Influence of pH on the Stability of 2-Substituted 1,3-Thiazolidine-4-Carboxylic Acids in Model Solutions

Upon beer storage, the levels of staling aldehydes increase, which coincides with the appearance of characteristic off-flavors. Bound-state aldehydes have been reported as potential sources of off-flavor appearance in aging beer. This study investigated the stability of cysteinylated aldehydes, also referred to as 2-substituted 1,3-thiazolidine-4-carboxylic acids, and the release of aldehyde compounds from cysteine adducts in model solutions at different pH values that are relevant in malting and brewing. The cysteinylated aldehydes were initially synthesized for their use as reference compounds in model solutions. Confirmation of their chemical structure was obtained by 1H-NMR. The results from the stability tests showed that degradation of cysteine-bound aldehydes results in concomitant release of the free aldehydes. The rate of degradation is highly dependent on the 2-substitution pattern of the thiazolidine ring, as well as on the pH of the model solution. At malting and brewing relevant pH values (pH 4.4, 5.2, 6.0), degradation of cysteine-bound aldehydes is observed, in particular at pH 4.4, which is representative of the beer pH. © 2018, © 2018 American Society of Brewing Chemists, Inc.

Bustillo Trueba P. , De Clippeleer J. , Van Der Eycken E. , Guevara Romero J.S. , De Rouck G. , Aerts G.1 , De Cooman L.
Taylor and Francis Inc.
Номер выпуска
  • 1 Department of Microbial and Molecular Systems (M2S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), KU Leuven, Technology Campus Ghent, Ghent, Belgium
  • 2 Faculty of Bioscience Engineering, Department of Biotechnology, Laboratory for Brewing Science & Technology, Ghent University, Ghent, Belgium
  • 3 Faculty of Science and Technology, Department of Biosciences and Food Sciences, Laboratory for Brewing Science & Technology, University College Ghent, Ghent, Belgium
  • 4 Department of Chemistry, Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), KU Leuven, Leuven, Belgium
  • 5 Peoples’ Friendship University of Russia (RUDN University), Moscow, Russian Federation
  • 6 Laboratory of Food Chemistry, Wageningen University, Wageningen, Netherlands
Ключевые слова
2-substituted 1,3-thiazolidine-4-carboxylic acids; beer aging; cysteine; cysteinylated aldehydes; flavor instability; staling aldehydes
Дата создания
Дата изменения
Постоянная ссылка

Другие записи