Macrowine 2021
IVES 9 IVES Conference Series 9 Influence of SO2 and Zinc on the formation of volatile aldehydes during alcoholic fermentation

Influence of SO2 and Zinc on the formation of volatile aldehydes during alcoholic fermentation


Laboratório de Análisis del Aroma y Enologia (LAAE). Department of Analytical Chemistry, Faculty of Sciences, Universidad de Zaragoza, 50009, Zaragoza, Spain, During alcoholic fermentation, fusel (or Strecker) aldehydes are intermediates in the amino acid catabolism to form fusel alcohols following the Ehrlich Pathway (1). One of the main enzymes involved in this pathway is Alcohol Dehydrogenase (ADH), whose activity is highly strain dependent and determines the rate of conversion of aldehydes into fusel alcohols (2). This enzyme has a Zn2+ catalytic binding site, which suggests that the must Zn2+ levels will most likely influence the rate of reduction of aldehydes into alcohols. On the other hand, SO2 is commonly used in winemaking for its antiseptic and antioxidant properties. This molecule is highly reactive and can form strong associations (alkylhydroxy sulfonates) with aldehydes. Levels of SO2 present in the alcoholic fermentation could then, at least theoretically, prevent the reduction of aldehydes to alcohols. Aldehydes could accumulate under the form of non-volatile adducts which could be released back once SO2 levels drop with aging or oxidation contributing to the development of oxidation off-odors (3). A set-up of fermentations of synthetic must containing known content of amino acids and nitrogen sources as well as elements necessary to the yeast metabolism were prepared. Different levels of Zinc or SO2 were tested. Three different commercial Saccharomyces cereviase yeast strains were selected for fermentation. Fusel alcohols and Strecker aldehydes were determined in the finished wines by GC-FID and GC-MS, respectively. Results confirm that all the factors are significant and that must Zn and SO2 levels influence the presence of Strecker aldehydes in the final wine.

1. Hazelwood, L. A.; Daran, J. M.; van Maris, A. J.; Pronk, J. T.; Dickinson, J. R., The Ehrlich pathway for fusel alcohol production: a century of research on Saccharomyces cerevisiae metabolism. Appl Environ Microbiol 2008, 74, 2259-66. 2. Singh, R.; Kunkee, R. E., Alcohol Dehydrogenase Activities of Wine Yeasts in Relation to Higher Alcohol Formation. Applied and Environmental Microbiology 1976, 32, 666 – 670. 3. Bueno, M.; Franco-Luesma, E.; Carrascon, V.; Ferreira, V., Evaluation of key and bound aroma carbonyls in wine for a better understanding of their release or formation through oxidation. Flavour Science. Proceedings of the XIV Weurman Flavour Research Symposium 2015, 397-402.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster


Inês Oliveira*, Mónica Bueno, Purificación Hernández-Orte, Vicente Ferreira

*University of Zaragoza

Contact the author


IVES Conference Series | Macrowine | Macrowine 2016


Related articles…

Impact of sulfur compounds to the antioxidant stability of white wines

The chemical mechanisms involved in oxidation/reduction potential of wine during winemaking and aging are affecting its color, aroma and taste. Chemical oxidation is one of the major causes of development of off-flavors during ageing1. Thus, the chemical changes in wine during storage should be controlled to ensure the sensory quality of the product and avoid consumer rejection that will compromise the economic value of the product. The 1-hydroxyethyl radical has been recognized as the key radical intermediate in the oxidative reactions in wine2. Based on the kinetic study of POBN-1-hydroxyethyl spin adduct formation in wines initiated via the Fenton reaction, a novel tool was recently developed in our laboratory to quantify the resistance of wines against oxidation3.

Crown procyanidin: a new procyanidin sub-family with unusual cyclic skeleton in wine

Condensed tannins (also called proanthocyanidins) are a widely distributed throughout in plants kingdom and are one of the most important classes of secondary metabolites, in addition, they are part of the human diet. In wine, they are extracted during the winemaking process from grape skins and seeds. These compounds play an important role in red wine organoleptic characteristics such as color, bitterness and astringency. Condensed tannins in red wine are oligomers and polymers of flavan-3-ols unit such as catechin, epicatechin, epigallocatechin and epicatechin-3-O-gallate. The monomeric units can be linked among them with direct interflavanoid linkage or mediated by aldehydes.

Nitrogen – Lipid Balance in alcoholic fermentations. Example of Champagne musts

Nutrient availability – nitrogen, lipids, vitamins or oxygen – has a major impact on the kinetics of winemaking fermentations. Nitrogen is usually the growth-limiting nutrient and its availability determines the fermentation rate, and therefore the fermentation duration. In some cases, in particular in Champagne, grape musts have high nitrogen concentrations and are sometimes clarified with turbidity below 50 NTU. In these conditions, lipid deficiencies may occur and longer fermentations can be observed. To better understand this situation, a study was realized using a synthetic medium simulating the composition of a Champagne must : 180 g/L of sugar, 360 mg/L of assimilable nitrogen and a lipid content ranging from 1 to 8 mg/L of phytosterols (mainly β-sitosterol).

Ethyl esters interact with the major wine Thaumatin Like Protein VVTL1

The interactions among aromatic compounds and proteins is an important issue for the quality of foods and beverages. In wine, the loss of flavor after vinification is associated to bentonite treatment and this effect can be the result of the removal of aroma compounds which are bound wine proteins. This phenomenon was recently demonstrated for long chain fatty acids and their ethyl esters (1). Since these latter compounds are spectroscopically silent, their association with proteins is not easy to measure.

The impact of branched chain and aromatic amino acids on fermentation kinetics and aroma biosynthesis by wine yeast Saccharomyces cerevisiae

One of the major determinants of wine quality is the aroma. Wine aroma is the human perception of the matrix of grape and yeast derived volatiles and their interaction that contribute to flavour wine. Most common are higher alcohols, ester and aldehydes. In previous studies the formation of characteristic volatile compounds have been linked to the metabolism of branched-chain and aromatic amino acids
(BCAAs) in synthetic grape must. Here we report on an investigation to assess the impact of the initial amino acid concentration on the production of aroma compounds by the industrial yeast VIN13 grown in both synthetic and real grape musts.