The Mechanism of Quality Changes in Grass Carp (Ctenopharyngodon idella) During Vacuum-Assisted Salting Brining with Physicochemical and Microstructural View

Abstract

This study investigated the effects of vacuum impregnation (V) and atmospheric pressure impregnation (C) on the quality and microstructure of grass carp (Ctenopharyngodon idella) fillets during a 120 min brining period under 5.8% NaCl (w/v) and 4 °C. Vacuum impregnation significantly enhanced brining efficiency, achieving higher salt content (2.01%) and accelerated mass transfer kinetics, as evidenced by Peleg model parameters. Both treatments improved the water-holding capacity (WHC), increasing from 80.16% to 91.47% (C) and 89.92% (V), while reducing free water proportion. A microstructural analysis revealed a reduction in extracellular space in fillets, which further affected the fillet WHC and texture. Vacuum brining also mitigated lipid oxidation, yielding lower thiobarbituric acid-reactive substances (TBARSs: 0.237 mg MDA/kg). Texture analysis indicated reduced hardness and increased springiness/cohesiveness in fillets. Despite a slight decrease in lightness, vacuum-assisted brining preserved sensory quality and aligned with low-salt dietary trends. These findings underscore vacuum technology’s potential to optimize brining efficiency and product quality in industrial applications.