Extraction and flocculation properties of okra polysaccharide

Three kinds of polysaccharide were extracted from okra fruit by ultrasonic technology using water, acid and alkali as soaking solvents.They were characterized by infrared spectroscopy and gel permeation chromatography.The results showed that three kinds of polysaccharide had almost the same composition and different molecular weight. Using kaolin suspensions as flocculating object, the flocculation properties of okra polysaccharide, ferric sulfate and ferric sulfate-okra polysaccharide composite flocculant were investigated.The results suggested that poor flocculation properties were exhibited by adding only okra polysaccharide as flocculant.Only the concentration of Fe³⁺close to 0.1 mmol/L, ferric sulfate could reach flocculation rate of90%.However, ferric sulfate-okra polysaccharide composite flocculant could reach flocculation rate of 90% in a wide Fe³⁺concentration range of 0.1⁰.6 mmol/L, and the flocculation time was also short.The order of flocculation rate from high to low and flocculation time from short to long was okra polysaccharide extracted by alkaline, okra polysaccharide extracted by acid and okra polysaccharide extracted by water.