Subscribe to RSS
DOI: 10.1055/s-0034-1394616
Supercritical fluid extraction of carotenoids from Ulva lactuca (Chlorophyta)
Ulva lactuca is an edible species of green macroalgae containing a high amount of nutrients and functional bioactive compounds such as carotenoids. Industrially, carotenoids are used in pharmaceuticals, animal feed and as colorants in cosmetics and foods [1]. However, most of the naturally produced and harvested U. lactuca biomass is not optimally used nowadays [2]. One reason is the absence of environmentally friendly, efficient, and industrially viable technologies for extraction processes. Supercritical fluid extraction (SCFE) is a promising alternative separation technique in the field of food and nutraceutical applications. SCFE has been found to be selective in the extraction of desired compounds without leaving toxic residues in extracts and to reduce the risk of degradation of thermal labile or easily oxidized compounds such as lipids and carotenoids [3]. The aim of this study was to characterize the effect of pressure (100 to 400 bars), temperature (35 and 55 °C), and percentage of co-solvent (0 and 5%) on SCFE of carotenoids from freeze-dried Ulva lactuca (Fig. 1). By considering the economic viability of the process as well as the possible thermal degradation of carotenoids, especially in industrial scale, it is not recommended to increase the pressure and temperature beyond the range studied. All the experiments were carried out with a solvent flow rate of 20 g/min for three hours and results were compared with conventional EtOH extraction. In both SCFE processes, the highest carotenoid content and total extract yield were obtained at 400 bars and 55 ° C. Applying SC-CO2 was not as efficient as conventional extraction in pure EtOH. However, adding 5% of EtOH as co-solvent increased the total carotenoid content to about 55 mg/kg of dried alga, which is 70% and 53% higher than the amount obtained using pure SC-CO2 and EtOH, respectively. The SCFE technique is promising and should be considered for further investigation under different flow rates and scales.
Keywords: Green macroalgae, Supercritical fluid extraction, Carotenoids
References:
[1] Yaich H, Garna H, Besbes S, Paquot M, Blecker C, Attia H. Chemical composition and functional properties of Ulva lactuca seaweed collected in Tunisia. Food Chem 2011; 128: 895 – 901.
[2] Bruhn A, Dahl J, Nielsen HB, Nikolaisen LS, Rasmussen MB, Markager S, Olesen B, Arias C, Jensen PD. Bioenergy potential of Ulva lactuca: growth yield, methane production and combustion. In, Bioresour Technol; 2011: 2595 – 2604.
[3] Macías-Sánchez MD, Mantell Serrano C, Rodríguez Rodríguez M, Martínez de la Ossa E, Lubián LM, Montero O. Extraction of carotenoids and chlorophyll from microalgae with supercritical carbon dioxide and ethanol as cosolvent. J Sep Sci 2008; 31: 1352 – 1362.