Table 2.
Phenolic compounds identified in oat samples by HPLC-ESI-QTOF-MS.
| Class | Sub-class | Compound | Formula | Fragments | OG | OH | SO | EH1-OH | EH2-OH | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Error | Fraction | Error | Fraction | Error | Fraction | Error | Error | |||||
| Phenolic acids | Hydroxybenzoic acids | Protocatechuic acid | C7H6O4 | 151, 136, 112 | -4.34 | FP | n.d. | n.d. | 3.46 | BP | n.d. | n.d. |
| Hydroxybenzoic acid | C7H6O3 | 135, 125, 121 | -3.49 | BP | -2.05 | FP | 4.47 | BP | n.d. | 3.75 | ||
| Hydroxycinnamic acids | Ferulic acid | C10H10O4 | 178, 149, 134 | -1.89 | BP | 57.88 | BP | 0.17 | BP | 2.23 | 1.2 | |
| p-Coumaric acid | C9H8O3 | 119 | n.d. | n.d. | -2.64 | BP | n.d. | n.d. | 1.63 | -2.03 | ||
| Sinapic acid | C11H12O5 | 208 | -2.24 | BP | n.d. | n.d. | -0.91 | BP | n.d. | n.d. | ||
| Avenantrahamide 2c | C16H13NO6 | 270, 178, 161 | n.d. | n.d. | -0.28 | FP | 0.99 | FP-BP | n.d. | n.d. | ||
| Avenanthramide 2p | C16H13NO5 | 254, (226), (160) | n.d. | n.d. | -4.03 | FP | 9.01 | FP | n.d. | n.d. | ||
| Avenanthramide 2f | C17H15NO6 | 284 | -2.25 | FP | -2.55 | FP | 1.4 | FP-BP | n.d. | n.d. | ||
| Diferulic isomer 1 | C20H18O8 | 341, (282), 193, (112) | -1.58 | BP | n.d. | n.d. | 1.79 | BP | n.d. | n.d. | ||
| Diferulic isomer 2 | C20H18O8 | 359, 341, 326 | -3.65 | BP | n.d. | n.d. | -1.58 | BP | n.d. | n.d. | ||
| Diferulic isomer 4 | C20H18O8 | 341, 326, 282, 248, 227 | -3.39 | BP | n.d. | n.d. | -2.35 | BP | n.d. | n.d. | ||
| Diferulic isomer 5 | C20H18O8 | 347, 313, 261, 217, 193, 178 | -4.69 | BP | n.d. | n.d. | -0.54 | BP | n.d. | n.d. | ||
| Diferulic isomer 6 | C20H18O8 | 341, 303, 239, 193, 178 | -0.54 | BP | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | ||
| Caffeic acid | C9H8O4 | (165), 135, 127 | -5.1 | FP-BP | 7.68 | BP | -1.76 | BP | -2.32 | -5.1 | ||
| Isoferulic acid | C10H10O4 | 178, 149, 134 | -1.38 | BP | n.d. | n.d. | -0.35 | BP | n.d. | n.d. | ||
| 1-O-Sinapoyl-beta-D-glucose | C17H22O10 | 216, 162, 119 | -0.98 | FP | n.d. | n.d. | -0.46 | FP | n.d. | n.d. | ||
| Flavonoids | Flavones | Apigenin-6-C-arabinoside-8-C-hexoside III | C26H28O14 | 221, 137 | n.d. | n.d. | -1.19 | FP | 0.05 | FP | n.d. | n.d. |
| Others | Hydroxybenzaldehyde acids | 4-Hydroxybenzaldehyde | C7H6O2 | (112) | 0.84 | BP | -3.25 | FP-BP | 0.84 | BP | 1.66 | -8.99 |
Abbreviations: OG: oat grain, OH: oat hulls, SO: sprouted oat, EH1-OH: enzymatic hydrolysate oat hulls with UltraFloXL, EH2-OH: enzymatic hydrolysate oat hulls with Viscoferm, FP: free polyphenols fraction, BP: bound polyphenols fraction, n.d.: not detected. Fragments in parentheses are minority. Error expressed in ppm.