Understanding starch digestibility of rice: a study in white rice

Abstract

SummaryIn vitro starch digestibility, chemical, pasting, and gelatinisation properties of 10 uncooked pigmented and non‐pigmented Thai white rice were studied. Differing in amylose and starch contents, the samples were also significantly (P ≤ 0.05) different in pasting and gelatinisation properties, maximum digestible starch (40–53 g/100 g dry starch), and rate of starch digestion (0.028–0.054 min−1). The starch digestograms were adequately described (r2 > 0.63; P ≤ 0.001) by objective logarithm of slope (Sopade Objective Procedure), modified first‐order kinetic, and two‐term exponential and non‐exponential models to be all truly monophasic. The estimated glycaemic index (g/100 g) ranged from 64 and 84, compared to 41–95 for their brown rice forms (International Journal of Food Science and Technology, 2022, 57, 6699), highlighting how bran and hull components influence starch digestion of polished and non‐polished rice. This study is foundational to detailedly understand starch digestibility when the rice is further treated.