Starch enzymatic hydrolysis, structural, thermal and rheological properties of pigeon pea (Cajanus cajan) and dolichos bean (Dolichos lab-lab) legume starches

Abstract

Cajanus Cajans and Dolichos lab-lab legume starches from Argentine cultivars were investigated under a technological and nutritional point of view. Their physico-chemical, structural, thermal and the rheological properties of their gels were evaluated. Rice (RS) and potato (PS) starches were included as references. In vitro digestibility from Englyst method was also evaluated. Legume starches had the highest amylose content and the most stable chemical structure. Their rapidly digestible starch and starch digestibility rate index were very low, similar to PS, and fivefold lower than RS. They had a much higher slowly digestible starch content than PS. Legume starches showed the highest gel stability versus heating and stirring and an intermedium pasting temperature between RS and PS. They formed viscoelastic gels at 6% concentration with stronger elastic-like behaviour and higher yield stress than references. Our results indicate these legumes represent an efficient starch source to provide tailor-made properties to food/industrial applications.