Xylo-oligosaccharides (XOS) are considered non-digestible fibers produced mainly from agricultural biomass and are classified as "emerging prebiotic" compounds. Since XOS were shown to promote the growth of bifidobacteria in the gut with potential effects on one's health, scientists used them as food ingredients. For example, the addition of XOS in bakery products could improve their physicochemical characteristics. The current work aimed to investigate the effect of XOS and glucose addition on wheat flour sourdough fermented with Bifidobacterium animalis subsp. lactis (BB-12) strain in terms of organic acid production. The effect on viscoelastic changes during frozen storage and after the thawing process was also studied. The results showed that the viability of BB-12 increased slightly with the increase in XOS and glucose concentrations, which determined dough acidification due to accumulation of organic acids, that positively influenced the dough's rheological properties such as a higher elasticity before and after frozen storage. With 10% XOS-addition, the acetic acid quantity reached 0.87 ± 0.03 mg/L, and the highest lactic acid concentration was found in the 10% XOS-enriched doughs, the glucose-enriched doughs and in the control sample (100% wheat dough). The quantity of glucose, maltose, XOS, and xylose decreased until the end of fermentation.
Keywords: Bifidobacterium bifido; rheology; sourdough; wheat flour; xylo-oligosaccharides.