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Advisor(s)
Abstract(s)
Strecker degradation (SD) leading to the formation of phenylacetaldehyde (PA) was studied in wine systems.
New insights were gained by using two full factorial designs focusing on the effects of (1) pH and (2) temperature. In each
design of experiments (DoE) three factors, glucose, gallic acid, and metals at two levels (present or absence), were varied while
phenylalanine was kept constant. The obtained results gave a clear indication, with statistical significance, that in wine conditions,
the SD occurs in the presence of metals preferentially via the phenolic oxidation independent of the temperature (40 or 80 °C).
The reaction of the amino acid with the o-quinone formed by the oxidation of the gallic acid seems to be favored when compared
with the SD promoted by the reaction with α-dicarbonyls formed by MR between glucose and phenylalanine. In fact, kinetics
results showed that the presence of glucose had an inhibitory effect on PA rate of formation. PA formation was 4 times higher in
the control wine when compared to the same wine with 10 g/L glucose added. By gallic acid quinone quantitation it is shown that glucose affects directly the concentration of the quinone. decreasing the rate of quinone formation. This highlights the role of sugar in o-quinone concentration and consequently in the impact on Strecker aldehyde formation, a promising new perspective regarding wine shelf-life understanding.
Description
Keywords
Strecker degradation Phenylacetaldehyde Phenolic oxidation Sugar Phenolic O-quinone
Citation
Monforte, A.R., Martins, S.I.F.S., Ferreira, A.C.S. (2018). Strecker Aldehyde Formation in Wine: New Insights into the Role of Gallic Acid, Glucose, and Metals in Phenylacetaldehyde Formation. Journal of Agricultural and Food Chemistry, 66(10), 2459-2466
Publisher
American Chemical Society