUTIONS

• All equipment used in the preparation of fruit juices and squashes should be rust and acid proof.

• Copper and iron vessels should be strictly avoided as these metals react with fruit acids, and cause blackening of the product.