Carbonyl compounds in different stages of vinification and exposure risk assessment through Merlot wine consumption

ABSTRACT

The objective of this research was to estimate for the first time the transformations that the free form of some target carbonyl compounds may undergo during winemaking and assess the exposure risk to these compounds through the consumption of the Merlot commercial wines under study. Acrolein and furfural were found in grapes and the respective wines, although levels were observed to decline throughout the winemaking process. Formaldehyde was found in all stages of wine production in levels lower than the limit of quantification of the method and ethyl carbamate was not found in samples. Acetaldehyde seems to be a precursor of acetoin and 2,3-butanediol, since the levels of this aldehyde decreased along winemaking and the formation of the ester and alcohol was verified. Furfural levels decreased, while the occurrence of furan-containing compounds increased during winemaking. The formation of acetaldehyde during alcoholic fermentation and the potential environmental contamination of grapes with acrolein and furfural are considered as the critical points related to the presence of toxic carbonyl compounds in the wine. Acrolein was found in the samples under study in sufficient quantities to present risk to human health, while other potentially toxic carbonyl compounds did not result in risk. This study indicated for the first time the presence of acrolein in grapes suggesting that environmental pollution can play an important role in the levels of this aldehyde detected in wines. Reduction of the emission of this aldehyde to the environment may be achieved by replacing wood burning by another heat source in fireplaces or wood stones, and abandoning the practice of burning garbage and vegetation.

Graphical Abstract

KEYWORDS:

• Toxic compounds
• carbonyl compounds
• Merlot
• processing effect
• exposure evaluation
• winemaking
• vinification
• health

Acknowledgments

Authors thank National Council of Technological and Scientific Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq. Project BJT 401581/2014-4; CNPq project Pq 306067/2016-1), the Coordination for the Improvement of Higher Education Personnel (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES) and Research Support Foundation of Rio Grande do Sul (Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, FAPERGS, Project Pesquisador Gaúcho 1995-2551/13-7) for financial support and scholarships. The authors also thank Embrapa researchers and SIBRATEC/FINEP/FAPEG (01.13.0210.00, Project IP-Campanha) for supporting sampling, transportation, and vinification.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data can be accessed on the publisher's website.

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [BJT 401581/2014-4,Pq 306067/2016-1];Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul [Project Pesquisador Gaúcho 1995-2551/13-7].