Chromatographic methods for Nannochloropsis gaditana microalgae extracts' profiling

Resumen del trabajo presentado al XVI Scientific Meeting of the Spanish Society of Chromatography and Related Techniques, celebrado en Sevilla (España) del 2 al 4 de noviembre de 2016.Microalgae are natural products that have gained a lot of attention in the last years as a feedstock for biorefinery. They are rich in bioactive compounds such as long chain polyunsaturated fatty acids (LC‐PUFAs), carotenoids and proteins. The development of sustainable processes for the fractionation of natural products in biofuels plus ingredients for nutraceuticals, cosmetics or bioplastics is a hot topic of research nowadays. In the present work, the extraction of bioactive compounds with antioxidant activity from Nannochloropsis gaditana has been investigated. High‐pressure homogenization (HPH) was used to break down the strong cell wall. Supercritical fluid extraction (SFE) using pure CO2 was performed based on previous reports available in the literature. The remaining byproduct was treated by pressurized liquid extraction (PLE). An experimental design based on response surface methodology (RSM) was proposed for the recovery of bioactive compounds by PLE using green solvents such as water and ethanol. Solvent composition and temperature were the independent factors. Several chromatographic methods were used for the characterization of the obtained extracts, in an attempt to correlate the composition of the extracts with the antioxidant activity obtained. Reverse phase High‐performance liquid chromatography with diode array detection (HPLC‐DAD) was used for the characterization of pigments profile; normal phase HPLC with evaporative light scattering detection (HPLC‐ELSD) was used for the study of lipids profile, and gas chromatography with mass spectrometry detection (GC‐MS) was employed to determine the fatty acids profile. The present study points out the importance of chromatographic methods as essential analytical tools in the field of food science and natural products research.The authors acknowledge funding from EU MIRACLES project (Grant agreement 613588) (http://miraclesproject.eu/). B.G.L. thanks MINECO (Ministerio de Economía y Competitividad) for her Juan de la Cierva postdoctoral research contract.Peer Reviewe