Highlight on the problems generated by p-coumaric acid analysis in wine fermentations

• Published in: Food chemistry 2008-04, Vol.107 (4), p.1661-1667
• Main Authors: Salameh, Dominique, Brandam, Cédric, Medawar, Wissam, Lteif, Roger, Strehaiano, Pierre
• Format: Article
• Language: English
• Subjects: Adsorption; alcoholic fermentation; Biological and medical sciences; biotransformation; Brettanomyces; chemical reactions; Chromatographic analysis; Ethanol; ethylphenol; Fermentation; Fermented food industries; food analysis; food composition; Food industries; Fundamental and applied biological sciences. Psychology; p-Coumaric acid; Temperature; Vitaceae; winemaking; wines; Wines and vinegars; yeasts
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2007.09.052

p-Coumaric acid is a natural hydroxycinnamic acid existing in grapes and wine. It is the precursor of the 4-ethylphenol molecule through the bioconversion reaction by Brettanomyces yeast. Chromatographic methods are the most common techniques to detect p-coumaric acid. It is known that this acid is highly unstable in analysis and fermentation experiments. This paper highlights the problems occurring in p-coumaric acid analysis in wine fermentation conditions when studying its bioconversion. First, it was shown that p-coumaric acid was unstable at elevated temperature. On the other hand, it was found that in our experimental conditions p-coumaric acid reacted with ethanol. This work revealed also that the p-coumaric acid is partially adsorbed on Brettanomyces yeast, certainly on cell walls. Because of these phenomena the quantity of p-coumaric acid which can participate to the bioconversion into ethylphenol decreases.