The effect of chitosan enriched with different essential oils on the physicochemical and microbiological quality of trout burgers stored at 4 °C

This study examined the effects ofchitosan films enriched with various essential oils onthe quality characteristics ofrainbow trout burgers stored at(4±1 C) for 21days. Five groups were prepared: acontrol group (C), achitosan film group (CF), and groups ofchitosan films enriched with 1% oregano essential oil (OEO), citrus essential oil (CEO), and rosemary essential oil (REO). Microbiological counts and physicochemical factors were assessed. Significant differences (P<0.05) inphysicochemical properties were observed among the treatments, with OEO showing the lowest pH (6.67), the lowest peroxide value (PV; 12meqO2·kg–1), and the lowest thiobarbituric acid reactive substances (TBARS) level [1.159 malondialdehyde (MDA)·kg–1]. Microbial results indicated that the shelf life ofthe treated groups was extended byupto9days compared tothe control. The lowest counts ofEnterobacteriaceae, yeast and mould, and lactic acid bacteria inOEO were 5.17, 4.87, and 5.10log CFU·g–1, respectively, while the lowest counts ofpsychrophilic and mesophilic bacteria were observed inthe REO group, at6.34 and 6.29log CFU·g–1, respectively. In conclusion, combining essential oils, particularly oregano and rosemary, with chitosan effectively enhances seafood freshness and extends its shelf life.