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Figure 1.
Venn diagram of volatile compounds. (a) Comparison of the number of volatile compounds in unfermented and fermented beans within the same group. (b) Comparison of the number of volatile compounds between unfermented and fermented beans in the three groups. (c) Number of volatile compounds shared by unfermented and fermented beans in the three groups (Un: unfermented beans, Fe: fermented beans).
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Figure 2.
Volatile compound buildup map. (a) Total area abundance of volatile components. (b) Number of volatile components. (c) Relative content of volatile components.
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Figure 3.
Number of volatile compounds within the three cacao groups. The three dots on the box represent the number of volatile compounds for the three replicates; 'Ave' represents the average (rounded).
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Figure 4.
Peak areas of major volatile compounds.
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Figure 5.
PCA analysis of unfermented and fermented beans in three cacao groups. (a) unfermented beans. (b) Fermented beans. The code in the figure corresponds to the corresponding compound.
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Figure 6.
Volatile compounds cluster heat map. The code in the figure corresponds to the corresponding compound.
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Germplasm Cocoa butter
(%)Theobromine
(mg/g)Caffeine
(mg/g)Polyphenol
(mg GAE/g)F0 42.37 ± 1.94ab 13.83 ± 0.50a 1.92 ± 0.83a 63.54 ± 4.69a C0 42.12 ± 1.46ab 14.49 ± 0.84a 1.24 ± 0.11a 64.40 ± 2.96a T0 44.00 ± 2.24a 13.56 ± 1.67a 2.69 ± 1.10a 66.21 ± 1.92a F1 38.76 ± 2.58b 12.01 ± 1.24a 1.73 ± 0.75a 53.64 ± 6.53ab C1 37.98 ± 1.93b 11.68 ± 1.53a 1.18 ± 0.09a 45.35 ± 12.44b T1 38.30 ± 1.36b 12.49 ± 1.18a 2.04 ± 0.58a 46.41 ± 5.49b The value for each group is the mean ± SD of the triplicate material in the group. Mean values assigned with a common letter within the same column are not significantly different according to Duncan's multiple range tests at the 5% level. Table 1.
Quality traits of unfermented and fermented beans for the three cacao groups.
