Metabolic Profiling of Tea

A new study published in the Journal of Chromatography A presents metabolite profiling of tea (Camella sinensis) harvested from the Bulang Mountains in Yunnan, China, using multidimensional gas chromatography–mass spectrometry (GC×GC–MS) to determine the impact of seasonal changes.¹

The Yunnan Province in China is a major tea producing area that is affected by the East Asian Monsoon season and is therefore vulnerable to the effects of climate change. Compared to historical records, the East Asian Monsoon now begins earlier and lasts longer in the Yunnan Province than in the past, shortening the optimum harvest period. Tea typically needs 1500–1800 mm of rainfall annually and is harvested seasonally. During the monsoon season, the price of tea harvested can drop by up to 30% because of a decrease in flavour attributed to increasing rainfall. The study authors have previously found that the concentration of catechin and methylaxanthine can drop by more than 50% from the spring to the monsoon season.²

Tea leaves were sampled from three areas at elevations between 1600 m and 1850 m in the Bulang Mountains over 18 days during the spring and monsoon season in 2012. Samples were then extracted and analyzed using automated sequential GC×GC–MS. The authors reported that 201 spring metabolites and 196 monsoon metabolites were identified, of which 59 were seasonally unique compounds. - B.D.  

References
1. A. Kowalsick et al., Journal of Chromatography A 1370, 230–239 (2014).
2. S. Ahmed et al., PLoS ONE9, e109126 (2014).

This story originally appeared in The Column. Click here to view that issue.