Oligosaccharides as prebiotics in beer and their conversion during brewing via enzymatic transglycosylation

Beer brewing generally includes saccharification, wort boiling with hops, yeast fermentation, and with/without pasteurization to obtain the final beer. Oligosaccharides are carbohydrates formed through the polymerization of 2–10 monosaccharide molecules via glycosidic bonds. As prebiotics, they possess the potential to modulate the intestinal microbiota of mammals and regulate blood glucose concentrations. In recent years, considerable attention has been devoted to investigating beer enriched in prebiotics oligosaccharides. Herein, the research progress of beer oligosaccharides and enzymatic transglycosylation, including the types and content of oligosaccharides in ordinary and prebiotics beers, the production control during beer brewing, the influence of saccharification and yeast selection on the content of oligosaccharides in beer, and the transglycosylation effect of natural and tailored transglycosidases, is summarized and discussed. In the beer brewing process, beyond the artificial supplementation of exogenous oligosaccharides, the content of oligosaccharides in the final beer product can be elevated by controlling the saccharification temperature and utilizing yeast strains that exhibit limited capacity to decompose long-chain oligosaccharides. However, most natural transglycosidases have lower transglycosylation activity in high water and low sugar-content environments. Customizing suitable transglycosidase has become the focus of research nowadays showing significant potential in prebiotics food processing.