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Code Compound LRI Relative content (%) Aroma description F0 C0 T0 F1 C1 T1 Alcohols A1 2-Methyl-3-buten-2-ol 1002 1.98 ± 0.58 0.65 ± 0.65 1.01 ± 0.53 0.03 ± 0.03 0.08 ± 0.08 0.01 ± 0.01 Herbal, earth, oily A2 Isobutanol 1068 0.46 ± 0.27 0.28 ± 0.26 0.47 ± 0.31 0.07 ± 0.03 0.22 ± 0.14 0.10 ± 0.07 Apple, cocoa, wine A3 2-Pentanol 1108 46.33 ± 13.39 29.22 ± 7.88 38.31 ± 24.80 NA NA NA Green, fusel oil A4 3-Methyl-1-butanol 1202 3.37 ± 1.45 3.85 ± 3.29 5.05 ± 0.69 0.32 ± 0.22 1.44 ± 1.17 0.72 ± 0.08 Banana, fruity, fusel oil A5 1-Pentanol 1247 0.17 ± 0.17 0.12 ± 0.12 0.06 ± 0.04 NA 0.03 ± 0.03 NA Fruity, green A6 2-Hexanol 1311 0.50 ± 0.50 0.26 ± 0.01 0.43 ± 0.14 NA NA NA Wine, fruity, fatty A7 2-Heptanol 1322 1.04 ± 1.72 6.31 ± 3.44 6.80 ± 1.27 0.06 ± 0.05 0.51 ± 0.57 0.13 ± 0.07 Fruity, citrus A8 1-Hexanol 1342 0.18 ± 0.18 0.40 ± 0.05 0.23 ± 0.04 NA 0.04 ± 0.04 NA Green, herbal, fruity A9 3-Ethoxy-1-propanol 1374 NA NA NA 0.06 ± 0.06 0.13 ± 0.08 0.06 ± 0.02 Fruity A10 2-Octanol 1421 NA NA NA 0.08 ± 0.05 0.06 ± 0.02 NA Spicy, green, wood A11 2-Nonanol 1519 NA 0.27 ± 0.10 0.83 ± 0.83 0.19 ± 0.08 1.01 ± 0.21 0.27 ± 0.20 Fruity, green A12 2,3-Butanediol 1536 1.03 ± 0.91 1.55 ± 0.62 1.19 ± 0.55 13.24 ± 7.34 10.22 ± 4.77 12.89 ± 2.84 Creamy, fruity A13 Linalool 1544 0.49 ± 0.49 0.30 ± 0.30 0.35 ± 0.16 0.27 ± 0.16 0.16 ± 0.14 0.08 ± 0.02 Rose, floral, green A14 1-Octanol 1555 NA 0.14 ± 0.14 0.07 ± 0.07 0.03 ± 0.03 0.08 ± 0.08 0.05 ± 0.01 Waxy, green A15 1,3-Butanediol 1574 3.15 ± 1.97 3.12 ± 1.55 4.23 ± 3.31 4.74 ± 1.67 4.04 ± 0.93 4.74 ± 0.87 A16 Propylene glycol 1587 NA 0.13 ± 0.13 0.08 ± 0.06 0.07 ± 0.07 0.11 ± 0.04 0.07 ± 0.03 A17 1-Phenylethanol 1798 0.38 ± 0.38 NA 0.17 ± 0.17 0.09 ± 0.05 0.20 ± 0.15 0.04 ± 0.00 Floral, honey, rose A18 Benzyl alcohol 1857 NA NA NA 0.02 ± 0.00 0.12 ± 0.08 0.03 ± 0.02 Floral, rose A19 2-Phenylethanol 1890 0.63 ± 0.21 1.19 ± 0.19 1.42 ± 0.75 6.17 ± 5.01 18.88 ± 13.74 8.10 ± 6.24 Floral, honey, rose Esters E1 Ethyl acetate 903 10.09 ± 4.66 13.03 ± 4.23 9.70 ± 6.52 2.34 ± 2.08 8.94 ± 6.12 3.90 ± 2.51 Fruity, sweet, grape E2 Isobutyl acetate 973 NA NA NA 0.12 ± 0.01 0.10 ± 0.03 0.12 ± 0.01 Apple, floral, herbal E3 Ethyl butanoate 994 0.57 ± 0.57 0.74 ± 0.18 0.15 ± 0.15 NA 0.12 ± 0.12 NA Fruity, green, apple E4 2-Pentyl acetate 1039 1.53 ± 0.32 7.32 ± 3.01 1.92 ± 0.84 0.03 ± 0.01 0.05 ± 0.05 0.05 ± 0.01 Herbal, fruity, green E5 Isopentyl acetate 1104 NA NA NA 0.72 ± 0.44 1.01 ± 0.02 1.34 ± 0.50 Fruity, sweet, banana E6 Ethyl hexanoate 1225 0.27 ± 0.27 0.26 ± 0.16 0.22 ± 0.13 0.13 ± 0.10 0.21 ± 0.13 0.12 ± 0.14 Fruity, green, banana E7 2-Heptyl acetate 1257 0.19 ± 0.19 1.95 ± 0.58 0.27 ± 0.27 0.04 ± 0.04 0.17 ± 0.17 0.13 ± 0.13 Fenugreek, fruity E8 Ethyl heptanoate 1329 NA NA 0.07 ± 0.07 0.03 ± 0.01 0.04 ± 0.02 0.02 ± 0.02 Fruit, wine E9 Acetoin acetate 1377 NA NA NA 0.32 ± 0.15 0.19 ± 0.11 0.31 ± 0.14 Sweet, creamy E10 Ethyl octanoate 1429 NA NA NA 0.09 ± 