The physicochemical and simulated digestive characteristics of yam flours processed by different thermal processing methods.

This study investigated the digestibility and colonic fermentation characteristics of Dioscorea fordii flours processed by steaming-refrigeration (SRY), extrusion-refrigeration (ERY), and baking (BY). SRY and ERY exhibited 31.19% and 18.52% higher resistant starch contents than BY, likely due to the higher degree of starch structural order. Simulated digestion indicated medium estimated glycemic indices (eGI) for SRY (67.38) and ERY (68.48), and a high eGI for BY (75.69). Allantoin was well preserved across all thermally processed yam flours. Saponins and polyphenols decreased by 19.15% and 28.86% in ERY, respectively. Simulated digestion and fermentation revealed that BY released more bioaccessible bioactive components, while SRY and ERY promoted greater production of short-chain fatty acids (SCFAs) and enriched beneficial bacteria, including Bifidobacterium and Ligilactobacillus. Steaming-refrigeration and extrusion-refrigeration effectively modulate starch digestibility of yam flour and may benefit glucose metabolism through enhanced SCFA production and probiotic enrichment. They are more suitable for processing glucose-friendly foods.