Aims: The first step in the purification of omega-3 is to extract oil. The aim of this study was to evaluate the effects of Wet Pressing (WP), Cold Extraction (CE), and Enzyme Extraction (EE) methods on tuna by-products oil and their moisture as well as chemical parameters.
Materials and Methods: The methods used in this experimental study to extract oil from primary raw materials were WP, CE, and EE and the efficiency rate of the methods was calculated. Regarding the qualitative evaluation, moisture content, volatile compounds, neutralized lipid levels, fatty acid profiles, acidity rates, and also levels of mercury, arsenic, cadmium, and lead were measured. Data analysis was performed by SPSS 22, using one way ANOVA and Duncan test.
Findings: The amount of oil extracted by EE method was significantly higher than the other two methods (p<0.05). The amount of oil moisture did not have a significant difference in 3 methods (p>0.05). Cholesterol levels in the samples of oils obtained from these methods were not significantly different. Free fatty acid profile in these treatments did not show significant difference. Acidity value in EE group was significantly higher than 2 other treatments. Also, the amount of toxic metals like Hg and As in oils obtained by EE method was significantly higher than that of WP and CE treatments. On the other hand, Pb level did not have a significant difference in the experimental groups.
Conclusion: Due to the quality of the obtained oil and the fact that EE method does not harm the environment, it can be a good method to extract fish oil.