0.03 0.22 ± 0.12 0.09 ± 0.08 Fruity, apricot, brandy E11 2-Hydroxyethyl acetate 1627 NA NA NA 0.19 ± 0.04 NA 0.19 ± 0.04 E12 Ethyl decanoate 1630 NA NA NA 0.01 ± 0.01 0.02 ± 0.01 NA Grape, brandy, grape E13 Diethyl succinate 1667 NA NA 0.22 ± 0.22 NA 0.24 ± 0.05 NA Fruity, floral E14 1-Phenylethyl acetate 1684 NA 0.11 ± 0.11 0.08 ± 0.08 0.02 ± 0.00 0.02 ± 0.00 0.02 ± 0.02 Green, fruity E15 Ethyl phenylacetate 1766 NA 0.11 ± 0.11 NA 0.08 ± 0.02 0.15 ± 0.06 0.12 ± 0.05 Floral, rose, honey E16 2-Phenylethyl acetate 1793 NA NA NA 2.58 ± 2.01 2.94 ± 2.08 3.14 ± 0.50 Floral, rose, honey E17 Isobutyl benzoate 1816 NA NA 0.44 ± 0.17 0.04 ± 0.01 0.04 ± 0.02 0.07 ± 0.01 Sweet, fruity E18 Ethyl laurate 1834 NA NA NA 0.02 ± 0.02 0.02 ± 0.00 0.01 ± 0.01 Sweety, floral E19 Ethyl cinnamate 2097 NA NA NA 0.02 ± 0.02 0.03 ± 0.02 0.02 ± 0.02 Balsamic, fruity E20 Eugenyl acetate 2239 NA NA NA 0.02 ± 0.02 0.17 ± 0.17 0.25 ± 0.25 Woody, clove, floral E21 Ethyl palmitate 2246 NA NA NA 0.12 ± 0.01 0.13 ± 0.07 0.12 ± 0.02 Waxy Acids Ac1 Acetic acid 1443 6.30 ± 3.52 9.15 ± 0.82 6.22 ± 4.56 52.56 ± 9.01 35.42 ± 20.58 52.57 ± 8.27 Sour, vinegar, pungent Ac2 Propanoic acid 1531 NA NA NA 0.06 ± 0.03 0.04 ± 0.04 0.04 ± 0.01 Acidic, pungent, cheesy Ac3 Isobutyric acid 1561 NA NA NA 0.28 ± 0.17 0.30 ± 0.22 0.20 ± 0.04 Acidic, buttery, cheese Ac4 Butanoic acid 1622 NA NA NA 0.03 ± 0.01 0.03 ± 0.01 0.03 ± 0.03 Acetic, cheese, butter Ac5 2-Methylbutanoic acid 1662 NA NA NA 2.94 ± 2.94 0.28 ± 0.28 NA Pungent, cheese Ac6 Isovaleric acid 1664 0.30 ± 0.30 0.36 ± 0.07 0.17 ± 0.08 0.68 ± 0.42 0.68 ± 0.49 0.58 ± 0.14 Sour, stinky Ac7 Hexanoic acid 1839 NA NA NA 0.03 ± 0.01 0.05 ± 0.03 0.03 ± 0.00 Sour, fatty Ac8 Octanoic acid 2056 NA NA NA 0.05 ± 0.01 0.05 ± 0.02 0.04 ± 0.01 Acid, cheese Aldehydes Ald1 Hexanal 1046 0.24 ± 0.24 0.54 ± 0.54 0.37 ± 0.37 NA 0.01 ± 0.01 NA Grass, fresh, fruity Ald2 Octanal 1279 NA 0.12 ± 0.12 0.10 ± 0.05 0.02 ± 0.01 0.02 ± 0.01 NA Citrus, fatty Ald3 Nonanal 1387 1.19 ± 0.78 0.99 ± 0.67 0.77 ± 0.47 0.15 ± 0.02 0.14 ± 0.07 0.13 ± 0.07 Citrus, fatty Ald4 2-Furaldehyde 1448 0.58 ± 0.58 0.54 ± 0.54 NA NA 0.15 ± 0.15 0.14 ± 0.14 Baked bread, almond Ald5 Decanal 1480 NA NA NA 0.07 ± 0.02 0.04 ± 0.02 0.27 ± 0.01 Orange peel, floral Ald6 Benzaldehyde 1503 0.13 ± 0.13 NA NA 0.10 ± 0.06 0.35 ± 0.27 0.17 ± 0.09 Almond, cherry Ald7 Phenylacetaldehyde 1619 NA NA NA 0.05 ± 0.02 0.08 ± 0.03 0.04 ± 0.03 Honey, nutty Ald8 2-Phenyl-2-butenal 1899 NA NA NA NA 0.09 ± 0.06 0.03 ± 0.03 Cocoa, honey, roast Ketones K1 2-Pentanone 946 11.10 ± 1.17 9.06 ± 0.52 10.71 ± 5.75 0.26 ± 0.25 0.13 ± 0.09 0.12 ± 0.02 Fruity K2 