Gelatinization, Retrogradation and Gel Properties of Wheat Starch-Wheat Bran Arabinoxylan Complexes

Gelatinization, retrogradation and gel properties of wheat starch-wheat bran arabinoxylan (WS-WBAX) complexes have been evaluated. The results of rapid viscosity analyzer (RVA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) confirmed that WBAX samples with larger Mw and branching degree (HWBAX) significantly impeded gelatinization process of starch by effectively reducing the amount of water available for starch gelatinization. DSC analysis showed that both molecular characteristics and additive amount of WBAX samples have an effect on the long-term retrogradation behavior of starch. For the rheological studies of WS-WBAX mixed gels, the elastic moduli (G') and shear viscosity of WS-WBAX mixed gels increased with the increase in additive amount of WBAX. WS-HWBAX mixed gels exhibited the lower G' compared with starch gels containing WBAX with lower Mw and branching degree (LWBAX) at the same amount. The scanning electron micrographs (SEM) revealed that the microstructures of WS-WBAX mixed gels were mainly affected by the amount of WBAX, but hardly by the molecular characteristics of WBAX. Texture profile analysis (TPA) showed that the cohesiveness of fresh WS-WBAX mixed gels became larger with an increase in the WBAX addition amount. The hardness of WS-WBAX mixed gels tended to increase over the 14-day storage.