Effects of abdominal emptying and immersion in salt in different concentrations on fatty acids profile and spoilage indices of fish Kotr (Sphyraena jello) during freezing

Many studies showed that the nutritional value and the fish spoilage changed during handle and processing. In this research, 20 pieces of the Kotr fish were purchased from Behbahan market. After washing the fish, some as whole fish were frozen (sample A) and some were descaled and emptied and without salt frozen (sample B) and some were immersed in saltwater with 4% concentrations (sample C), 8% (sample D) and 12% (sample E) which then frozen. After 30 days of freezing, samples were transferred to the laboratory to measure fatty acids profile, spoilage indices, proximate composition, and microbial load. The results showed that the percentage of saturated fatty acids in whole fish was significantly lower than the other treatments. However, the percentage of omega‐3, omega‐6, and MUFA and PUFA fatty acids in different samples did not show a significant difference, but the ratio between DHA/EPA fatty acids changed significantly. Spoilage indexes in Sphyraena jello fillet had a significant difference in process methods. The amount of the indexes decreased with the addition of salt. The addition of salt and the abdominal emptying of S. jello resulted in a change in the fat content of the fish fillet, but did not a significant effect on protein, moisture, and ash content of fish fillet. The number of sycrophile bacteria in treatment A was 158 × 10(3) Cfu/g, which was higher than the other treatments. The lowest level was observed in salted 12% sample. It can be concluded that abdominal emptying and immersion of the Kotr fish in saltwater can lead to preserve the nutritional value and decrease the spoilage indices and increase the shelf life of the product.