Table 4.
Phenolic profile of spent grain obtained in optimal conditions using the HPLC-DAD method.
| Compound | Molecular Weight | Wavelength (nm) | Retention Time (min) | Ultra-Turrax Phenolic Content (mg/100g dw) | Ultrasound-Assisted Phenolic Content (mg/100g dw) |
|---|---|---|---|---|---|
| Protocatechuic acid | 154.12 | 280 nm | 13.756 | 0.7 ± 0.05 | N.D. |
| p-hydroxybenzoic acid | 138.12 | 280 nm | 17.876 | 1.1 ± 0.06 | N.D. |
| Vanillic acid | 168.14 | 280 nm | 22.627 | 3.1 ± 0.8 | 10.0 ± 1.03 |
| Caffeic acid | 180.159 | 320 nm | 20.557 | 0.7 ± 0.03 | N.D. |
| Chlorogenic acid | 354.31 | 320 nm | 21.971 | 5.4 ± 1.1 | N.D. |
| p-coumaric acid | 164.047 | 320 nm | 27.503 | 20.4 ± 1.72 | 14.0 ± 1.14 |
| Rosmarinic acid | 360.31 | 320 nm | 30.989 | 6.5 ± 0.96 | 4.0 ± 0.76 |