title: Effects of heat processing and storage on flavanols and sensory qualities of green tea beverage.
abstract: This research was conducted to understand the effects of heat processing and storage on flavanols and sensory qualities of green tea extract. Fresh tea leaves were processed into steamed and roasted green teas by commercial methods and then extracted with hot water (80 degrees C) at 1:160 ratio (tea leaves/water by weight). Green tea extracts were heat processed at 121 degrees C for 1 min and then stored at 50 degrees C to accelerate chemical reactions. Changes in flavanol composition and sensory qualities of green tea extracts during processing and storage were measured. Eight major flavanols (catechin, epicatechin, gallocatechin, epigallocatechin, epicatechin gallate, catechin gallate, epigallocatechin gallate, and gallocatechin gallate) were identified in the processed tea extract. Among them, epigallocatechin gallate and epigallocatechin appeared to play the key role in the changes of sensory qualities of processed green tea beverage. The steamed tea leaves produced a more desirable quality of processed green tea beverage than the roasted ones.
authors.affiliation: Korea Food Research Institute, Bundang, Seongnam, Kyonggi 463-420, Korea, and Department of Food Science and Technology, Cornell University, Geneva, New York 14456, USA.
authors.forename: L F
authors.initials: LF
authors.lastname: Wang
authors.forename: D M
authors.initials: DM
authors.lastname: Kim
authors.forename: C Y
authors.initials: CY
authors.lastname: Lee
mesh_terms: D005419:Flavonoids / Q000737:chemistry*; D005511:Food Handling; D006358:Hot Temperature; D012903:Smell; D013649:Taste; D013662:Tea
chemical_list: D005419:Flavonoids; D013662:Tea