Enhancing the Shelf Life of Tilapia Surimi with Mosambi Peel Extract: Protection against Oxidative, Structural, and Textural Degradation during Frozen Storage

This work evaluated the influence of mosambi peel extract (MPE) on the stability of tilapia surimi properties during frozen preservation at −20 °C for 180 days. The findings revealed that 0.60% MPE-fortified surimi enhanced protein solubility, water-holding capacity, Ca2+-ATPase activity, and sulfhydryl content while reducing the total carbonyls and surface hydrophobicity compared to those of the control group treated with synthetic cryoprotectants, suggesting that MPE effectively countered protein denaturation and oxidation during storage. Furthermore, MPE slowed down the increase in total volatile basic nitrogen (TVBN) and protein degradation index, as evidenced by higher intensities of myosin heavy chain (MHC) and actin in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. MPE also exhibited antioxidant properties, limiting the peroxide value (PV) and thiobarbituric acid content (TBA). Fourier-transform infrared spectroscopy (FTIR) results indicated that MPE enhanced the stability of α-helices and β-sheets, improving gel and textural properties. Consequently, 0.60% MPE has the potential as a natural additive to replace synthetic cryoprotectants, ensuring the oxidative stability of tilapia surimi while enriching it with bioactive compounds.