Abstract
Abstract: Resistant starch is the undigested starch fraction that escapes small intestinal digestion and absorption, and then reaches the large intestine for partial or complete fermentation by the colonic microbiota. Fermentation of resistant starch into short-chain fatty acids (i.e., acetic, propionic, and butyric particularly) in the colon has been reported to bring about positive changes in microbiota composition and reduce the risk of colon-related diseases as well as some metabolic syndromes, such as obesity, diabetes, chronic kidney disease, and systemic inflammation. Rapid fermentation of resistant starch in the large intestine causes its metabolites to gradually decrease between the proximal colon and the distal colon. A slow fermentation rate of resistant starch results in a steady metabolite production release and even distribution in the entire colon, increasing likelihood of meeting the energy requirements of the distal colon. Considering the potential relationship between fermentation performance and health, here we proposed three principles for designing fermentable resistant starch: slow fermentation in the colon; high butyrate and/or propionate production; and selective bacterial growth, promoting the beneficial bacteria that improve the intestinal barrier function. Some strategies will be given to modulate the in vitro fermentation rate and short-chain fatty acid profiles of resistant starches, including the effect of genetic modification of rice varieties on the colonic fermentation properties.
