Abstract:In this study, Robusta green coffee beans were used as the research object, and head space-solid phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC/MS) and electronic nose technology were used to analyse the volatile compounds of the coffee beans during an accelerated storage. Results showed that a total of 56 volatile compounds were identified in the green coffee bean samples. With the extension of storage time, the content of acids increased first and then decreased, the content of the ester compounds increased gradually, whilst the content of aldehydes decreased first and then increased (increased from 13.72% before storage to 25.46% after the storage at 60 ℃). The higher the accelerated storage temperature, the faster the increasing rate of volatiles (the volatile content increased from 24.12 μg/g DW to 31.34 μg/g DW). Electronic nose data analysis could discriminate samples subjected to different storage periods. The samples derived from different storage stages were clustered into different classes respectively, with a more compact cluster achieved at 60 ℃. Through the analyses of the changes in the contents of volatile compounds and the characteristic response values of electronic nose sensors, as well as the principal component analysis (PCA), it can be preliminarily speculated that hexanal, benzaldehyde, phenylacetaldehyde, acetic acid, hexanoic acid, and benzoic acid were the characteristic compounds that contributed greatly to flavor deterioration of green coffee beans during the accelerated storage. Thus, HS-SPME/GC-MS, electronic nose technology combined with PCA can evaluate comprehensively the flavor characteristics of green coffee beans during storage.
