Antioxidative activity of volatile chemicals extracted from beer

Volatile chemicals obtained from a commercial beer by liquid-liquid continu ous extraction were evaluated for antioxidant activity. The inhibitory abil ity of this extract toward the conversion of hexanal to hexanoic acid was m onitored over a 35-day period. The volatile extract demonstrated > 99% effe ctiveness at inhibiting hexanal oxidation at 50 mug/mL, comparable to that of the natural antioxidant alpha -tocopherol (vitamin E). Volatile compound s contained in the extract were isolated and identified by gas chromatograp hy-mass spectrometry (GC-MS). From the volatile constituents identified in beer extract, phenylethyl alcohol, maltol, and 2-furanmethanol were examine d for antioxidative activities. At a concentration of 500 mug/mL, maltol an d 2-furanmethanol demonstrated approximately 95 and 100% inhibition of hexa nal oxidation over 35 days, respectively. Phenylethyl alcohol did not show any appreciable level of inhibition of hexanal oxidation. Heterocyclic comp ounds, some of which are known to possess antioxidative activities, were al so identified in the volatile extract.