In vitro fermentation of pretreated oat bran by human fecal inoculum and impact on microbiota

Abstract

• There was no significant change in dietary fiber and β-glucan content after in vitro digestion of pretreated oat bran. • The steaming oat bran had a greater effect on inhibiting Escherichia-Shigella and promoting Faecalibacterium prausnitzii . • The steaming oat bran produced more acetic acid, propionic acid, and butyric acid than the microwave and hot-air drying oat bran. • Steaming was the most effective way that could modulate the diversity of the intestinal flora and effectively prohibit the multiplication of harmful bacteria. Owing to its potential role in improving intestinal health, oat bran has received a lot of attention. In vitro digestion and fermentation were performed on oat brans that had been pretreated with steaming, microwave, and hot-air drying. The results showed that the dietary fiber after in vitro digestion and β -glucan content of pretreated oat brans changed insignificantly (p > 0.05). The abundance of Firmicutes and Proteobacteria varied significantly between samples (p < 0.05). The steaming oat bran was utilized by gut microbiota to produce acetate, propionate, and butyrate, the relative abundance of Faecalibacterium prausnitzii significantly increased, and Escherichia-Shigella significantly decreased. Furthermore, the genus level flora differed significantly between steaming, microwave, and hot-air drying oat bran. Overall, steaming improved oat bran fermentability, promoting increased SCFA production and bacterial shifts associated with health benefits. Our findings provide a solid foundation for further research into the role of oat bran and gut microbiota in host health.