Kvasny Prum. 1998; 44(2): 40-42 | DOI: 10.18832/kp1998003

New Contributions to Radical Theory of Aging of Beer.Peer-reviewed article

J. ŠAVEL, D. ZDVIHALOVÁ, M. PROKOPOVÁ

Sensory active compounds are developed during aging of beer by direct reaction of active forms of oxygen with amino acids and higher alcohols. Intensively sensory active products were obtained by controlled oxidation of proline, isoleucine, methionine and phenylalanine with potassium peroxo(di)sulfate. Different active forms of oxygen provide different sensory active compounds. The course of those reactions are influenced by substances of an unhopped wort, a hopped wort and ethanol. The evidence of those reactions is decolourizing of chromatic substances of beer at 380 nm by action of active forms of oxygen and intensive absorbance of volatile compounds of beer in the range 200 up to 240 nm.It is supposed, that those compounds are formed by oxidation of amino acids with aromatic or heterocyclic nucleus. By oxidation of the model mixture of amino acids, maltose and ethanol with potassium peroxo(di)sulfate were obtained solutions with stale flavour of beer, while photochemical oxidation provided sulphur compound off-flavour.
(In Czech, English summary only)

Keywords: beer ageing, radicals, active oxygens, aminoacids

Published: February 1, 1998