白及多糖的超声-微波协同提取工艺及其抗氧化活性研究

目的:研究白及多糖的超声-微波协同提取工艺优化及其抗氧化活性。方法:以多糖得率为考察指标,通过单因素实验对料液比、浸泡时间、微波功率和协同提取时间4个影响因素进行考察,采用正交实验设计对超声波-微波协同提取白及多糖的工艺条件进行优化,并研究白及多糖对羟基自由基（·OH）、超氧阴离子（O₂^-·）和1,1-二苯基-2-苦肼基自由基（DPPH·）的清除率以评价其体外抗氧化活性。结果:最佳提取工艺条件为:液料比20∶1 m L/g,浸泡时间6 min,微波功率200 W,协同提取时间5 min,该工艺条件下多糖得率达6.98%±0.19%。单独超声波提取法和单独微波提取法的多糖得率仅为超声-微波协同提取法的46.28%和87.96%,表明超声-微波协同提取优于单独超声波提取和单独微波提取。抗氧化活性研究表明在实验范围内,白及多糖对O-2·无明显清除作用,但对·OH和DPPH·具有明显的清除作用,采用超声-微波协同提取法提取的白及多糖较微波提取法具有更高的·OH和DPPH·清除活性,当多糖浓度为0.5 mg/m L时,对·OH和DPPH·清除率分别为92.82%和74.21%。结论:超声-微波协同提取具有省时高效的特点,特别适用于多糖类物质的提取。 

Study on ultrasonic- microwave synergistic extraction of polysaccharose from Bletilla striata and its antioxidant activity

Objective: To study the ultrasonic- microwave synergistic extraction of Bletilla striata polysaccharose and its antioxidant activity. Methods: Used polysaccharose yield as index,the liquid / solid ratio,immersion time,microwave power,extraction time were prescreened by single factor test.And the main factors levels were selected by orthogonal test design to optimize the best conditions of ultrasonic- microwave synergistic extraction technology.In vitro antioxidant activities of Bletilla striata polysaccharose were evaluated through the clearance abilities of hydroxyl radicals( ·OH) 、O_2~-· and DPPH·.Results: The optimum technological conditions were as follows: liquid / solid ratio 20∶ 1( m L / g),immersion time 6 min,microwave power 200 W,extraction time 5 min. Under the optimum conditions,the yield of lentinan was 6.98% ± 0.19%. The ultrasonic- microwave synergistic extraction technology was better than single ultrasonic extraction and single microwave extraction. Within the scope of the experiment,Bletilla striata polysaccharose had no obvious scavenging effect of O-2,but had good scavenging effect of ·OH and DPPH·.Bletilla striata polysaccharose,which was extracted with ultrasonic- microwave synergistic extraction,had higher scavenging activities of ·OH and DPPH· than that of microwave extractiontechnology. When the polysaccharose concentration of 0.5 mg / m L,the scavenging yields of·OH and DPPH·were92.82% and 74.21%. Conclusion: The ultrasonic- microwave synergistic extraction technology,which had many advantages such as saving time and high efficiency,was especially suitable for the extraction of polysaccharide substance.