Effects of Carnosine Combined with Ultra High Pressure on the Lipid Oxidation and Myofibrillary Protein of Snakehead Fish

The study aimed to investigate the effect of carnosine combined with ultra-high pressure (CUH) on the lipid oxidation and myofibrillar protein (MP) of snakehead fish meat during refrigerated storage. Studies on lipid and protein oxidation, protein degradation and protein structure were used to analyze the effect of CUH treatment (carnosine concentration 25 mmol/L, ultra-high pressure pressure 300 MPa, pressure holding time 900 s) on snakehead fish. The lipid oxidation of fish meat was analyzed by measuring the lipoxygenase activity and the change of MDA content in CUH-treated fish. The change in the carbonyl content of MP during refrigerated storage was used to characterize the degree of fish protein oxidation. SDS-PAGE, TCA-soluble peptides and total protease activity were used to determine the effect of CUH treatment on fish protein degradation. In order to further understand the effect of CUH treatment on the structure of snakehead fish meat and MP during refrigerated storage, SEM and CD tracking measurements were carried out on fish. The results showed that the lipoxygenase activity of fish meat treated with ultra-high pressure decreased by 64.46%. The inhibition rates of lipid oxidation and protein oxidation of fish treated with CUH were 51.25% and 3.63% on the 9th day of the refrigerated storage period, respectively. The total protease activity of fish after UHP treatment decreased by 25.75%. CUH treatment significantly reduced the degradation of MP during refrigerated storage (P<0.05). The protein degradation inhibition rate was 63.41% on the 9th day. The CUH-treated fish had complete and tight fibers during refrigerated storage. New hydrogen bonds were formed in the MP and the structure of proteins was more orderly arranged. In summary, CUH treatment could not only inhibit the lipid and protein oxidation and protein degradation of snakehead fish, but also maintain the structure of fish meat and MP. CUH treatment significantly improved the quality of snakehead fish and would provid a theoretical basis for improving the storage quality of black fish meat.