Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Osman Kadir TOPUZ, Adem KAYA, Ali Can Alp
Microalgae are a recognized source of fatty acids and fatty acid-based lipids of potential interest in preparation of functional health products. Unlike terrestrial crops, these photoautotrophic microorganisms can directly produce polyunsaturated fatty acids (PUFA) and, although microalgae are not suitable for direct human consumption, their nutritional value can also be exploited if added to animal feeds. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) belongs to the omega-3 fatty acids group. In recent years, omega-3 fatty acids rich oil has attracted much attention because of its recognized beneficial effect on human health. In this study, response surface methodology was used to investigate the effect of ultrasound-assisted extraction variables including extraction temperature (25-6°C), extraction time (30-90 min.) and solvent: microalga ratio (10:1-30:1 ml:mg) on the omega-3 EPA content of N. oculata microalga. The experimental results showed that the extraction temperature and time were the significant parameters for the EPA rich oil extraction, while the solvent:microalga ratio was insignificant. The optimum oil extraction parameters for the maximum omega-3 EPA content were as follows: extraction temperature, 27.6°C; extraction time, 34.00 min. and solvent:microalga ratio, 21:3 ml:mg. Under the above predicted optimum conditions, the experimental oil yield and omega-3 EPA content were 62.8 % and 16.25%, respectively. The drying of algal biomass by freeze dryer improved the green color intensity and omega-3 EPA content.
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