Aroma profiling by HS-SPME/GC-MS of black tea produced from different leaf grades

Abstract

Leaf grade is a critical factor influencing black tea aroma formation, yet the precise relationship between leaf grade and aroma characteristics, along with their key volatile compounds, remains unclear. This study employed sensory evaluation combined with headspace solid phase microextraction/gas chromatography-Mass spectrometry (HS-SPME/GC-MS), odor activity values (OAV), partial least squares (PLS) regression, and correlation analysis to investigate the association between leaf grades and aroma attributes, as well as their key volatile compounds. Sensory evaluation and quantitative analysis revealed that as fresh tea leaf grade decreased, the sweet aroma attribute gradually declined, while the floral aroma initially decreased before increasing. GC-MS and OAV analyses identified 22 and 23 differential aroma-active compounds in 'Jinguanyin' (JGY) and 'Jinmudan' (JMD) black teas of different grades, respectively. Furthermore, PLS modeling and correlation analysis determined that β-damascenone, β-myrcene, geraniol, linalool, and trans -β-ocimene were key compounds responsible for sweet aroma variations across leaf grades, whereas methyl jasmonate, β-ionone, and jasmine lactone were identified as critical compounds influencing floral aroma differences. This study deciphered the chemical basis of how leaf grades affect black tea aroma quality, providing theoretical guidance for precision processing of black tea.