Effect of Carboxymethyl Chitosan-Locust Bean Gum Active Coatings Incorporated with Melissa officinalis L. Essential Oil Nanoemulsions on the Quality of Sea Bass (Lateolabrax japonicus) During Refrigerated Storage at 4 °C

This research was to evaluate the effects of locust bean gum (LBG) and carboxymethyl chitosan (CMCS) active coatings supplemented with Melissa officinalis L. essential oil (MOEO) nanoemulsions to extend the shelf life of sea bass ( Lateolabrax japonicus ) fillets during refrigerated storage at 4 °C. The results indicated that the active coatings could delay the increase in microbiological, pH, and K value of sea bass fillets. At the same time, the active coatings markedly depressed the off-flavor compounds productions such as the trimethylamine (TMA), total volatile basic nitrogen (TVB-N), hypoxanthine (Hx), hypoxanthine riboside (HxR) and reduced free amino acids (FAAs) accumulation during refrigerated storage. 24 volatile compounds were identified and the active coatings treated significantly reduced the fishy flavor compounds, such as 2-ethyl-1-hexanol, 3-methylbutanol, 2-methylbutanol, hexanal, and 1-octen-3-one. The shelf life of uncoated sea bass was 6 days, and sea bass treated with CMCS/LBG, CMCS/LBG-0.5%MOEO, CMCS/LBG-1%MOEO and CMCS/LBG-2%MOEO were 6, 9, 12 and 15 days, respectively, which suggested that the active coatings were a potential option in maintaining the quality of sea bass during refrigerated storage. Graphical Abstract