Extrusion-cellulase modification of dietary fiber of Flammulina velutipes can enhance prebiotic potential and alleviate lead stress: an in vitro study

Modified dietary fiber has shown great application potential in the fields of nutrition, food science and health. The aim of this study is to investigate the modification of dietary fiber of Flammulina velutipes by extrusion and expansion technology and cellulase. The differences of gut microbiota, SCFAs (short-chain fatty acids) and lead ion stress between FDF (Dietary Fiber from Flammulina velutipes ) and MFDF (Modified Dietary Fiber from Flammulina velutipes ) were clarified in vitro fermentation. The results demonstrated that the extrusion-cellulase technology could effectively reduce the molecular weight of FDF, adjust the monosaccharide composition and change the micromorphology. In vitro microbial fermentation results showed that FDF and MFDF adjusted the composition of gut microbiota, increased excellent lead ion adsorption capacity of intestinal flora, promoted the production of acetic acid, propionic acid, and n-butyric acid, increased the presence of beneficial bacteria such as Macrophages , Bifidobacterium , Faecalibacterium , and Mitsuokella , and reduced the levels of harmful bacteria such as Escherichia Shigella and Salmonella . In comparison, MFDF also showed better lead ion adsorption capacity of intestinal flora, produced more SCFAs and more significant biomarkers, highlighting a potential gut prebiotic role. This study provides valuable data support for the modified application of innovative processing techniques to edible fungi and highlights the potential application of dietary fiber-related functional products to promote gut health.