Effects of fermentation period and soybean flour supplementation on the glycemic indices and starch digestibility of biofortified provitamin A cassava meal

Abstract

Background and aim: Across the globe, the prevalence of diabetes mellitus is rapidly increasing, even in populations with significant undernutrition. In this study, the effect of the fermentation period and soybean flour (SBF) supplementation on the glycemic indices and starch digestibility of biofortified provitamin A cassava meal was investigated. Methods: Biofortified provitamin A cassava (TMS 011368) was processed into cassava meal (garri) under two fermentation periods (24 h and 72 h) and supplemented with SBF at 0 – 80 % to produce different composite meals. These later were evaluated for their predicted glycemic index (pGI) and in vitro starch digestibility. Results: SBF supplementation significantly (p<0.05) decreased the hydrolysis index and pGI from 68.15 – 47.28 % and 73.20 – 44.56 % for composite meals fermented for 24 and 72 h, respectively. pGI, digestible starch, and resistant starch contents were significantly (p < 0.05) higher in composite meals fermented for 72 h than for 24 h. An increase in SBF supplementation significantly (p < 0.05) decreased the resistant starch, and digestible starch contents of the samples. Conclusion: Composite meals fermented for 24 h and supplemented with 40 – 80 % SBF had a reduced rate of in-vitro starch hydrolysis and glycemic indices, which may therefore be better suited for dietary prevention and management of diabetes mellitus.