Effect of Barley β-Glucan on the Gluten Polymerization Process in Dough during Heat Treatment

Barley (Hordeum vulgare L.) β-glucan (BBG) is of interest as a result of its health benefits, but BBG presents significant disruptions on the gluten network, with a negative impact on food texture. To clarify the interaction between BBG and gluten in dough, the dynamic rheological, thermochemical process of gluten and microstructure of dough with BBG during heating were detected. The results showed that BBG delayed the gluten thermopolymerization reaction during heating and affected polymerization of specific molecular weight protein subunits. These impacts depended upon the heating temperature and time. When heating under 25-65 °C, tan δ of the dough reached the highest level at the BBG concentration of 1%. However, under the temperature of 65-95 °C, tan δ was positively correlated with the BBG content (0-3%). The differential scanning calorimetry curves revealed that the peak temperature (T_P) of the two endothermic peaks increased by 3.86 and 3.10 °C. Size-exclusion high-performance liquid chromatography analysis showed that BBG mainly affected the peak area of gliadin and glutenin. Furthermore, after 3% BBG was added, the bands of 59.8 and 64.9 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns delayed, vanishing for 120 s when heating at 95 °C. Therefore, BBG delayed the polymerization reaction of specific molecular weight protein subunits rather than all of the proteins.