Obtention and characterization of resistant starch from creole faba bean (Vicia faba L. creole) as a promising functional ingredient

ABSTRACT A procedure easy to upscale industrially aimed at obtaining resistant starch (RS) type III (RS-III) was optimized, using a native faba bean from Mexico (Vicia faba L. creole) as RS source for the first time. Pullulanase debranching treatment (6-18 enzyme units (U)/g starch; 0–27 h) and retrogradation process (-30 oC, 2 oC or 20 oC; 1-6 days) was optimized for faba beans. Optimal conditions were determined at 18 U/g for 27 h and a retrogradation process at 20 oC for 6 days. Obtained faba bean RS was also compared with RS obtained from conventional sources, beans (Phaseolus vulgaris L. Jamapa) and maize, under these optimal conditions. Beans (faba beans, 64.88%; beans, 64.84%) yielded greater RS-III than maize (58.44%). The retrogradation process increased the crystallinity structure of the RS samples compared to their respective NS. Typical legume C pattern (faba bean and beans) and cereal A pattern (maize) of samples changed to an irregular polymorphic morphology type B+V, caused by retrogradation, and increasing RS content. As consequence, the digestibility of the retrograded samples was significantly reduced (approximately 50%) and increasing the amount of slow digestible starch fraction (SDS).