title: Beta-cyclodextrin/surface plasmon resonance detection system for sensing bitter-astringent taste intensity of green tea catechins.
abstract: To develop a methodology for creating a sensor with a receptor for specific taste substances, we focused on constructing a sensing system for the bitter-astringent taste intensity of green tea catechins: (-)-epigallocatechin-3-O-gallate (EGCg), (-)-epicatechin-3-O-gallate (ECg), (-)-epigallocatechin (EGC), and (-)-epicatechin (EC). (1)H NMR titration experiments revealed that beta-cyclodextrin was an adequate receptor for sensing the bitter-astringent taste intensity of catechins. A surface plasmon resonance (SPR) system immobilized beta-cyclodextrin indicated larger responses for the gallate-type catechins in comparison to the non-gallate-type catechins. These responses corresponded to the tendency of the bitter-astringent taste intensity of the catechins felt by humans. Furthermore, the SPR system detected the larger stability of the complex between the gallate-type catechins and beta-cyclodextrin, which was interpreted as the aftertaste produced in humans by the gallate-type catechins. These results demonstrate that the beta-cyclodextrin/SPR system can sense the bitter-astringent taste intensity of the green tea catechins similar to human gustation. The methodology presented in this study can be used as a basic strategy for developing taste sensors with specific receptor functions.
authors.affiliation: National Institute of Vegetable and Tea Science, National Agriculture and Food Research Organization, Shimada, Shizuoka, Japan. hayn@affrc.go.jp
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hayashi
authors.forename: Ronggang
authors.initials: R
authors.lastname: Chen
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Hiraoka
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ujihara
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Ikezaki
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000032:analysis*; D006801:Humans; D010936:Plant Extracts / Q000032:analysis*; D020349:Surface Plasmon Resonance / Q000379:methods*; D013649:Taste; D013662:Tea / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000032:analysis*
chemical_list: D010936:Plant Extracts; D013662:Tea; D047392:beta-Cyclodextrins; D002392:Catechin; C031215:betadex