Extraction of Antioxidants from Brown Algae Ascophyllum nodosum Using a Binary Solvent Extraction System

This research was aimed to understand the effects of extraction temperature, liquid-to-solid ratio, and ethanol concentration of an ethanol - water solvent system on crude antioxidants obtained from edible macroalgae Ascophyllum nodosum. The total phenol content (TPC), total carbohydrate content (TCC), and DPPH radical scavenging assays were measured for both the fresh extract (FE) and dried extract (DE). The highest TPC in FE was observed at 30 degrees C, 90 mL/g, and 100% ethanol concentration. The TCC of FE tended to increase with increasing temperature and decreasing liquid-to-solid ratio, while moderate ethanol concentration (40%) resulted in the highest TCC. The strongest antioxidant activity of the FE was observed at low temperatures (30 or 40 ??C), relatively low liquid-to-solid ratio (30 mL/g), and high ethanol concentration (80 or 100%). All DE, except for those obtained at 60 or 70 degrees C, showed lower TPC, TCC, and DPPH radical scavenging activity than their FE counterparts.