油橄榄叶羟基酪醇提取工艺优化及抗氧化研究

Study on Extraction Processing Optimization of Hydrotyrosol from Olive Leaves and Their Antioxidant Activities

研究油橄榄叶中羟基酪醇(HT)的最佳提取工艺及其抗氧化活性。在单因素试验基础上,采用BoxBehnken中心组合设计原理,研究了提取温度、时间、盐酸浓度和液料比对羟基酪醇提取率的影响。比较了不同浓度羟基酪醇、维生素C、橄榄叶粗提物、白藜芦醇的还原能力、羟自由基清除能力以及DPPH·清除能力大小。以羟基酪醇提取率为响应值,利用Design Expert 7.0软件得到回归方程的预测模型并进行响应面分析;油橄榄叶羟基酪醇最佳提取条件为:液料比50.74︰1(m L/g),提取温度92.39℃,盐酸浓度0.14 mol/L,提取时间6.02 h。该条件下羟基酪醇的提取率达到0.58%。验证性试验表明,所得模拟方程能较好地预测试验的结果。体外抗氧化试验结果表明,HT具有较强的体外抗氧化活性,对DPPH·清除的能力超过了维生素C。

The optimal extracting conditions of hydroxytyrosol from olive leaves were investigated and their antioxidant capacities in vitro were also determined. On the basis of single factor experiment, Box-Behnken central combination designer was used to study the effect of extracting temperature, extracting time, HC1 concentration and solid-liquid ratio on the extracting rate of hydroxytyrosol （HT） from olive leaves produced in Wudou district in Gansu province, and then antioxidant activity in vitro of liT was also investigated. With extracting rate of liT as response value, Design Expert 7.0 was used to get regression equation and response surface method was analyzed. The optimum extracting conditions were following as liquid-solid ratio 50.74 ： 1 （mL/g）, optimum temperature 92.39℃, HC1 concentration 0.14 mol/L and the best extracting time 6.02 h. Under the optimum extracting conditions, the extracting ratio of HT was amounted to 0.58%. The antioxidant activities in vitro with DPPH method were indicated that HT had stronger antioxidant capacity than that of vitamin C, a common food additive.