Table 3.
Determination of bound phenolic acid content in seven commonly consumed vegetables in China by UPLC-MS/MS (mg/kg FW).
| Vegetables | Region | Caffeic Acid | Ferulic Acid | p-Coumaric Acid | Sinapic Acid | p-Hydroxybenzoic Acid | Protocatechuic Acid | Syringic Acid | Vanillic Acid | Total Bound Phenolic Acid |
|---|---|---|---|---|---|---|---|---|---|---|
| kidney bean | BJ | n.d. | n.d. | 0.54 ± 0.03 a | n.d. | n.d. | n.d. | n.d. | n.d. | 0.54 ± 0.03 a |
| HZ | n.d. | n.d. | 0.59 ± 0.08 a | n.d. | n.d. | n.d. | n.d. | n.d. | 0.59 ± 0.08 a | |
| GZ | n.d. | n.d. | 0.42 ± 0.09 a | n.d. | n.d. | n.d. | n.d. | n.d. | 0.42 ± 0.09 a | |
| cow pea | BJ | n.d. | n.d. | 9.55 ± 0.06 a | n.d. | n.d. | n.d. | n.d. | n.d. | 9.55 ± 0.06 a |
| HZ | n.d. | n.d. | 7.59 ± 0.31 b | n.d. | n.d. | n.d. | n.d. | n.d. | 7.59 ± 0.31 b | |
| GZ | n.d. | n.d. | 4.41 ± 0.18 c | n.d. | n.d. | n.d. | n.d. | n.d. | 4.41 ± 0.18 c | |
| snow pea | BJ | n.d. | 0.14 ± 0.01 a | 1.48 ± 0.03 a | 0.29 ± 0.01 a | n.d. | 4.35 ± 0.25 b | n.d. | n.d. | 6.26 ± 0.28 b |
| HZ | n.d. | 0.14 ± 0.01 a | 1.52 ± 0.07 a | 0.28 ± 0.01 a | n.d. | 5.30 ± 0.10 a | n.d. | n.d. | 7.20 ± 0.14 a | |
| GZ | n.d. | 0.08 ± 0.01 b | 0.56 ± 0.01 b | 0.23 ± 0.02 b | n.d. | 2.86 ± 0.11 c | n.d. | n.d. | 3.73 ± 0.12 c | |
| hyacinth bean | BJ | 1.74 ± 0.05 b | 0.23 ± 0.01 a | 0.24 ± 0.01 b | n.d. | n.d. | 0.11 ± 0.01 a | n.d. | n.d. | 2.32 ± 0.07 b |
| HZ | 1.34 ± 0.04 c | 0.21 ± 0.01 a | 0.28 ± 0.01 a | n.d. | n.d. | 0.12 ± 0.01 a | n.d. | n.d. | 1.95 ± 0.07 c | |
| GZ | 4.41 ± 0.23 a | 0.10 ± 0.00 b | 0.18 ± 0.01 c | n.d. | n.d. | 0.08 ± 0.01 b | n.d. | n.d. | 4.77 ± 0.25 a | |
| green soy bean | BJ | n.d. | 22.09 ± 1.32 a | 3.77 ± 0.17 b | 16.34 ± 0.69 a | 0.78 ± 0.05 a | n.d. | 45.10 ± 2.18 a | 20.67 ± 1.33 a | 108.75 ± 3.57 a |
| HZ | n.d. | 18.33 ± 0.89 b | 1.32 ± 0.56 c | 13.54 ± 0.52 b | 0.80 ± 0.03 a | n.d. | 33.40 ± 1.97 c | 18.17 ± 0.73 b | 85.56 ± 2.88 b | |
| GZ | n.d. | 12.91 ± 0.61 c | 7.81 ± 0.37 a | 12.85 ± 0.49 b | 0.81 ± 0.03 a | n.d. | 36.87 ± 1.24 b | 12.65 ± 0.45 c | 83.9 ± 2.54 b | |
| soybean sprouts | BJ | n.d. | 0.84 ± 0.03 b | 1.22 ± 0.05 a | n.d. | 0.42 ± 0.01 a | n.d. | 17.63 ± 0.76 a | 4.68 ± 0.16 a | 24.79 ± 1.55 a |
| HZ | n.d. | 0.71 ± 0.04 c | 0.84 ± 0.03 b | n.d. | 0.44 ± 0.02 a | n.d. | 10.22 ± 0.47 c | 3.51 ± 0.12 b | 15.72 ± 0.77 c | |
| GZ | n.d. | 1.13 ± 0.06 a | 0.64 ± 0.02 c | n.d. | 0.44 ± 0.01 a | n.d. | 14.98 ± 0.39 b | 3.41 ± 0.15 b | 20.60 ± 1.02 b | |
| daylily | BJ | 7.98 ± 0.36 a | 8.23 ± 0.37 a | 22.43 ± 1.04 a | n.d. | 2.00 ± 0.05 b | 3.02 ± 0.03 a | 0.07 ± 0.01 a | 2.31 ± 0.10 a | 46.04 ± 2.01 a |
| HZ | 5.88 ± 0.30 b | 5.24 ± 0.39 b | 20.15 ± 1.12 b | n.d. | 2.92 ± 0.14 a | 2.51 ± 0.04 b | 0.05 ± 0.01 ab | 1.87 ± 0.06 b | 38.62 ± 1.28 b | |
| GZ | 5.18 ± 0.31 c | 4.71 ± 0.22 b | 16.31 ± 0.77 c | n.d. | 1.38 ± 0.04 c | 2.38 ± 0.06 c | 0.04 ± 0.01 b | 1.55 ± 0.05 c | 31.55 ± 1.27 c |
n.d.: not detected (below LOD); BJ: Beijing; HZ: Hangzhou; GZ: Guangzhou. Values (mean ± SD, n = 3) of the same compound were showed. Values followed by a different letter (a, b, c) represent a statistically significant difference of the same vegetable amongst the three regions (p < 0.05).