Effect of Particle Size Control of Wheat Bran via Different Milling Techniques on the Structural and Physicochemical Properties of Arabinoxylan

This study investigated how milling methods impact the extraction yield, structural features, and physicochemical properties of arabinoxylan (AX) isolated from wheat bran. Bran from three wheat cultivars (Goso, Hojoong, and Joongmo) was milled using an ultracentrifugal, mortar, or ball mill to generate fractions with different particle sizes. AX was extracted from each fraction and analyzed for yield, monosaccharide composition, arabinose-to-xylose (A/X) ratio, ferulic acid content, substitution patterns, and antioxidant-related indices. Ball milling produced the smallest particles and the highest AX yields, accompanied by increased ferulic acid release. NMR analysis indicated that ball milling reduced disubstituted xylose residues, suggesting partial disruption of highly substituted regions within the AX backbone. The A/X ratio varied by wheat type and milling method (0.44–0.60). Xylose and arabinose were the predominant monosaccharides, whereas residual glucose indicated incomplete starch hydrolysis. Ball milling also notably increased total phenolic content and ABTS radical scavenging activity, highlighting its role in releasing bioactive phenolic compounds. Overall, increased milling intensity improved AX extractability and enhanced the functional potential of wheat bran as a source of dietary fiber and antioxidant-active phytochemicals.