The effect of chitosan‐essential oils complex coating on physicochemical, microbiological, and quality change of grass carp (<italic>Ctenopharyhgodon idella</italic>) fillets.

Abstract: The effects of chitosan coating enriched with lemon and thyme essential oils on the physicochemical, microbiological, and quality changes of grass carp fillets during 2 °C storage were determined during 16 days of storage. The pH, total volatile basic nitrogen, thiobarbituric acid reactive substances, color, texture, sensory quality, total viable count, psychrotrophic bacteria, pseudomonads, <italic>Shewanella putrefaciens</italic>, Enterobacteriaceae, and lactic acid bacteria counts were analyzed. The results indicated that chitosan coating (1.5%) incorporated with lemon or thyme essential oils (0.5%) maintained higher hardness and retarded the oxidation of lipid and protein. The most effective treatment was chitosan coating (1.5%) enriched with lemon and thyme essential oils (0.25 and 0.25%) together, which maintained the color and texture properties, and reduced the microorganisms counts. The results suggested that the synergized use of lemon and thyme essential oils increased the efficiency of chitosan coating, maintained fish fillets quality and extended its shelf life to 16 days. Practical applications: The commercial value of fresh fish fillets is lost in a few days. Many methods have been used to inhibit the spoilage caused by microorganisms, retard the degradation of protein, and extend the shelf life of fish fillets. As an alternative to chemical and synthetic preservatives, many studies are currently focused on using natural products to improve the quality of fish products. This study reports that chitosan coating incorporated with lemon and thyme essential oils together is a promising edible coating for use in commercial applications for prolonging the shelf life of fish fillets. [ABSTRACT FROM AUTHOR]