P-8
Influence of pH on beer staling. In beer and other beverages, flavor quality is of major importance to the
consumer. The flavor characteristics of beer appear to greatly alter with time,
at a rate depending on the beer composition and storage conditions. pH seems to
be an important factor influencing beer aging. Some authors demonstrated that
the concentration of trans-2-nonenal, responsible for cardboard flavor in
aged beer, is limited when the pH is higher. The aim of this study was therefore
to further investigate the effect of pH on the stability of beer flavor during
storage, using both instrumental and sensory analyses. The formation of
dimethyltrisulfide, responsible for onion-like off-flavor, and
trans-2-nonenal was compared at different pH. Another suspected staling flavor, beta-damascenone, and various aroma compounds, such as
3-methylthiopropionaldehyde
and heterocyclic compounds, were also monitored by gas chromatography.
GC-olfactometry and descriptive quantitative analysis were used to determine the
key differences in flavor attributes between fresh and aged beers.
Professor at the University of Louvain-la-Neuve (UCL, Belgium). Head of
the Laboratory of brewing sciences. Author of more than 50 papers in scientific
journals.
Laurence Gijs, Fabienne Chevance, Christine Guyot-Declerck, and SONIA COLLIN.
Université catholique de Louvain, Unité de brasserie et des industries
alimentaires, Belgium.