Process optimization and antioxidant activity study of wheat bran hydrolysate prepared by combined anti-nutritional factor removal and enzymatic hydrolysis

Further synergistic hydrolysis was performed with the addition of 0.2% flavourzyme (400 U/g substrate). The DH was increased to 10.07%. The resulting hydrolysates contained 91.91% of molecular weight components below 3 kDa and 79.14% of components below 1 kDa.

The wheat bran hydrolysates presented bright yellow color and exhibited the highest solubility under alkaline conditions. Antioxidant assays indicated that both the crude hydrolysates and their ultrafiltrated fractions possessed broad-spectrum and high-efficiency radical scavenging capacities. The fraction with molecular weight less than 1 kDa showed the best antioxidant activity.

Its IC₅₀ values against DPPH radical, ABTS cation radical, hydroxyl radical and superoxide anion radical were 0.48 mg/mL, 0.14 mg/mL, 0.85 mg/mL and 2.18 mg/mL, respectively. This study demonstrates that the technique combining anti-nutritional factor removal and composite enzymatic hydrolysis effectively disrupts the dense structural barrier of wheat bran, enabling the efficient removal of anti-nutritional factors while enhancing the degree of protein hydrolysis and the enrichment of highly active small-molecule components.

These findings provide a theoretical basis for the functional development of wheat bran hydrolysates.