Application of chitosan and Satureja khuzestanica essential oil coating on the shelf life of Mugil cephalus L fillets

In this regard, the present study is aimed to assess the effect of chitosan and Satureja khuzestanica essential oil (SKEO) on the prolongation of the shelf life and quality of Mugil cephalus L fillet. Edible coating based on biopolymers and phenolic compounds is an effective way to preserve the quality of fish.  There is a growing demand for bio-based and active packaging as one of the preferred emerging technologies to improve food quality and extend shelf-life. To this end, the influences of various variables such as storage time (0, 7days+12hours (7.5) and 15 days), storage temperature (-10, -3, and 4 ℃ ), and essential oil content (0.5, 1 and 1.5) were assessed on the shelf life of M. cephalus fillets through the use of RSM software. A significant rise was observed in the pH of all samples by increasing the storage time (p<0.05).Thiobarbituric acid and nitrogen bases (mainly composed of trimethylamine, dimethylamine, and ammonia), as well as peroxid, also increased by prolonging the storage time and reached their highest level at the end of the storage period (p<0.05). On days 7.5 and 15, treatment (temperature of -3℃, and 2% essential oil) and treatment (temperature of -10℃ and essential oil of 2%) showed the lowest microbial load (2.39± 0.55 and 5.96± 0.23 log cfu/g, respectively) while the highest microbial load was detected in the treatment involving 0.5% essential oil and storage temperature of 4℃  (p<0.05). Based on sensory tests, no significant difference was observed in the total acceptance of the treatments. The results of the current research indicated that coating with chitosan (2%) and S. khuzestanica essential oil (especially 1%) can enhance the storage time of M. cephalus fillets in the refrigerator.