Dissertation/Thesis Abstract

Revealing the Hidden Fate of Acetaldehyde in Wine by NMR and GC-MS: Thermodynamics and Kinetics
by Peterson, Ana Lucia, Ph.D., University of California, Davis, 2017, 132; 10248981
Abstract (Summary)

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.

Indexing (document details)
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
Source Type: DISSERTATION
Subjects: Food Science, Analytical chemistry
Keywords: Acetaldehyde, Gas chromatography mass spectrometry, Kinetics, Nuclear magnetic resonance, Thermodynamics, Wine oxidation
Publication Number: 10248981
ISBN: 9781369795455
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