关键词: 绿茶；栗香；杀青方式；顶空固相微萃取；偏最小二乘-判别分析；层次聚类分析；香气活度值

Abstract: This study was executed in order to explore the effect of different innovative fixation methods: roller-microwave fixation (ROWF), roller-far infrared fixation (ROIF), roller-microwave-far infrared fixation (RWIF) and roller-far infrared-microwave fixation (RIWF) on the formation of chestnut-like aroma in green tea in comparison with roller fixation (ROLF). Sensory evaluation was carried out on the finished tea samples, where a total of 68 aroma compounds were detected by gas chromatography-mass spectrometry (GC-MS). Partial least squares-discriminant analysis (PLS-DA), hierarchical clustering analysis (HCA), odor activity values (OAVs), and significant difference analysis were used to identify the best fixation method for the formation of the chestnut-like aroma of green tea and to find out key components responsible for the chestnut-like aroma. The results showed that fixation with roller-far infrared combinations improved the chestnut-like aroma of green tea. RIWF produced a long-lasting chestnut-like aroma and a refreshing taste, leading to the best overall sensory quality. ROIF, RWIF and RIWF could be beneficial to the formation and transformation of high-boiling alcohols, ketones and aromatic hydrocarbons such as linalool and trans-β-ionone, and RIWF produced significantly larger amounts of these compounds than ROIF and RWIF. PLS-DA and HCA could accurately distinguish and cluster the five fixation methods according to the concentration of chestnut-like aroma. Further according to OAV, trans-β-ionone, linalool, (Z)-hexanoic acid, 3-hexenyl ester, nonanal, geraniol, and phenylacetaldehyde were identified as the key compounds contributing to the chestnut-like odor. The results of this study can provide a theoretical basis and technical guidance for the directed and standardized production of high-quality green tea with chestnut-like aroma.

Key words: green tea; chestnut-like aroma; fixation methods; headspace solid phase microextraction; partial least squares-discriminant analysis; hierarchical clustering analysis; odor activity value