Abstract: To comprehensively analyze the characteristic aroma components of bud-leaf type yellow tea, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), sensory evaluation and chemometrics were used to determine the aroma components of bud-leaf type yellow tea. It was found that the bud-leaf yellow tea was mainly characterized by a clear and sweet aroma, which was divided into three categories of “fresh-tender aroma”, “chestnut-sweet aroma” and “sweet aroma” by sensory evaluation. A total of 119 volatile components were detected by GC-MS, and then the candidate volatiles were screened out by the VIP values of cluster analysis (HCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Further, ROAV with GC-O analysis was used to clarify the key aroma components of bud-leaf type yellow tea. There were 60 characteristic aroma components with ROAV>1 in the bud-leaf type yellow tea, among which aldehydes dominated the “fresh-tender” type, alcohols dominated the “chestnut-sweet” type, 2-ethyl-5-methylpyrazine and 2,3-diethyl-5-methylpyrazine contributed significantly to the “sweet” type. The olfactory validation indicates that phenylethanol was the most important component for the fresh and sweet aroma of yellow tea. The key aroma of “fresh-tender” included phenylethanol, jasmine ketone, styrene, linalool, nonanal. The “chestnut-sweet aroma” was mainly derived from the components of heptanal, β-damascenone and 2-n-pentylfuran, while the “sweet aroma” was dominated by pyrazines and aldehydes, which presented a unique sweet and caramelized aroma. This study reveals the diversity of aroma components in bud-leaf type yellow tea, and elucidates the aroma differences between aroma types and their causes.

Key words: bud-leaf type yellow tea, aroma properties, GC-O, key aroma components