Table 2.
Individual phenolic compounds contents in free and bound fractions of six buckwheat samples from China.
| Analytes | Status | Contents (μg/g DW) | |||||
|---|---|---|---|---|---|---|---|
| S1 | S2 | S3 | S4 | S5 | S6 | ||
| Gallic acid (GA) | FP | 22.96 ± 5.4c | 13.30 ± 2.60b | 9.55 ± 1.56a | 75.01 ± 1.53d | ND | ND |
| BP | 67.06 ± 0.82a | 64.76 ± 0.75a | 71.18 ± 3.12b | 60.66 ± 1.07a | 68.73 ± 0.38b | 59.79 ± 1.00a | |
| TP | 90.02 ± 4.99d | 78.05 ± 3.32c | 80.74 ± 4.90c | 135.67 ± 1.31e | 68.73 ± 0.38b | 59.79 ± 1.00a | |
| 4-Hydroxybenzoic acid (4-HA) | FP | 99.39 ± 0.71a | 97.63 ± 1.07a | 96.80 ± 0.40a | 93.26 ± 0.55a | 122.57 ± 1.23c | 102.64 ± 8.18b |
| BP | 175.29 ± 6.65d | 165.75 ± 3.58c | 78.85 ± 5.33b | 164.31 ± 8.44c | 193.72 ± 10.89e | 61.57 ± 7.28a | |
| TP | 274.68 ± 6.53d | 263.38 ± 2.55c | 175.65 ± 4.95b | 257.58 ± 8.04c | 296.58 ± 12.12e | 164.21 ± 6.72a | |
| 5-Caffeoylquinic acid (5-CA) | FP | 4.20 ± 0.06b | 6.73 ± 6.03c | 17.68 ± 2.06d | ND | 19.55 ± 0.71d | 2.20 ± 0.09a |
| BP | 33.82 ± 2.43b | 2.61 ± 0.99a | 46.96 ± 0.01c | ND | ND | ND | |
| TP | 38.02 ± 2.49d | 9.65 ± 5.43b | 64.64 ± 2.06e | ND | 19.55 ± 0.71c | 2.20 ± 0.09a | |
| Syringic acid (SA) | FP | ND | 19.39 ± 0.44a | ND | 31.99 ± 3.35b | 36.75 ± 0.51b | 34.50 ± 7.91b |
| BP | 66.97 ± 2.43d | 27.46 ± 1.97c | 6.69 ± 0.47b | 25.74 ± 2.76c | 4.28 ± 0.16a | 6.93 ± 1.21b | |
| TP | 66.97 ± 2.43d | 46.85 ± 1.96b | 6.69 ± 0.47a | 57.73 ± 4.90c | 41.03 ± 0.64b | 41.44 ± 6.90b | |
| Dihydromyricetin (DIM) | FP | ND | ND | ND | ND | ND | ND |
| BP | 123.13 ± 12.37c | 299.93 ± 1.43e | 83.25 ± 0.57b | 148.95 ± 0.42d | 57.94 ± 0.50a | 57.85 ± 0.14a | |
| TP | 123.13 ± 12.37c | 299.93 ± 1.43e | 83.25 ± 0.57b | 148.95 ± 0.42d | 57.94 ± 0.50a | 57.85 ± 0.14a | |
| Rutin (RUT) | FP | 3813.38 ± 110.33a | 1294.63 ± 38.38b | 3273.15 ± 86.34d | 6288.26 ± 144.01f | 2646.60 ± 142.33c | 3409.12 ± 66.11e |
| BP | 244.75 ± 7.45b | 236.66 ± 11.82b | 324.15 ± 21.98c | 85.02 ± 4.76a | 222.05 ± 11.55c | 416.83 ± 10.87d | |
| TP | 4058.13 ± 107.06e | 1531.29 ± 32.71a | 3597.30 ± 64.89c | 6373.28 ± 148.57f | 2868.66 ± 140.69b | 3825.95 ± 76.95d | |
| Ferulic acid (FA) | FP | ND | 9.26 ± 0.18a | 12.77 ± 0.31b | 9.69 ± 0.21a | 10.95 ± 0.37a | 12.39 ± 0.17b |
| BP | 3.88 ± 0.10a | 3.41 ± 0.13a | 3.71 ± 0.19a | 6.32 ± 0.83b | 3.15 ± 0.11a | 3.08 ± 0.09a | |
| TP | 3.88 ± 0.10a | 12.67 ± 0.29b | 16.49 ± 0.37c | 16.01 ± 0.68c | 14.10 ± 0.41b | 15.46 ± 0.10c | |
| Kaempferol-3-O-rutinoside (KAE-3-RUT) | FP | 1639.34 ± 56.63d | 511.06 ± 15.67a | 1100.85 ± 31.49c | 3618.65 ± 111.97e | 979.31 ± 50.05b | 1077.41 ± 21.29c |
| BP | 212.33 ± 6.29c | 215.77 ± 13.92c | 229.35 ± 20.47d | 43.34 ± 1.34a | 161.17 ± 13.32b | 230.85 ± 16.41d | |
| TP | 1851.67 ± 54.34d | 726.83 ± 14.66a | 1330.20 ± 12.43b | 3661.99 ± 111.75d | 1140.48 ± 49.60c | 1146.31 ± 37.59c | |
| Quercetin (QUE) | FP | 262.14 ± 3.35b | 872.93 ± 21.23d | 328.32 ± 8.74c | 1379.54 ± 33.82e | 144.05 ± 1.68a | 141.03 ± 2.03a |
| BP | 49.51 ± 0.38a | 52.56 ± 2.91b | 47.99 ± 0.16a | 58.35 ± 0.17c | 48.38 ± 0.03a | 47.96 ± 0.11a | |
| TP | 311.65 ± 3.69b | 925.49 ± 21.13d | 376.30 ± 8.61c | 1437.89 ± 33.96e | 192.43 ± 1.71a | 188.99 ± 2.10a | |
| Apigenin (API) | FP | 110.25 ± 1.31b | 108.97 ± 0.03a | 108.86 ± 0.13a | 114.07 ± 0.58b | 113.94 ± 2.47b | 113.70 ± 2.87b |
| BP | 70.58 ± 2.28a | 77.41 ± 6.94b | 79.33 ± 2.38b | 82.69 ± 0.53b | 82.53 ± 0.88b | 79.25 ± 1.09b | |
| TP | 180.83 ± 3.57a | 186.38 ± 6.92b | 188.19 ± 2.33b | 196.76 ± 0.62c | 196.48 ± 2.55c | 192.95 ± 3.66b | |
| Kaempferol (KAE) | FP | 106.24 ± 0.21a | 139.15 ± 1.38b | 108.39 ± 0.39a | 140.10 ± 1.12b | 101.03 ± 0.05a | 100.90 ± 0.08a |
| BP | 64.98 ± 0.31a | 64.20 ± 0.17a | 62.36 ± 0.07a | 62.90 ± 0.02a | 62.37 ± 0.02a | 63.75 ± 0.17a | |
| TP | 171.22 ± 0.52b | 203.35 ± 1.22c | 170.75 ± 0.42b | 203.00 ± 1.10c | 163.40 ± 0.07a | 164.65 ± 0.09a | |
Different lowercase letters (a–e) mean statistically significant differences following different samples at the same status (p < 0.05). FP, free phenolic; BP, bound phenolic; TP, total phenolic. N.D. not detected.