Rheological and functional properties of oat β-glucan with different molecular weight

Three kinds of oat beta-glucan oligosaccharides (beta G-L, beta G-M, and beta G-H) with different molecular weights (1.83 x 10(3) Da, 4.55 x 10(3) Da, and 2.75 x 10(4) Da) were prepared through acid degradation of oat beta-glucan. The structure analysis implied that the characteristic absorptions of oat beta-glucan were not changed during acid degradation. Viscosity decreased obviously with the decreasing of the molecular weight of oat beta-glucan oligosaccharides, and viscoelastic property varied during acid degradation of beta-glucan. The functionalities oat beta-glucan related to its viscosity were enhanced or decreased after acid degradation. The swelling power of oat beta-glucan was disappeared after acid degradation. Fat binding capacity and bile acid binding capacity of oat beta-glucan increased or decreased after acid degradation. Glucose availability of three kinds of oat beta-glucan oligosaccharides decreased, which implied the hypoglycemic effect increased after acid degradation. Acid degradation endowed oat beta-glucan with antioxidant and antibacterial properties. The antioxidant activities increased with the increasing of molecular weight of oat beta-glucan oligosaccharides in the experimental. beta G-M possessed the best antibacterial activity against Staphylococcus aureus and Escherichia coli (except 5% concentration). The results indicated that the functionalities and bioactivities of oat beta-glucan were related to its viscosity and molecular weights. (C) 2020 Elsevier B.V. All rights reserved.