2-Heptanone 1166 0.57 ± 0.71 2.64 ± 1.20 4.01 ± 3.35 0.10 ± 0.10 0.24 ± 0.22 0.08 ± 0.07 Fruity, green K3 Acetoin 1271 1.02 ± 0.26 0.84 ± 0.21 0.69 ± 0.45 3.67 ± 2.59 1.63 ± 0.74 2.09 ± 0.39 Buttery, creamy K4 Hydroxyacetone 1285 NA 0.13 ± 0.13 NA 0.02 ± 0.00 0.03 ± 0.02 0.02 ± 0.01 Caramellic, buttery K5 2-Hydroxy-3-pentanone 1348 NA NA NA 0.19 ± 0.19 0.04 ± 0.02 0.02 ± 0.02 Truffle, earthy, nutty K6 2-Nonanone 1383 NA 0.70 ± 0.06 0.26 ± 0.26 0.05 ± 0.05 1.73 ± 1.46 0.03 ± 0.03 Green, herbal K7 Acetophenone 1625 3.20 ± 3.20 0.17 ± 0.17 0.72 ± 0.43 0.35 ± 0.10 0.65 ± 0.37 NA Floral, almond Hydrocarbons H1 β-Myrcene 1148 0.98 ± 0.98 NA 0.66 ± 0.41 0.22 ± 0.16 0.13 ± 0.10 0.04 ± 0.01 Balsam, spicy H2 Styrene 1242 NA NA NA 0.03 ± 0.01 0.02 ± 0.00 0.02 ± 0.02 Balsam, plastic H3 Alloocimene 1366 NA NA NA 0.08 ± 0.08 0.02 ± 0.02 NA Floral, herbal H4 α-Humulene 1643 0.38 ± 0.10 0.29 ± 0.29 0.48 ± 0.26 0.08 ± 0.03 0.08 ± 0.02 0.05 ± 0.01 Woody Pyrazines P1 2,3-Dimethylpyrazine 1338 0.16 ± 0.12 0.16 ± 0.11 0.11 ± 0.03 0.25 ± 0.20 3.31 ± 3.86 0.27 ± 0.03 Caramel, roasted, nutty P2 Trimethylpyrazine 1397 NA NA NA 0.18 ± 0.16 0.06 ± 0.03 0.18 ± 0.02 Nutty, cocoa, baked potato P3 Tetramethylpyrazine 1464 NA NA NA 4.43 ± 6.06 0.51 ± 0.36 4.27 ± 1.19 Chocolate, coffee, cocoa Furans F1 trans-Furan linalool oxide 1461 0.66 ± 0.66 NA 0.21 ± 0.05 0.05 ± 0.03 0.07 ± 0.04 0.05 ± 0.01 Floral, citrus F2 Furaneol 2017 NA NA NA 0.02 ± 0.02 0.05 ± 0.05 0.05 ± 0.05 Caramel, sweet, strawberry Lactone L1 γ-Valerolactone 1583 0.15 ± 0.15 NA NA 0.04 ± 0.03 NA 0.09 ± 0.09 Herbal, sweet L2 γ-Butyrolactone 1599 0.57 ± 0.32 0.56 ± 0.47 0.60 ± 0.76 0.30 ± 0.16 0.50 ± 0.18 0.42 ± 0.36 Creamy, caramel L3 Pantolactone 2001 NA NA NA 0.08 ± 0.03 0.12 ± 0.06 0.10 ± 0.05 Cotton candy, burnt L4 5-Acetyldihydro-2(3H)-furanone 2024 NA NA NA 0.02 ± 0.00 0.04 ± 0.02 0.06 ± 0.01 Wine Others O1 Methionol 1704 NA 0.11 ± 0.11 NA 0.06 ± 0.06 0.43 ± 0.39 0.12 ± 0.17 Onion, soup O2 trans-Pyran linalool oxide 1756 NA NA NA 0.03 ± 0.01 0.04 ± 0.01 0.03 ± 0.01 Floral, sweet O3 2-Acetylpyrrole 1946 NA NA NA 0.04 ± 0.01 0.03 ± 0.02 0.07 ± 0.02 Bready, cocoa, hazelnut O4 Eugenol 2152 0.12 ± 0.12 0.39 ± 0.39 0.17 ± 0.17 0.03 ± 0.03 0.18 ± 0.18 0.04 ± 0.02 Clove, spicy O5 Elemicin 2207 NA 1.93 ± 1.93 NA 0.04 ± 0.03 0.13 ± 0.16 0.20 ± 0.20 Spicy, floral The value for each group is the mean ± SD of the triplicate material in the group. 'NA' indicates that the substance has not been detected. Table 2.
Volatile compounds before and after fermentation of three groups cocoa beans.
Figures
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Tables
(2)