Abstract: Research results on parameters of tea juice concentrating showed that, after tea was extracted, the bulk filtration and fine filtration were carried out, then the macro molecule substances were separated and removed by using ultra-filtrating membrane method, then cycling concentrated by reverse-osmosis membrane, the high quality concentrated tea juice was obtained. The pore diameter of the ultra-filtration membrane is 8×10⁴—10×10⁴ molecule weight for green tea and Oolong tea, and larger than 10×10⁴ for black tea. The working pressure of ultra-filtration membrane is 0.2~0.3βMPa, suitable temperature for tea juice is lower than 40℃. The working pressure of reverse-osmosis membrane is 1.5~3.0βMPa, suitable temperature for tea juice is lower than 50℃. The tea juice productivity of the producing line designed on the base of above technique is 100βkg/h, with concentration of tea juice 20% (Brix) and better quality compared with that of traditional product.

Key words: Tea, Concentrated juice, Ultra-filtration, Reverse-osmosis membrane