GB860240A - Improvements in or relating to beverages - Google Patents

Abstract

860,240. Tea extracts. UNILEVER Ltd. June 3, 1957 [June 4, 1956], No. 17551/57. Class 129. A process for reducing the tendency of a soluble tea product to produce haziness with hard water comprises treating an aqueous tealeaf extract substantially free from undissolved tea solids with a calcium compound soluble therein and after a sufficient time removing the precipitate formed by the calcium compound with a proportion of the tea solids. As shown, tea leaves are introduced at 12 to a countercurrent extractor 10, hot extractant is introduced at 15 and extracted leaves are removed at 11. The extraction time is such as to produce a concentration of at least 2.5% and usually 3.5 to 5% and the liquid is withdrawn through pipe 16 as " dilute extract" which then passes through a strainer 21 or is centrifuged at about 60‹ C. The tea aroma may be removed, with some of the water, by evaporation and then concentrated. The remaining " de-aromatized extract " containing, e.g. 4 to 6% soluble tea solids, is fed through pipe 29 to vessel 31 to which a calcium salt usually in aqueous solution is added through valve 31<SP>1</SP> where it remains until a precipitate has formed when it is passed on to centrifuge 32. The precipitate is removed at 35 and the clear "de-aromatized extract " flows through pipe 36 into a vacuum concentrator 37 in which liquid is heated in a tubular heater 38 and evaporation takes place in chamber 37<SP>1</SP>. The concentrator may operate at 650 to 720 mm. Hg and 65‹ to 40‹ C. effluent temperature. Alternatively a falling film evaporator may be used and several stages may be provided. The effluent-" concentrated extract " contains 25 to 50% tea solids and flows through pipe 40 to vessel 41 where the concentrated aroma may be added thereto after which it may be spray-dried. The concentration of soluble tea solids may be as high as saturation at the temperature prevailing in the extractor. The amount of calcium compound required depends on the type of tea used but calcium compound to at least about 0.3% by weight of the total tea solids in solution expressed as equivalent calcium. Conveniently the extract is treated with the calcium compound at 40‹ C. or below and the de-creaming process as described in Specification 844,451 may be carried out at the same time. Examples are given using different types of tea. Specification 857,517 also is referred to.