响应面复合酶法提取紫薯多糖及抗氧化活性研究

Study on Extraction of Polysaccharides from Purple Sweet Potato by Response Surface and Compound Enzymatic Methods and the Antioxidant Activity

为确定复合酶法提取紫薯多糖的最佳工艺及其抗氧化活性,以新鲜紫薯为原料,设计复合酶法多糖提取工艺单因素试验,并依据Plackett-Burman试验设计原理,分析每个因素的显著性,筛选关键因素,再利用Box-Behnken中心组合进行响应面分析,确定最优工艺。通过测定紫薯多糖对羟基自由基(·OH)、超氧阴离子自由基(O_(2)^(-)·)和1,1-二苯基-2-苦肼基(DPPH·)的清除能力评价其抗氧化活性。结果表明,复合酶法提取紫薯多糖的最佳工艺参数为液料比31∶1(mL/g),酶解时间95 min,复合酶添加量4%,酶解温度44℃,多糖得率为2.759%。最优提取工艺条件下紫薯多糖对·OH、DPPH·、O_(2)^(-)·的清除能力明显,且紫薯多糖浓度越高,清除率越大,虽然清除能力较抗坏血酸低,但紫薯多糖具有一定的抗氧化活性,有益身体健康。

In order to determine the best technology for extracting polysaccharides from purple sweet potato by compound enzymatic method and the antioxidant activity,in this experiment,fresh purple sweet potato is used as the raw material,single factor test is designed for the extraction process of polysaccharides by compound enzymatic method,and according to the Plackett-Burman experimental design principle,the significance of each factor is analyzed,and the key factors are screened.Response surface analysis is conducted using Box-Behnken center combination to determine the optimal process.The antioxidant activity of purple sweet potato polysaccharides is evaluated by determining their scavenging ability on hydroxyl radical(·OH),superoxide anion radical(O_(2)-·)and 1,1-diphenyl-2-picrhydrazyl(DPPH·).The results show that the optimal extraction process parameters of polysaccharides from purple sweet potato by compound enzymatic method are as follows:the liquid-solid ratio is 31∶1(mL/g),the enzymatic hydrolysis time is 95 min,the compound enzyme additive amount is 4%,the enzymatic hydrolysis temperature is 44℃,and the yield of polysaccharides is 2.759%.Under the optimal extraction conditions,purple sweet potato polysaccharides have obvious scavenging ability on·OH,DPPH·and O_(2)^(-)·,and the higher the concentration of purple sweet potato polysaccharides,the higher the scavenging rate.Although the scavenging ability is lower than that of ascorbic acid,purple sweet potato polysaccharides have certain antioxidant activity,which is beneficial to human health.