Table 3.
The contents of 16 polyphenols in walnut husk and pellicle during development by HPLC.
| Husk | Pellicle | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Compounds | FBS | FES | HSS | KFS | MS | FES | HSS | KFS | MS |
| Gallic acid | 16.52 ± 0.49 a | 2.88 ± 0.30 c | 2.72 ± 0.08 c | 4.24 ± 0.08 b c | 1.11 ± 0.01 d | 77.08 ± 6.11 d | 214.28 ± 6.62 c | 353.38 ± 12.26 a | 325.78 ± 1.93 b |
| Neochlorogenic acid | 89.09 ± 3.90 a | 34.61 ± 1.25 b | 23.42 ± 1.50 d | 17.34 ± 0.62 c | 13.65 ± 0.58 e | <LOD a | <LOD a | 374.60 ± 20.48 b | 530.92 ± 18.87 a |
| Catechin | 162.37 ± 3.30 a | 93.97 ± 0.99 b | 68.37 ± 0.29 c | 63.30 ± 2.53 c | 54.71 ± 4.50 c | 587.29 ± 47.49 b | 787.23 ± 44.09 a b | 942.33 ± 53.93 a | 302.39 ± 6.83 c |
| p-Hydroxybenzoic acid | 10.44 ± 0.87 a | 0.30 ± 0.01 c | 0.26 ± 0.01 d | 1.01 ± 0.03 b c | 1.10 ± 0.11 b | 152.98 ± 3.36 b | 174.55 ± 7.91 a | 171.54 ± 18.13 a | 195.56 ± 8.64 a |
| Chlorogenic acid | 2.41 ± 0.14 a | 1.61 ± 0.08 b | 1.18 ± 0.01 c | <LOD a | <LOD a | 15.96 ± 1.32 c | 30.25 ± 0.01 b | 41.36 ± 1.29 a | <LOD a |
| Vanillic acid | 30.25 ± 0.12 a | 0.25 ± 0.04 e | 0.57 ± 0.02 d | 0.94 ± 0.08 c | 1.47 ± 0.04 b | <LOD a | 77.09 ± 6.11 a | 47.24 ± 0.60 b | <LOD a |
| Caffeic acid | <LOD a | <LOD a | <LOD a | <LOD a | 0.66 ± 0.01 a | 13.42 ± 0.86 c | 24.83 ± 0.68 b | 60.12 ± 2.51 a | 80.15 ± 2.75 a |
| Epicatechin | <LOD a | <LOD a | <LOD a | <LOD a | 1.31 ± 0.08 a | <LOD a | <LOD a | <LOD a | <LOD a |
| Syringic acid | 8.23 ± 0.05 a | 2.18 ± 0.15 c | 5.46 ± 0.05 b | 1.61 ± 0.09 c | 2.07 ± 0.22 c | 113.94 ± 5.77 c | 154.54 ± 2.94 b | 210.84 ± 9.07 a | 214.35 ± 8.67 a |
| p-Coumaric acid | 0.76 ± 0.06 a | <LOD a | 0.12 ± 0.00 d | 0.16 ± 0.00 c | 0.29 ± 0.00 b | 2.99 ± 0.26 d | 5.42 ± 0.32 c | 7.42 ± 0.17 b | 12.72 ± 0.02 a |
| Ferulic acid | 2.14 ± 0.10 a | 0.37 ± 0.01 c | 0.46 ± 0.04 b c | 0.30 ± 0.03 d | 0.65 ± 0.03 b | 1.49 ± 0.03 c | 4.70 ± 0.06 a | 1.85 ± 0.12 c | 4.24 ± 0.11 b |
| o-Coumaric acid | 0.37 ± 0.01 a | 0.17 ± 0.01 d | 0.29 ± 0.01 c | 0.19 ± 0.00 d | 0.33 ± 0.01 b | 0.52 ± 0.03 c | 1.50 ± 0.05 b c | 1.52 ± 0.10 b | 1.77 ± 0.06 a |
| Rutin | 54.39 ± 2.53 a | 6.21 ± 0.75 b c | 8.33 ± 0.95 b | 1.52 ± 0.36 d | 2.63 ± 0.04 c | 308.37 ± 10.35 d | 1023.80 ± 7.62 c | 1626.42 ± 7.61 b | 3623.17 ± 32.49 a |
| Myricetin | 326.56 ± 5.48 a | 64.16 ± 7.63 b | 61.21 ± 12.95 b | 34.20 ± 5.14 c | 34.98 ± 2.37 c | 3366.58 ± 9.27 c | 3086.85 ± 37.77 d | 4375.62 ± 83.86 b | 8453.82 ± 383.06 a |
| Quercetin | 23.32 ± 0.79 a | 6.02 ± 0.04 c | 9.99 ± 0.44 b | 5.97 ± 0.44 c | 6.48 ± 0.20 c | 24.52 ± 2.14 b | 34.84 ± 0.75 a | 18.04 ± 1.97 c | 4.54 ± 0.07 d |
| Juglone | 15.42 ± 0.46 a | 5.44 ± 0.20 b | 1.88 ± 0.13 c | 0.79 ± 0.01 d | 0.57 ± 0.01 e | 2.13 ± 0.17 a | 1.37 ± 0.04 b | 2.10 ± 0.08 a | 1.78 ± 0.01 a |
Note: FBS, fruit-bearing stage; FES, fruit enlargement stage; HSS, hard-stone stage; KFS, kernel filling stage; MS, mature stage; LOD, limit of detection. The number of independent original samples is 3; data are shown as mean ± standard deviation (μg/g fresh weight). Different letters for the same phenolic compound indicate significant differences among the different developmental stages (p < 0.05).