Modulating the digestibility of cassava starch by esterification with phenolic acids

This study applied ferulic acid, sinapic acid, and p -coumaric acid to synthesise esters with cassava starch and investigated their digestibility, GI and starch structure alterations. Starch after esterification contained less rapidly digestible starch (as low as 44.59%) and more resistant starch. Sinapic acid starch ester (SASE) had the lowest hydrolysis rate, which was 61.04% in this study. The GI of ferulic acid, p -coumaric acid, and sinapic acid starch esters were 53.5, 58.4, and 47.1, respectively. They were all significantly decreased compared with native cassava starch (81.5) (P < 0.05). The steric hindrance of phenolic acid moiety and increased hydrophobicity led to the reduced digestibility of starch esters. All these results indicated that phenolic acid starch esters could help to reduce postprandial blood glucose spikes, and therefore became a potential tool for diabetes management. ∙ Cassava starch esterified with phenolic acids resist in vitro enzymatic digestion. ∙Glycaemic index of phenolic acid starch esters are lower than native starch. ∙The particle size negatively correlates to the in vitro digestibility. ∙Esterification resulted in the steric hindrance to α-amylase and α-glucosidase. ∙Sinapic acid starch ester is promising as low glycaemic index food.