Effect of arabinoxylans with different molecular characteristics on the gelatinization and long-term retrogradation behavior of wheat starch

Authors: YAN, WENJIA - China Agricultural University; ZHANG, MINGHAO - China Agricultural University; ZHANG, MENG - China Agricultural University; Yadav, Madhav; JIA, XIN - China Agricultural University; YIN, LIJUN - China Agricultural University

Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2022
Publication Date: 5/7/2022
Citation: Yan, W., Zhang, M., Zhang, M., Yadav, M.P., Jia, X., Yin, L. 2022. Effect of arabinoxylans with different molecular characteristics on the gelatinization and long-term retrogradation behavior of wheat starch. Carbohydrate Polymers. https://doi.org/10.1016/j.carbpol.2022.119581.
DOI: https://doi.org/10.1016/j.carbpol.2022.119581

Interpretive Summary: Wheat bran is a low-valued byproduct of wheat grains processing. Wheat arabinoxylan is prepared from wheat bran by its extraction with alkaline water. To improve the functional properties of starch prompted us to study the effect of different sizes of wheat arabinoxylan on the gelatinization and the realignment behavior of starch molecules. Arabinoxylan is a natural dietary fiber and its addition to starch increases its nutritional value and it also may help prevent colon cancer. It was found that adding larger arabinoxylan with high branching protects starch molecules from thermal treatment and mechanical shearing during the heating process. It significantly hinders the gelatinization process of wheat starch by reducing the water availability for starch gelation. Thus, the large size arabinoxylan molecules may protect starch granules more effectively and may make the final food products more appealing to consumers. Many processed foods contain some kind of thickener, stabilizer and gelling agent and the wheat arabinoxylan composite with starch has a potential to be used for these applications. Viscosity is one of the most widely used properties in food applications. In this respect, these arabinoxylan composites can be used in foods where oil or fat content has to be reduced. Arabinoxylan has a great effect on the viscosity of other carbohydrate polymers, so its mixture with starch can control the viscosity of the food system, which in turn helps to replace fat or oil in the final products. Such properties may also enable it to be used as a low calorie replacement for carbohydrate additives used as thickeners, flavor carriers and suspension stabilizers in a wide variety of food products. These findings will benefit U. S. farmers and wheat processors by adding value and creating additional markets for their by-products.

Technical Abstract: Wheat bran arabinoxylans (WBAX) with different molecular characteristics were produced by alkaline extraction and ethanol precipitation technology. In this study, the effect of WBAX with different molecular characteristics on the gelatinization and long-term retrogradation behavior of wheat starch have been evaluated. The results of rapid viscosity analyzer (RVA) showed that the increases in peak viscosity, final viscosity and setback were less pronounced due to the increase in the molecular weight and the degree of branching of WBAX. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy confirmed that WBAXs with the higher Mw and high degree of branching could impede the gelatinization process more than the one with the lower Mw and the less degree of branching by reducing the amount of water available for starch gelatinization process. WBAX samples with the lower degree of branching could inhibit the long-term retrogradation of starch through hindering the rearrangement of amylopectin and double-helical associations of amylose through hydrogen bonding during long-term storage due to hydrogen-bonding interaction between WBAX and amorphous region of starch pastes. Moreover, WBAXs with various molecular characteristics could affect the mechanical strengths and microstructures of starch pastes as a result of the formation of new hydrogen bonding network.