Project Number
WW 08-34
Project title
The effect of enological parameters on acetaldehyde kinetics during alcoholic fermentation and its impact on ethanol producing organisms in South African wine and must
Project leader
Van Jaarsveld, F P
Team members
Van Jaarsveld, F P
Jolly, N P
Du Plessis, H W
Hart, R S
October, F M
Ohlson, S
Van Breda, V
Malek, K
Paulsen, C
Project description
Acetaldehyde (ethanol) is a volatile chemical compound found to play a significant role in wine aroma, colour and microbiological stability. It is formed during the anaerobic fermentation of grape must to wine, and is also the most important carbonyl compound produced by yeast metabolism during alcoholic fermentation. Post-fermentation activity, like the oxidation of ethanol in wine, can also lead to the production of acetaldehyde.
This important aldehyde has relevance in ethanol-production yields and toxicology of the ethanol-producing microorganisms (e.g. yeasts). It has been established that, depending on its concentration levels, acetaldehyde may have an effect on yeast metabolism and can therefore influence fermentation kinetics by the inhibition or stimulation of the lag phase and growth rate, which in turn has an impact on the cell yield (biomass). High concentration levels of acetaldehyde, intracellularly and extracellularly, may also retard or inhibit yeast ethanol formations, resulting in sluggish or stuck fermentations.
The aim of this study will be to investigate the effect of enological parameters on acetaldehyde kinetics during fermentation, and to investigate the influence of added acetaldehyde on the metabolism of selected Saccharomyces cerevisiae and non-Saccharomyces yeast strains, as well as combinations of the two genera, during the alcoholic fermentation of two South African wine cultivars, Sauvignon blanc and Pinotage.
Presentation(s)
Van Jaarsveld, F P, October, F M, Rohwer, J, Du Toit, W. 2013. Effect of enological parameters on acetaldehyde kinetics. Papaer presented at the 35th International Conference of the South African Society for Enology and Viticulture.13-15 November, Somerset West, South Africa.
Article
Van Jaarsveld, F P, October, F M. 2015. Asetaldehied in wyn, Winetech Tegnies, Mnth June (310) (p. 73-76)
Article.pdf
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