K-Patents has released a new application note on Tea Extract Reverse Osmosis (RO) Membrane Filtration. In order to produce instant tea, active substances of tea leaves must be extracted from the tea leaf cells by means of aqueous extraction. It is important to preserve the soluble components since they are responsible for the taste, aroma and effect. There are also undesired insoluble components responsible for turbidity, thus they have to be removed from the tea extract by means of separators or decanters. After extraction and separation stages the 2-3 Brix extract proceeds to the concentration.
Tea extracts are heat-sensitive. When exposed to high temperatures, extracts may lose colour, flavour and active components. Thus, as an alternative to traditional thermal concentration reverse osmosis (RO) membrane filtration of tea extracts has been introduced. Reverse osmosis, a membrane filtration process, is used to concentrate tea extracts at temperature of 25 ℃ - 30℃ (77℉ - 86℉), thus causing no changes in the physical structure of water. Moreover, concentration by RO ensures high quality of products due to the maintenance of the extract aroma and flavour, as well as its nutritional characteristics.
By means of the RO membrane filtration the tea extract is concentrated to 15-18 Brix. In order to comply with the stringent product requirements, the extract concentration control is performed with K-Patents Sanitary Refractometer PR 23-AC.
Ref.2.06.01 Tea Extract Reverse Osmosis (RO) Membrane Filtration (pdf)