Table 1.
Volatiles profile of cooked brown rice under different soaking conditions during cooking.
| Compound (ng/g) | Unsoaked | 40-30 | 40-60 | 50-30 | 50-60 | 60-30 | 60-60 | 70-30 | 70-60 | CRI | LRI |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Hydrocarbons | |||||||||||
| Octane | 2.27 ± 0.27 | 2.18 ± 0.11 | 2.45 ± 0.22 | 2.31 ± 0.18 | 2.39 ± 0.30 | 2.38 ± 0.23 | 2.29 ± 0.28 | 2.31 ± 0.10 | 2.16 ± 0.25 | 798 | 800 |
| α-Pinene | 0.61 ± 0.09 | 0.53 ± 0.13 | 0.43 ± 0.05 | 0.46 ± 0.02 | 0.55 ± 0.09 | 0.49 ± 0.07 | 0.58 ± 0.11 | 0.65 ± 0.05 | 0.52 ± 0.07 | 1032 | 1029 |
| 4-Methylene-1-(1-methylethyl)- bicyclo[3.1.0]hexane |
3.45 ± 0.19 | 3.26 ± 0.25 | 3.31 ± 0.33 | 3.35 ± 0.15 | 3.21 ± 0.07 | 3.29 ± 0.20 | 3.47 ± 0.23 | 3.38 ± 0.36 | 3.27 ± 0.28 | 1109 | 1116 |
| Pentylcyclopropane | 0.15 ± 0.03 | 0.16 ± 0.01 | 0.15 ± 0.02 | 0.14 ± 0.03 | 0.17 ± 0.02 | 0.17 ± 0.03 | 0.13 ± 0.01 | 0.14 ± 0.02 | 0.18 ± 0.01 | 1538 | NF |
| Aldehydes | |||||||||||
| Hexanal | 12.24 ± 1.39 | 10.88 ± 0.98 | 11.34 ± 0.33 | 11.60 ± 1.24 | 11.94 ± 0.89 | 13.18 ± 0.85 | 12.02 ± 0.92 | 11.27 ± 0.98 | 12.44 ± 1.34 | 1077 | 1080 |
| Octanal | 3.70 ± 0.24 | 3.64 ± 0.14 | 3.74 ± 0.34 | 3.54 ± 0.35 | 3.42 ± 0.38 | 3.48 ± 0.30 | 3.31 ± 0.07 | 3.58 ± 0.10 | 3.25 ± 0.22 | 1280 | 1284 |
| Nonanal | 9.44 ± 0.52 a | 7.51 ± 0.86 b | 8.32 ± 0.55 ab | 7.24 ± 0.76 b | 7.69 ± 0.46 b | 6.96 ± 0.28 b | 8.25 ± 0.65 ab | 7.77 ± 0.20 b | 8.38 ± 0.42 ab | 1372 | 1390 |
| (E)-2-Octenal | 0.37 ± 0.06 b | 0.45 ± 0.07 ab | 0.32 ± 0.03 b | 0.40 ± 0.06 b | 0.41 ± 0.05 b | 0.49 ± 0.08 ab | 0.58 ± 0.09 a | 0.48 ± 0.03 ab | 0.38 ± 0.02 b | 1410 | 1416 |
| Decanal | 0.27 ± 0.06 | 0.32 ± 0.07 | 0.23 ± 0.03 | 0.28 ± 0.02 | 0.24 ± 0.04 | 0.22 ± 0.03 | 0.33 ± 0.06 | 0.29 ± 0.08 | 0.24 ± 0.06 | 1477 | 1484 |
| Benzaldehyde | 1.15 ± 0.19 | 1.21 ± 0.20 | 1.27 ± 0.17 | 1.39 ± 0.07 | 1.07 ± 0.07 | 1.21 ± 0.06 | 1.38 ± 0.04 | 1.23 ± 0.11 | 1.12 ± 0.09 | 1500 | 1508 |
| (E)-2-Nonenal | 0.31 ± 0.04 ab | 0.40 ± 0.05 a | 0.34 ± 0.04 ab | 0.30 ± 0.08 ab | 0.27 ± 0.03 ab | 0.26 ± 0.05 b | 0.34 ± 0.06 ab | 0.23 ± 0.02 b | 0.26 ± 0.04 ab | 1508 | 1502 |
| Furans | |||||||||||
| 2-Ethylfuran | 0.89 ± 0.09 | 0.83 ± 0.07 | 0.90 ± 0.02 | 0.85 ± 0.05 | 0.84 ± 0.06 | 0.83 ± 0.02 | 0.89 ± 0.05 | 0.81 ± 0.03 | 0.92 ± 0.06 | 944 | 945 |
| 2-n-Butylfuran | 0.96 ± 0.11 | 0.85 ± 0.08 | 0.82 ± 0.06 | 0.78 ± 0.04 | 0.90 ± 0.05 | 0.97 ± 0.09 | 0.86 ± 0.06 | 0.85 ± 0.07 | 0.92 ± 0.08 | 1134 | 1126 |
| 2-Pentylfuran | 26.78 ± 1.25 | 25.19 ± 1.65 | 27.40 ± 2.48 | 27.17 ± 1.05 | 27.10 ± 1.59 | 25.80 ± 0.87 | 26.40 ± 2.09 | 25.57 ± 0.84 | 26.74 ± 2.14 | 1220 | 1226 |
| 2,3-Dihydrobenzofuran | 1.00 ± 0.04 abc | 0.94 ± 0.03 abc | 0.86 ± 0.10 bc | 1.02 ± 0.08 ab | 0.98 ± 0.05 abc | 0.95 ± 0.07 abc | 1.05 ± 0.06 a | 0.99 ± 0.05 abc | 0.85 ± 0.04 c | 2292 | NF |
