The Quality of Fresh Mackerel Tuna (Euthynnus affinis) Preserved with Different Icing Methods

Fish is a highly perishable food material, so the quality is very susceptible to degradation. The damage to the fish may occur starting from catching or harvesting, post-harvest handling to distribution, and consumers. The primary factor causing quality degradation in fish is the activity of enzymes and bacteria, which ultimately shortens the shelf life of the fish. This study aimed to analyze the effect of different icing methods on the quality of mackerel tuna (Euthynnus affinis). This study used a completely randomized factorial design (RAL)involving 2 factor treatments with 3 levels, and each treatment was carried out in 3 replicates. The treatments used were the fish icing method (bulk, 1-layered fish, and 2-layered fish)with a ratio of ice and fish 1:1 and a storage durationof 12, 24, and 36 hours. The quality indices analyzed included histamine level, total volatile bases nitrogen (TVB-N), peroxide value, and total plate count (TPC). Results indicated that after 36 h of storage the histamine, TVB-N, peroxide and TPC contents of the mackerel tuna had increased to 8.1-19.4 mg/100g, 47.9 mgN/100g, 48.1 mEq/kg, and 1.8 x 103 colony/g, respectively from the initial values of 8.1 mg/100g, 25.7 mgN/100g, 5.3 mEq/kg and 2.6 x 102 colony/g, respectively. Sharp increases were observed in the 1-layered and especially in the 2-layered fish icing methods, while in the bulk icing methods the values of the parameters remained similar to that of the control fish.