Table 2.
Volatile compounds (%) in MPs and SPs (10 mg/mL) treated with S. xylosus protease.
| Compound | Degree of hydrolysis – MP |
Degree of hydrolysis – SP |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Control | DH3.5 | DH5.3 | DH6.5 | DH7.5 | Control | DH2.8 | DH4.8 | DH7 | DH8.5 | |
| Aldehydes (3) | ||||||||||
| Nonanal | 3.00 ± 0.10c | 3.16 ± 0.13c | 3.44 ± 0.10b | 3.62 ± 0.15b | 3.84 ± 0.11a | 1.32 ± 0.08c | 1.48 ± | 1.55 ± 0.14abc | 1.68 ± 0.16ab | 1.79 ± 0.15a |
| 0.11bc | ||||||||||
| Pentanal | n. d. | n. d. | n. d. | n. d. | n. d. | 0.17 ± 0.02a | n. d. | n. d. | n. d. | n. d. |
| Hexanal | 0.24 ± 0.02a | 0.22 ± 0.01a | 0.22 ± 0.02a | 0.24 ± 0.03a | 0.25 ± 0.03a | n. d. | n. d. | n. d. | n. d. | n. d. |
| Alcohols (7) | ||||||||||
| Ethanol | n. d. | 0.07 ± 0.01d | 0.10 ± 0.01c | 0.12 ± 0.02b | 0.15 ± 0.01a | 0.10 ± 0.01e | 0.14 ± | 0.20 ± 0.02c | 0.23 ± 0.03b | 0.27 ± |
| 0.01d | 0.03a | |||||||||
| (E)-2- | 3.69 ± 0.15e | 5.17 ± 0.11d | 6.45 ± 0.11c | 6.94 ± 0.20b | 7.74 ± 0.18a | n. d | n. d. | n. d. | n. d. | n. d. |
| Tridecan-1-ol | ||||||||||
| Hexanol | n. d. | 2.28 ± 0.18d | 3.05 ± 0.19c | 4.16 ± 0.20b | 5.11 ± 0.17a | 1.54 ± 0.09e | 2.36 ± 0.07d | 3.54 ± 0.06c | 4.24 ± 0.13b | 5.06 ± 0.12a |
| 2,3- | n. d. | 0.12 ± 0.02d | 0.18 ± 0.01c | 0.22 ± 0.01b | 0.25 ± 0.02a | n. d | 0.07 ± 0.01d | 0.13 ± 0.01c | 0.17 ± 0.03b | 0.21 ± 0.02a |
| butanediol | ||||||||||
| 1-Dodecanol | n. d. | n. d. | n. d. | n. d. | n. d. | 0.17 ± 0.02a | 0.14 ± 0.01a | 0.17 ± 0.01a | 0.16 ± 0.03a | 0.14 ± 0.02a |
| 3-Phenylpropanol | n. d. | 0.13 ± 0.01d | 0.19 ± 0.03c | 0.24 ± 0.02b | 0.27 ± 0.02a | n. d. | 0.04 ± 0.01c | 0.11 ± 0.02b | 0.16 ± 0.01a | 0.18 ± 0.02a |
| 2-Ethylhexanol | 8.26 ± 0.21d | 8.57 ± 0.17cd | 8.72 ± 0.12c | 9.13 ± 0.21b | 10.01 ± 0.22a | n. d. | 0.17 ± | 3.44 ± 0.13c | 4.21 ± 0.04b | 5.51 ± 0.18a |
| 0.02d | ||||||||||
| Acids (1) | ||||||||||
| Hexanoic acid | n. d. | 0.23 ± 0.03d | 0.31 ± 0.07c | 0.38 ± 0.05b | 0.42 ± 0.05a | n. d. | 1.79 ± 0.10c | 3.11 ± 0.13c | 4.51 ± 0.07c | 2.97 ± 0.06c |
| Esters (1) | ||||||||||
| Ethyl hexanoate | n. d. | 0.52 ± 0.07d | 0.78 ± 0.05c | 0.95 ± 0.10b | 1.15 ± 0.08a | 1.33 ± 0.04c | 2.27 ± 0.06c | 2.82 ± 0.09c | 3.46 ± 0.10b | 4.34 ± 0.15a |
| Hydrocarbons (3) | ||||||||||
| Tetradecane | n. d. | 0.91 ± 0.07d | 1.51 ± 0.11c | 1.85 ± 0.05b. | 2.13 ± 0.13a | n. d. | 0.40 ± | 1.21 ± 0.09c | 2.08 ± 0.10b | 2.76 ± 0.14a |
| 0.02d | ||||||||||
| Octadecane | 0.42 ± 0.05a | 0.41 ± 0.02a | 0.38 ± 0.01ab | 0.34 ± 0.01bc | 0.32 ± 0.03c | n. d. | n. d. | n. d. | n. d. | n. d. |
| Heptadecane | n. d. | n. d. | n. d. | n. d. | n. d. | 1.01 ± 0.03a | 0.92 ± | 0.88 ± 0.04b | 0.82 ± 0.02bc | 0.76 ± 0.02c |
| 0.05b | ||||||||||
| Other (1) | ||||||||||
| 2-methoxy-3- Phenol | n. d. | n. d. | n. d. | 1.05 ± 0.07b | 2.82 ± 0.12a | n. d. | 1.81 ± 0.11d | 3.68 ± 0.15c | 4.29 ± 0.22b | 5.98 ± 0.18a |
a–e Means within the same row with different superscript letters differ significantly (P < 0.05).
n. d.: not detected.