四川边茶中茶多糖提取条件的优化研究

Study on the Optimum Conditions in Extracting Polysaccharides in Sichuan Brick Tea

运用四因素二次回归正交旋转组合设计方法研究了温度、时间、茶水比、pH值对四川边茶中茶多糖(TPS)提取率的影响,结合影响TPS生物活性的因素,确定了TPS较优提取范围.试验结果通过贡献率法计算表明,在试验范围内各因子对TPS提取率作用的大小依次为pH值＞温度＞茶水比＞时间;数学回归模型通过降维分析可知在试验范围内温度和pH值处于较高水平时,TPS提取率有明显增加,并且二者的交互作用显著一致,时间和茶水比的水平变化对TPS提取率影响较小;频率分析得到TPS提取率＞8%的优化条件:温度为74.06～80.74℃,时间为69.56～79.58 min,茶水比为38.49～42.59倍,pH值为7.411～8.284的范围内;所建立数学回归模型在试验范围内能较准确的预测TPS的提取率.

By means of orthogonally rotational combination design, a four-factor （temperature, time, ratio between tea and water, pH） substrate cultivation experiment was conducted by using of brick tea. The regression equations of the relationship between temperature, time, ratio between tea and water, pH and extraction rate of tea polysaccharides （TPS） were established. The results indicated that extraction rate of TPS was affected obviously in successive order by pH, temperature, ratio between tea and water and time. In range of experiment, extraction rate of TPS was increased obviously when pH and temperature were in higher levels, and the interaction of pH and temperature to the ratio between tea and water was significant, but the change of time and ratio between tea and water had less influence effects on extraction rate of TPS. Considering the high extraction rate and activity of TPS, the extraction conditions were optimized by frequency analysis that were 74.06-80.74℃ temperature, 69.56-79.58 min time, 38.49-42.59 ratio between tea and water, 7.411-8.284 pH.