Table 3.
Free and bound polyphenols content (mg GAE g−1 dm) and phenolic acids profile (µg g−1 dm) of spent grains and spent hop samples from the brewing of Imperial red and Belgian strong ale beers.
| Brewing Spent Grains | Brewing Spent Hop | |||
|---|---|---|---|---|
| IRA | BSA | IRA | BSA | |
| FP (mg GAE g−1 dm) | 2.49 ± 0.12 a | 2.44 ± 0.12 a | 9.51 ± 0.11 A | 15.73 ± 1.30 B |
| BP | 4.80 ± 0.11 a | 7.11 ± 0.10 b | 1.38 ± 0.12 A | 1.84 ± 0.02 B |
| TP | 7.30 ± 0.23 a | 9.55 ± 0.22 b | 10.90 ± 0.23 A | 17.58 ± 1.32 B |
| FPA (µg g−1 dm) | ||||
| 4-hydroxybenzoic | 3.89 ± 0.05 a | 6.89 ± 0.06 b | 0.77 ± 0.05 | - |
| 2,6-dihydroxybenzoic | - | - | 3.09 ± 0.01 | - |
| Vanillic | 14.63 ± 0.06 a | 5.40 ± 0.02 b | 1.41 ± 0.01 | - |
| 3-hydroxybenzoic | 19.74 ± 0.75 | - | 9.59 ± 0.34 | - |
| Caffeic | 1.87 ± 0.09 | - | 6.19 ± 0.03 | - |
| Chlorogenic | - | 1.31 ± 0.03 | 0.77 ± 0.01 | - |
| Syringic | 34.33 ± 0.16 a | 67.51 ± 0.31 b | 3.02 ± 0.16 | - |
| Homovanillic | 19.99 ± 0.84 a | 39.32 ± 1.66 b | 9.16 ± 0.14 | - |
| p-coumaric | - | 4.44 ± 0.06 | 0.76 ± 0.02 A | 2.20 ± 0.22 B |
| Salicylic | - | 8.48 ± 0.31 | 6.12 ± 0.44 A | 16.49 ± 0.92 B |
| Ferulic | 3.96 ± 0.27 a | 15.53 ± 0.60 b | 0.38 ± 0.02 A | 14.97 ± 1.40 B |
| m-coumaric | - | 1.64 ± 0.06 | - | - |
| Sinapic | 10.96 ± 0.85 a | 3.79 ± 0.12 b | 1.01 ± 0.05 A | 6.77 ± 0.19 B |
| Total FPA | 109.36 ± 3.08 a | 158.86 ± 3.20 b | 36.96 ± 1.25 A | 40.43 ± 2.73 B |
| BPA (µg g−1 dm) | ||||
| 3,5-dihydroxybenzoic acid | - | - | - | 6.73 ± 0.03 |
| 2,5-dihydroxybenzoic acid | - | - | - | 4.70 ± 0.26 |
| 4-hydroxybenzoic | 4.11 ± 0.26 a | 12.73 ± 0.10 b | 0.55 ± 0.03 | - |
| Vanillic | 11.46 ± 0.40 a | 1.28 ± 0.01 b | 38.75 ± 1.27 | - |
| Caffeic | 39.78 ± 0.70 a | 89.68 ± 2.65 b | - | 1.31 ± 0.07 |
| Chlorogenic | - | - | 1.07 ± 0.01 A | 0.89 ± 0.010 B |
| Syringic | 27.36 ± 3.00 a | 19.52 ± 0.16 b | 8.21 ± 0.74 | - |
| Homovanillic | 12.12 ± 0.96 a | 9.36 ± 0.20 b | 2.65 ± 0.08 | - |
| p-coumaric | 256.38 ± 4.09 a | 584.84 ± 5.17 b | - | 18.68 ± 0.12 |
| Salicylic | 491.56 ± 30.99 a | 102.36 ± 0.73 b | 1.80 ± 0.01 A | 28.24 ± 0.15 B |
| Ferulic | 476.98 ± 11.82 a | 692.15 ± 6.81 b | 2.56 ± 03.05 A | 51.72 ± 0.19 B |
| Sinapic | 116.25 ± 4.51 a | 322.97 ± 20.85 b | - | 10.72 ± 0.22 |
| Total BPA | 1431.87 ± 56.47 a | 1859.60 ± 37.85 b | 17.94 ± 0.92 A | 123.17 ± 1.04 B |
| TPA | 1541.24 ± 59.55 a | 2018.46 ± 41.05 b | 54.90 ± 2.17 A | 163.60 ± 3.78 B |
n = 3; Values in the same row followed by different lowercase letters for BSG, and uppercase letters for BSH, are statistically different, p ≤ 0.01; IRA = Imperial red ale; BSA = Belgian strong ale; FP = free polyphenols; BP = bound polyphenols; TP = total polyphenols; FPA = free phenolic acids; BPA = bound phenolic acids; TPA = total phenolic acids; dm = dry matter.