Water-Extractable Arabinoxylan-Induced Changes in the Conformation and Polymerization Behavior of Gluten upon Thermal Treatment
Pei Wang, Xiaohui Zhao, Runqiang Yang, Yulin Zhou, Qin Zhou, Zhenxin Gu, Dong Jiang
Abstract
Interactions between gluten proteins and water-extractable arabinoxylan (WEAX) during the heating stage are crucial for the organoleptic quality of high-fiber cereal products. To reveal the molecular mechanism of WEAX on gluten characteristic upon heating, the current study comparatively investigated the effects of WEAX with different molecular weights (Mw) on the heat-evoked conformational variation and polymerization behavior of gluten. Results showed that WEAX, especially low Mw WEAX (L-WEAX), facilitated the polymerization ability of α-/γ-gliadins into glutenins, whereas high Mw WEAX (H-WEAX) reduced the polymerizing temperature of glutenin and gliadin. L-WEAX could develop more hydrogen bonds with tyrosine of gluten and stabilize the secondary structure more evidently than H-WEAX upon heating. Compared with disulfide bridge formation, hydrophobic interactions were not the driving force involved in the heat-induced polymerization behavior affected by WEAX. WEAX evoked the reinforced glutenin network and heterogeneous distribution of gliadin, with a more uniform molecular surface developed for gluten.