Comparative studies on physicochemical properties, starch hydrolysis, predicted glycemic index of Hom Mali rice and Riceberry rice flour and their applications in bread

Abstract

Physicochemical properties, predicted glycemic index (pGI) and bread qualities of a non-pigmented white rice flour (Hom Mali, HM) and a pigmented rice flour (Riceberry rice flour, RB) were investigated. In the present study, RB (15.3% amylose) contained higher total polyphenolics, anthocyanins, and ferric reduction activity power than HM (21.3% amylose). RB had lower swelling power and higher gelatinization temperatures. In addition, RB contained higher levels of beneficial resistant starch (RS) and lower levels of slowly digestible starch (SDS) with medium pGI. RB provided slower glucose release than HM. The pasting characteristics showed that peak and final viscosity, trough and setback value, and breakdown of RB was lower than HM. RB bread had lower cohesiveness, gumminess, chewiness and adhesiveness than HM bread. Furthermore, RB bread demonstrated lower starch hydrolysis and pGI than HM bread. These findings suggest that anthocyanin-rich RB could be used as an alternative food ingredient for gluten-free bread.

Keywords: Bread; Hom Mali rice; Physicochemical properties; Predicted glycemic index; Riceberry rice; Starch hydrolysis.