Jump to Main Content
One-Step Concentration of Highly Unsaturated Fatty Acids from Tuna Oil by Low-Temperature Crystallization
- Zhang, Yu, Wang, Xiaosan, Xie, Dan, Li, Yongru, Wang, Xingguo
- The journal of the American Oil Chemists' Society 2017 v.94 no.3 pp. 475-483
- acetonitrile, crystallization, docosahexaenoic acid, docosapentaenoic acid, eicosapentaenoic acid, evaporation, free fatty acids, highly unsaturated fatty acids, human health, nutrition, solvents, temperature, tuna oil, United States
- Highly unsaturated fatty acids (HUFA), including eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3 and 22:5n-6) and docosahexaenoic acid (DHA, 22:6n-3), play an important role in human health and nutrition. In this study, concentration of HUFA in free fatty acids (FFA) form by low-temperature crystallization was investigated. For this purpose, tuna oil (7.1% EPA, 26.8% DHA) was first converted into corresponding FFA. Subsequently, crystallization conditions of various solvent types, the ratio of FFA to acetonitrile, operation temperature and crystallization time were optimized at a small scale of 2 g tuna oil fatty acids. Taking purity and yield into account, the optimum conditions were a 1:10 ratio of FFA to acetonitrile (w/v), −60 °C, and 1 h. The optimal conditions resulted in concentrations of EPA, DHA and HUFA of 15.1, 58.4 and 79.6%, respectively, with corresponding yields of 61.5, 61.8 and 60.7%, respectively. Crystallization was carried out under the optimal conditions at a large scale of 200 g tuna oil FFA, and a similar concentration result was achieved. After evaporating away the solvent, the residual amount of acetonitrile met the US Pharmacopoeia requirement of <410 ppm. The process for enrichment of HUFA is readily scalable, effective and time-saving.