Optimization of Extraction of Antioxidant Compounds in Microwave-Assisted Extracts of Brown Algae Sargassum angustifolium

Microwave-assisted extraction was applied for extraction of algal extracts from brown algal species (Sargassum angustifolium). Extraction condition consists of three solvents (ethanol, methanol and water), three extraction times and powers of microwave (10min×90W, 20min×180W and 30 min×270W) and three ratios of algae to solvent (1:5, 1:10 and 1:20). All the experimental parameters were applied at three levels according to Taguchi's statistical design. Total phenol contents, individual phenolic compounds, DPPH scavenging activity, ferrous reducing power and total antioxidant activity of the extracts were determined. According to results, the best condition for extraction of antioxidant compounds from S.angustifolium was aqueous extract, ratio of sample to solvent 1 to 20 and 30 minute extraction time and microwave power of 270 W. The TPC, DPPH scavenging activity, FRAP and TAA in optimized treatment are respectively; 2.60 TAE, 1.80 ASAE, %60.04 and 36.45 ASAE. The water extract of Sargassum have phenolic compund such as, gallic Acid (7.33 µg/ml), Protocatechuic acid (29.93 µg/ml) gentistic acid (15.15 µg/ml) and hydroxy benzoic acid (14.61 µg/ml). Results show that this algae was suitable for the extraction of antioxidant compounds.