Effect of cherry products addition on beer fermentation

Abstract

Fruits has been used in brewing as a source of sugars, colour and flavour. Cherry (Prunus avium L.) products such as juice and pomace can be used in brewing in order to increase beer biological value. In this study, cherry juice and pomace in concentration of 15 % were added at first and seventh day of beer fermentation. The effect of cherry products addition was investigated by measuring the content of yeast metabolites (ethanol, aldehydes, higher alcohols, esters, and vicinal diketones) in cherry beers and control sample without cherries. The alcohol content in all the cherry beers was higher than the control sample. The cherry juice addition at the beginning of fermentation led to the formation of more secondary metabolites than the control. Cherry juice addition at the seventh day of fermentation resulted in a decrease in higher alcohols and esters concentration, but in an increase in carbonyls concentration compared to the control. Cherry pomace addition led to a significant increase in esters and vicinal diketones concentration. Aldehydes concentration was not affected by cherry pomace addition. Higher alcohols were influenced only by pomace addition at the seventh day of fermentation. Sensory evaluation was also made because yeast metabolites affected beer flavour and aroma.