In vitro dynamic digestion properties of cooked rice and effect of the digesta on gut microbiota in a colonic fermentation model

Abstract

The aim of this study was to evaluate the in vitro dynamic digestion behavior of three main rices [Indica rice (IR), Japonica rice (JR) and Waxy rice (WR)] and the influence of their digesta on the microorganism growth. Herein was shown that the cooked JR with the highest ratio of amylose (6.8 ± 0.2%) and lowest protein content (3.4 ± 0.1%) had the highest gastric retention rate (19.3 ± 5.2%) and exhibited slowest hydrolysis rate of starch (73.5 ± 2.5%) under simulated small intestinal conditions. The microstructure of WR disintegrated the fastest during the gastric stage, which may be attributed to its most soften texture (hardness: 2859.9 ± 214.5 g), lowest content of amylose (0.8 ± 0.1%) and highest ratio of protein (3.8 ± 0.1%). Besides, 16 sRNA detection possessed the digesta of these cooked rices can regulate the growth of beneficial bacteria in the Changdao Moni simulation system (CDMN) and reduce the abundance of proliferation of Shigella and Escherichia coli. JR digesta had the strongest ability to promote the synthesis of butyric acid (1.6 mg/mL) and valeric acid (1.8 mg/mL). The results may offer some suggestions on designing low glycemic food for special populations, and hope to inspire the development of novel starchy products to regulate the gut microbiota.