Fraser K, Lane GA, Otter DE, Harrison SJ, Quek SY, Hemar Y, Rasmussen S. Non-targeted analysis by LC-MS of major metabolite changes during the oolong
tea manufacturing in New Zealand.
Food Chem 2013;
151:394-403. [PMID:
24423549 DOI:
10.1016/j.foodchem.2013.11.054]
[Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/04/2013] [Accepted: 11/11/2013] [Indexed: 01/05/2023]
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.
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