Effect of Different Extraction Methods on the Properties of Longan Polysaccharides

Five different extraction methods(hot water extraction,enzymatic extraction,alkali extraction,acid extraction and ultrasonic extraction) were used to extract longan polysaccharides.The extraction yield,reducing power,DPPH radical scavenging activity and monosaccharide composition were evaluated to compare the advantage and disadvantage of different extraction methods.The results showed that polysaccharide prepared by enzymatic extraction had the highest extraction yield 6.78%,while that of alkali extraction had the lowest yield 1.84%.The polysaccharide prepared by enzymatic extraction exhibited the strongest antioxidant activity,ultrasonic extraction ranked the second,while that of alkali extraction showed the lowest antioxidant activity.