CHARACTERIZATION OF THE EXTRACELLULAR POLYSACCHARIDE FROM FRESH-WATERMICROALGAE CHLORELLA SP

The aim of this study was the characterization of the extracellular po lysaccharide (gum) from freshwater microalgae Chlorella sp. For this p urpose, determination of the component monosaccharides and minerals we re chosen as the structural properties, while the thickening effect on aqueous systems and the effect on the dispersed phase volume fraction of oil in water (o/w) emulsions were selected as the functional prope rties. The gum was found to contain the monosaccharides: glucuronic ac id (385 g/kg); arabinose (325 g/kg); glucose (193 g/kg); fucose [alpha - and beta-anomers (31 g/kg and 14 g/kg, respectively)]; and the miner als: calcium (16.3 g/kg); sodium (7.7 g/kg); potassium (20.4 g/kg); an d zinc (1.1 g/kg) reported on a dry weight basis. The gum from Chlorel la sp. was found to be a potential thickening agent. Its thickening an d secondary emulsifying effects were found to be compatible with most of the food-grade salts when these salts are used in the recommended r ange (1 to 30 g/L) for foods. It was found that its thickening and sec ondary emulsifying effects are confined to the acidic range (pH 4 to 6 ).