title: Non-targeted analysis by LC-MS of major metabolite changes during the oolong tea manufacturing in New Zealand.
abstract: Oolong tea is a semi-fermented tea that is partially oxidised during the manufacturing process to create a product unique in composition. In this study, we investigated the potential of non-targeted LC-MS with two complementary chromatographic modes to provide a "comprehensive and unbiased" view of biochemical compositional changes occurring during oolong tea manufacturing in New Zealand. Tea leaf samples from throughout the manufacturing/fermentation process during three different harvest periods (spring, summer and autumn) were analysed by four different LC-MS streams. Principal component analysis revealed the de-greening stage of the manufacturing process was responsible for major changes in the biochemical profile, with the methodology detecting changes in a wide range of metabolites of differing polarities, such as flavonoids, nucleosides and primeverosides. Changes during the fermentation phase of the manufacturing process were less marked, however significant increases in levels of free amino acids, a hydroxyjasmonic acid and related metabolites were observed.
authors.affiliation: AgResearch, Private Bag 11008, Tennent Drive, Palmerston North 4410, New Zealand; School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand. Electronic address: karl.fraser@agresearch.co.nz.
authors.forename: Karl
authors.initials: K
authors.lastname: Fraser
authors.affiliation: AgResearch, Private Bag 11008, Tennent Drive, Palmerston North 4410, New Zealand.
authors.forename: Geoff A
authors.initials: GA
authors.lastname: Lane
authors.affiliation: AgResearch, Private Bag 11008, Tennent Drive, Palmerston North 4410, New Zealand.
authors.forename: Don E
authors.initials: DE
authors.lastname: Otter
authors.affiliation: AgResearch, Private Bag 11008, Tennent Drive, Palmerston North 4410, New Zealand.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Harrison
authors.affiliation: School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand.
authors.forename: Siew-Young
authors.initials: SY
authors.lastname: Quek
authors.affiliation: School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand.
authors.forename: Yacine
authors.initials: Y
authors.lastname: Hemar
authors.affiliation: AgResearch, Private Bag 11008, Tennent Drive, Palmerston North 4410, New Zealand.
authors.forename: Susanne
authors.initials: S
authors.lastname: Rasmussen
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D005419:Flavonoids / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods*; D009520:New Zealand; D013662:Tea / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D013662:Tea
keywords: Fermentation; HILIC; Mass spectrometry; Profiling; Tea; Tea manufacturing; UHPLC