Abstract: Freshness is one of the most important quality parameters of salmon, which has a great influence on its processing suitability. In order to explore the potential relationship between salmon muscle proteins and freshness, isobaric tags for relative and absolute quantification (iTRAQ) technique was used to investigate the change of proteins in salmon meat during storage at 0 ℃. Compared with the fresh control group, totally 62 differentially expressed proteins were identified in salmon with different storage times (5, 10 and 15 days). Further bioinformatics analysis revealed that these proteins were mainly enriched in metabolic pathways and the glycolysis/gluconeogenesis pathways. A total of 28 differentially expressed proteins possibly related to freshness changes during storage were selected, of which two were up-regulated at the initial storage stage, but began to degrade with the prolongation of storage time; ten degraded significantly after 5 days of storage, and with the prolongation of storage time, the degradation continued to occur in varying degrees; three did not change significantly after 5 days, but began to degrade after 10 days; 13 did not change significantly within 10 days, but degraded significantly after 15 days, and these proteins were mainly involved in glucose metabolism, muscle twitch, protein skeleton and energy metabolism. These results showed that all these proteins were closely related to changes in salmon freshness, which provide a rationale for understanding the mechanism of freshness changes at different storage time.

Key words: proteomic; salmon; isobaric tags for relative and absolute quantification; freshness; bioinformatics