VIEW ARTICLE    DOI: 10.1094/ASBCJ-52-0106

Selective Measurement of Acetohydroxy Acid Precursors of Vicinal Diketones in Beer by Decarboxylation with Aniline Hydrochloride. Ben C. Hardwick, Anheuser-Busch, Inc., Technical Center 36-5, 1 Busch Place, St. Louis, MO 63118-1852. J. Am. Soc. Brew. Chem. 52:0106, 1994.

A method was developed to distinguish acetohydroxy acid precursors of vicinal diketones (VDK) from other precursors in beer. Aniline hydrochloride (aniline HC1) was added to one of two duplicate beer samples before analysis by headspace gas chromatography. Acetohydroxy acids, if present, were decarboxylated to form VDK without heat. Heat treatment decarboxylated the acetohydroxy acids, but the yield of VDK was lower than that from aniline HC1 addition. Heat converted acetolactate partially to acetoin in addition to diacetyl, whereas aniline HC1 formed diacetyl but no acetoin. Aniline HC1 is specific for conversion of acetohydroxy acids to VDK, whereas heat can generate VDK in beer devoid of acetohydroxy acids.

Keywords: Acetohydroxy acids, Aniline HC1, Diacetyl, Pentanedione, VDK, VDK precursor conversion