Physicochemical and Fatty Acid Profile of Refined Tuna Fish Oil By-Product from Canning and Meal Fish Industries

Fish oil by-product (FOB) recovered from the precooking process in the cannery industry and the pressing process in fish meal production are potential resources. However, this fish oil still needs a refinery process to improve the quality of fish oil. This study aimed to identify the physicochemical characteristics of the initial fish oil by-product, the physicochemical profiles, and fatty acids of the fish oil by-product after degumming neutralization and bleaching (bentonite, zeolite, and carbon adsorbents) processes from the cannery and fish meal industry. Results showed the initial physicochemical characteristics of fish oil waste from fish flour have lower quality than canned products (acid value, free fatty acids, PV, AV, TOTOX value, viscosity, and refractive index) but are inversely proportional to the iodine value. Results showed degumming (D) and neutralization (N) processes from the Fish oil canning process (FCP) and Fish oil meal process (FMP) could improve the quality parameters of fish oil by-products by reducing the acid value (7.90, 0.65, 9.17, 0.58  mg KOH/g), respectively;  free fatty acid (3.97, 0.33, 4.60, 0.29 % oleic) respectively; peroxide value (PV) (15.18, 7.38, 17.64, 7.10 mEq/kg), respectively;  anisidine value (AV) (14.36, 6.61, 14.64, 6.51) respectively; total oxidation (TOTOX) value (44.72, 21.37, 49.64, 20.71) respectively; and iodine (167, 153, 163, 155 mg/100 g), respectively as well as increasing the lightness (23.80, 25.70, 20.65, 26.00), respectively. In the bleaching process (B), zeolite (15 %) was an effective adsorbent to obtain oil with the best quality parameters due to zeolite possessed greater polarity and surface area at a higher concentration, which resulted in the acid value for FCP and FMP (0.26, 0.22 mg KOH/g); free fatty acid (0.13, 0.15 % oleic); PV (2.44, 5.71 mEq/kg); AV (2.5, 4.9); TOTOX value (7.16, 9.11); and iodine (138, 151 mg/100 g) as well as increasing the lightness (37.08, 36.74) that are appropriate to International Fishmeal & Oil Manufacturers Association (IFOMA), Codex Alimentarius Committee (CAC), and International Fish Oils Standards (IFOS) standards (p < 0.05). All adsorbents effectively increase the brightness of the FOB. The higher the concentration of adsorbents, the higher the clarity of the FOB. For zeolite absorbents, there was an increase of 16.73 - 32.3 % for FCP and 15.39 - 32.69 % for FMP, but the viscosity decreased with a range of 24.50 - 36.50 cPs. FCP contains 14 fatty acids, while FMP contains 12 fatty acids. The number of SFA and MUFA detected in FCP is lower than in FMP. In contrast, the amount of PUFA in FCP is relatively higher than in FMP. The percentage of EPA and DHA in FCP is lower than in FMP. Overall, the refining process affects the fatty acid composition of fish oil by-products both in the canning process and in fish meal. HIGHLIGHTS   Fish oil by-product (FOB) of yellowfin tuna (Thunnus albacares) from the fish canning process (CP), and fish meal process (MP) streams were successfully purified through a chemical process which was by IFOMA, CAC, and IFOSH standards Zeolite resulted in the best fish oil quality at higher concentrations The Final Fish oil canning process (FCP) was mainly composed of linoleic, whereas the Fish oil meal process (FMP) was highly distributed in oleic and palmitic acid The sum of PUFA in FCP after bleaching was relatively higher than in FMP GRAPHICAL ABSTRACT