The synergistic effect of lactic acid bacteria fermentation combined with gluten on the starch digestive properties of highland barley

In this study, the synergistic effect of fermentation and gluten on highland barley starch digestibility was investigated, and the possible mechanisms were explored. The addition of gluten during fermentation increased the resistant starch content from 16.03% to 28.57% in highland barley. Both fermentation and the addition of gluten inhibited starch swelling and gelatinization. The combination of fermentation and gluten exhibited the most pronounced synergistic effect. Fermentation, with/without gluten addition, had a significant influence on the long-range ordered structure, while only fermentation with gluten addition influenced the short-range ordered structure. Furthermore, confocal laser scanning microscopy images indicated that fermentation facilitated the interaction between exogenously added gluten and starch, forming a dense protective layer around starch granules. This protective layer limited starch gelatinization and protected the starch from enzymatic attack. The results of rheological analyses suggested that the interaction between gluten and starch was primarily driven by hydrogen bonding. These findings will enrich the theory that the synergistic effect of fermentation and gluten improves the digestive properties of cereal starch and facilitates the development of healthy cereal products.