Jelly is a product obtained by cooking pectin rich fruit extract with sugar and citric acid to a desirable thick consistency. Codex Alimentarius Commission has defined Jelly as ‘a product prepared from a suitable ingredient and practically free from suspended fruit particles; mixed with a carbohydrate sweetener and processed to a semi solid consistency.’ According to FSSAI “Fruit Jelly means the product prepared by boiling fruit juice or fruit (s) of sound quality, with or without water, expressing and straining the juice, adding nutritive sweeteners, and concentrating to such a consistency that gelatinisation takes place on cooling. The product shall not be syrupy, sticky or gummy and shall be clear, sparkling and transparent.” Jelly should have colour and flavour of the fruit and shall contain no apparent objects except seeds if jelly is prepared from passion fruits and berries. It should also be reasonably clear or transparent. Normally 55 parts of sugar is added to every 45 parts of fruits. The all pectin, sugar, acid and water constituents of jelly must be present in a desirable proportion. Jelly should be transparent and retain its shape when removed from the mould and it should also retain its shape and show a clear cut surface when it is cut.
FSSAI Standard
Fruit content: not less than 45 percent
T.S.S: not less than 65 percent
Preservative(Maximum):Benzoic Acid-200 ppm or SO2- 40 ppm or Sorbic Acid- 500 ppm
Artificial Sweeteners & Polyols (maximum): Aspartame- 1000 ppm or Sorbitol- 30%
Moulds count: Positive is not more than 40 % of field
Examined, not more than 125 per 1/60 c.m.m.
Suitable Fruits
Any fruit rich in pectin content may be utilized in jelly preparation. Guava, Phalsa, Gooseberry, Karonda, Wood Apple, Papaya, Plum, Crab and sour Apple and Strawberries are some important fruits those yield good jelly. If the fruit is poor in pectin content then artificial pectin is added into fruit extract for jelly preparation. The extract of fruits rich in acids like citric acid, tartaric acid, malic acid or other fruit acids requires comparatively lesser quantity of citric acid. The pectin is a polysaccharide which is present in the cell walls of the fruits primarily in calcium pectate form and accountable for fruit firmness. The pectin changes into different forms with growth, development and ripening of fruits. The proto pectin present in immature fruits is water insoluble , the pectinic acid or pectin present in mature and semi-ripe fruits is water soluble and cab be extracted into water while pectic acid is also water insoluble and present in ripe and over ripe fruits. This is the reason behind that utilization of both mature and ripe fruits in 3:1 ratio are advised for jelly making to get the sufficient pectin as well as natural flavour of fruit into finished product and immature and over ripe fruits are not fit for jelly.
Recipe for some important fruits
Fruit Extract (L) Sugar (Kg) Citric acid (g)
Guava 1 0.75 4
Sour Apple 1 0.75-1.0 2-3
Gooseberry 1 1.0 -
Karonda 1 1.0 2-3
Papaya 1 1.0 3
Wood Apple 1 1.0 -
Plum 1 0.75 3
Pectin Requirements
Pectin is a type of polysaccharides present in the intercellular wall of the plants. About 0.5-1.0 percent pectin of good jelly grade in the extract is sufficient to prepare good jelly. The capacity of the pectin to jell with sugar is called the jelly grade in other words 1g pectin with how many grams of sugar jells under optimum conditions ( 65% TSS and 3.0 to 3.1 pH) is called jelly grade of the pectin. Excess pectin produces firm and tough jelly whereas low pectin in extract results failure of jelly to set. The pectin, Sugar, acid and water are the four essential constituents of jelly. The jelly should content pectin 1percent, sugar not less than 65 percent, fruit acid 0.5 to 0.6 percent and water 33 to 35 percent.
Extraction of pectin
The jelly is prepared from clear extract of the fruit containing pectin. To extract the pectin the fruits are washed and cut into small pieces or slices while bitter fruits like oranges are peeled to remove the outer yellow flavedo to get bitterness free extract. Normally equal to 1.5 times water by weight is used in the extraction. Too excessive and too small quantity water should not be used as excess water dilute the pectin concentration in extract and small amount water gives undesirable non clear cloudy extract. The second and third extraction may be taken by using minimum quantity of water. Water along with fruit pieces is boiled for 5 to 20 minutes depending upon types of fruits. The boiled material is strained through muslin cloth or cheese cloth with out squeezing to get clear extract. Squeezing may pass pulp to extract yielding cloudy extract.
Test for pectin content
There are following methods to determine pectin content of fruit extract:
Alcohol Test
In this method 1 spoon full of fruit extract is poured into a glass or beaker and allowed to cool. Then 3 spoons full methyl alcohol are mixed with extract and allowed to stand for 2 minutes. Thereafter following observations may be recorded to determine the amount of sugar to be added into extract:
The appearance of single transparent lump or clot indicates that extract is rich in pectin and equal amount of sugar has to be added in extract.
The appearance of less firm fragmented clots means extract is moderate in pectin content and 750g sugar to each kg of extract (3/4th amount) has to be added in the extract.
If several small granular clots are formed it means extract is poor in pectin content and half amount of sugar has to be added in the extract.
