In vitro and in vivo hydrolysis of legume starches by α-amylase and resistant starch formation in legumes—a review

Starch represents the major source of available carbohydrate in the human diet. Starch is the most abundant (22–45%) carbohydrate in the legume seed. The rate of starch digestion in legumes is lower both in vitro and in vivo, than that of cereals. In vivo, starch is hydrolyzed by salivary and pancreatic α-amylase. However, a proportion of starch in starchy foods generally escapes complete digestion. This fraction is called ‘resistant starch’. Resistance starch has properties similar to fermentable fibers. This review summarizes the current knowledge on: (1) the extent of in vitro hydrolysis of native legume starches by α-amylases of different origin; (2) the structural and morphological changes that occur in legume starches as a result of α-amylolysis; (3) the reactivity of amylases towards gelatinized, retrograded and modified legume starches; (4) effect of food processing on in vitro hydrolysis; (5) in vivo digestibility; and (6) resistant starch formation in legumes.