EXTRACTION AND ANTIOXIDANT ACTIVITY OF CAROTENOID FROM ALGAE Chaetomorpha linum

Carotenoids are natural pigments that are found in plants, algae and microorganisms and have antioxidant, anti-inflammatory and disease prevention properties. The effect of various factors on carotenoid extraction from Chaetomorpha linum by static maceration and ultrasound-assisted extraction (UAE) was investigated. The effect of five solvents (ethanol, methanol, n-hexane, petroleum ether and acetone), the static extraction time (60, 90, 120, 150 and 180 minutes), the static extraction temperature (30, 40, 50, 60 and 70 °C) and the solid to solvent ratio (1:20, 1:25, 1:30, 1:35 and 1:40 w/v) were systematically investigated. Ultrasound-assisted extraction was examined at solid-to-solvent ratios (1:30, 1:35, 1:40, 1:45 and 1:50 w/v), amplitudes (20, 25, 30, 35 and 40%) and sonication times (5, 10, 15, 20 and 25 minutes). Use of response surface methodology (RSM) followed for the optimisation of the ultrasound-assisted extraction conditions. The antioxidant activity of the extracts obtained was assessed by two different assays: FRAP (ferric reducing antioxidant power) and RP (reducing power). The ultrasound assisted extraction process produced a higher amount of carotenoids (3.016 mg/g DM) than static maceration (2.819 mg/g DM). The RSM optimum was a solid-to-solvent ratio of 1:46 w/w, 36.3% amplitude and 16.39 minutes of sonication. Antioxidant activity was confirmed by both FRAP and RP. The findings indicated that C. linum could be a valuable source of bioactive carotenoids and ultrasound-assisted extraction could enhance the yield and antioxidant capability for food and biomedical uses.