SPME-GC-MS Technique Combined with rOAV for the Analysis of Key Aroma Substances of Zijuan White Tea with Different Processing Processes

In order to study the key aroma compounds of Zijuan white tea with different processing technologies, headspace solid-phase micro extraction and gas chromatography mass spectrometry (HS-SPME-GC-MS), combined with sensory evaluation, PCA validation, OPLS-DA analysis and relative odor activity value (rOAV), was used to analyze and screen the key aroma compounds of Zijuan white tea. The results showed that 82 major aroma components were detected, mainly alcohols, esters, heterocyclic and aromatic compounds, with relatively high contents of linalool, methyl salicylate, benzyl alcohol and β-Ionone. The results of rOAV analysis showed that 9 volatile organic compounds including 1-octen-3-ol, α-Ionone, phenylacetaldehyde and methyl salicylate contributed to the aroma formation of natural withering Zijuan white tea (TZW) with floral and fruity aroma and spicy medicinal aroma, and 9 volatile organic compounds including 1-octen-3-ol, α-Ionone, β-Ionone and benzaldehyde contributed to the aroma formation of compound withering Zijuan white tea (CZW) with floral and fruity aroma and spicy aroma. OPLS-DA analysis combined with rOAV showed that 1-octene-3-ol and methyl salicylate were the key compounds for aroma difference between TZW and CZW. In summary, the flower and fruit aroma of Zijuan white tea processed by natural wilting was more abundant, which could effectively improve the aroma quality of Zijuan white tea.