Study on extraction and antioxidant activity of polysaccharides from ginkgo residue by ultrasonic wave and microwave

Synergistic extraction technology of polysaccharides from ginkgo residue was studied by using an ultrasound wave and microwave synergistic extraction equipment.Effects of microwave power,extraction time and ratio of material to liquid on extraction rate of polysaccharides were investigated through single factor and orthogonal test.The optimum extraction conditions for polysaccharides were identified as the follows:purified water as solvent,ratio of raw material to extract solvent 1:20(W/V),synergistic extraction time 100s with ultrasound wave and microwave which power of microwave was 300W for one time.The extraction yield was 5.07%,which was about 88.7% that of hot water refluxing extraction for 6h.The antioxidant activity of polysaccharides was studied.Results showed that the extract of polysaccharides had good scavenging effect to hydroxyl free radical and DPPH free radical,and the scavenging activity had obvious dose-effect relationship of concentration.