Nutraceuticals have gained growing attention during the last year, becoming one of the most relevant areas of investigation. Among the existing natural sources of high value bioactive compounds, microalgae have assumed paramount importance. Indeed, they are a natural source of carotenoids, essential omega-3 fatty acids, proteins, carbohydrates, pigments, vitamins and minerals. Among these components, beta-carotene, a potent antioxidant pigment, is particularly attractive to the nutraceutical and cosmetic sector, being an ingredient in many supplements, functional, cosmetic and pharmaceutical products. Moreover, beta-carotene is one of the forms (precursor) of Vitamin A, which may be used in the manufacture of food supplements according to Directive 2002/46/EC. Even though some cyanobacteria produce beta-carotene (80% of total carotenoids) as the major components followed by zeaxanthin, the commercial biological source of beta-carotene is Dunaliella salina. This microalga lives in very saline environment and has the capacity to produce beta-carotene up to 10% of the dry weight. In this work, beta-carotenewas extracted by using supercritical CO2 under optimized operational conditions, resulting in increased amount of carotenoids (from 3.46% to 18.62%), proteins (from 10.03% to 43.08%), and lipids (from 3.49% to 7.93%). Then, the investigation on the main operational parameters affecting extraction from Dunaliella salina and a cost-effectiveness evaluation of the process are presented; the results evidence as 194.3-366.6 kWh/day reflecting a cost of 26.89-52.60euros/day are required for natural based beta-carotene recovery(59.3%) from Dunaliella salina.
Keywords: nutraceutical, microalgae, beta-carotene, Dunaliella salina, supercritical extraction.