武夷肉桂加工中挥发性成分糖苷结合物和香气品质形成研究OA北大核心CSTPCD

'Rougui',the main cultivar of Wuyi rock tea,is characterized by a rich floral and pungent cinnamon aroma.To elucidate the contribution of key aroma constituents and glycosidically bound volatiles(GBVs)to Wuyi Rougui rock tea,this study employed ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry(UHPLC-Q-TOF/MS)and headspace solid-phase microextraction-gas chromatography-mass spectrometry(HS-SPME-GC-MS)to investigate the dynamic changes of GBVs and aroma constituents during the processing of Wuyi Rougui rock tea.The results reveal that a total of 276 aroma constituents were identified from 11 different processing stages of Wuyi Rougui rock tea.These aroma constituents belong to various chemical classes,including esters,alcohols,heterocyclic constituents,ketones,aldehydes and terpenes,with heterocyclic constituents,esters,terpenes and alcohols being the predominant aroma components.Orthogonal partial least squares-discriminant analysis(OPLS-DA)identified 35 characteristic aroma constituents in Wuyi Rougui rock tea,as indicated by their Variable Importance in Projection(VIP)values and Odor Activity Values(OAV)greater than 1.Notably,the contents of constituents associated with green and grassy flavor,such as(Z)-3-hexen-1-ol,(E)-2-nonenal and hexanal,exhibited decreasing trends during the processing,while aroma constituents associated with floral or fruity aromas,like linalool,benzyl alcohol,benzaldehyde,eugenol and β-ocimene,displayed increasing trends.Furthermore,in fresh leaves of Wuyi Rougui rock tea,aroma constituents including linalool,benzyl alcohol,benzaldehyde,2-ethoxy-3-methylpyrazine and(E,E)-3,5-octadien-2-one exhibited ACI values greater than 1,suggesting they are key aroma constituents during the processing of Wuyi Rougui rock tea.Constituents such as dehydrocinnamyl alcohol and α-ionone contributed to the characteristic cinnamon aroma of Wuyi Rougui rock tea.In addition,ten GBVs were identified.During the processing,the contents of glucosides showed an upward trend,while primeveroside showed trend.The total contents of GBVs remained relatively stable.During the late stages of fermentation,both GBVs demonstrated declining trends,particularly constituents like benzyl primeveroside,2-phenylethyl primeveroside,geranyl glucoside,linayl primeveroside and benzyl glucoside.The results indicate that GBVs were involved in the development of the faint scent and floral-fruity notes of Wuyi Rougui rock tea.This study clarified the role of characteristic aroma constituents and GBVs in the aroma formation of Wuyi Rougui rock tea,in order to better improve the aroma quality of Wuyi Rougui rock tea.