Starch digestion and physiochemical properties of a newly developed rice variety with low glycemic index

This study aimed to clarify the starch digestion characteristics and related physicochemical properties of the newly developed low-GI rice variety, Ditangliangyou 335 (D335), in comparison with two widely grown rice varieties, Xiangzaoxian 45 (X45) and Zhongzao 39 (Z39). The results showed that D335 had an active digestion duration (286 min) that was 101-190 % shorter, a glucose production rate (1.06 mg g^-1 min^-1) that was 57-73 % slower, and a total glucose production (303 mg g^-1) that was 11-19 % less than X45 and Z39. These differences were attributable to the distinct starch physicochemical properties, including amylose content, amylose-to-amylopectin ratio, starch granule size, amylopectin chain length, and starch molar mass, as well as the different pasting properties of rice flour, such as pasting temperature and breakdown viscosity. These findings reveal the starch digestion characteristics and the key physicochemical properties that determine these characteristics in the low-GI rice variety D335.