| Salmon is mainly distributed in the north of the Pacific Ocean and the waters between the Atlantic Ocean and the Arctic Ocean.It has delicious meat and high nutritional value,so it is popular with consumers.Salmon is mainly eaten raw,so its quality is very high.Atlantic salmon is the most common salmon in the market.It is rich in fatty acids and protein,and is the best in raw food restaurants.However,the high protein and fatty acid also lead to salmon deterioration in the process of transportation and storage,such as protein degradation,fatty acid oxidation,and the continuous reproduction of microorganisms,which not only damage the muscle tissue,greatly reduce the nutritional value,but also produce substances harmful to human body.If you eat salmon that is not fresh,it will pose a threat to human health.However,due to the rich nutrition and high logistics cost of the frozen Atlantic salmon,some illegal businesses in the market,driven by economic interests,replace the Atlantic salmon with the dog salmon and rainbow trout with rough meat.And some people unfreeze the non fresh salmon stored for many days or the salmon frozen for transportation and storage and then pretend to sell as the frozen fresh salmon,which disrupts the aquatic market.Therefore,in this paper,we use shotgun proteomics to distinguish Atlantic salmon and its near source adulterated species,and use isotopic tags for relative and absolute quantification Quantification technology was used to quantitatively label the muscle protein of Atlantic salmon with different freshness(different storage time,ice fresh or frozen storage),and to screen out the different protein,which not only realized the accurate differentiation of different samples,but also provided the theoretical basis for the mechanism analysis of quality change.The main results are as follows:(1)Using UPLC-TripleTOF-MS system and based on shotgun proteomics,the whole proteins of Atlantic salmon,dog salmon and rainbow trout were identified.Using the MRM method established by UPLC-QTrap-MS system,four characteristic peptide segments of Atlantic salmon,one characteristic peptide segment of dog salmon and two characteristic peptide segments of rainbow trout were identified,which provided theoretical support for the accurate differentiation of Atlantic salmon and its near-source adulteration.(2)The freshness of Atlantic salmon stored at 0 ? for different time was studied by iTRAQ technology.28 differential proteins related to the quality change of Atlanticsalmon during storage were screened out.These proteins were verified by MRM,and the key peptide segments containing degradation sites were found.They were confirmed by iTRAQ results and divided into Six kinds of metabolic pathways were analyzed in detail.These proteins were down-regulated and up-regulated in varying degrees with the prolongation of storage time,and were closely related to post-mortem rigidity and deflexion,glucose anaerobic fermentation,organelle stability,muscle contraction and protein synthesis and decomposition.Therefore,they can be used as potential differential proteins to study the freshness change of Atlantic salmon.In order to further understand the Atlantic salmon products with different storage time at 0 ? The mechanism of qualitative change provides some reference.(3)Using iTRAQ technology to distinguish fresh Atlantic salmon and Atlantic salmon stored at-18 ? for one month,20 differential abundance proteins related to the quality change of Atlantic salmon after freezing and thawing were screened out.MRM was used to verify these proteins,and the key peptide segment containing degradation site was found in the changed protein,which was mutual with iTRAQ results.The results provide a theoretical basis for explaining the quality change of Atlantic salmon after freeze-thaw treatment. |
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