Dissolved oxygen and antioxidants.

Brenner, M.W. and Stern, H.

Abstract
A Delta Schwarz Dissolved Oxygen Meter has been used to measure the rate of disappearance of dissolved oxygen from beers containing both high and low initial levels of oxygen. It was found that the oxygen disappeared at the same rate from untreated beers as it did from beers with addition of either sulphite or iso ascorbate antioxidants. Similarly, sulphur dioxide disappearance was the same regardless of the presence or absence of antioxidants. The authors suggest that the oxygen catalysed polymerization of phenolic compounds may be the normal mechanism of oxygen uptake in beer and that the deleterious effect of dissolved oxygen on flavour and the role of antioxidants may not be as closely linked as previously thought. It may be that many "oxidized" off-flavours are due to the products of oxygen initiated browning reactions and that the sulphite antioxidants could well act by inhibition of browning reactions which occur between carbonyl compounds and amino compounds in beer.
Keywords: antioxidant beer oxygen