超声波辅助浸提茶鲜叶中茶多酚的工艺研究

Technological Experiments on Ultrasound Assisted Extraction Tea-polyphenols from Tea Fresh Leaves

由于当前中国农村劳动力的缺乏,机采茶已逐步成为茶叶采收的主要方式。为了提高机采茶的利用价值、降低其加工成本,本文研究了机采茶鲜叶浸提茶多酚的工艺与方法。本文进行了以机采茶鲜叶为浸提原料,以水做溶剂,采用超声波辅助浸提茶多酚工艺试验,研究了浸提时的超声波功率、茶叶粉碎粒度、浸提温度和茶水比对茶多酚浸提效果的影响。在单因素试验的基础上,通过L9(34)正交试验设计,确定了超声波辅助浸提茶多酚的主次影响因素和最佳工艺参数,即:茶水比为1:20、浸提温度为60℃、超声波功率为350W,茶叶粉碎粒度为1.5mm。在此条件下,茶多酚的浸提得率η可达95.86%。此方法较常规水浴浸提茶多酚含量高、用时短、浸提次数少,与超声波辅助浸提干茶叶的茶多酚浸提得率相当。由此可见,采用超声波辅助浸提机采茶鲜叶中茶多酚的方法是可行的。

According to the lack of rural labor force in China nowadays,tea-picking by machines has gradually become the main form of tea harvest.In order to improve the value of tea picking by machines and reduce the processing costs,the technology and methods of extracting the fresh leaf are studied.This experiment used fresh leaves of tea as raw material,the water as solvent and ultrasonic wave as an assisted way to extract tea-polyphenols in fresh leaves of tea.The effect of different ultrasonic wave output power,granularity,extraction temperature and ratio of solid—liquid on extracting tea polyphenols is studied.Based on the single factor experiment,optimized process parameter,primary and secondary factors of the extraction are determined by L9（34） orthogonal experimental design.The optimal extraction process parameters by the experimental results were： extraction solid-liquid ratio is 1：20,extraction temperature is 60℃,extraction ultrasonic-wave power is 350W,and tea smashing granularity is 1.5mm,meanwhile,in which tea-polyphenols raises rate is 23.88%.Compared to the water bath extraction method,extraction rate of tea-polyphenols is higher,using time is shorter and extracting times is few than the conventional by the ultrasonic wave.And the quantities of extracting tea polyphenols are the same as the dried tea.Thus it can be seen extracting tea polyphenols in the fresh leaves using ultrasound is feasible.