Effect of Garcinia indica, Kokum extract on shelf life of Indian Mackerel, Rastrelliger kanagurta (Cuvier, 1816) during chilled storage

Fish has been a vital source of food for humanity across the globe since ancient times. Although fish is an important constituent of human diet which provides protein, vitamins, minerals, fats, etc. but being perishable, gets decomposed if not stored and handled properly. Natural plant-based products have been widely studied and used to extend the shelf life of food products and improve their microbiological quality. The study investigated the effect of kokum, Garcinia indica extract as a natural preservative on the shelf life of Indian mackerel, Rastrelliger kanagurta packed in Low density polyethylene bags during chilled storage (0-4 °C). Study focused on standardizing the concentration of kokum extract (0%, 5%, 10%, and 15). Quality assessments included proximate composition, biochemical parameters (pH, Total volatile base nitrogen, trimethyl amine nitrogen, free fatty acid and peroxide value), microbiological counts, and sensory attributes. Results indicated that kokum extract-treated fish exhibited significantly lower increases in pH, TMA-N, TVB-N, FFA, PV, and microbial counts compared to untreated controls, thereby delaying spoilage. The proximate composition of fresh Indian mackerel (Rastrelliger kanagurta) meat had 76.65±0.94%, 18.58±0.07%, 3.44±0.08% and 1.17±0.01% of moisture, protein, fat and ash respectively. The proximate composition showed good retention in treated samples as compared to the control samples. Sensory evaluation indicated that T3 retained higher overall acceptability and extended up to 18 days compared to the control sample. Among the concentrations tested, 15% kokum extract showed the most effective preservation. Overall, kokum extract demonstrated significant potential in enhancing the shelf life and quality of chilled mackerel, supporting its application as a natural preservative in fish preservation.