Optimization of Ultrasonic-Microwave Combined Extraction Process and Antioxidant Activity of Polysaccharides from Chroogomphus rutilus

In this paper, the best test conditions for extracting polysaccharides from Chroogomphus rutilus and its antioxidant activities were studied by ultrasonic-microwave extraction. Response surface experiment was used to optimize the ultrasonic-microwave extraction of Chroogomphus rutilus polysaccharides based on single factor experiments. The yield, extracting rate of Chroogomphus rutilus polysaccharides and antioxidant activities in vitro of Chroogomphus rutilus were compared with those obtained with traditional water extraction and ultrasonic extraction. The results indicated that the optimum conditions for the extraction of Chroogomphus rutilus polysaccharides by ultrasonic and microwave combined extraction were as follows:Ultrasonication time 8 min, microwave time 6 min, microwave temperature 92℃, and ratio of liquor to solvent 29:1 mL/g. The predicted value was 8.69%±0.19%. Compared with the traditional water extraction method, the extraction rate increased by 12.89% and the time reduced by 88.33%. Compared with the ultrasonic extraction method, the extraction rate increased by 8.63% and the time reduced by 30.00%. Different extraction methods had significant effects on hydroxyl radical scavenging rate, ABTS free radical scavenging rate, DPPH free radical scavenging rate, superoxide anion scavenging rate and reducing capacity. The antioxidant activities of the polysaccharides obtained by the three extraction methods in order from strong to weak was:The ultrasonic-microwave combined extraction method, ultrasonic extraction method, traditional water extraction method. Therefore, the use of ultrasonic and microwave combined extraction method could significantly improve the antioxidant activity of the polysaccharide of Chroogomphus rutilus.