Effect of wheat bran arabinoxylan on the gelatinization and long-term retrogradation behavior of wheat starch

The effect of wheat bran arabinoxylan (WBAX) with different molecular characteristics on the gelatinization and long-term retrogradation behavior of wheat starch (WS) have been evaluated. WBAXs with Mw of 280-754 kDa and Ara/Xyl of 0.45-0.62 were obtained through alkaline extraction with graded ethanol precipitation. WBAXs with larger Mw and branching degree could impede gelatinization process of wheat starch by effectively decreasing the water availability for starch gelatinization. The hydrogen-bonding interactions between WS and WBAX could enhance the gel strength of WS-WBAX mixed pastes. WBAXs with lower branching degree could inhibit the long-term retrogradation of starch through hindering the rearrangement of amylopectin and double-helical associations of amylose during long-term storage, due to hydrogen-bonding interaction between WBAX and starch. Low-field nuclear magnetic resonance (LF-NMR) relaxometry analysis confirmed that the addition of WBAXs could improve the water holding properties of retrograded starch gels.