Fermented barley bran addition improved the digestive properties, gastrointestinal phenol release and the antioxidant activities of extruded rice

Abstract

Fermented barley can be used as a functional ingredient of staple foods. In the present study, the effect of fermented barley bran addition on extruded rice was investigated in terms of digestive properties, gastrointestinal phenol release and antioxidant activities. Different nutrient compositions were observed between fermented barley extruded rice (FBER) and barley extruded rice (BER). After fermented barley bran addition, the resistant starch proportion increased to 17.49% and the glycemic index decreased to 68.82 in FBER. The release of phenols was more significant in FBER than in BER during digestion and colonic fermentation, leading to enhanced in vitro antioxidant activities. Among the phenolic compounds, ferulic acid exhibited different variation tendencies when comparing BER with FBER during colonic fermentation. According to the results of microbiota analysis, higher abundances of Lactobacillus and Bifidobacterium were observed in FBER-fermented faecal samples. Correlation network analysis further revealed the potential role of Megasphaera and Bifidobacterium in the biotransformation of specific phenols.