CCDS Pectin is a natural and commercially produced essential ingredient in preserves, like jellies and jams. Without pectin, jellies and jams won't gel. Pectin is a type of starch, called a heteropolysaccharide, that occurs naturally in the cell walls of fruits and vegetables and gives them structure. When combined with sugar and acid, it is what makes jams and jellies develop a semi-solid texture when they cool.