Table 5. Significant individual phenolic compounds in the seed of Meili grapes based on density classes (μg g-1 seed).
| Phenolic compounds | Density level | ||
|---|---|---|---|
| D3 | D4 | D5 | |
| Nonflavonoid phenolics | |||
| Hydroxybenzoic acids | 87.44(39.22%) | 105.46(36.78%) | 142.44(43.07%) |
| Gallic acid | 24.32 ± 0.66(a) α | 26.81 ± 0.35(a) | 31.07 ± 1.34(b) |
| Benzoic acid | 4.13 ± 0.29(a) | 6.26 ± 0.08(a) | 16.61 ± 2.33(b) |
| Vanillic acid | 38.54 ± 5.85(a) | 41.92 ± 0.84(a) | 63.70 ± 1.81(b) |
| Syringic acid | nd β | nd | nd |
| p-Coumaric acid | 5.50 ± 0.12(a) | 9.81 ± 1.06(b) | 6.65 ± 1.51(ab) |
| Salicylic acid | 14.95 ± 1.89(a) | 20.66 ± 1.88(b) | 24.41 ± 0.71(b) |
| Hydroxycinnamic acids | 42.15(18.90%) | 46.00(16.04%) | 53.23(16.09%) |
| Chlorogenic acid | nd | nd | nd |
| Caffeic acid | 9.18 ± 0.05(a) | 12.05 ± 0.83(a) | 11.68 ± 1.43(a) |
| Ferulic acid | 32.97 ± 1.06(a) | 33.95 ± 2.96(a) | 41.55 ± 2.11(b) |
| Stilbenes | 0.93(0.42%) | 1.10(0.38%) | 1.37(0.41%) |
| trans-Resveratrol | 0.93 ± 0.03(a) | 1.10 ± 0.02(b) | 1.37 ± 0.04(c) |
| Benzopyrone | 5.95(2.67%) | 17.34(6.05%) | 14.83(4.48%) |
| Coumarin | 5.95 ± 0.61(a) | 17.34 ± 0.57(c) | 14.83 ± 0.29(b) |
| Sum of individual nonflavonoid phenolics | 136.47(61.21%) | 169.90(59.26%) | 211.87(64.06%) |
| Flavonoids | |||
| Flavan-3-ols | 60.01(26.91%) | 88.63(30.91%) | 92.36(27.92%) |
| (+)-Catechin | 36.61 ± 2.03(a) | 57.72 ± 7.76(b) | 61.44 ± 7.57(b) |
| (-)-Epicatechin | 23.40 ± 0.37(a) | 30.91 ± 0.09(b) | 30.92 ± 0.06(b) |
| Flavonols | 26.49(11.88%) | 28.17(9.83%) | 26.52(8.02%) |
| Rutin | 2.21 ± 0.43(a) | 2.42 ± 0.78(a) | 3.49 ± 0.25(a) |
| Morin | nd | nd | nd |
| Quercetin | 14.14 ± 1.05(a) | 16.15 ± 2.34(a) | 16.96 ± 2.17(a) |
| Kaempferol | 10.14 ± 1.60(b) | 9.60 ± 0.70(b) | 6.07 ± 0.03(a) |
| Hesperetin | nd | nd | nd |
| Sum of individual flavonoid phenolics | 86.50(38.79%) | 116.80(40.74%) | 118.88(35.94%) |
| Sum of individual phenolics | 222.97 ± 11.21(a) | 286.70 ± 17.16(b) | 330.75 ± 2.89(c) |
α Values are the mean ±standard deviation (n = 3) and are based on the fresh weight of seed. Within lines, significant differences according to the Fisher’s LSD test at the P≤0.05 level are indicated by different letters.
β nd: not detected.