Arabinoxylan supplemented bread: From extraction of fibers to effect of baking, digestion, and fermentation.

The intake of dietary fibers is related with important benefits for human health. We produced two different arabinoxylan fibers with (FAX) and without ferulic acid linked (AX), 12.5 and 0.1 mg g-1 of ferulic acid respectively, by subcritical water extraction of wheat bran. Both FAX and AX fibers were used as supplement in bread production, while non-supplemented bread was used as control. Through an enzymatic deconstruction process we investigated the effect of bread making on the fibers, the preservation of their molecular structure (A/X ratio of 0.13 and Mw of 105 Da) and the interaction with other macromolecules in the bread. By mimicking the upper track digestion, we could confirm the non-digestability of the fibers and we used them for the fermentation with B. ovatus and B. adolescentis. The presence of AX fibers during fermentation showed specific substrate adaptation by the probiotic bacteria in correlation with its potential prebiotic effect.