Table 2.
Main volatile compounds in the R–B mixed juice before and after fermentation with L. plantarum TUST-232.
| Number | Name | Retention Time (min) | Relative Content (%) | p-Value | |
|---|---|---|---|---|---|
| Before | After | ||||
| Aldehyde | |||||
| A1 | 3-methylbutyraldehyde | 2.756 | 0.41 | - | |
| A2 | valeraldehyde | 3.822 | 0.51 | - | |
| A3 | hexanal | 6.125 | 6.16 | 2.38 | * |
| A4 | heptanal | 8.827 | 3.35 | - | |
| A5 | 5-methylhexanal | 8.417 | - | 0.19 | |
| A6 | hexen-2-al | 9.989 | 2.25 | 0.16 | * |
| A7 | octanal | 11.926 | 3.14 | 2.81 | |
| A8 | (2Z)-2-heptenal | 13.105 | 11.23 | 9.23 | * |
| A9 | nonanal | 14.971 | 3.20 | 3.06 | |
| A10 | 2-octenal | 16.089 | 9.97 | 14.80 | * |
| A11 | furfural | 17.106 | 0.91 | - | |
| A12 | decanal | 18.367 | - | 0.67 | |
| A13 | lauric aldehyde | 18.467 | - | 0.34 | |
| A14 | benzaldehyde | 18.658 | 3.95 | 1.26 | * |
| A15 | 2-nonenal | 19.656 | 0.98 | 1.25 | |
| A16 | 2-decenal | 22.399 | 3.26 | 3.15 | |
| A17 | 2,4-nonadienal | 23.775 | 0.12 | 0.27 | |
| A18 | 2-undecenal | 24.929 | 1.25 | 2.41 | * |
| A19 | 2-trans, 4-trans-decadienal | 24.916 | - | 0.27 | |
| A20 | 5-hydroxymethyl-2-furaldehyde | 38.962 | 0.56 | 0.22 | |
| Olefin | |||||
| B1 | 2-methyl-6-methyl-2-methylene | 15.227 | - | 0.91 | |
| B2 | 3-ethyl-2-methyl-1,3-hexadien | 15.659 | 0.08 | 0.25 | |
| B3 | 2,4-dimethyl-1,3-pentadiene | 17.160 | - | 0.58 | |
| B4 | 3,5,5-trimethyl-2-Hexene | 17.558 | 0.10 | - | |
| B5 | 2-methyl-1,5-hexadiene | 20.783 | - | 0.11 | |
| Ketone | |||||
| C1 | 3-hydroxy-4-hexanone | 9.416 | 0.29 | 1.75 | * |
| C2 | 3-octanone | 10.917 | 0.13 | - | |
| C3 | 1-octen-3-one | 12.379 | 5.08 | 7.07 | * |
| C4 | 6-methyl-5-hepten-2-one | 13.457 | 0.47 | 0.89 | * |
| C5 | 2-nonanone | 14.883 | 0.11 | 0.37 | * |
| C6 | 2-octanone | 20.917 | - | 0.35 | |
| C7 | 6-methyl-2-heptanone | 23.618 | 0.33 | - | |
| C8 | l-fenchone | 26.238 | 0.56 | - | |
| C9 | nerylacetone | 26.913 | - | 0.59 | |
| C10 | 6,10-dimethyl-5,9-undecadien-2-one | 27.172 | 0.27 | - | |
| C11 | 4,5-dimethyl-2-cyclohexen-1-one | 30.164 | 0.48 | - | |
| C12 | 3,6-dimethyl-5-octen-2-one | 31.557 | - | 0.05 | |
| C13 | 6,10-dimethyl-2-undecanone | 33.092 | 0.40 | 0.46 | |
| Alcohol | |||||
| D1 | 3-octyn-2-ol | 7.558 | 0.12 | - | |
| D2 | 3,5,5-trimethyl-1-hexanol | 7.857 | - | 0.16 | |
| D3 | amyl alcohol | 11.201 | 0.08 | - | |
| D4 | hexyl alcohol | 14.007 | 0.57 | 0.67 | |
| D5 | 3,5-octadien-2-ol | 15.500 | 0.16 | 0.15 | |
| D6 | 1-octen-3-ol | 16.623 | 2.97 | 1.55 | * |
| D7 | heptyl alcohol | 16.775 | - | 0.33 | |
| D8 | 1-octanol | 19.821 | 0.72 | 0.71 | |
| D9 | (E)-2-octen-1-ol | 21.215 | 1.59 | 0.92 | * |
| D10 | menthol | 21.755 | - | 0.38 | |
| D11 | nonyl alcohol | 22.198 | - | 1.21 | |
| D12 | nerolidol | 26.048 | - | 1.30 | |
| D13 | benzyldehyde | 27.112 | - | 0.58 | |
| D14 | farnesol | 28.528 | - | 0.17 | |
| D15 | (2E,6E)-2,6-dimethyl-2,6-octadiene-1,8-diol | 29.730 | - | 0.09 | |
| D16 | pentaethylene glycol | 43.650 | 1.48 | - | |
| Ester | |||||
| E1 | methyl benzoate | 21.458 | 0.72 | 0.35 | * |
| E2 | geranyl phenylacetate | 21.907 | 1.51 | - | |
| E3 | methyl Laurate | 26.125 | 0.52 | 0.39 | |
| E4 | (Z)-3-decen-1-yl acetate | 26.308 | - | 0.27 | |
| E5 | 10-undecen-1-yl acetate | 30.056 | - | 0.46 | |
| E6 | decyl propionate | 35.042 | - | 0.30 | |
| E7 | benzyl salicylate | 42.976 | - | 0.24 | |
| Acid | |||||
| F1 | acetic acid | 16.974 | 0.67 | 0.91 | * |
| F2 | valeric acid | 24.010 | - | 0.03 | |
| F3 | hexanoic acid | 26.500 | 0.77 | 1.80 | * |
| F4 | heptanoic acid | 28.836 | 0.86 | 1.47 | * |
| F5 | octanoic acid | 31.057 | 1.26 | 2.83 | * |
| F6 | nonanoic acid | 33.382 | 0.69 | 0.88 | |
| F7 | decanoic acid | 35.357 | 5.83 | 7.06 | * |
| F8 | undecanoic acid | 37.183 | 0.18 | 0.14 | |
| F9 | lauric acid | 38.739 | 6.37 | 8.72 | * |
| F10 | myristic acid | 41.607 | 2.99 | 5.37 | * |
| F11 | palmitic acid | 44.527 | 2.98 | 2.40 | |
| F12 | oleic acid | 45.251 | 1.94 | - | |
| Others | |||||
| G1 | 2-pentylfuran | 9.937 | 0.10 | 0.13 | |
| G2 | azulene | 24.312 | 0.39 | 0.07 | * |
| G3 | adenosine cyclophosphate | 29.060 | 0.08 | - | |
| G4 | 2-methoxy-4-vinylphenol | 37.310 | - | 0.35 | |
Relative content (%) represents the share of a given substance in the entire pool of volatile compounds; ‘before’ indicates the relative percentage in the R–B mixed juice before fermentation; ‘after’ indicates the relative percentage in the R–B mixed juice after fermentation; the differences between groups were analyzed by a two-tailed paired Student’s t-test; * p < 0.05.