OXIDATION OF HIGHER ALCOHOLS BY MELANOIDINS IN BEER

Abstract

Volatile aldehydes are formed during storage of bottled beer on the shelf and give the beer an off‐flavour. Results showed that these aldehydes are formed by oxidation of higher alcohols in beer with melanoidins. On oxidation of the alcohols, hydrogen or an electron is probably transferred from the higher alcohols to reactive carbonyl groups of the melanoidins of lower molecular weights. The carbonyl groups are formed by the amino‐carbonyl reaction during boiling of wort. Molecular oxygen does not oxidize alcohols in the absence of melanoidins, but accelerates their oxidation by melanoidins. The oxidation of alcohols to aldehydes proceeds more rapidly at high storage temperature and low pH value. 1972 The Institute of Brewing & Distilling