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Exogenous acetaldehyde as a tool for modulating wine color and astringency during fermentation
Marlena K Sheridan1, Ryan J Elias1
1Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA, USA.
Food Chemistry
|February 10, 2015
Summary
Adding acetaldehyde during wine fermentation modifies tannins, reducing astringency and improving color stability. This method avoids harmful oxidation, offering a new approach for winemaking.
Area of Science:
- Enology
- Food Chemistry
- Wine Science
Background:
- Wine tannins change during fermentation and storage, affecting astringency and color.
- Acetaldehyde bridges tannins, creating modified forms and pigments that reduce tannin-protein interactions.
- Oxygen treatment to produce acetaldehyde in red wines can cause unwanted oxidation.
Purpose of the Study:
- To investigate the effects of exogenous acetaldehyde on wine tannin modification during fermentation.
- To assess if acetaldehyde addition can enhance color stability and reduce astringency without causing oxidation.
- To evaluate the impact of low and high acetaldehyde concentrations on wine composition.
Main Methods:
- Exogenous acetaldehyde was added at low and high concentrations during wine fermentation.
- Analyzed the formation of modified tannins and polymeric pigments.
- Measured free and sulfite-bound acetaldehyde concentrations.
- Assessed protein-tannin precipitation levels.
Main Results:
- High acetaldehyde treatment significantly increased polymeric pigments.
- No significant increase in free or sulfite-bound acetaldehyde was observed.
- Protein-tannin precipitation was significantly reduced by acetaldehyde addition.
- Exogenous acetaldehyde promoted tannin modification without deleterious oxidation.
Conclusions:
- Exogenous acetaldehyde effectively modifies wine tannins during fermentation.
- This treatment enhances wine color stability and decreases astringency.
- Early acetaldehyde addition is a promising strategy for improving finished wine quality.
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