Rainbow trout (Oncorhynchus mykiss) is a popular commercial fish in China owing to its delicious and nutritious meat. However, it is extremely prone to spoilage and deterioration during storage, transportation, and sale, which affects its edible value. To study the efficient preservation proposal for rainbow trout during storage and extend its shelf life, this study uses 4 ℃-cold storage as control and studies the effects of the ice temperature (0 ℃) storage combined with composite bio-preservatives (the mass concentration of chitosan, tea polyphenols, and lemon juice are 1.75%, 0.25%, and 4.98%, respectively) on the quality of rainbow trout by measuring the drip loss, pH, and total volatile base nitrogen (TVB-N) of meat samples under different experimental conditions. The results show that the various indicators and their increasing amplitudes over time of the 0 ℃ ice temperature storage group are better than those of the 4 ℃ storage group, which can effectively slow down the spoilage process of rainbow trout meat. On the 12th day, the pH and TVB-N values of the 4 ℃ and 0 ℃ groups are 6.86 and 51.89 mg/100g, and 6.56 and 31.82 mg/100g, respectively, whereas those of the 0 ℃ with bio-preservative group are only 6.32 and 16.96 mg/100g, respectively. This scheme has a better preservation effect on rainbow trout meat and can effectively extend its shelf life.

Rainbow trout were used as a research subject to investigate the effects of different preservation techniques on the quality and physicochemical properties of aquatic products during storage. Total volatile basic nitrogen (TVB-N), total viable count (TVC), pH, and drip loss rate were used as technical indicators. A comparative study was conducted on the preservation effects of four preservation methods on rainbow trout flesh, including refrigeration (4 ℃ ±1 ℃), ice temperature (-1 ℃ ±1 ℃), high-voltage electrostatic field (HVEF, 3k V/m) + ice temperature (-1 ℃±1 ℃), and HEVF (3 k V/m) + compound biological preservative (mass fraction: 1.40% chitosan + 0.05% lysozyme + 1.30% theaflavin) + ice temperature (-1 ℃ ± 1 ℃). The results showed that treatment with HVEF + compound biological preservatives effectively inhibited microbial growth. Samples from the refrigeration and ice temperature groups had already decayed by the 10th and 12th day, with TVC reaching 7.12 lg(CFU/g) and 7.13 lg(CFU/g), respectively. In contrast, the TVC values of the HVEF + ice temperature and HVEF + compound biological preservative + ice temperature groups were only 6.32 lg(CFU/g) and 5.89 lg(CFU/g) on the 12th day. On the 14th day of storage, the TVB-N of the HVEF + compound preservative + ice temperature group was only 20.17 mg/100 g, which was much lower than that of the other three groups. This investigation indicates that compared to refrigeration and ice-temperature storage, treatment with HVEF + composite preservatives can effectively delay the spoilage process of fish and extend the shelf life of rainbow trout by four days.