title: Changes in flavor volatile composition of oolong tea after panning during tea processing.
abstract: Panning is a processing step used in manufacturing of some varieties of oolong tea. There is limited information available on effects of panning on oolong tea flavors. The goal of this study was to determine effects of panning on flavor volatile compositions of oolong using Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Olfactometry (GC-O). SDE and SPME techniques were applied for extraction of volatiles in panned and unpanned teas. A total of 190 volatiles were identified from SDE and SPME extractions using GC-MS and GC-O. There were no significant differences (P > 0.05) in aldehyde or terpene contents of unpanned and panned tea. However, alcohols, ketones, acids and esters contents were significantly reduced by panning. Among 12 major volatiles previously used for identification and quality assessment of oolong tea, trans nerolidol, 2- hexenal, benzaldehyde, indole, gernaiol, and benzenacetaldehyde contents were significantly decreased (P < 0.05) by panning. Panning increased (P < 0.05) contents of linalool oxide, cis jasmone, and methyl salicylate. The GC-O study also showed an increase of aroma active compounds with sweet descriptions and decrease of aroma active compounds with fruity and smoky descriptions after panning. Panning significantly changes the volatile compositions of the tea and created new aroma active compounds. Results from this study can be used in quality assessment of panned oolong tea.
authors.affiliation: Department of Food Science and Technology Virginia Tech Blacksburg Virginia 24061.
authors.forename: Ershad
authors.initials: E
authors.lastname: Sheibani
authors.affiliation: Department of Food Science and Technology Virginia Tech Blacksburg Virginia 24061.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Duncan
authors.affiliation: Department of Food Science and Technology Virginia Tech Blacksburg Virginia 24061.
authors.forename: David D
authors.initials: DD
authors.lastname: Kuhn
authors.affiliation: Department of Civil and Environmental Engineering Virginia Tech Blacksburg Virginia 24061.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Dietrich
authors.affiliation: Department of Food Science and Technology Virginia Tech Blacksburg Virginia 24061.
authors.forename: Jordan J
authors.initials: JJ
authors.lastname: Newkirk
authors.affiliation: Department of Food Science and Technology Virginia Tech Blacksburg Virginia 24061.
authors.forename: Sean F
authors.initials: SF
authors.lastname: O'Keefe
keywords: Flavor analysis; GC‐MS; GC‐O; oolong tea; panning