Chemometric analysis on volatile components and their differences between moldy and non-moldy cigar tobacco leaves using HS-SPME-GC-MS

To investigate the composition, relative contents, and their differences on volatile chemical components between moldy and non-moldy cigar tobacco leaves, a headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method was established to analyze the volatile components in 18 samples of moldy and non-moldy cigar tobacco leaves. Chemometric methods including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and variable importance in projection were used to identify the main differences in the volatile components in these samples. The results showed that: 1) Ninety-five volatile components in the moldy and non-moldy samples were identified and semi-quantified by the established method. 2) The volatile components in the moldy and non-moldy samples showed a certain degree of discrimination by PCA. 3) The results of identification and analysis using an OPLS-DA model (R²X=0.74, R²Y=0.90, Q²=0.60) showed that the moldy and non-moldy cigar leaves were more clustered in their categories, and there was a good degree of separation between the categories, which effectively distinguished the two types of samples. 4) There were 22 differential volatile components, such as nicotyrine and β-damascone, with larger contributions (VIP > 1)to the model classification in the moldy and non-moldy samples.