The Preservation of Nano-edible Coating on Texture Stabilization of Blunt Snout Bream (Megalobrama amblycephala): Focus on Physicochemical Properties and Proteomics Analysis

A natural nano-edible coating based on fish gelatin-rosemary essential oil was developed for the preservation of blunt snout bream (Megalobrama amblycephala) fillets. The results showed that the coating treatment effectively maintained the texture stability of the fish fillets, including appearance and water-holding capacity, significantly delayed lipid and protein oxidation, and inhibited microbial growth. On day 10, compared to the CK group, the TVB-N and TVC of the CT decreased by 41.46% and 31.36%, respectively. Proteomics was used to reveal the biochemical mechanisms affecting fish quality characteristics. Bioinformatics analysis of differential abundant proteins (DAPs) showed that the effects of the coating were related to the cellular process, skeleton structure, and enzymatic activity. Meanwhile, 65 DAPs which related to quality changes were further screened out, and most DAPs showed upregulation in coated fish fillets compared to the control, including myosin heavy chain, myosin-7, T-complex protein 1, isocitrate dehydrogenase (NADP (+)), 40S ribosomal protein, and HSPs, while Prdx-6 showed downregulation. It is believed that the coating delayed and prevented the generation of microbial degradation products and reduced the damage to the protein structure by suppressing microbial growth and protease activity, thereby stabilizing texture properties of refrigerated fish fillets. The shelf life of fillets during storage at 4 °C was significantly extended by at least 30%. The study provides an innovative method for the fish preservation and a theoretical basis for the protective effect of the coating on protein structures at the molecular level.