Enzymatic extraction increases the recovery of protein and antioxidant compounds from wheat bran

Wheat bran, a by-product of grain milling, is often discarded despite containing valuable organic compounds. This study compared the recovery of protein and antioxidant compounds from wheat bran using aqueous (AEP) and enzymatic-assisted extraction process (EAEP). A Box-Behnken design (BBD) was employed to investigate the effects of enzyme concentration, temperature, and time on four dependent variables (protein yield, degree of hydrolysis (DH%), antioxidant activity (ABTS assay), and zeta potential). EAEP significantly improved protein recovery (up to 53.9%) and antioxidant activity (up to 38.2%). Response Surface Methodology (RSM) was employed to optimize the extraction conditions, and the predicted outcomes were experimentally validated, confirming the reliability of the model. The optimized extracts were further characterized by their functional properties. Notably, the water and oil holding capacities were enhanced due to enzymatic hydrolysis, which exposed hydrophilic and hydrophobic groups, respectively. Emulsion stability also improved, particularly at moderate degrees of hydrolysis. These findings highlight the potential of EAEP as a sustainable and efficient approach for valorizing wheat bran, providing protein-rich extracts with desirable functional and bioactive properties suitable for food applications. This work supports the transitioning towards a circular economy by promoting the reuse of agricultural by-products through green extraction technologies. • Enzymatic extraction of proteins and antioxidants from wheat bran was optimized. • Extraction parameters were adjusted to maximize protein yield (53.9%). • Water- and oil-holding capacities were enhanced through moderate enzymatic hydrolysis. • Response surface modeling validated optimal extraction conditions. • Circular valorization of a by-product was achieved for functional food ingredient s recovery.