摘要:采用正交设计对水浸提法、水浸提+微波辅助法、乙醇浸提法、乙醇浸提+微波辅助法进行比较,以咖啡提取物中绿原酸的含量为评判指标,考察时间、温度、乙醇体积分数、微波功率等对提取物有效成分绿原酸含量的影响。采用高效液相色谱法测定该成分的含量。结果表明,绿原酸最佳提取工艺为乙醇浸提+微波辅助法,最佳提取条件为微波时间5 min,功率300 W,乙醇体积分数60%,此条件下提取绿原酸的含量最高。影响提取的主次因素为:乙醇体积分数>功率>微波时间。
关键词:咖啡;绿原酸;高效液相色谱法;正交设计
Abstract: Using the content of chlorogenic acid of coffee as indexes, four extraction methods including water extracting method, water+microwave extracting method, ethanol extracting method and ethanol+microwave extracting method were compared with orthogonal design. The factors affecting the content of chlorogenic acid such as the extracting time, the extracting temperature, the volume fraction of ethanol and microwave power were studied. The content of chlorogenic acid was determined by HPLC. The results showed that the optimal method was ethanol+microwave. The optimal extraction conditions were microwave 5 min, 300 W and 60% ethanol. Under these conditions, the content of chlorogenic acid reached the highest level. The factors affecting extraction efficiency were in the order of volume fraction of ethanol>power>times of microwave extraction.
Key words:coffee;chlorogenic acid;HPLC;orthogonal design
1 材料与方法
1.1 材料与仪器
试验所用咖啡豆为市售咖啡豆。绿原酸标准品、甲醇、乙醇为色谱纯;冰醋酸为分析纯。
绿原酸含量=C×V×N/W×100%
式中,C为测量液总绿原酸浓度(mg/mL);V为粗提液体积(mL);N为稀释倍数;W为原料重量(mg)。
2 结果与分析
2.1 方法学考察
2.1.4 重复性考察 取咖啡样品,按供试样品溶液的制备方法得到6份溶液,精确吸取5 μL, 注入高效液相色谱仪检测。结果表明,绿原酸保留时间的RSD=0.753%,峰面积的RSD=1.589%,结果表明该方法的重复性良好。
2.2 正交试验结果
3 讨论
微波提取技术具有快速简便、高效、不易破坏天然活性成分等优点。由于微波辐射对吸收介质有瞬时加热的特性,密封容器有与外界隔绝和增温增压的作用,故利用微波浸提技术,可使样品在很短时间内得以较完全的浸提[11]。本研究中采用高效液相色谱法分析从咖啡中提取绿原酸的4种方法,结果表明最佳提取工艺为乙醇浸提+微波辅助法,最佳提取条件为微波时间5 min,功率300 W,乙醇体积分数60%,此条件下提取到的绿原酸含量最高。影响提取的主次因素为乙醇体积分数、功率、微波时间。本研究为从咖啡中提取绿原酸提供了一种高效、节能的新型提取工艺,为更加广泛及合理地利用丰富的资源,大力开展绿原酸的提取、纯化与绿原酸产品的开发研究提供了一些理论依据。
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