A comparative analysis of the volatile components of green tea produced from various tea cultivars in China

Abstract

: China is a major producer and consumer of green tea and possesses numerous high-quality tea cultivars, which can beused to make green tea. However, the green teas produced from these tea cultivars vary markedly in aroma. In this study, a sensoryevaluation method and headspace solid-phase microextraction combined with GC-MS were employed to determine the primarysubstances that contribute to the aromas and key differences in the aroma components of green tea produced from 20 tea cultivars.The results revealed 57 major volatile components, among which aldehydes, alcohols, and esters were the most prevalent. For thevolatile components, the linalool, nonanal, and geraniol contents were the highest, followed by dimethyl sulfide, methyl salicylate,heptanal, and caproicacidhexneylester. The volatile components varied considerably among the green tea samples, and some containedsubstances with a high content that gave off unique aromas. The correlation analysis revealed significant correlations between thesensory evaluation scores and contents of linalool, geraniol, methyl salicylate, cis-linalool oxide, 3-carene, phenethyl alcohol, limonene,(Z)-3-cis-3-hexenyl isovalerate, citral, (E)-β-ocimene, alcohols, esters, and alkenes, as well as between the sensory evaluation scoresand total volatile component contents. Aromatic substances with the highest odor activity values were, in descending order, linalool,capraldehyde, dimethyl sulfide, β-ionone, geraniol, nonanal, heptanal, (E)-2-nonenal, and caproicacidhexneylester. These substanceswere the major contributors to aroma formation in the green tea samples. The principal component analysis and orthogonal projectionsto the latent structure-discriminant analysis suggested that the 20 tea cultivars could be grouped into 6 categories and that the highcontent of linalool, nonanal, and geraniol substantially contributed to the categorization of the tea cultivars. A key variable analysisrevealed that 23 volatile components played a critical role in the categorization of the tea cultivars.