| Alcohols | |||||||||||
| 2,3-Dimethylcyclohexanol | 0.24 ± 0.05 | 0.22 ± 0.03 | 0.24 ± 0.04 | 0.21 ± 0.02 | 0.27 ± 0.01 | 0.23 ± 0.04 | 0.26 ± 0.03 | 0.25 ± 0.03 | 0.20 ± 0.02 | 1058 | NF |
| 1-Hexanol | 0.87 ± 0.07 bc | 0.93 ± 0.09 ab | 0.78 ± 0.05 bc | 0.83 ± 0.04 bc | 0.81 ± 0.06 bc | 0.86 ± 0.03 bc | 0.73 ± 0.05 c | 1.04 ± 0.06 a | 0.85 ± 0.02 bc | 1355 | 1354 |
| Ketones | |||||||||||
| 2-Heptanone | 0.33 ± 0.05 bcd | 0.30 ± 0.03 d | 0.45 ± 0.05 ab | 0.34 ± 0.03 bcd | 0.44 ± 0.05 abc | 0.38 ± 0.02 abcd | 0.32 ± 0.04 cd | 0.39 ± 0.08 abcd | 0.49 ± 0.05 a | 1185 | 1183 |
| 2,2,6-Trimethylcyclohexanone | 0.20 ± 0.04 ab | 0.15 ± 0.03 b | 0.23 ± 0.04 a | 0.15 ± 0.02 ab | 0.22 ± 0.04 ab | 0.17 ± 0.03 ab | 0.18 ± 0.01 ab | 0.17 ± 0.02 ab | 0.18 ± 0.03 ab | 1288 | 1282 |
| 2,3-Octanedione | 1.46 ± 0.16 | 1.29 ± 0.12 | 1.34 ± 0.05 | 1.40 ± 0.08 | 1.26 ± 0.07 | 1.29 ± 0.11 | 1.29 ± 0.03 | 1.50 ± 0.07 | 1.44 ± 0.03 a | 1316 | 1325 |
| 6-Methyl-5-hepten-2-one | 0.48 ± 0.07 abc | 0.31 ± 0.03 d | 0.37 ± 0.04 bcd | 0.39 ± 0.11 bcd | 0.52 ± 0.05 ab | 0.36 ± 0.03 cd | 0.55 ± 0.04 a | 0.49 ± 0.04 abc | 0.33 ± 0.03 d | 1330 | 1341 |
| 5-Ethyl-6-methyl-3E-hepten-2-one | 1.96 ± 0.10 | 1.86 ± 0.09 | 2.10 ± 0.14 | 1.85 ± 0.05 | 2.02 ± 0.17 | 1.99 ± 0.16 | 1.90 ± 0.07 | 2.01 ± 0.10 | 1.88 ± 0.06 | 1443 | NF |
| 6,10-Dimethyl-5,9-Undecadien-2-one | 0.80 ± 0.07 | 0.91 ± 0.11 | 0.77 ± 0.03 | 0.89 ± 0.06 | 0.79 ± 0.06 | 0.86 ± 0.02 | 0.93 ± 0.04 | 0.89 ± 0.09 | 0.90 ± 0.07 | 1838 | 1865 |
| Others | |||||||||||
| 2-Acetylthiazole | 0.12 ± 0.02 ab | 0.09 ± 0.01 b | 0.13 ± 0.02 ab | 0.14 ± 0.01 ab | 0.12 ± 0.02 ab | 0.15 ± 0.03 a | 0.11 ± 0.02 ab | 0.13 ± 0.02 ab | 0.16 ± 0.02 a | 1621 | 1643 |
| Cyclopentyl 4-ethylbenzoate | 0.31 ± 0.02 ab | 0.42 ± 0.03 a | 0.28 ± 0.06 b | 0.29 ± 0.07 ab | 0.22 ± 0.03 b | 0.34 ± 0.04 ab | 0.31 ± 0.07 ab | 0.24 ± 0.05 b | 0.25 ± 0.02 ab | 1798 | 1835 |
| Phenol | 0.06 ± 0.02 b | 0.07 ± 0.01 ab | 0.10 ± 0.01 a | 0.05 ± 0.01 b | 0.08 ± 0.02 ab | 0.07 ± 0.01 ab | 0.08 ± 0.01 ab | 0.06 ± 0.02 b | 0.09 ± 0.01 ab | 1964 | 2002 |
| 2-Methoxy-4-vinylphenol | 0.89 ± 0.08 | 0.86 ± 0.03 | 0.91 ± 0.06 | 1.06 ± 0.10 | 0.93 ± 0.05 | 0.94 ± 0.11 | 1.02 ± 0.08 | 0.90 ± 0.12 | 0.87 ± 0.06 | 2146 | 2212 |
| Indole | 0.41 ± 0.05 | 0.43 ± 0.08 | 0.38 ± 0.02 | 0.45 ± 0.04 | 0.42 ± 0.07 | 0.40 ± 0.04 | 0.49 ± 0.07 | 0.51 ± 0.04 | 0.52 ± 0.14 | 2438 | 2450 |
Means followed by different lowercase letters within rows are significantly different (p < 0.05). Rows without letters indicate that there is no significant difference. CRI, calculated retention index; LRI, literature retention index, ND, not determined; NF, no literature found.