Quality changes in Indian mackerel (Rastrelliger kanagurta) during preservation with saturated brine fermentation technique

Indian mackerel, Rastrelliger kanagurta is one of the most preferred fatty fish; however, economical preservation of fatty fishes is least documented in India. Saturated brine (23%) fermentation of Indian mackerel was studied for 120 days. Increment of lipid (2.25%), reduction of protein (5%) and salt content of 14%-15% with pH of around 6.0 was observed. Hardness fluctuated initially but stabilized at maturation. Fermentation imparted pleasant aroma to the product with minimal fat oxidation. Total plate count ranged from 3.80 to 5.44 log cfu/g. Coliforms and Escherichia coli were <1.8 MPN/g in final product. The product was stable at ambient condition under 95% vacuum in retortable pouch throughout the storage period (30 days). Botulinum toxin was examined and found absent in the analyzed samples. Sensory score indicated high acceptance of the product. Thus, the study illustrated that saturated brine fermentation preserves fatty fish adequately, producing safe and healthy fermented fish product with enhanced shelflife. Practical applications Indian mackerel being a fatty fish is prone to quick oxidation and spoilage; hence, a cost-effective preservation technique is required. Saturated brine fermented Indian mackerel has benefits of enhanced taste and aroma with minimal oxidation of the product. This preservation technique induces the product to remain stable at ambient condition with added shelflife owing to reduced pH and water activity. The preservation process of saturated brine fermentation acts as a value addition to Indian mackerel as it develops the product with similar attributes of lona ilish, a popular salt-fermented fish product in North-East India. This product can be economically adopted by fisher folks, self-help groups, and several other communities. This product can help to improve food and nutritional security in rural areas.