Production and evaluation of enzymatically processed oat fibres as potential prebiotics

Abstract: Insoluble oat bran fibres, with substantial arabinoxylan (AX) content, are obtained as a byproduct from industrial processing of oat. By further processing it is possible to solubilise and hydrolyse AX into (arabino)xylo-oligosaccharides ((A)XOS). (A)XOS derived from other crops have shown to have prebiotic potential by stimulation of probiotic bacteria (Falck et al., 2013). In this study the enzymatic production of (A)XOS from insoluble oat fibres and their prebiotic potential was examined. Heat extraction and alkali extraction was separately investigated as two methods for solubilising AX. Both methods were shown to be equally efficient with 49 % and 44% recovery of AX, but heat extraction led to a higher purity. Hydrolysis of AX into (A)XOS was investigated by different enzymes, individually and in pairs. No positive synergy in (A)XOS production could be observed with enzymes in pair compared to their individual effect. Rather, Pentopan 500 BG was found to be the most efficient enzyme as a wide range of (A)XOS was produced. Thus Pentopan 500 BG was used for further production of (A)XOS. Lactobacillus brevis (DSM 1269) and Bifidobacterium adolescentis (DSM 20083) was utilised to investigate the prebiotic potential of the produced (A)XOS. It was shown that both strains consumed (A)XOS while producing short chain fatty acids (SCFA). Specifically, B. adolescentis utilised both XOS and AXOS. L. brevis utilised XOS with DP 2-3, possibly utilisation of A3X was seen. It was hence concluded that (A)XOS derived from insoluble oat fibres have prebiotic potential.