Effect of slightly acidic electrolyzed water（SAEW） combined with ultrasound sterilization on quality of Bigeye tuna (Thunnus obesus) during cryogenic storage

Abstract

The quality, protein degradation, microstructure and moisture content of tuna fish were analyzed by using different concentrations of slightly acidic electrolyzed water (28, 55, 77 mg/mL) combined with 280 W ultrasonic treatment and single concentration of slightly acidic electrolyzed water (28, 55, 77 mg/mL). Fish freshness was evaluated by pH, TVB-N, TBA, color difference, TVC and texture. Protein degradation was studied by TCA-soluble peptide and myofibrin fragmentation index, and water status and tissue structure were evaluated by low field NMR and HE staining. The results showed that SAEW and SAEW+Ult treatment not only inhibited the increase of total viable counts (TVC), but also inhibited the increase of total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) and pH. Among them, 55 mg/mL+Ult treatment had better inhibition of protein degradation, and the microstructure and texture of fish tissues maintained the best, and the water loss was the slowest. Therefore, 55 mg/mL+Ult treatment is an effective way to maintain the quality and prolong the shelf life of tuna during refrigeration.