Flavour Instability of Pale Lager Beers: Determination of Analytical Markers in Relation to Sensory Ageing

Sofie Malfliet^1,2, Filip Van Opstaele¹, Jessika De Clippeleer¹, Evelien Syryn¹, Koen Goiris¹, Luc De Cooman¹ and Guido Aerts¹
¹ Laboratory of Enzyme, Fermentation and Brewing Technology, KaHo St.-Lieven, Gebroeders Desmetstraat 1, B-9000 Gent, Belgium—Leuven Food Science and Nutrition Research Centre (LFoRCe), Department M2S, Katholieke Universiteit Leuven,Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
² Corresponding author. E-mail: sofie.malfliet@kahosl.be

J. Inst. Brew. 114(2), 180–192, 2008 | VIEW ARTICLE

ABSTRACT
Flavour changes of six Belgian pale lager beers were studied in order to estimate the importance of different parameters and reactions in relation to the ageing process. An attempt was made to link analytical data with sensory evaluation using multivariatestatistical analysis. Partial least squares regression techniques (PLSR) were employed on the analytical and sensory data. As apparent from the PLSR model, significant indicators of lager beer ageing are aldehyde markers (especially total aldehydes, furfural, hexanal, 2-methylpropanal, 2-methylbutanal, and 3- methylbutanal), cold and permanent haze, and beer colour. Conversely, compounds or parameters that load negatively in the PLSR model for beer ageing are trans-isohumulones, cis-isohumulones, total bitterness, the T/C-ratio, polyphenolic markers (especially proanthocyanidins), the flavanoid content, and, to a lesser extent, the TB-index and reducing power (TRAP). The integrated analytical-sensorial methodology is proposed as a useful tool for evaluation of the flavour instability of pale lager beers.

Key words:
analytical markers, beer ageing, flavour instability,partial least squares regression.