Two‐Step Enzymatic Approach to Improve the Physicochemical and Functional Properties of Dietary Fiber From Corn Bran

Corn bran (CB), a major by‐product of corn starch processing, represents an abundant and low‐cost source of dietary fiber (DF). In this study, crude dietary fiber (CDF) was prepared from CB through a multienzyme pretreatment. The structural, physicochemical, and functional properties of soluble (SDF) and insoluble dietary fiber (IDF) obtained after cellulase and xylanase modification were investigated. Compositional analyses verified the substantial removal of starch, fat, and protein by the first‐step enzyme treatment and an approximately 5% increase in total DF content. Scanning electron microscopy (SEM), Fourier‐transformed infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) indicated that the enzymatic treatment altered the morphology, chemical structure, and thermal properties of CDF. IDF displayed a high oil‐holding capacity (OHC) of (3.71 g/g) but limited swelling capacity (SC), while SDF exhibited significantly improved binding capacities for glucose and cholesterol in vitro (15.34 and 50.80 mg/g, respectively). Moreover, all fiber samples demonstrated greater binding capacity for sodium taurocholate compared with sodium cholate and sodium glycocholate, highlighting their potential for bile acid interaction. Overall, the two‐step enzymatic approach proved effective in tailoring the physicochemical properties of CB‐derived DFs, providing a sustainable and promising strategy for producing high‐value functional ingredients from agricultural by‐products with applications as value‐added ingredients in food products. Practical Applications Corn bran dietary fiber produced by two‐step enzymatic modification showed improved functional properties, including enhanced water solubility and in vitro binding capacities for glucose, cholesterol, and bile salts. This approach may help convert corn bran, an abundant starch‐processing by‐product, into value‐added dietary fiber ingredients for use in functional and health‐oriented food formulations.