PULSED ELECTRICAL FIELDS (PEF) PRETREATMENT TO ENHANCE THE EXTRACTION OF PIGMENTS FROM TETRASELMIS CHUII MICROALGAE Fadila Al Khawli1, Marialena Kokkali2, Francisco J. Martí-Quijal1, María J. Ruiz, Francisco J. Barba1, Emilia Ferrer1, Katerina Kousoulaki2 1
Department of Preventive Medicine and Public Health, Food Science, Toxicology and Forensic
Medicine, Faculty of Pharmacy, Universitat de València, Avda. Vicent Andrés Estellés, s/n 46100 Burjassot, València. 2Department of Nutrition and Feed Technology, Nofima AS, 5141 Bergen, Norway
Marine microalgae, such as Tetraselmis chuii (T. chuii), have become well-known over the last decades as a good source of several nutrients and bioactive compounds. Carotenoids (Cr) and chlorophylls (Chl), the major pigment species in microalgae, have shown the interest due to their food colorants, antioxidant and anti-inflammatory role among others. Thus, these pigments have been widely used in cosmetics, food and pharmaceutical applications. However, the extraction of pigments was based on the application of traditional methods (maceration and thermal extraction using different solvents). Green solvents or binary water with organic solvent mixture was used, reducing the amount of solvent. In addition, in order to enhance the extraction efficiency of valuable compounds from microalgae, the application of pulsed electrical fields (PEF) for the extraction was proved. PEF assisted technology, which is a non-thermal treatment of very short duration (several nanoseconds or milliseconds) with electrical pulses amplitudes from 100V/cm to 10KV/cm, was used as an effective tool for the extraction of valuable compounds from microalgae. The effect of the pretreatment of dried T. chuii using PEF as well as the effect of extraction time and type of solvent on the amount of Cr, chlorophyll A, chlorophyll B and total chlorophyll was evaluated. Extraction time and solvent were tested at two levels each one (4h vs 24h & water vs DMSO, respectively), while treatment with PEF was tested at three-level factor (No treatment, PEF1: 1KV/cm and 400 pulses, PEF2: 3KV/cm and 45 pulses). The Cr and Chl content was estimated spectrometrically according to the method described by Lichtenthaler and Buschmann (2001). It was shown that the higher amounts of all pigments were extracted after PEF2 treatment and incubation of 24h using DMSO as solvent. In conclusion, PEF treatment, extraction solvent and time affected significantly the amounts of pigments extracted from T. chuii.
Keywords: Microalgae, Tetraselmis chuii, Pulsed electrical fields, carotenoids, chlorophyll.
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