Multidimensional Relationships of Starch Digestibility with Physicochemical, Pasting and Textural Properties of 30 Rice Varieties

Abstract

Consuming rice with low starch digestibility is beneficial for reducing the risk of diabetes. Several factors have been shown to influence starch digestibility, but the combined effects of these factors on starch digestibility have not been studied. We assessed multidimensional relationships between the glucose production rate (GPR) of cooked rice with 16 indexes, including physicochemical, pasting and textural properties in 30 rice varieties. The stepwise multiple regression analysis showed that amylose content (AC), gel consistency (GC) and pasting temperature (PT) were closely related to GPR. This relationship could be described by the equation: GPR = −0.080 AC + 0.008 GC + 0.034 PT + 0.720, with a determination coefficient of 0.84. The variation partitioning analysis further indicated that AC, GC and PT independently explained 36%, 5% and 4% of the GPR variation, respectively. The interaction of AC and GC explained 46% of the variation in GPR. This study identifies the key indexes (AC, GC and PT) affecting starch digestibility and quantifies contributions of these indexes to the variation in GPR. The finding of our study provides useful information for breeding and selecting rice varieties with low GPR.