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Effects of cosolvents on the decaffeination of green tea by supercritical carbon dioxide

Title
Effects of cosolvents on the decaffeination of green tea by supercritical carbon dioxide
Authors
Park H.S.Lee H.J.Shin M.H.Lee K.-W.Lee H.Kim Y.-S.Kim K.O.Kim K.H.
Ewha Authors
김광옥김영석
SCOPUS Author ID
김광옥scopus; 김영석scopus
Issue Date
2007
Journal Title
Food Chemistry
ISSN
0308-8146JCR Link
Citation
vol. 105, no. 3, pp. 1011 - 1017
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Due to the adverse effects of the caffeine in a variety of plant products, many methods have been explored for decaffeination, in efforts to remove or reduce the caffeine contained in plant materials. In this study, in order to remove caffeine from green tea (Camellia sinensis) leaves, we have employed supercritical carbon dioxide (SC-CO2), which is known to be an ideal solvent, coupled with a cosolvent, such as ethanol or water. By varying the extraction conditions, changes not only in the amount of caffeine, but also in the quantities of the principal bioactive components of green tea, including catechins, such as epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC), were determined. The extraction conditions, including temperature, pressure and the cosolvent used, were determined to affect the efficacy of caffeine and catechin extraction. In particular, the type and concentration of a cosolvent used constituted critical factors for the caffeine removal, combined with minimal loss of catechins, especially EGCG. When the dry green tea leaves were extracted with SC-CO2 modified with 95% (v/v) ethanol at 7.0 g per 100 g of CO2 at 300 bar and 70 °C for 120 min, the caffeine content in the decaffeinated green tea leaves was reduced to 2.6% of the initial content. However, after the SC-CO2 extraction, a substantial loss of EGCG, as much as 37.8% of original content, proved unavoidable. © 2007 Elsevier Ltd. All rights reserved.
DOI
10.1016/j.foodchem.2007.04.064
Appears in Collections:
엘텍공과대학 > 식품공학전공 > Journal papers
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