In vitro antioxidant capacity from wort to beer

The concentration of phenols (total, tannins, non-tannin flavonoids, non-tannin non-flavonoids), selected minerals (selenium, zinc and copper) and dextrins were measured in wort and beer produced in Italy. Samples were withdrawn at different phases of beer brewing: wort (step I), beer at the end of maturation (step 2), filtered beer (step 3), beer after bottling and pasteurization (step 4). On the same samples the total antioxidant capacity and the inhibitory effect on low density lipoprotein (LDL) oxidative modification were tested. Total antioxidant capacity was measured by monitoring the loss of fluorescence of a probe compound. During beer brewing the phenolic concentration decreased by 28% corresponding to a parallel decrease of the antioxidant activity (-29%). This decay was explained by the loss of tannins and non-tannic flavonoids during the technological process. Wort was more efficient than beer in inhibiting LDL oxidation at step 4 both by metal catalyst or peroxyl radicals However, the better protection provided by both wort and beer on metal-catalyzed LDL oxidation indicates a prevalent chelating action. The data suggest that beer in the diet can supply molecules with antioxidant activity which could play a role in antioxidant activity in vivo.