| Abstract
| - In this work, extraction of antioxidant compounds from Dunaliella salina microalga is optimized bycombining pressurized liquid extraction (PLE) and experimental design (three-level factorial design)with three different solvents (hexane, ethanol, and water). Two main factors were considered, theextraction temperature (40, 100, and 160 °C) and the extraction time (5, 17.5, and 30 min). As responsevariables, the extraction yield (percent dry weight/initial weight) and the antioxidant activity of theextracts (determined using the TEAC method) were used. The parameters of the model were estimatedby multiple linear regression. Results showed that the extraction temperature was the factor havingthe strongest influence (positive) on the two response variables. The best yields were obtained withethanol at the higher extraction temperature and time tested. Besides, although hexane extractsprovided the best antioxidant activity, ethanol extracts were also very active. The chemicalcharacterization of ethanol extracts was carried out using HPLC-DAD, and attempts have been madeto correlate their chemical composition with the antioxidant activity measured. Results pointed outthat the extracts contained, besides all-trans-β-carotene and isomers, several different minorcarotenoids that seemed to make a contribution to the antioxidant activity of the extracts. Keywords: PLE; Dunaliella salina; TEAC; antioxidant compounds; optimization
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