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

Hyong Seok Park, Hee Jin Lee, Min Hye Shin, Kwang Won Lee, Hojoung Lee, Young Suk Kim, Kwang Ok Kim, Kyoung Heon Kim

Research output: Contribution to journalArticle

77 Citations (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.

Original languageEnglish
Pages (from-to)1011-1017
Number of pages7
JournalFood Chemistry
Volume105
Issue number3
DOIs
Publication statusPublished - 2007

Keywords

  • Caffeine
  • Catechins
  • Decaffeination
  • Green tea
  • Supercritical carbon dioxide

ASJC Scopus subject areas

  • Analytical Chemistry
  • Food Science

Fingerprint Dive into the research topics of 'Effects of cosolvents on the decaffeination of green tea by supercritical carbon dioxide'. Together they form a unique fingerprint.

  • Cite this