How HPLC helps to identify stale flavor in beer
Unfortunately, due to Covid, parades and parties will again have to be renounced or take place virtually. Even with all that is going on, one will certainly be allowed to drink a beer to St. Patrick. It is well known that beer tastes best when served fresh and well chilled. A beer’s taste characteristics will deteriorate over time or suboptimal storage conditions (pH, temperature). Aged beers typically develop a stale taste, which is usually perceived as “cardboard”-like. During the aging process many products are formed but there are two main compounds that are responsible for the stale aroma:
Trans-2-nonenal & beta-damascenone(1).
Access to application: Simultaneous determination of E-2-Nonenal and β-Damascenone in beer by RP-HPLC on a MACHEREY-NAGEL NUCLEOSIL C18 column with UV-detection
Trans-2-nonenal (synonym E-2-nonenal) is claimed to be one of the main determinants of beer staling. The long-chain unsaturated aldehyde is a degradation product from enzymatic or non-enzymatic oxidation of lipids(2) or oxidized free fatty acids(3). The aroma is noticeable at concentration levels higher than 0.1 µg/L(4).
The terpenic ketone beta-damascenone is a flavor compound with pleasant, but intensive scent. It is constituent of many fruits and alcoholic beverages, e.g. wine, Kentucky Bourbon(5/6) and other spirits. The content of the compound in fresh beer is very low 6–25 ng/g. However, after 5 days of storage at 40 °C the level increased twentyfold of the initial value indicating the deterioration of the beers intended flavor(7).
References:
(1) Laurence Gijs, Fabienne Chevance, Vesna Jerkovic, Sonia Collin, J Agric Food Chem 2002 Sep 25; 50(20): 5612-6.
(2) B.W. Drost, R. van den Berg, F.J.M. Freijee, E.G. van der Velde, and M. Hollemans, Heineken Technisch Beheer, P.O. Box 510, 2380 BB Zoeterwoude, Netherlands. J. Am. Soc. Brew. Chem. 48:0124, 1990.
(3) Bamforth, C.W., & Lentini, A. “The flavor instability of beer.” In Beer: A quality perspective, ed. C.W. Bamforth, 85–109. Burlington, MA: Academic Press, 2009.
(4) J.R Santos, J.R Carneiro, L.F Guido, P.J Almeida, J.A Rodrigues, A.A Barros, Journal of Chromatography A, Volume 985, Issues 1–2, 2003, Pages 395-402.
(5) José Rodrigues, Paulo Almeida, in Beer in Health and Disease Prevention, edited by Victor R. Preedy, Elsevier Inc. London 2009, pages 395-402
(6) https://www.chemistryworld.com/podcasts/beta-damascenone/4010639.article
(7) Fabienne Chevance, Christine Guyot-Declerk, Jérome Dupont, and Sonia Collin, J. Agric. Food Chem. 2002, 50, 13, 3818-3821
