Quality and fatty acid profiles of fish oil from tuna by-products extracted using a dry-rendering method

Djamaludin H, Sulistiyati TD, Chamidah A, Nurashikin P, Roifah M, Notonegoro H, Ferdian PR. 2023. Quality and fatty acid profiles of fish oil from tuna by-products extracted using a dry-rendering method. Biodiversitas 24: 6100-6106. Tuna is an export commodity with a high fat content, making it a valuable source of fish oil. However, a substantial portion of tuna, including viscera, eyes, and liver, some parts are underutilized, leading to waste. The study aims to determine the impact of extraction temperature (50°C, 60°C, and 70°C) on the yield, peroxide value, free fatty acids (%), p-anisidine value, and total oxidation value of the extracted oil from tuna (Euthynnus sp.) by-products. This research used the dry-rendering method to extract crude oil from tuna by-products and analyze quality characteristics and fatty acids. The results from the proximate value indicated that the crude lipid content in tuna by-products ranged from 13.03% to 19.01%. Extraction temperature significantly affected the yield, with the highest yield at 70°C correlating with the highest lipid content in innards. The lowest peroxide value is obtained from an extraction temperature of 50°C from all parts of tuna by-products, ranging from 2.01 to 2.09 meq/kg. Free fatty acid (%) levels in this study met the International Fish Oil Standards, and different temperature treatments had a significant effect (P<0.05). The p-anisidine lowest value of 6.11 meq/kg was obtained from an extraction temperature of 50°C for innards samples, and the p-anisidine value increased with temperature, reflecting secondary oxidation products. The total oxidation lowest value was obtained from extraction at 50°C (14.84 meq/kg) from viscera by International Fish Oil Standards (≤20 meq/kg), and it was within acceptable limits. The fatty acid profile of the crude extract of tuna by-product oil resulting from extraction at a temperature of 50°C, where extraction results at 50°C obtained a fatty acid profile of saturated fatty acids>mono-unsaturated fatty acids>poly-unsaturated fatty acids, with significant levels of omega-3 fatty acids such as eicosapentaenoic acid and docosahexaenoic acid.