Effect of low voltage electrostatic field assisted partial freezing on large yellow croaker protein properties and metabolomic analysis during storage.

BACKGROUND: Large yellow croaker is highly perishable during storage because of high protein and moisture contents, and the degradation of fish is mainly attributed to microbial growth and enzymes activities, so it is vital to find an efficiently storage method to delay the shelf life of large yellow croaker.

METHODOLOGY: The effect of low voltage electrostatic field combined with partial freezing treatment on the physicochemical properties of myofibrillar protein (MP) and metabolomic analysis of large yellow croaker during preservation was investigated in this study. The samples in chilled storage (C), partial freezing storage (PF) and 6 KV/m electrostatic field partial freezing storage (LVEF-PF) were analyzed during 18 days.

RESULTS: The results were that compared with C and PF groups, LVEF-PF delayed the oxidation of MP by inhibiting the formation of carbonyl groups content (2.25 nmol/mg pro), and maintaining higher sulfhydryl contents (29.73 nmol/mg pro). In addition, the FT-IR and fluorescence spectroscopy analysis manifested that the LVEF-PF treatment maintained the stability of protein structure by increasing the ratio of α-helix (19.88%) and reducing the ratio of random coils (17.83%). Scanning electron microscopy observed that compared with LVEF-PF group, there are more degeneration and aggregation of MP in C and PF group after 18 days storage. The results of untargeted metabolomic showed that 415 kinds of differential metabolites were identified after storage, and the level of differential metabolites were least between the samples treated with LVEF-PF stored at 9th day and the fresh samples. The main differentia metabolic pathways during storage were amino acid metabolism, lipid metabolism and the pathway of ABC transporters.

CONCLUSION: Therefore, the LVEF-PF treatment could maintain the stability of myofibrillar protein in large yellow croaker during storage. These results evidenced a potential application of LVEF-PF method for aquatic products preservation. This article is protected by copyright. All rights reserved.