Table 1.
Flavor compounds identified in vinegar Pei samples.
| Code | Compounds | Basis of identificationa | Concentration (mg/kg) | ||
|---|---|---|---|---|---|
| Early stage | Medium stage | Later stage | |||
| Organic acids (7) | |||||
| AC1 | Acetic acid | MS | 3.95 × 104 | 1.24 × 105 | 1.75 × 105 |
| AC2 | Lactic acid | MS | 7.16 × 104 | 7.41 × 104 | 5.31 × 104 |
| AC3 | Succinic acid | MS | 1.73 × 104 | 5.37 × 104 | 5.05 × 104 |
| AC4 | Citric acid | MS | 7.64 × 103 | 2.41 × 104 | 3.22 × 104 |
| AC5 | Oxalic acid | MS | 6.37 × 102 | 9.50 × 102 | 1.03 × 103 |
| AC6 | Tartaric acid | MS | 1.98 × 103 | 2.83 × 103 | 3.15 × 103 |
| AC7 | α-Ketoglutaric acid | MS | 1.31 × 103 | 1.95 × 103 | 1.98 × 103 |
| Σ | 1.40 × 105 | 2.81 × 105 | 3.27 × 105 | ||
| Esters (26) | |||||
| E1 | Ethyl acetate | MS | 10.80 | 5.86 | 4.44 |
| E2 | Hexanoic acid, ethyl ester | MS | 1.33 | 0.70 | 0.62 |
| E3 | Propanoic acid, 2-hydroxy-, ethyl ester | MS | 1.46 | 0.88 | 0.30 |
| E4 | Acetic acid, 2-phenylethyl ester | MS | 0.65 | 1.66 | 2.47 |
| E5 | Pentanoic acid, 2-hydroxy-4-methyl-,ethyl ester | MS | 1.27 | 1.31 | 1.08 |
| E6 | 1-Butanol, 3-methyl-, acetate | MS | 1.01 | 2.69 | 1.39 |
| E7 | Butanedioic acid, diethyl ester | MS | 1.26 | 0.68 | 0.49 |
| E8 | Acetic acid, hexyl ester | MS | 0.02 | 0.03 | 0.02 |
| E9 | Heptanoic acid, ethyl ester | MS | 0.21 | 0.12 | 0.11 |
| E10 | Octanoic acid, ethyl ester | MS | 0.69 | 0.41 | 0.09 |
| E11 | Nonanoic acid, ethyl ester | MS | 0.27 | 0.16 | 0.12 |
| E12 | 3-(Methylthio)propanoic acid ethyl ester | MS | 0.11 | 0.09 | 0.07 |
| E13 | Isoamyl lactate | MS | 0.13 | 0.08 | 0.01 |
| E14 | Decanoic acid, ethyl ester | MS | 0.25 | 0.13 | 0.09 |
| E15 | Benzoic acid, ethyl ester | MS | 0.16 | 0.09 | 0.09 |
| E16 | Benzeneacetic acid, ethyl ester | MS | 0.72 | 0.30 | 0.32 |
| E17 | Dodecanoic acid, ethyl ester | MS | 0.21 | 0.13 | 0.06 |
| E18 | Benzenepropanoic acid, ethyl ester | MS | 0.05 | 0.05 | 0.07 |
| E19 | Tetradecanoic acid, ethyl ester | MS | 0.24 | 0.13 | 0.07 |
| E20 | Pentadecanoic acid, ethyl ester | MS | 0.04 | 0.03 | NDb |
| E21 | Hexadecanoic acid, ethyl ester | MS | 1.37 | 0.84 | 0.51 |
| E22 | Ethyl 9-hexadecenoate | MS | 0.04 | 0.02 | ND |
| E23 | (E)-9-Octadecenoic acid ethyl ester | MS | 0.32 | 0.21 | 0.17 |
| E24 | 9,12-Octadecadienoic acid, ethyl ester | MS | 0.54 | 0.36 | 0.21 |
| E25 | Dibutyl phthalate | MS | 0.01 | 0.02 | ND |
| E26 | [1,1′-Bicyclopropyl]-2-octanoic acid,2′-hexyl-, methyl ester | MS | ND | ND | 0.01 |
| Σ | 23.16 | 16.99 | 12.80 | ||
| alcohols (7) | |||||
| AL1 | Ethanol | MS | 12.41 | 6.41 | 1.93 |
| AL2 | 3-methyl-1-butanol | MS | 3.33 | 2.11 | 1.21 |
| AL3 | Phenylethyl alcohol | MS | 4.32 | 3.12 | 3.26 |
| AL4 | 1-Hexanol | MS | 0.19 | 0.02 | ND |
| AL5 | 2-methyl-1-Hexadecanol | MS | 0.01 | 0.02 | 0.03 |
| AL6 | [S-(R*,R*)]-2,3-Butanediol | MS | ND | 0.11 | 0.12 |
| AL7 | 1-Propanol, 3-(methylthio)- | MS | 0.10 | 0.01 | ND |
| Σ | 20.36 | 11.80 | 6.54 | ||
| ketones (4) | |||||
| K1 | Acetoin | MS | 0.48 | 0.87 | 1.89 |
| K2 | 2-Octanone | MS | 0.77 | 0.15 | 0.27 |
| K3 | 3-Acetoxy-2-butanone | MS | ND | 0.08 | 0.28 |
| K4 | Acetophenone | MS | 0.02 | 0.01 | 0.01 |
| Σ | 1.27 | 1.11 | 2.46 | ||
| aldehydes (5) | |||||
| ALD1 | Furfural | MS | ND | 0.40 | 1.04 |
| ALD2 | Benzaldehyde | MS | 0.28 | 1.06 | 1.43 |
| ALD3 | 2(3 H)-Furanone, dihydro-5-pentyl- | MS | 0.19 | 0.21 | 0.34 |
| ALD4 | Benzeneacetaldehyde | MS | 0.06 | 0.08 | 0.09 |
| ALD5 | 1H-Indene-4-carboxaldehyde, 2,3-dihydro- | MS | 0.04 | 0.05 | 0.11 |
| Σ | 0.57 | 1.80 | 3.02 | ||
aMS, compounds were identified by MS spectra.
bND, Not Detected.