Title: Comparison and evaluation of the quality of fish oil and fishmeal extracted from the heads of Yellowfin tuma (Thunnus albacares) and Albacore tuna (Thunnus alalunga)

This study focuses on the utilization of tuna heads and exploring its efficiency. Fish oil and fish meal were extracted from the heads of two tuna species, albacore tuna (Thunnus alalunga) and yellowfin tuna (Thunnus albacares), using an experimental method performed under laboratory conditions. These by-products were investigated for proximate composition and quality analysis. The crude fish oil and semi-refined fish oil extracted from both species had a similar yield of 2% and 1% respectively. The fishmeal also had a somewhat similar yield around 23% from both species. The fatty acid composition of the oil was analyzed and the saturated fatty acid, mono-unsaturated fatty acid and poly-unsaturated fatty acid that had been detected ranged from 1.67- 37.99%, 3.17-38.34%, and 0.70-34.99% respectively. Palmitic acid, oleic acid and DHA were the dominant fatty acids in both oils. The albacore tuna liquid phase and semi-refined oil had lower oxidation by-product values and higher omega-3 fatty acids than the yellowfin tuna, but an extremely low lipid content and a very high moisture content, which would make it unacceptable for the consumer despite the desired fatty acid profile and required quality factors. The overall composition and quality factors of the yellowfin tuna oil were within the standard range and is according to these parameters considered an acceptable edible fish oil. The level of Hg, Pb and Cd was similar and within acceptable levels, whereas As had high levels in the tunas. The fishmeal protein content was 59.1% for albacore tuna and 56.2% for yellowfin tuna.