Kvasny Prum. 1997; 43(10): 268-270 | DOI: 10.18832/kp1997019

Methods of Detection of Active Forms of Oxigen in Unhopped Wort and Beer.Peer-reviewed article

J. ŠAVEL, D. ZDVIHALOVÁ, M. PROKOPOVÁ

Solution of amino acids and alcohols were oxidized with ammonium peroxo (di) sulfate in an aqueous and ethanol medium. By oxidation inan aqueoussolution sensory active compounds have arisen, the charcter of them being changed in the presence of ethanol. Oxidative products of pfenylalanine and 2-phenylethanol have formed an intensive haze in an agueous solutin and strongly absorbed in the ultraviolet region, whileleucine, isoleucine, 3-methyl-1-butanol and 2-methyl-3-butanol have provided transparent products with a lower absobance in the UV region. Ethanol suppressed the formation of haze and the oxidation  of amino acids. Volatile products, developed by the oxidation of 2-phenylethanol and phenylalanin under a simultaneous steam distillation, have also possible to follow according to the decrease of amino acids by reaction with trinitobenzensulfonic acid by reaction of products with Nessler's agent. Intensively absorbing volatile products have been also detected in an unhopped wort and hopped wort after a stem distillation and their content has increased after oxidation with kalium peroxo (di) sulphate. The described reaction are possible to use for the detection of active forms of oxygen.
(In Czech, English summary only)

Keywords: oxyge, beer ageing, spectrophotometry, chemiluminiscence

Published: October 1, 1997