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

Three kinds of oat β-glucan oligosaccharides (βG-L, βG-M, and βG-H) with different molecular weights (1.83 × 103 Da, 4.55 × 103 Da, and 2.75 × 104 Da) were prepared through acid degradation of oat β-glucan. The structure analysis implied that the characteristic absorptions of oat β-glucan were not changed during acid degradation. Viscosity decreased obviously with the decreasing of the molecular weight of oat β-glucan oligosaccharides, and viscoelastic property varied during acid degradation of β-glucan. The functionalities oat β-glucan related to its viscosity were enhanced or decreased after acid degradation. The swelling power of oat β-glucan was disappeared after acid degradation. Fat binding capacity and bile acid binding capacity of oat β-glucan increased or decreased after acid degradation. Glucose availability of three kinds of oat β-glucan oligosaccharides decreased, which implied the hypoglycemic effect increased after acid degradation. Acid degradation endowed oat β-glucan with antioxidant and antibacterial properties. The antioxidant activities increased with the increasing of molecular weight of oat β-glucan oligosaccharides in the experimental. βG-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 β-glucan were related to its viscosity and molecular weights. [Display omitted] •Viscosity decreased with the decreasing of molecular weight (Mw) of oat β-glucan.•Functionalities related to viscosity were increased/decreased after degradation.•Degradation endow β-glucan with good antioxidant and antibacterial activities.•The functionalities of oat β-glucan were correlated to its viscosity and Mw.