Cold plasma-activated lactic acid ice improved myofibrillar protein gel properties in tilapia fillets: A synergistic preservation mechanism.

The quality of refrigerated tilapia fillets rapidly declines due to microbial spoilage and oxidative degradation of proteins and lipids. To address this, we developed plasma-activated lactic acid ice (PALAI) as a synergistic preservation method and evaluated its efficacy against tap water ice (TWI) and plasma-activated ice (PAI) over 7 days at 4 °C. PALAI outperformed controls by more effectively inhibiting microbial growth, delaying lipid oxidation, and suppressing protein oxidation. It better preserved myofibrillar protein (MP) integrity, maintaining higher carbonyl content (3.16 ± 0.50 nmol/mg) and Ca2+-ATPase activity (0.096 ± 0.02 U/mg prot). Consequently, PALAI-treated MP formed gels with superior strength (45.15 ± 3.70 g·mm), whiteness, and water-holding capacity. High-throughput sequencing showed PALAI selectively suppressed Gram-negative spoilage bacteria. Correlation analysis linked freshness indicators to MP properties (P < 0.05), demonstrating PALAI as a multi-target technology for maintaining tilapia quality during storage.