Journal of
Medicinal Plants Research

  • Abbreviation: J. Med. Plants Res.
  • Language: English
  • ISSN: 1996-0875
  • DOI: 10.5897/JMPR
  • Start Year: 2007
  • Published Articles: 3830

Full Length Research Paper

Decaffeination of green tea by supercritical carbon dioxide

Qing-Lei Sun1, Shu Hua1, Jian-Hui Ye1, Jian-Liang Lu2, Xin-Qiang Zheng1and Yue-Rong Liang1*
1Zhejiang University Tea Research Institute, Hangzhou 310029, PR China. 2The State Agriculture Ministry, Laboratory of Horticulture, Plant Growth Development and Quality Improvement, Hangzhou 310029, PR China.
Email: [email protected]

  •  Accepted: 06 April 2010
  •  Published: 18 June 2010

Abstract

Effects of cosolvent, tea particle size, extraction temperature and time on the removal of caffeine and catechins from green tea using supercritical carbon dioxide method were investigated. It showed that ethanol was optimal cosolvent. Water and 50% aqueous ethanol were not suitable for cosolvents because a large percentage of catechins were removed. Based on the orthogonal array design tests, optimal protocol for green tea decaffeination was screened as 10 g of 0.2 - 0.6 mm particle size green tea was extracted using 15 ml ethanol cosolvent at 80°C for 2 h when flow rate and pressure of SC- CO2 were at 1.5 L min-1 and 300 bars, during which 70.2% caffeine and 6.2% catechins were removed, respectively.

 

Key words: Decaffeinated tea, supercritical fluid extraction, cosolvent, particle size, temperature, caffeine, catechins.