綠茶膜過濾之研究

Abstract

中文摘要 本研究以低溫長時間萃取之綠茶茶湯為研究對象，利用陶瓷摩和聚合膜過濾材質來探討不同孔徑大小下、不同操作條件下對膜過濾之透流量、茶湯成分的保留、微生物和茶湯風味的影響並和傳統熱加工比較其茶湯成分上的保留和其抗氧化性。結果發現，使用孔徑0.5μm，操作溫度為40℃，操作壓力1.8psi在透流量方面、成分的保留和風味的表現方面較佳，且無微生物的檢出。在聚合膜方面，以孔徑0.45μm，操作溫度為40℃，操作壓力1.9psi在透流量方面、成分的保留和風味的表現上較優，也無微生物的檢出。經過熱加工的茶湯在蓊游離胺基酸、還原糖、catechin、EGCg、ECG比膜過濾還高，但在清除DPPH和螯合亞鐵離子的表現上，卻比膜過濾還要佳。

ABSTRACT The material of this research is green tea infusion that extract at low temperature for a long time. To utilize ceramic membrane and PVDF membrane as filter material to investigate the effect on the flux, composition of tea infusion, content of microorganism and flavor under varied size pole and different operate condition. The finding of the experiment demonstrated that the optimal operate condition for ceramic membrane is 0.5 μm diameter of pole, 40°C and 1.8 psi. There was no microorganism detected. It could obtain the best performance of flux, retainment of tea composition and flavor under such operate condition. For PVDF membrane, the optimal operate condition is 0.45 μm, 40°C, and 1.9 psi. No microorganism detection as well. To compare two kinds of tea process method, one is traditional heating process and another is membrane filtration. The content of total free amino acid, reducing sugar, catechin, EGCG, and ECG of tea infusion after heating process was higher than membrane-filtered one. The antioxidant activity of tea infusion by heating was also better than filtered by membrane. The antioxidant activity was carry out by scavenging ability on DPPH radicals and chelating capacity of ferrous ion.