Arabinoxylan from wheat bran: research and applications1Academy of science, Liaoning University, Shenyang 110036
2College of Food Science, Shenyang Agricultural University, Shenyang 110161
3College of light industry, Liaoning University, Shenyang 110036
4Sandy Land Amelioration and Utilization Research Institute of Liaoning, Fuxin 123000, Liaoning)
Abstract Wheat bran has a great value-added potential due to its rich source, low cost and abundance of bioactive ingredients. Arabinoxylan (AX) is the primary soluble dietary fibre from wheat bran. In the present study, wheat bran was alkali soaked and extrusion processed to improve the extraction yield of AX. The obtained AX as the primary research focus was involved in three aspects as follows. First, the structure and functional relationships of AX were studied. AX samples with various Mws and degrees of branching were prepared using different modification methods. Their physicochemical and functional properties and proper fluorescence labeling methods were also compared. The inhibition effects of AX on starch digestibility and its bread application were studied as well. The results provided a deep understanding of the structure & function relationship of AX, which showed that the higher the molecular weight and viscosity of AX, the lower the GI value of bread. Second, the covalent interactions between AX and different polyphenols were studied. Two AX-phenolic acid conjugates were prepared, and their functional and physiological properties were investigated. The results showed that AX-polyphenol conjugates showed overall decreased Mw, increased antioxidant effects and inhibition effects against starch digestibility compared to the original AX. The conjugating strategy of AX with polyphenols could enhance the biological activity of AX and widen its application in food and medicine areas. Third, Interactions between AX and protein were studied. AX-WPI (whey protein concentrate) conjugates were prepared through both dry heating and enzymatical methods. The structural features and emulsifying properties of conjugates were investigated. The results showed that the emulsifying properties of AX-WPI conjugates were 30 times higher than that of commercial gum arabic, which can be applied as a new novel polysaccharide emulsifier in dairy products, meat products, etc. Successful delivery of these studies not only provides the theoretical basis for the industrial application of AX in food, cosmetics and pharmaceuticals but also explores novel value-added applications of wheat bran and other cereal brans as well.
Keywords wheat bran; arabinoxylan; molecular structure; molecular modification; functions; molecular interactions