Starch is a carbohydrate reserve in plants and a major source of energy for humans. In plants, starch is found in chloroplasts of leaf and in the amyloplasts of tuber and seeds. Structurally, starch consists of two major polysaccharides, namely amylose and amylopectin. Both consists of chains of -(1,4)-linked D-glucose residues interconnected through -(1,6)-glycosidic linkages. Potato starch is superior to others, functionally, because of its low lipid level. Nutritional composition of starch comprises of rapidly digestible starch, slowly digestible starch, and resistant starch (RS). Amylases are the starch degrading enzymes. Starch digestibility affects the blood glucose levels and is controlled by factors like carbohydrate contents of foods, nutritional composition of starch and cooking foods. Inhibition of pancreatic amylase is of therapeutic importance for delaying starch digestion, to prevent postprandial hyperglycemia. Food industries use starch as thickening agent.
Starch from potato has been used as a substrate for α-amylase inhibition assay, by use of raw and cooked food samples and aerial parts of Trichosanthes cucumerina Linn, as a substrate to determine SusG activity, in animal gut microbiota activity using DNSA assay.