Kim, Wan-Joo Kim, Jae-Duck Kim, Jaehoon Oh, Seong-Geun Lee, Youn-Woo 2024-01-20T22:06:50Z 2024-01-20T22:06:50Z 2021-09-03 2008-12 0260-8774 https://pubs.kist.re.kr/handle/201004/132958 Caffeine and EGCG (epigallocatechin gallate) were extracted from green tea using supercritical carbon dioxide (SCCO2) 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 degrees C, pressure ranging 200-400 bar, and water contents ranging 4-7 wt%. At 40 degrees 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 SCCO2/water and caffeine/EGCG. The extraction results using SCCO2/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 SCCO2 extraction with water as a cosolvent is suitable for the selective extraction of caffeine from the green tea. (C) 2008 Elsevier Ltd. All rights reserved. English ELSEVIER SCI LTD FLUID EXTRACTION RETROGRADE CONDENSATION CAMELLIA-SINENSIS CATECHINS POLYPHENOLS WATER CONSUMPTION SOLUBILITY Selective caffeine removal from green tea using supercritical carbon dioxide extraction Article 10.1016/j.jfoodeng.2008.05.018 1 JOURNAL OF FOOD ENGINEERING, v.89, no.3, pp.303 - 309 JOURNAL OF FOOD ENGINEERING 89 3 303 309 scie scopus 000257967000008 2-s2.0-46049091527 Engineering, Chemical Food Science & Technology Engineering Food Science & Technology Article FLUID EXTRACTION RETROGRADE CONDENSATION CAMELLIA-SINENSIS CATECHINS POLYPHENOLS WATER CONSUMPTION SOLUBILITY caffeine EGCG (epigallocatechin gallate) green tea solubility parameter supercritical carbon dioxide extraction