Mechanistic Insights Into the Effect of Chitosan Composite Edible Coating Based on Cinnamon/Clove Extract on the Preservation and Flavor Maintenance of Lightly Fermented Tilapia

Abstract

To address the quality deterioration of fermented fish during storage due to microbial contamination and lipid oxidation, a chitosan-based edible coating incorporated with cinnamon and clove extracts was fabricated and applied to lightly fermented tilapia held at 4°C. Results showed that the coating with an extract concentration of 1.5% (CC_1.5) exhibited the best preservation effect. Following the 12-day storage at 4°C, the total color difference (ΔE) of CC_1.5 exhibited a 22.5% reduction compared to that of the control (CC₀), and its overall texture change rate (ΔT) was only 48.8% of that of CC₀. Meanwhile, the moisture content of CC_1.5 (68.89%) was 6.3% higher than that of CC₀ (64.82%), indicating that the coating effectively inhibited color and texture deterioration and moisture loss in the fish. The pH value of CC_1.5 remained at 6.62, close to its fresh state, while the pH value of CC₀ reached 6.95, indicating spoilage. The TBARS and TVB-N values of CC_1.5 were 1.69 mg/kg and 25.9 mg/100 g, respectively, representing reductions of 41.1% and 16.8% compared to CC₀, with the TVB-N value below the national standard limit. Microbial proliferation was also significantly inhibited. GC–MS analysis identified 22 volatile compounds. Among them, 1-octen-3-ol and 2-octenal were the main flavor contributors, and the coating enhanced the flavor of mushrooms and oils. Higher concentrations of extract slowed the accumulation of off-flavor compounds such as 3-octanone. In conclusion, the 1.5% cinnamon/clove-chitosan composite coating can extend the refrigerated shelf life of lightly fermented tilapia by approximately 3 days at 4°C, with the TVB-N limit in the national standard as the core spoilage criterion, providing a feasible strategy and scientific reference for the preservation of lightly fermented fish products.