Table 4.
Phenolic acids, flavonoids, and resveratrol contents of conventional beers by high performance liquid chromatography with diode array detector (HPLC-DAD) (mg/L).
| Beer Code | ALE 1 | ALE 2 | ALE 3 | LAGE 1 | LAGE 2 |
|---|---|---|---|---|---|
| Phenolic Acids: | |||||
| Chlorogenic | nd | nd | nd | nd | nd |
| Vanillic | |||||
| Free | nd | nd | 2.09 ± 0.08 | nd | nd |
| Total | 2.80 ± 0.05 | 3.58 ± 0.07 | 4.65 ± 0.06 | 4.46 ± 0.12 | 2.3 ± 0.07 |
| Caffeic | |||||
| Free | nd | nd | 1.24 ± 0.10 | nd | nd |
| Total | 3.00 ± 0.20 | 3.38 ± 0.01 | 5.99 ± 0.11 | 1.70 ± 0.08 | 1.61 ± 0.04 |
| Syringic | |||||
| Free | nd | nd | 0.25 ± 0.01 | nd | nd |
| Total | 0.71 ± 0.09 | 0.67 ± 0.04 | 0.51 ± 0.03 | nd | 0.32 ± 0.01 |
| p-Coumaric | |||||
| Free | 0.53 ± 0.03 | 1.12 ± 0.05 | 0.68 ± 0.02 | 1.06 ± 0.05 | 0.35 ± 0.04 |
| Total | 2.00 ± 0.10 | 2.77 ± 0.09 | 2.13 ± 0.04 | 1.56 ± 0.08 | 0.77 ± 0.01 |
| Ferulic | |||||
| Free | 0.90 ± 0.03 | 11.03 ± 0.54 | 2.91 ± 0.11 | 2.12 ± 0.06 | 1.81 ± 0.03 |
| Total | 10.27 ± 1.00 | 19.90 ± 0.21 | 21.66 ± 0.55 | 11.0 ± 0.07 | 13.71 ± 0.49 |
| Sinapic | |||||
| Free | 0.41 ± 0.01 | 0.44 ± 0.21 | 0.98 ± 0.10 | 0.36 ± 0.04 | 1.07 ± 0.04 |
| Total | 4.80 ± 0.05 | 2.19 ± 0.07 | 3.95 ± 0.11 | 3.53 ± 0.03 | 3.07 ± 0.06 |
| Total Phenolic Acids a | 23.58 ± 1.56 | 32.49 ± 0.49 | 38.89 ± 0.90 | 22.25 ± 0.38 | 21.78 ± 0.68 |
| Flavonoids: | |||||
| Catechin | nd | nd | nd | nd | nd |
| Epicatechin | nd | nd | nd | nd | nd |
| Rutin | nd | nd | nd | nd | nd |
| Myricetin | nd | nd | nd | nd | nd |
| Quercetin | nd | nd | nd | nd | nd |
| Stilbenes: | |||||
| Resveratrol | nd | nd | nd | nd | nd |
Values are means ± SE (n = 3). nd, not detectable. a Total phenolic acids content was calculated by the sum of single phenolic acids content obtained after alkaline hydrolysis.