The fermentation kinetics and physicochemical properties of special beer with addition of Prokupac grape variety

Abstract

Over the last decade, the market of special beers with improved healthy function and/or with new refreshing taste has significantly increased. One of the possible solutions enables grape and mixing beer with bioactive component responsible for well known health promoting action of red wine. The influence of the addition of Prokupac grape on the physicochemical properties and the fermentation kinetics of the grape beer were studied and results were compared with control lager beer. The effect of grape addition on the activity of yeast was also studied. Original extract, alcohol content, degree of fermentation, fermentation rate and yeast growth were significantly higher in beers with grapes as a consequence of higher concentration of simple sugars in grapes compared with pure wort. Based on the CIELab chromatic parameters the color of grape beer samples was yellow with certain proportion of redness, while the control beer was purely yellow. The increase in the concentration of grape mash affects the reduction of lightness and yellowness of beers, while the redness of samples was directly proportional with grape quantity. The phenolic content and antioxidant capacity of grape beers was remarkably higher compared with control beer, which indicates that the grape beer is a better source of natural antioxidants than regular lager beer. [Projekat Ministarstva nauke Republike Srbije, br. 46001]

Keywords

• beer
• grape
• phenolic compounds
• antioxidants
• yeast growth