Selective caffeine removal from green tea using supercritical carbon dioxide extraction

Caffeine and EGCG (epigallocatechin gallate) were extracted from green tea using supercritical carbon dioxide (SCCO 2) with water as a cosolvent. Experimental conditions were carefully chosen to selectively extract a large amount of caffeine from the green tea while to remain a large amount of EGCG...

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Bibliographic Details
Published in:Journal of food engineering 2008-12, Vol.89 (3), p.303-309
Main Authors: Kim, Wan-Joo, Kim, Jae-Duck, Kim, Jaehoon, Oh, Seong-Geun, Lee, Youn-Woo
Format: Article
Language:English
Subjects:
Biological and medical sciences
Caffeine
Carbon dioxide
Coffee, tea and other stimulative beverage industries
decaffeination
EGCG (epigallocatechin gallate)
epigallocatechin
Ethanol
Ethyl alcohol
Extraction
Food engineering
Food industries
food processing quality
Fundamental and applied biological sciences. Psychology
General aspects
Green tea
Moisture content
plant extracts
Selectivity
Solubility parameter
Solvent extraction
solvents
Supercritical carbon dioxide
supercritical fluid extraction
water solubility
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Summary:Caffeine and EGCG (epigallocatechin gallate) were extracted from green tea using supercritical carbon dioxide (SCCO 2) with water as a cosolvent. Experimental conditions were carefully chosen to selectively extract a large amount of caffeine from the green tea while to remain a large amount of EGCG in the green tea. Various experimental conditions were explored including temperatures ranging 40–80 °C, pressure ranging 200–400 bar, and water contents ranging 4–7 wt%. At 40 °C, 400 bar and the water content of 7 wt%, the caffeine extraction yield was 54% while the EGCG extraction yield was 21%, resulting in caffeine/EGCG extraction selectivity of 2.57. The larger caffeine extraction yield agreed well with estimation of solubility parameter differences between SCCO 2/water and caffeine/EGCG. The extraction results using SCCO 2/water were compared with conventional liquid solvent extraction using water or ethanol. The selectivity of caffeine/EGCG extraction with water was 0.88 and the selectivity of caffeine/EGCG extraction was 0.24 with ethanol. Thus SCCO 2 extraction with water as a cosolvent is suitable for the selective extraction of caffeine from the green tea.
ISSN:0260-8774
1873-5770
DOI:10.1016/j.jfoodeng.2008.05.018