Here, we aimed to study the changes in proteome of golden pompano fillets during post-mortem storage. TMT-labeled quantitative proteomic strategy was applied to investigate the relationships between protein changes and quality characteristics of modified atmosphere packaging (MAP) fillets during superchilling (-3 ℃) storage. Scanning electron microscopy was used to show that the muscle histology microstructure of fillets was damaged to varying degrees, and low-field nuclear magnetic resonance was used to find that the immobile water and free water in the muscle of fillets changed significantly. Total sulfhydryl content, TCA-soluble peptides and Ca²⁺-ATPase activity also showed that the fillet protein had a deterioration by oxidation and denaturation. The Fresh (FS), MAP, and air packaging (AP) groups were set. Total of 150 proteins were identified as differential abundant proteins (DAPs) in MAP/FS, while 209 DAPs were in AP/FS group. The KEGG pathway analysis indicated that most DAPs were involved in binding proteins and protein turnover. Correlation analysis found that 52 DAPs were correlated with quality traits. Among them, 8 highly correlated DAPs are expected to be used as potential quality markers for protein oxidation and water-holding capacity. These results provide a further understanding of the muscle deterioration mechanism of packaging golden pompano fillets during superchilling.

Proteins play a substantial role in the deterioration of partial freezing shrimp product quality. In this study, traditional protein indicators were used to determine changes in shrimp muscle quality during storage, and the changed proteins were identified using proteomic analysis. The decrease in total sulfhydryl (SH) content and the increase in carbonyl content indicate protein is denatured. The decrease in Ca²⁺-ATPase activity and the increase in surface hydrophobicity also indicate protein denatured. The increase of hydrophobic interaction and disulfide bonds suggest a larger and closer network among proteins. A total of eight changed protein bands were detected on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) diagram under partial freezing storage. Three of them were identified as α-actinin (97 kDa), invertebrate connectin (I-connectin (55 kDa)), and troponin I (30 kDa), respectively, which are essential components of myofibrillar protein. The results of the bioinformatic analysis showed that α-actinin and troponin I are unstable proteins with a secondary structure dominated by α-helix, while I-connectin is a stable protein with a secondary structure dominated by random coil. All three proteins are hydrophilic and predicted to be non-toxic on ToxinPreds.