Moderate protein degradation and lipid oxidation induced by cold plasma and its effect on the quality of dried fish products

In this study, atmospheric cold plasma (CP) was applied to treat dried fish products at 65 kV and 60 Hz, and its effects on the composition associated with the physicochemical properties were investigated. The CP treatment for 5 min induced the fracture and contraction of fish muscle fibers and increased the microporous structure, and the moisture content of the samples reduced from 39.88 % to 37.88 %. Compared to the control group, the 5-min CP treatment decreased the puncture hardness from 10.42 to 8.43 N (p < 0.05), and increased the final rehydration ratio from 20.86 % to 28.84 %. In addition, the 5-min CP treatment increased cathepsin B + L by 58 %, and increased trichloroacetic acid (TCA) soluble peptides content by 12 % (p < 0.05), which indicated that CP contributed to protein degradation. Besides, the CP treatment also promoted lipid oxidation (TBARs value increased from 1.12 to 1.96 mg/Kg) and the production of dicarbonyl compounds (3-deoxyglucuronide and 2,3-butanedione were increased from 0.56 and 0.51–0.95 and 1.75 μg/g, respectively) (p < 0.05). In conclusion, CP is promising for improving storage stability, chewiness and rehydration of dried fish products, which associated with moderate protein degradation and lipid oxidation in fish muscle.