响应面法优化甜高粱籽粒总黄酮提取及主要组分测定

Optimization of Extraction Process by Response Surface Methodology and Determination of Main Components of Total Flavonoids from Sweet Sorghum Grain

确定甜高粱籽粒总黄酮最佳提取工艺,测定籽粒总黄酮主要组分及其含量,并评价其体外抗氧化性。以陇甜粱2号成熟期籽粒为研究对象,以黄酮含量为指标,在单因素实验基础上,利用响应面优化法确定甜高粱籽粒总黄酮最佳提取工艺为料液比1.0∶15.5(g/mL)、乙醇体积分数70%、提取温度80℃、超声时间29.5 min,所得黄酮含量理论为34.14 mg/g,实际可达(34.22±0.30)mg/g。采用高效液相色谱法(HPLC)测得陇甜粱2号籽粒总黄酮中(+)-儿茶素和芦丁含量最高,分别为3.5578、2.1146 mg/g。籽粒总黄酮清除羟基自由基(·OH)和1,1-二苯基-2-三硝基苯肼(DPPH)自由基的IC 50分别为0.5442、0.1438 mg/mL,1 mg/mL籽粒总黄酮溶液对DPPH自由基的清除率可达(93.31±0.60)%,具有良好的体外抗氧化性。

In this paper,the optimal extraction process of total flavonoids of sweet sorghum grain was determined,the main components and contents were measured,and the antioxidant activity in vitro was evaluated.Based on the single factor experiments,the optimal extraction process of total flavonoids from sweet sorghum(Longtianliang 2)grain at maturity was determined by response surface methodology with the content of flavonoids as the index,including the material-to-liquid ratio of 1.0∶15.5(g/mL),the ethanol concentration of 70%,the extraction temperature of 80℃,and the ultrasound duration of 29.5 minutes.The obtained flavonoid content was 34.14 mg/g in theory,and(34.22±0.30)mg/g in practice.The contents of catechin and rutin in the total flavonoids of Longtianliang 2 grains were the highest,being 3.5578 mg/g and 2.1146 mg/g,respectively.The IC 50 value of the extract for scavenging hydroxyl radical(•OH)and DPPH radical was 0.5442 mg/mL and 0.1438 mg/mL,respectively.The DPPH radical scavenging rate of 1 mg/mL total flavonoids solution was up to(93.31±0.60)%.The results indicated that it was feasible to extract total flavonoids from sweet sorghum grain by this process,and the extract had good antioxidant properties in vitro.