Structural alterations and property improvements of corn bracts insoluble dietary fiber via various modification methods: microwave, ultrasound, enzymatic hydrolysis, alkaline hydrogen peroxide, and cross-linking

Abstract This research meticulously explored the impact of five modification methods, namely microwave (M), ultrasonic (U), enzymatic hydrolysis (E), alkaline hydrogen peroxide (A), and cross-linking (C), on the structure, physicochemical properties, and functional characteristics of corn bracts insoluble dietary fiber (CBIDF). The results showed that all modifications disrupted the dense surface of CBIDF. Among them, A-CBIDF completely shrank due to decomposition of lignin and hemicellulose through alkaline hydrogen peroxide treatment, and C-CBIDF formed a fragmented network structure. All modifications significantly improved water holding capacity (WHC) and oil holding capacity (OHC), with the WHC of A-CBIDF increasing by 95.14%. Microwave and ultrasonic modifications significantly enhanced swelling capacity (SC) by 23.51% and 21.92%, respectively. C-CBIDF (DPPH scavenging rate 36.5%) and E-CBIDF (hydroxyl radical scavenging rate 37.1%) had the best antioxidant properties, but the antioxidant property of A-CBIDF decreased due to the destruction of phenolic compounds. The glucose adsorption capacity (GAC) and nitrite adsorption capacity (NIAC) were enhanced after modification. Among them, the GAC of U/C/A-CBIDF increased significantly, and the NIAC of E-CBIDF was the highest under gastric conditions (pH = 2.0). This study provided a theoretical basis and technical support for the high-value utilization of corn bracts dietary fiber.