Abstract

Currently, one of the main quality problems of beer is the change of its chemical composition during storage, which alters its sensory properties. In this study, ale and lager beers were produced and aged for three months at two storage temperatures. Concentration of volatile ester compounds (VECs) in the beers was regularly monitored by gas chromatographic analysis of the headspace samples to establish changes in ester flavour profile with time. Generally, VECs were more stable during storage at 4°C, compared to room temperature for both ale and lager beer produced. Of the VECs produced, ethyloctanoate was the least stable in ale beer, with 32.47% decrease in concentration observed at room temperature, while phenyl ethyl acetate was the most stable compound decreasing by only 9.82% after three months. In lager beer, VECs were relatively stable decreasing by only 7.93% after three months, while ethyl decanoate was the least stable, with 36.77% decrease in concentration observed at room temperature. Results obtained in this study can be helpful in developing appropriate technological process to control the stability of these important flavour esters in beer.

Key words: Esters, stability, storage temperature, storage duration.