Plasma activated water (PAW), Ozonated water (OW) and Slightly acidic electrolytic water (SAEW) treated tilapia fillets during chilled storage: A comparative study on quality changes and related mechanisms

Changes in protein degradation and lipid oxidation in tilapia fillets treated with plasma-activated water (PAW), ozonated water (OW), and slightly acidic electrolyzed water (SAEW) were investigated during refrigeration (12 d) at 4 degrees C. Compared to the control group, PAW, OW, and SAEW effectively delayed the formation of trichloroacetic acid (TCA)-soluble peptides and free amino acids, and significantly reduced the drip loss rate by 1.52-3.60% after 12 d (P < 0.05). However, the total content of unsaturated fatty acids in all treatment groups decreased after 12 d. Compared to PAW and OW, SAEW better-maintained protein secondary and tertiary structure stability and preserved the most polyunsaturated fatty acids (27.32%). UHPLC-Q-TOF/MS analysis showed that accumulation of dipeptides/tripeptides (such as Trp-Trp-Pro, Tyr-Thr-Trp, Leu-Gln-Phe) enhanced the bioavailability and potential bioactivity of the proteins in all treatment groups. The 4-hydroxy-octanoic acid and 4-amino-pentanoic acid from fatty acid oxidation were significantly (P < 0.05) down-regulated in PAW and SAEW. Overall, PAW, OW, and SAEW may be feasible techniques for improving the quality of tilapia fillets during cold storage.