Abstract: Based on the researched fact that if the ratio of simple catechin /estered catechin is more than 0.5, the instant green tea has no bitter taste, the ultra-filtration and concentration tests for the micro-filtrated steamed green tea liquid by pilot instruments were carried out in order to process the cold soluble de-bitter instant green tea .The result showed that under the conditions of 35℃, 1.74βMpa and 2 times dialysis while the ultra-filtrated liquor was 80% of the original liquor and the weight of each dialytic water is 10% of the original liquor, the rate of simple catechin /estered catechin in the mixed liquid of 3500βDa ultra-filtrated liquid and dialysed liquid could reach 0.53, the yield rate of simple catechins, estered catechins, EGCG, and total catechins reached 57.00%, 20.00%, 20.00% and 30.0%, respectively, whose content was 14.47%, 12.78%, 8.34% and 26.32% respectively, and the instant green tea product had no bitter taste. The concentration method of 300βDa nano-filtration for the mixed liquid under the conditions of 35℃, 2.4βMpa showed the best work efficiency, the product 0.45g could easily dissolved in 140βml 4 ℃water within 20 second ,and the quality component losed little .

Key words: Tea comprehensive processing, Cold soluble type, De-bitter instant green tea, Membrane system