Standardization of conditions for effective clarification and concentration of green tea extract by membrane filtration

Studies on clarification of tea extracts with membrane filters was carried out, as a mode of concentration, of the soluble components of tea, prior to drying to reduce creaming in tea based products. The reduction of flux rate was high in reverse osmosis membranes microfiltration compared to ultrafiltration, and prefiltration enabled removal of mainly particulate components of the tea. Catechin content was high in the retentate under 1000 Kpa pressures in all types of filtration process as compared to the original content in the fresh green tea leaves. Alkali and enzyme treatments of the precipitate for maximum recovery of catechins that developed on chilling after filtration improved the solubility of the extract. A partial reduction in the pectin content in the retentates with a concomitant increase in carbohydrates, protein, turbidity, catechins was noted with ultrafiltered and microfiltered extracts. Ultrafiltration caused a rejection of 24% pectin, 23.40% catechins in permeate, and 18.11% caffeine in the green tea extract.