超声波辅助提取茶多糖及其分子量变化的研究

为了解超声波强化茶多糖提取的效果及其对茶多糖分子量的影响,本实验研究了茶多糖提取过程中温度、液料比、时间、pH值及超声功率等因素对提取率的影响。实验结果表明,传统提取方法的最优条件为:温度60℃,液料比20:1,时间120min,pH值6.0,在最优条件下茶多糖的得率为4.26%;超声波辅助提取法的最优条件为:超声功率150W,液料比30:1,时间40min,温度60℃,pH值7.0,在此条件下茶多糖的得率为5.15%。提取得到的茶多糖样品通过GPC测定,传统提取法得到的茶多糖样品平均相对分子质量为66439,而超声波提取得到的样品的平均相对分子质量为47447。超声波辅助提取可明显提高茶多糖的得率,但同时对茶多糖产生降解作用。

Study on Effects of Ultrasonic on Extracion of Tea Polysaccharide and Changes of Molecular Weight

In order to find out the effects of ultrasonic on the extraction and relative molecular weight of tea polysaccharide, the factors including temperature, material to liquid ratio, time, pH and ultrasonic power, which affect the extraction rate of tea polysaccharide were studied. The test was arrange by orthogonal design. The results showed that the optimum conditions of the traditional preparation method are: 60 ℃, 20:1 of the material to liquid ratio, 120 min, pH6.0; under these conditions, the extraction yield of tea polysaccharide is 4.26%. The optimum conditions of ultrasonic-assisted extraction are: 150 W, 30:1 of the material to liquid ratio, 40 min, 60 ℃, pH7.0, and the extraction yield of tea polysaccharide is 5.15%. Through the GPC determining, relative molecular weight of tea polysaccharide obtained from conventional extraction is 66439, and that of tea polysaccharide obtained from ultrasonic-assisted extraction is 47447. The results showed that ultrasonic-assisted extraction could increase the extraction yield of tea polysaccharide, but tea polysaccharide was depolymerized.