Planta Med 2014; 80 - P1N26
DOI: 10.1055/s-0034-1394616

Supercritical fluid extraction of carotenoids from Ulva lactuca (Chlorophyta)

BR Parjikolaei 1, LC Cardoso 2, MT Fernandez-Ponce 2, CM Serano 2, A Bruhn 3, KV Christensen 1, XC Fretté 1
  • 1Department of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
  • 2Department of Chemical Engineering and Food Technology, Science Faculty, University of Cádiz International Agri-food Campus of Excellence, ceiA3, P.O.Box 40, Puerto Real 11510, Cádiz, Spain
  • 3Department of Bioscience, Aarhus University, Vejlsøvej 25, DK-8600 Silkeborg, Denmark

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.

Fig. 1: Total carotenoid content and total extract yield of freeze-dried Ulva lactuca at 20 g/min flow rate (*Data on top of each bar represents the total extract yield (%)).

Keywords: Green macroalgae, Supercritical fluid extraction, Carotenoids

References:

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