Abstract: The Oolong tea juice was ultra-filtrated by using the plate-frame module and choosing three kinds of CA membrane with three pore diameter . Study on effect of different ultra-filtration process on the contents of main compounds including tea polyphenols, amino acids, caffeine, soluble sugar, pectin, protein etc in Oolong tea juices and colour difference, sensory quality, pH, ultra-filtration flux, etc. The results showed that ultra-filtration can clarify the Oolong tea juice effectively. The ultra-filtration can obstruct high-molecular mass that easy to participate higher retaining rate of the main compounds under the suitable ultra-filtration parameter. Sensory quality of the green tea juice ultra-filtrated was fine.

Key words: Ultra-filtration, Membrane, Oolong tea juice, Clarification