Wheat bran sourdough-like fermented: a potential source of prebiotics and probiotics

Objective: This study aims to increase the amount of wheat bran's bioactive compounds through a sourdough-like fermentation process, in order to use the fermented bran as a potential functional ingredient. In particular, the solubilization of arabinoxylans, the main non-starch polysaccharides of bran, deserve particular attention because of (the positive influence on glucose metabolism) and the prebiotic potential of the resulting soluble arabinoxylan-oligosaccharides. Methods: The amounts of soluble fiber, water-extractable arabinoxylans were determined before and after bran fermentation. Bioprocessed bran was fermented in vitro with human faecal inoculum in order to test the modulation of the growth and/or the activity of some intestinal bacteria, by means of DAPI and FISH techniques and short chain fatty acid determination. Moreover, lactic acid bacteria strains isolated from the fermented bran were characterized by probiotic properties, such as acid and bile tolerance, anti-listeria activity and adhesion ability to Caco-2 cells, as well as exopolysaccharide production and safety. Results: Bran fermentation contribute to fiber (+22%) and arabinoxylans solubilization. Preliminary results suggest that fermented bran induces the in vitro production of butyrate, a protective agent against colon cancer. Moreover, Pediococcus pentosaceus CE65 seems to be a candidate for use as probiotic. Conclusions: The current study suggests that sourdough-like fermentation process is an efficient means for the nutritional enhancement of wheat bran and provide additional information for the future purpose to add fermented bran as a functional ingredient. Moreover, wheat bran sourdough proved a good source of interesting microbial strains with potential for future applications.