Influence of frozen storage period on the biochemical, nutritional, and microbial quality of Skipjack tuna (Katsuwonus pelamis) collected from the Bay of Bengal coast of Bangladesh

The biochemical and microbial quality of skipjack tuna (Katsuwonus pelamis) fillets were investigated at various storage periods (15d, 30d and 60d) under frozen (-18°C) storage conditions. In the present study, the biochemical components of frozen tuna fillets were found to be significantly different for the entire storage period (p<0.05). Furthermore, the histamine content was less than 50mg/kg from fresh to frozen storage. All the amino acids were significantly different (p<0.05) with the presence of high amounts of glutamic acid (11.11 to 11.22g/100g), histidine (8.42 to 8.97g/100g), leucine (7.44 to 7.50g/100g), aspartic acid (7.28 to 7.37g/100g), and lysine (6.22 to 6.29g/100g). Among the twelve fatty acids, docosahexaenoic acid (C22:6, DHA), oleic acid (C18:1), and palmitic acids were the most abundant. The lipid indices showed that tuna muscle is a potential source of ω-3 and ω-6 fatty acids. All the parameters used for determining the bacterial loads were within permeable limits set by ICMSF under frozen storage conditions. Finally, storing tuna fish fillets for up to 60 days exhibited no detrimental nutritional consequences and the safe for consumption.