Increasing wheat flour extraction rate for balanced starch-protein digestion and gut microbiota optimization: A strategy to enhance nutrition and mitigate food crises

In this study, the influence of wheat flour extraction rate on starch and protein hydrolysis degree, as well as fermentation characteristics of noodles was evaluated using an in vitro digestion-fermentation model. Results showed that as the flour extraction rate increased from 35 % to 95 %, the starch hydrolysis degree of noodles significantly decreased. Meanwhile, the protein hydrolysis degree (n = 3) exhibited a higher value of 22.56 %-23.53 % in noodles with an 80 %-90 % extraction rate, then declined to 21.69 % at a 95 % extraction rate. Noodles with an extraction rate of 75 % to 85 % produced significantly higher levels of short-chain fatty acids (247.19-254.73 mmol/L, n = 6) than other samples. Moreover, the ratio of Bacteroidetes/Firmicutes also increased with flour extraction rate, positively regulating gut microbiota. Notably, noodles with an 80 %-85 % extraction rate could maintain intestinal microecological balance. Overall, increasing flour extraction rate to 80 %-85 % balanced reduced starch digestibility, elevated protein utilization, and improved gut microbiota stability.