Table 2.
Coefficients of correlation of the 20 most contributory variables in the PCA to the three PCsa
| Group and variable | PC1 |
PC2 |
PC3 |
|||
|---|---|---|---|---|---|---|
| R | P value | R | P value | R | P value | |
| A | ||||||
| Acetoin | −0.55 | 1.45 × 10−5 | 0.77 | 1.54 × 10−11 | ||
| Acetaldehyde | 0.86 | 5.51 × 10−16 | −0.37 | 5.37 × 10−3 | ||
| 2-Nonanone | 0.31 | 2.19 × 10−2 | 0.89 | 9.87 × 10−20 | ||
| Butan-2,3-diol D+ | −0.46 | 5.24 × 10−4 | 0.81 | 8.77 × 10−14 | ||
| B | ||||||
| 2-Methylbutanal | −0.57 | 5.50 × 10−6 | 0.29 | 3.05 × 10−2 | 0.74 | 1.95 × 10−10 |
| Butyl acetate | −0.54 | 2.24 × 10−5 | −0.29 | 3.05 × 10−2 | 0.76 | 3.83 × 10−11 |
| 2-Methylpropan-1-ol | −0.33 | 1.54 × 10−2 | 0.51 | 7.56 × 10−5 | 0.73 | 2.64 × 10−10 |
| 2-Hydroxypentan-3-one | −0.61 | 8.44 × 10−7 | 0.43 | 1.10 × 10−5 | 0.60 | 1.39 × 10−6 |
| Ethanol | −0.28 | 4.22 × 10−2 | −0.43 | 1.19 × 10−3 | 0.90 | 8.02 × 10−21 |
| C | ||||||
| Octanol | 0.79 | 1.28 × 10−12 | 0.53 | 3.21 × 10−5 | ||
| Undecane-2-one | 0.90 | 1.94 × 10−20 | 0.36 | 7.82 × 10−20 | ||
| Butanoic acid | 0.96 | 8.93 × 10−30 | ||||
| 2-Tridecanone | 0.88 | 8.68 × 10−19 | 0.44 | 7.48 × 10−4 | ||
| Hexanoic acid | 0.93 | 5.21 × 10−24 | 0.28 | 3.73 × 10−2 | ||
| Heptanoic acid | 0.92 | 3.38 × 10−23 | 0.35 | 8.78 × 10−3 | ||
| 2-Pentadecanone | 0.89 | 8.43 × 10−20 | 0.42 | 1.43 × 10−3 | ||
| Octanoic acid | 0.92 | 3.71 × 10−22 | 0.34 | 1.23 × 10−2 | ||
| Nonanoic acid | 0.89 | 8.73 × 10−20 | 0.37 | 5.51 × 10−3 | ||
| Decanoic acid | 0.93 | 1.00 × 10−23 | 0.28 | 3.94 × 10−2 | ||
| δ-Dodecalactone | 0.90 | 2.95 × 10−29 | 0.32 | 1.73 × 10−2 | ||
a
Significance was defined as a P value below 0.05. R, coefficient of correlation of the variable to the PC. Hierarchical clustering of ascendant classification using the Euclidian distance metric and Ward's criterion is shown for groups A to C.