Abstract:
Volatile compounds in beer are substances that contribute significantly to the
organoleptic properties of beverages and thus affect product quality both in positive and
negative way. The objective of this study was to compare the level of flavor compounds of
Ethiopian alcoholic lager beers. The experimental design was purposive sampling
technique to see the level of volatile flavor compounds in industrially brewed alcoholic
lager beer in Ethiopia. A total of 220 beer samples from 11 brands were collected
randomly from different retail outlets across ten sub-cities of Addis Ababa. For each
brand, two beers were randomly collected from each sub city; two composite samples
were prepared by taking 20 ml from the 330 ml beer bottle and each brand were analyzed
in quadruplicate. VDKs were analyzed with HS-GC-ECD method, while Acetaldehyde,
Esters, Dimethyl sulfide (DMS) and higher alcohols were analyzed with HS-GC-FID
method. A structured questionnaire was used to undertake awareness on VDK. One-way
ANOVA were used to evaluate the significance difference between brands at the 0.05
level of significance and Duncan HSD was used to separate the means . Volatile flavor
compounds were detected in this study. For total vicinal diketones was between (13.8-128.2µg/l), Acetaldehyde, (1.65-8.0 mg/1), DMS (0.00-76.35µg/1) Ethyl acetate, (11.75-28.35 mg/l), n-propanol (8.40-20.95mg/1), Iso-butanol (5.85-17.7 mg/l), Isoamyl acetate
(0.10-3.95 mg/l), and Amyl alcohol (38.05-6.50 mg/l). For total VDK 27% of the samples
were above the threshold value and 18% of the samples were also above the threshold
value in acetaldehyde. For DMS 27% of samples were above the threshold value. For
Iso-amyl acetate, 91% of the samples were above the threshold value. For amyl alcohol
45% of the samples contain above the threshold value. By considering customer
satisfaction, brewers have to take actions and assess the root causes for those flavor
compounds which are above the threshold value. Moreover, knowledge of some
professional employees in the beer factories are not satisfactory, especially about
selected flavor compounds such as VDK so knowledge attitude and practice among beer
industries towards VDK should be improved.