Jellies and Juice Processing

Jellies
Fruit jellies are semisolid, preserved mixtures of fruit juice and sugar.
Substances essential for fruit jelly making are fruit flavor, pectin, sugar, acid, and water.

Pectin
Is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants.
It is produced commercially as a white to light brown powder, mainly extracted from citrus fruits, and is used in food as a gelling agent particularly in jams and jellies.

Acid and Sugar
A certain level of acidity (below pH 3.5) must be present for a jelly to form. If the fruit juice is not sufficiently acidic, a gel will not form. If too much acid is present, the jelly will lose liquid or weep.
Sugar helps in gel formation, contributes flavor to the jelly, and at the concentration of 55 percent by weight, serves as a preservative. …