Jelmeter Test
Jelmeter measures the viscosity of fruit extract which is used as an index for jellying capacity of the extract. Jelmeter is held in the left hand between the thumb and the first finger and the bottom outlet of jelmeter is closed with little finger. The fruit extract is cooled to between 21 to 38°C and filled into the jelmeter up to the brim .Then little finger is removed and extract is allowed to drop down for one minute thereafter outlet is again closed by little finger. The reading nearest the level of the liquid on jelmeter indicates the part of sugar required to each part of extract.
Test Jelly
In this method 3 to 5 samples are prepared keeping the extract quantity constant and varying amount of sugar. The sugar amount which gives best jelly sample is considered best and sugar is added accordingly in further preparation of jelly from the rest amount of extract.
Preparation Technique
Selection of fruits
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Washing
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Cutting into thin slices or pieces
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Boiling with water
Addition of citric acid@ 2g/Kg of fruit while boiling
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Strain the extract through muslin or cheese cloth
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Test of extract for pectin content
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Estimation of sugar amount as per pectin test
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Addition of sugar and half quantity of citric acid
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Boiling and removal of scum
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Addition of remaining citric acid and colour if required
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Judging of end point
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Filling hot into clean sterilized jelly bottles
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Waxing
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Capping and labeling
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Storage for further use
Judging of end point
When jelly reached to end point it becomes ready for filling into containers. The end point of the Jelly can be judged with the following methods:
Temperature
when temperature of the cooking mixture of extract and sugar is reached to 105°C at seal level cooking is stopped and jelly is filled into bottles. The correction in this temperature is essential according to altitude as boiling temperature increases with increasing altitude. Normally temperature of boiling mixture is kept about 5°C higher than the boiling point of water in that particular place.
Weight
When the weight of boiling mixture is reached to one and half time of sugar added the cooking is stopped and finished jelly is filled into bottles. The weight may be recorded by deducting the weight of empty pan from the weight of pan containing mixture and sugar.
Total soluble solids
Presence of 65 percent T.S.S. into boiling mixture at 200C indicates the end point of jelly.
Sheet or Flake test
In this method some amount of boiling mixture is taken into a spoon or wooden ladle and cooled slightly thereafter it is allowed to drop. If it drops like syrup it requires further boiling while its fall in the form of flake or sheet indicates the end point of jelly.
Drop test
The few drops of boiling mixture are poured into a glass containing water with the help spoon. If the drops dissolve and disappear before reaching at the bottom of glass further boiling is needed but in case intact drops reach to the bottom of glass jelly attains its end point.
Problems in jelly
Failure to set
A jelly may fail to set and remain syrupy after filling into the bottles because of the lack of pectin or acid or both in the fruits extract, Added sugar in excess, over or under boiling of mixture beyond the end point and prolonged slow cooking of mixture. These reasons must be avoided to ensure the proper setting of jelly.
Cloudy or Foggy Jelly
The cloudy or Foggy or unclear look of jelly impairs its aesthetic quality. The cloudy jelly is formed due to following reasons:
If unclear fruit extract is used for jelly making.
If immature fruits are used to prepare jelly then starch in the fruits is also extracted with pectin that remains insoluble in extract and gives cloudy appearance to jelly.
Over cooking beyond the end point yields gummy and sticky finished product of excessive viscosity. Such product does not become clear after pouring into the bottles and jelly gets cloudy appearance.
Over cooling enhances the viscosity of jelly subsequently jelly becomes cloudy.
If scum is not removed and it is filled into container with jelly, the jelly becomes Foggy.
If jelly is poured into bottles from more than 2.5 cm height bubbles are formed due to incorporation of air with jelly and jelly gets foggy appearance.
Excess pectin into extract causes premature gelation which traps air and makes jelly cloudy.
These reasons should be overcome to check the cloudy of foggy problem of jelly.
Crystal formation
If sugar is added in excess into low acid containing fruit extract sugar crystals are formed in jelly. The mixture should be boiled few minutes after adding the sugar to ensure the sufficient hydrolysis of sugars that prevents crystal formation in jelly.
Syneresis or Weeping jelly
The spontaneous exudation of fluid from the product is termed syneresis or weeping jelly. This is serious problem of jelly and following are the reasons of the problem-
If excess acid is present or added in extract more pectin is hydrolyzed that results breakdown of jelly structure. The weak jelly structure yields exudation of fluid. It may be prevented by adding low acid juice or more pectin to extract which increases the amount of added sugar thus acidity of jelly is decreasing by increasing its volume.
The pectin network holds more water under too low concentration of sugar in comparison to normal concentration of sugar. Holding of water encourages the syneresis. Proper concentration of sugar should be maintained to prevent the weeping problem.
Inadequate pectin in extract also causes weeping problem of jelly. Hence pectin rich extract should be used for jelly making.
If premature gel formation takes place the pectin network is broken during pouring of jelly into bottles and jelly becomes weak to hold the fluid. The problem can be controlled by Adding small amount of common salt or sodium citrate salt.
Jelly contains 65%T.S.S that prevents fermentation under normal conditions. If jelly contains less sugar fermentation may takes place that can be prevented by storing the jelly in a cool and dry place. Weeping jelly is more vulnerable to fermentation.
Moulding
If bottles are not sterilized, paraffin waxing is not done properly and jelly is stored at damp place the moulds can grow on the surface of jelly which termed as moulding. It can be checked by using sterilized containers, proper sealing the containers, filling jelly hot into bottles and storing jelly containers at dry place.
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