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.

合果胶存在于未熟果子的肉浆中，在熟过程中它胶质，在烹饪时胶质合果胶酸。