Red wines develop through oxidation and other aging mechanisms. For the most part, oxidative changes are desired and contribute to their quality and complexity. Investigations into the effects of micro-oxygenation on wine composition have revealed continuous oxygen consumption with no specific substances proving to be useful markers for monitoring wine development. Even acetaldehyde, a major product of nonenzymatic wine oxidation, does not appear to accumulate in micro-oxygenated wines. Because it rapidly undergoes reaction with various wine components, we believe there are sinks into which acetaldehyde flows, some of which are undetectable by common analysis methods. This project involved both the development of methods to measure acetaldehyde derivatives in wine (GC) and investigation of the kinetic and thermodynamic properties of acetaldehyde interactions (NMR). The analysis of important acetals from acetaldehyde and glycerol in wine by liquid-liquid extraction followed by GC-MS has been successfully optimized to improve recovery and reduce sample preparation time and applied to aged and micro-oxygenated wines. The nondestructive nature of NMR allows for the visualization of any form of acetaldehyde or alter the degree to which it is consumed. Quantitative one-dimensional NMR was applied to the analysis of relevant acetaldehyde reactions with nucleophiles (sulfites, thiols, alcohols, flavonoids) in model wine solutions. Equilibrium and rate constants were determined from the data obtained by the NMR method. Measurements by these methods have begun to explain the fate of acetaldehyde in wine, i.e. the outcome of oxidation. With this information, we hope to provide a means of predicting the distribution of acetaldehyde (once formed) into its various forms based on a wine’s composition.
|Advisor:||Waterhouse, Andrew L.|
|Commitee:||Boulton, Roger B., Holstege, Dirk, Waterhouse, Andrew L.|
|School:||University of California, Davis|
|Department:||Agricultural and Environmental Chemistry|
|School Location:||United States -- California|
|Source:||DAI-B 78/10(E), Dissertation Abstracts International|
|Subjects:||Food Science, Analytical chemistry|
|Keywords:||Acetaldehyde, Gas chromatography mass spectrometry, Kinetics, Nuclear magnetic resonance, Thermodynamics, Wine oxidation|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be