Technology of Decaffe ination of Green Tea Concentrative Liquid Using Supercritical CO2
Decaffeinating test of green tea concen t rative liqu id w as carried out using supercritical CO2. The effect of concent rative liquid consistence, operating pressure, operating temperature and extracting time on decaffeinat ionrate was investigated by using orthogonal experiments. The result s showed that great ma2jority of caffeine in green tea concentrative liquid could be removed with supercritical CO2. A new method of processing decaffeinated tea concen trative liquid or instant tea was presented through the experiment of continuous extraction.
Yue Pengxiang , Wu Shouyi
Tea is rich in caffeine, which accounts for 2% to 5% of the dry matter weight of tea. The concentration of caffeine in tea concentrates and instant tea is even higher. Theophylline has a wide range of effects on the body's metabolism. Some are beneficial and some are not. The excessive intake of caffeine is not good for human health. In recent years, low-caffeine or decaffeinated teas and their products have been marketed in European and American countries, making the technology of removing caffeine from tea increasingly important. At present, there are two main processes for removing caffeine from tea, namely the ethyl acetate extraction method and the supercritical CO 2 extraction method. The ethyl acetate method removes caffeine and also removes some other active ingredients in tea; supercritical The CO 2 method has obvious advantages due to its high selectivity, no loss and deterioration of effective ingredients, and no residual organic solvents. However, the industrial production has the disadvantage of the continuous operation of the extraction process. The processing of decaffeinated tea concentrate or instant tea is a process of decaffeinating the tea leaves before processing.In this paper, the green tea concentrated liquid is taken as the object, and the removal of caffeine is studied. At the same time, the test of non-releasing pressure, continuous feeding and continuous extraction is carried out, in order to provide suitable processes and parameters for the industrial production of decaffeinated tea deep-processing products.