Table 5.
The changes in amounts of substituted alkanals formed during the soybean oil heating process and food frying process a,b
| Substituted alkanals | Treatments | 1–2 h | 1–8 h | 2–2 h | 2–8 h | 3–2 h | 3–8 h | 4–2 h | 4–8 h | 5–2 h | 5–8 h | 6–2 h | 6–8 h | 7–2 h | 7–8 h |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Benzaldehyde | Oil heating | 0.63 ± 0.01b | 1.16 ± 0.01 | 1.34 ± 0.02a | 1.45 ± 0.02a | 0.65 ± 0.01 | 1.55 ± 0.02 | 1.83 ± 0.03 | 1.83 ± 0.02a | 1.91 ± 0.01 ac | 1.97 ± 0.02a | 1.86 ± 0.01a | 1.89 ± 0.04a | 2.04 ± 0.08a | 1.60 ± 0.01a |
| WD frying | ND | ND | ND | 0.22 ± 0.03b | ND | ND | ND | ND | 0.72 ± 0.02b | ND | 0.09 ± 0.04c | 0.65 ± 0.06b | 0.08 ± 0.08c | ND | |
| CBM frying | 0.79 ± 0.03a | ND | 0.96 ± 0.04b | ND | ND | ND | ND | 0.83 ± 0.05b | 0.63 ± 0.01c | 0.67 ± 0.04b | 0.70 ± 0.07b | 0.73 ± 0.06b | 0.76 ± 0.08b | 0.70 ± 0.08b | |
| Cyclohexanecarboxaldehyde, 4-(hydroxymethyl)- | Oil heating | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | 0.80 ± 0.04a | 0.25 ± 0.04b |
| 3-Methylbutanal | Oil heating | ND | ND | ND | ND | ND | 0.17 ± 0.04 | 0.05 ± 0.02 | ND | 0.28 ± 0.03 | 0.43 ± 0.03 | 0.49 ± 0.03 | ND | 0.02 ± 0.01c | ND |
| WD frying | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | 0.34 ± 0.07a | 0.43 ± 0.07a | 0.39 ± 0.07a | |
| CBM frying | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | ND | 0.03 ± 0.01b | 0.07 ± 0.02b | 0.12 ± 0.03b | |
| 4-Oxononanal | Oil heating | 0.95 ± 0.32ab | 1.46 ± 0.38b | 2.01 ± 0.49b | 4.52 ± 0.71a | 2.92 ± 0.48b | 5.17 ± 1.17a | 5.53 ± 1.12a | 5.52 ± 0.88a | 6.99 ± 1.01a | 4.82 ± 0.81a | 7.34 ± 1.15a | 5.55 ± 0.72a | 9.00 ± 1.35a | 4.52 ± 0.92a |
| WD frying | 1.38 ± 0.15a | 2.41 ± 0.38a | 3.26 ± 0.29a | 2.19 ± 0.17c | 1.73 ± 0.38c | 2.76 ± 0.45b | 2.76 ± 0.17b | 2.49 ± 0.10c | 2.42 ± 0.46b | 1.74 ± 0.56b | 3.19 ± 0.62b | 2.40 ± 0.37b | 1.73 ± 0.35b | 1.93 ± 0.62b | |
| CBM frying | 0.61 ± 0.05b | 2.38 ± 0.06a | 3.30 ± 0.06b | 3.65 ± 0.03b | 4.12 ± 0.05a | 2.95 ± 0.04b | 2.67 ± 0.09b | 2.89 ± 0.07b | 2.86 ± 0.07b | 1.37 ± 0.05b | 1.64 ± 0.10c | 0.86 ± 0.12c | 1.21 ± 0.13c | 0.48 ± 0.02c |
a Abbreviations: WD wheat dough, CBM chicken breast meat, 1–2 h oil sample collected at the second hour of the first day, ND not detected
b The relative contents of substituted alkanals were express as average value ± confidence interval. The lowercase (a,b,c) behind the content represents the significant difference among the three thermal treatments (p < 0.05, n = 3)