Gas Chromatographic Analysis of Aldehydes in Alcoholic Beverages Using a Cysteamine Derivatization Procedure

¹ Department of Viticulture and Enology, One Shields Avenue, University of California, Davis, Davis, CA 95616.

seebeler{at}ucdavis.edu

A series of short-chain, volatile, and saturated aldehydes (C₁ to C₉) were quantified in wines, brandy, and sherry. These compounds are known to impact alcoholic beverage quality as they contribute to overall flavor and they affect aging and color stability. An analytical method was validated which specifically measured the aldehydes present in just one assay. This method was based on a derivatization process involving the reactions of aldehydes with cysteamine (2-aminoethanethiol) at room temperature. A stable thiazolidine derivative was formed from each of the reacted aldehydes. The thiazolidine derivatives formed were extracted with cholorform then subsequently quantified by gas chromatography (GC) using a fused silica capillary column and a nitrogen-phosphorous detector (NPD). These procedures were used to analyze several red and white wines, brandy, and sherry; in addition to the predominant aldehyde — acetaldehyde — trace amounts of other aldehydes were also identified. The effects of derivatization and extraction at various pH levels to obtain free and bound aldehydes, and the effects of different levels of SO₂ and phenols on aldehyde recovery and precision were evaluated. Compared to the results from the standard AOAC distillation/titration method for aldehydes in wine, the cysteamine derivatization method was more accurate and gave higher recoveries (40% higher).

Key words: aldehydes, analysis, thiazolidines, cysteamine, gas chromatography

Submitted on October 13, 1998
Revised on March 23, 1999