大叶千斤拔多糖的超声波提取工艺及其抗氧化抑菌活性研究

Study on ultrasonic extraction technology of polysaccharides from Flemingia macrophylla (Willd.) and their antioxidant and antibacterial activities

开展大叶千斤拔多糖(FMP)的超声波提取工艺及其抗氧化抑菌活性研究。以FMP得率和FMP纯度的总评归一值为优选指标,采用正交设计表L9(34)优选FMP的超声波提取工艺,并采用醇沉法纯化并制备为精制FMP,并以1,1-二苯基-2-苦肼基(DPPH)自由基法测定FMP对DPPH自由基的清除活性,Schall烘箱储藏法测定FMP对花生油和玉米油的抗油脂氧化活性,以及纸片扩散法测定FMP的抑菌活性。所优选的FMP的提取条件为:超声波功率为160W、提取温度为60℃、料液比为1∶25(g/mL)和提取时间为30min,此时FMP纯度为31.02±0.14%,FMP得率为7.13±0.09%,经二次醇沉后,FMP纯度可达78.56%。在实验范围内,FMP对DPPH的清除作用与浓度存在明显的量效关系,FMP对DPPH清除率可达81.04%,其半数清除浓度(IC50)为3.328mg·mL^-1;FMP可较好地减缓花生油和玉米油的自氧化速度,FMP(0.06%)的抗油脂氧化效果与BHT(0.02%)相当;FMP抑菌作用大小依次为金黄色葡萄球菌>大肠杆菌>枯草芽孢杆菌,最小抑菌浓度(MIC)分别为2、4和4mg·mL^-1。FMP具有一定的清除DPPH活性、抗油脂氧化活性和抑菌活性,具有开发成为天然的食品抗氧化剂和防腐剂的潜力,有待进一步研究。

Ultrasonic extraction technology of Polysaccharides from Flemingia macrophylla(Willd.)and their antioxidant and antibacterial activity were studied.The polysaccharides’yield and purity were used as indexes,and orthogonal experiment was applied to optimize the extraction conditions.The refined polysaccharides of Flemingia macrophylla(FMP)were purified by alcohol precipitation method.The DPPH scavenging activities by FMP were determined.The antioxidant activities in peanut oil and corn oil were determined by Schall oven storage method.The antibacterial activities were determined by disc diffusion method.The optimum extraction conditions were as follows:solid/liquid ratio 1∶25(g/mL),ultrasonic power 180W,extraction temperature 60℃,extraction time 30 min.Under the optimum conditions,the yield of polysaccharidess was 7.13±0.09%,the purity of polysaccharidess was 31.02±0.14%.The FMP showed good scavenging activity on DPPH.When the polysaccharides concentration was 8.0 mg/mL,DPPH scavenging capacity and IC50 were 80.04%and 3.328mg/mL,respectively.In addition,FMP can obviously decrease the oxidation rate of peanut oil and corn oil.The antilipid oxidation capacity of 0.06%FMP is equivalent to that of 0.02% butylated hydroxytoluene(BHT).The order of FMP’s on inhibition of bacterial was Staphylococcus aureus>Escherichia coli>Bacillus subtilis,and MIC was 2、4 and 4 mg/mL,respectively.FMP showed some scavenging activity to DPPH,some antioxidant activities in peanut oil and corn oil as well as some antibacterial activity.FMP has the potential to be used as natural food antioxidant and preservative.Further study is needed.