Niosomal Encapsulation of Phenolic-Rich Extract from Fermented Corn Bran: Optimization, Characterization, and In Vitro Evaluation

Abstract

This study developed and optimized a niosomal delivery system for fermented corn bran extract (FCBE) to enhance its stability and evaluate its antioxidant potential for nutritional and health applications. Niosomes were prepared using a central composite design (CCD) to assess the effects of surfactant hydrophilic-lipophilic balance (HLB) and cholesterol content on encapsulation efficiency (EE) and particle size. The optimized formulation, obtained at an HLB of 13.5 and 92 mg cholesterol, achieved an EE of approximately 56% and a mean particle size of 205 nm. Antioxidant activity assays showed that the DPPH scavenging capacity of encapsulated FCBE was comparable to that of the free extract, whereas ABTS scavenging activity was lower for the encapsulated extract (9.54%) than for the free extract (16.8%). This lower apparent ABTS activity was attributed to the restricted release of phenolic compounds from the niosomal vesicles in the aqueous assay medium, rather than to a loss of their intrinsic antioxidant capacity. In vitro release studies confirmed that niosomal encapsulation provided a more controlled and sustained release profile. Stability evaluation demonstrated good preservation under refrigerated conditions, while higher temperatures and acidic pH reduced encapsulation efficiency over time. These findings highlight the potential of niosomes as carriers of plant-derived bioactive compounds for functional food and pharmaceutical applications.