Effects of Five Oxidative Decontaminating Agents on the Quality and Proteins of Tilapia Fillets

In this study, the effects of five common oxidative decontaminating agents (H₂O₂ solution, ClO₂ solution, NaClO solution, ozonated water and slightly acidic electrolytic water) on the bacterial decontamination of tilapia fillets and their influence on the texture, color and myofibrillar protein (MP) oxidation in tilapia fillets were investigated. The results showed that a decontamination rate of 80% was attained by immersion in 1 500 mg/L H₂O₂ solution for 8 min, 200 mg/L ClO₂ solution for 10 min, 200 mg/L NaClO solution for 10 min, 9 mg/L ozonated water for 10 min, or 30 mg/L slightly acidic electrolytic water for 20 min. Compared with the control group, treatment with decontaminating agents increased the hardness and L* value of tilapia fillets, decreased the a* value, MP content, total sulfhydryl group content, and raised the content of carbonyl groups and the amount of surface hydrophobic groups. The degree of protein denaturation in the slightly acidic electrolytic water and NaClO solution groups was the highest; the fluorescence intensity of MP was decreased after decontamination treatments, with the greatest decrease being found in the slightly acidic electrolytic water-treated group; the relative contents of α-helix and β-turn in MP were decreased, while the relative contents of β-fold and random coil were increased, with the most significant changes in the secondary structure of MP being observed in the slightly acidic electrolytic water-treated group (P < 0.05). MP underwent degradation to different extents, and the degradation degree of the slightly acidic electrolytic water group was higher than that of the other treatment groups. In summary, the oxidation of fish MP occurred to varying degrees after oxidative decontamination treatments, with slightly acidic electrolytic water treatment having the strongest oxidative effect.