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.

重合胶存在于未成熟中，在成熟过程中它变成胶质，在烹饪时胶质变成重合胶酸。