The role of β-glucanase in modifying dough characteristics, texture and <i>in vitro</i> starch digestibility of highland barley-enriched bread

Abstract This study aims to evaluate how β-glucanase impacts dough characteristics, and the in vitro starch digestibility and quality of breads from mixed wheat and highland barley flour at different wheat/highland barley flour weight ratios (70/30 and 50/50). The results showed that β-glucanase reduced the dough's viscoelasticity and enhanced its extensibility, softness, α-helix (2.52%–16.12%), β-sheet (11.10%–31.66%) and free sulfhydryl content (22.70%–34.49%). This helped to mitigate the negative effects of a high β-glucan content on the wheat/highland barley dough (P &amp;lt; 0.05). Moreover, β-glucanase improved the specific volume (44.67%–56.56%) and springiness (5.56%–40.41%) as well as reduced the hardness of wheat/highland barley bread (7.50%–71.32%). Furthermore, as the higher content of slowly digestible starch (20.81%–30.84%) reduced the enzymatic rate (k value), β-glucanase-treated wheat/highland barley bread exhibited lower starch digestibility (66.17%–71.16%) than white bread (75.37%). Therefore, this study indicated that β-glucanase played an offsetting role on highland barley bread while maintaining relatively low starch digestibility.