Antifreeze Polysaccharides from Wheat Bran: The Structural Characterization and Antifreeze Mechanism
Tao Yang, Yining Zhang, Li Guo, Dandan Li, Anqi Liu, Muhammad Bilal, Chong Xie, Runqiang Yang, Zhenxin Gu, Dong Jiang, Pei Wang
Abstract
Exploring a novel natural cryoprotectant and understanding its antifreeze mechanism allows the rational design of future sustainable antifreeze analogues. In this study, various antifreeze polysaccharides were isolated from wheat bran, and the antifreeze activity was comparatively studied in relation to the molecular structure. The antifreeze mechanism was further revealed based on the interactions of polysaccharides and water molecules through dynamic simulation analysis. The antifreeze polysaccharides showed distinct ice recrystallization inhibition activity, and structural analysis suggested that the polysaccharides were arabinoxylan, featuring a xylan backbone with a majority of Ara f and minor fractions of Man p, Gal p, and Glc p involved in the side chain. The antifreeze arabinoxylan, characterized by lower molecular weight, less branching, and more flexible conformation, could weaken the hydrogen bonding of the surrounding water molecules more evidently, thus retarding the transformation of water molecules into the ordered ice structure.