Water-Extractable Arabinoxylan-Induced Changes in the Conformation and Polymerization Behavior of Gluten upon Thermal Treatment

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 (<i>M</i>_w) on the heat-evoked conformational variation and polymerization behavior of gluten. Results showed that WEAX, especially low <i>M</i>_w WEAX (L-WEAX), facilitated the polymerization ability of α-/γ-gliadins into glutenins, whereas high <i>M</i>_w 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.