Proteomic analysis and biomarker discovery of water holding capacity differences in bighead carp eye and dorsal muscles during frozen storage

Abstract

Differentially abundant proteins (DAPs) in the eye muscle (EM) and dorsal muscle (DM) of bighead carp were compared at the initial state (-0) and after six months of frozen storage (-6) using proteomics. The WHC of EM and DM decreased by 21.08% and 12.79% after 6 months of frozen storage. Further comparative proteomic analysis revealed that a total of 20, 21, 78 and 58 DAPs were identified and focused in DM-6 vs. DM-0, EM-6 vs. EM-0, EM-0 vs. DM-0 and EM-6 vs. DM-6, respectively. Additionally, in DM-6 vs. DM-0, up-regulated DAPs involved myosin isoforms, actinin, and iron metabolism, while down-regulated DAPs involved myosin isoforms, actin, lactate synthesis, and protein degradation. In EM-6 vs. EM-0, up-regulated DAPs involved myosin isoforms, and down-regulated DAPs involved myosin isoforms, actin, glycolysis, and protein degradation. DAPs function analysis indicated that EM showed better MP repair, antioxidation, aerobic metabolism, and protein degradation but inferior glycolytic metabolism compared to DM. Tubulin beta chain could serve as a biomarker to reflect the extent of freezing in bighead carp muscle. Malate dehydrogenase had the potential to evaluate WHC difference between EM and DM. These results offer insights into the causes of WHC differences between EM and DM in bighead carp, providing a theoretical foundation for optimizing fish processing and tailoring storage in the industry.