Kvasny Prum. 1996; 42(3): 93-99 | DOI: 10.18832/kp1996006

Colour Changes During Beer Oxidation.Peer-reviewed article

J. ŠAVEL, D. ZDVIHALOVÁ, M. PROKOPOVÁ

Changes of beer absorption spectra in visible region during oxidation with air oxygen and potassium/ammonium peroxodisulfate were monitored. Oxidation processes connected with absorbance changes are in most rapid progress during initial oxidation phase, whereby absorbance may even temporary drop during initial stage of the visible spectrum, which may be caused by melanoidic compound oxidation. Differential measurements of absorbance changes at 380 and 540 nm during beer oxidation may serve as a judgement for proportional participation of melanoidic and phenolic compounds in the course of oxidation. Model oxidation of selected low-molecular phenolic compounds proved differences in product colour, the prevailing part of them rendering yellow to yellow-brownish solutions. 4-hydroxy-benzoic acid caused during oxidation brownish-red turbidities. Melanoidic compounds were decolourized during oxidation, which gives evidence of occurence of parallel oxidation reactions with different effect during beer oxidation.
(In Czech, English summary only)

Keywords: beer, osidation, colour

Published: March 1, 1996