Pectose exists in the fleshy pulp of unripe fruit;during the process of ripening it changes to pectin;by cooking, pectin is changed to pectosic acid, and by longer cooking to pectic acid.

重合果胶未成熟果子的肉浆中，成熟过程中它变成胶质，饪时胶质变成重合果胶酸。