Reduced in vitro starch hydrolysis and in vivo glycemic effects after addition of soy presscake to corn tortillas

Abstract

BACKGROUND: Chronically elevated blood glucose leads to development of prediabetes and type 2 diabetes, as well as increased risk for heart and kidney disease and vision loss. For many, elevated blood glucose can be managed through diet and exercise. Consequently, the availability of foods that limit blood glucose elevation would aid in addressing this global problem. This paper investigated the effect of adding soy presscake (SP) to corn tortillas on starch hydrolysis in vitro as well as the glycemic responses elicited in vivo upon consumption of these modified tortillas. RESULTS: SP in corn tortillas decreased the rate and extent of starch hydrolysis in vitro. The in vivo glycemic index (GI) values decreased from 43 for corn control tortillas to 31 with 40% SP fortification. A high correlation (r = 0.9781) was found between the GI values from in vivo analysis and the area under the curve of starch hydrolysis in vitro. The best correlations (r > 0.96) between GI and degree of hydrolysis were found at 45–90 min of in vitro starch hydrolysis. CONCLUSIONS: Incorporating SP into corn-based tortillas lowers glycemic responses to them. In addition, in vitro starch hydrolysis could be used to estimate the GI values of food products and, in particular, the comparison of multiple items during food product development. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.