Tailoring Highland Barley Bran Arabinoxylans: Insights into Composition, Structure, and Functional Properties

Abstract

Highland barley bran (HBB) stands as an underutilized source of arabinoxylans (AXs), presenting promising prospects for various applications. This study focuses on the isolation of four different AXs (S20, S40, S60, S80) from HBB using alkali extraction and gradient alcohol precipitation. These AXs exhibited diverse purity (56.47%–80.92%), monosaccharide compositions (A/X:0.47–0.96), and molecular weights (Mw) (173.5–498.2 kDa) of different AXs, along with different microstructural variations, amorphous qualities, and thermal stability. Rheological analyses demonstrated their shear-thinning behavior and distinctive gel-forming capacities, with S20 exhibiting superior viscosity and gel-forming ability. Notably, all four AXs demonstrate notable DPPH and ABTS radical scavenging capacities, with S80 demonstrating the highest antioxidant potency. Correlation analyses highlighted connections between molecular weight, branching degree, and rheological and antioxidant properties of AXs. Among different AXs, S20, with its low branching degree (0.47) and high molecular weight (390.4 kDa), exhibited significant viscosity, suggesting its suitability as a natural thickener in food processing. Conversely, S80, characterized by its low molecular weight (173.5 kDa), high branching degree (0.96), and potent antioxidant activity, holds promise as a natural antioxidant in functional foods. This study provides crucial insights for tailoring AX applications, unlocking the potential for the valorization of HBB in diverse scenarios.