Determination of volatile organic compounds, catechins, caffeine and theanine in Jukro tea at three growth stages by chromatographic and spectrometric methods

•Fresh Jukro tea leaves of 40, 60 and 90 days growth stages were semi-fermented.•VOCs were extracted by SDE and analyzed by GC/MS.•Catechins, caffeine and theanine were analyzed by HPLC.•159 VOCs were identified in the three growth stages Jukro tea leaves.•60 day leaves were the most suitable for making semi-fermented Jukro tea.

Tea contains characteristic volatile organic compounds, polyphenols, caffeine and catechins, and is therefore among the most widely consumed beverages all over the world. In this study, fresh Jukro tea leaves collected from Damyang-gun (Jeollanam-do) at 40, 60 and 90 day growth stages, were semi-fermented. The volatile organic compounds (VOCs) were extracted by simultaneous distillation-solvent extraction (SDE) and analyzed by gas chromatography/mass spectrometry (GC/MS). Catechins, caffeine and theanine were analyzed by high performance liquid chromatography (HPLC). A total of 159 VOCs were identified in the analyzed Jukro tea leaves. Comparatively, the increase in the concentrations of VOCs was high in 60 day leaves. The content of catechins increased along the three growth stages, whereas caffeine, compared to 90 day leaves, was higher for 40 and 60 day leaves. Based on the results, the 60 day leaves were found to be the most suitable and useful for making semi-fermented Jukro tea.