In vitro starch digestibility of fresh and sun-dried faba beans (Vicia faba L.)

Fresh and sun-dried faba beans (Vicia faba L.) were cooked, stored for various times at 4°C and analysed for available starch (AS), resistant starch (RS) and fibre-associated resistant starch (FARS) contents as well as α-amylolysis. Fresh beans required a shorter cooking time (25 min) than dried beans (158 min). Cooked fresh faba beans had a higher AS content than cooked dried faba beans. The AS content in both decreased during cold storage, with fresh beans showing a smaller decrease than dried beans with increasing storage time. Cooked fresh faba beans also had a higher total RS content than cooked dried faba beans, although a greater increase in RS content was recorded in the latter upon storage. Starch retrogradation was more prominent in cooked dried faba beans than in cooked fresh faba beans, as indicated by the consistently higher FARS content. The α-amylolysis rate decreased with increasing storage time, i.e. long-stored (72 h) cooked faba beans exhibited slower starch digestion, and differences were recorded between fresh and dried beans. The predicted glycaemic index ranged between 60.9 and 58.0% for cooked fresh faba beans and between 57.9 and 55.8% for cooked dried faba beans, which is suggestive of slow glucose release from starch in faba beans.