Jelly is a substance made by pectin and acidic rich fruits. Water extract of fruit is mixed with sugar to boil.
It is preserved by sugar, concentration and the mixed effect of temperature. The required amount of acid does allow micro-organism to grow.
Theory of Gel Formation
Pectin rich fruits are for the preparation of jelly. Water extract of fruit, sugar and citric acid are mixed in an exact ratio and boiled for a certain time of period. The whole process is called ‘Jelly Making’.
Different theories of jelly making:
- The particles of pectin are negatively charged.
- The particles of pectin are in neutral stage.
- Pectin is precipitated when sugar is added.
- Precipitation of of pectin by sugar is the reason of gel formation.
- Pectin is a negatively charged hydrophylic colloid.
- Sugar acts as dehydrating agent.
- Pectin and water are in non-equilibrium stage.
- Pectin breaks in indefinite numbers.
- Sugar entrers in pectin finally making jelly.
- The structure of pectin is complex, mixed and transformable.
- It is coagulation of pectin.
- The equilibrium stage of pectin and water become unbalanced.
- Pectin forms a web like body.
- Vacant place of the body is filled by sugar.
It is widely accepted opinion.
Method of Preparation of Jelly
- Pectin rich fruits.
- Jelly meter.
1. Selection of Fruits
Pectin and acid rich fruits are selected. Example- guava, apple, anola etc.
2. Cleaning of Fruits
Fruit should be cleaned with clean water before cutting.
3. Cutting of Fruits
Fruit should be cut in small pieces using clean knife. Don’t peel off the fruit.
4. Boiling of Fruit
Pieces of fruit are boiled in water for an certain time at a constant medium temperature.
Fruit juice juice is filtered using jelly bags or any other clean and fine cloth.
6. Pectin Test
Pectin test is done to determine the amount of sugar in water extract.
Alcohol test – Take one spoon of water extract in a cup. Add 2 spoon of alcohol.
- If it settles like curd means, it has sufficient amount of pectin. And equal quantity of sugar is added to juice.
- If it settles in two or three pieces means, it will require 3/4 quantity of sugar.
- Split milk shows low amount of pectin.
Jelly Meter Test – It is an advanced kit made by glass to test pectin.
7. Boiling Water Extract
In this step water extract or juice of fruit is boiled. Add sugar and citric acid, respectively when juice starts to boil. Filter the juice by cloth after one boil.
How Jelly is Tested?
- Take boiling juice in a spoon.
- Cold it down for 1/2 minute.
- Now drop the juice while keeping the spoon in slant position.
- If the juice drops as a stream means, Jelly is not ready.
- If the juice drops as a sheer means, Jelly is ready.
- Fill a glass with water.
- Pour a drop of boiling juice in glass.
- If the drop coagulates means, jelly is ready.
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