Studies on the membrane filtration of green tea
Date Issued
2006
Date
2006
Author(s)
Liu, Yin-Sen
DOI
zh-TW
Abstract
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.
Subjects
綠茶
膜過濾
抗氧化
The green tea
membrane filtration
anti-oxidant
Type
thesis
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