In vitro gastrointestinal digestion of Lentinus squarrosulus powder and impact on human fecal microbiota

Humans have long-used mushrooms as food and medicine, but digestion and colonic fermentation of most mushrooms, including Lentinus squarrosulus is markedly unknown. Here, nutritional profile, digestion and colonic fermentation of L. squarrosulus powder (LP) were determined. The powder contained mainly carbohydrate and protein. SEM and F-TIR analysis of the resistant hydrolysate (RH) revealed that the structure and ratio of carbohydrate and protein components were altered, and released known immunomodulation agents; beta-glucans and mannose. Both LP and RH promoted selected probiotic bacteria, especially Bifidobacterium strains. Using fecal microbiota of five volunteers (V1, V2, V3, V4 and V5), RH stimulated the microbiota of all used volunteers, via decreasing the ratio of Firmicutes/Bacteroidetes ranging from 1.3 to 8.2 times. Also, RH increased the relative abundance of vital immunomodulators; Bacteroides, Bifidobacterium, Clostridium cluster XIVa and IV, and Sutterella. Additionally, RH fermentation enriched the content of branch-chain fatty acids (BCFA) and short-chain fatty acids (SCFA), indicating protein and carbohydrate usage. Notably, propionic and butyric acids were abundant in V1, V2 and V3, while in V4 and V5, acetic and butyric acids were most enriched. Suggesting L. squarrosulus as functional mushroom to improve health and prevent diseases by enhancing gut health.