Quality Evaluation of Oil Recovered from By-products of Bigeye Tuna Using Supercritical Carbon Dioxide Extraction
2017
Ahmed, Raju | Haq, Monjurul | Cho, Yeon-Jin | Chun, Byung-Soo
Supercritical carbon dioxide (SE) and Soxhlet extractions with hexane (HE) were used to obtain oil from skins, scales and bones of bigeye tuna (Thunnus obesus). SE was done at a previously optimized conditions of 40° C and a pressure of 25 MPa with a gas-flow rate of 10 kg/h. By SE, 85.6, 83.2 and 87.7% of oil was recovered (extractability) from skins, scales and bones, respectively, considering the HE extraction to be the total oil. The oils obtained with SE and HE were evaluated for their physicochemical properties such as color, viscosity, acid value, peroxide value, free fatty acid value, fatty acid compositions and heavy metal content. The oils contained 27.7-31.5% polyunsaturated fatty acids including 24.7-28.3% eicosapentaenoic and docosahexaenoic acid. The extraction method did not significantly affect fatty acid composition (P>0.05) except for EPA and DHA. SE significantly (P≤0.05) reduced the heavy metal content of the oil. The color and viscosity were better by SE than HE. The acid, peroxide and free fatty acid values were also lower by SE than HE, suggesting that SE may be a potential commercial way to get a high qualified oil.
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