Macrowine 2021

A mechanistic investigation of H/D scrambling processes in flavonoids

Abstract

Several classes of flavonoids, such as anthocyanins, flavonols, flavanols and flavones, undergo a slow H/D exchange on aromatic ring A, leading to full deuteration at positions C(6) and C(8). Within the flavanol class, H-C(6) and H-C(8) of catechin and epicatechin are slowly exchanged in D2O to the corresponding deuterated analogues; even quercetin, a relevant flavonol representative, shows the same behaviour in a D2O/DMSOd6 1:1 solution. Detailed kinetic measurements of these H/D scrambling processes are here reported by exploiting the time-dependent changes of their peak areas in the 1H-NMR spectra taken at different temperatures. A unifying reaction mechanism is also proposed based on our detailed kinetic observations, even taking into account pH and solvent effects. Molecular modelling and QM calculations were also carried out to shed more light on several molecular details of the proposed mechanism.

DOI:

Publication date: September 16, 2021

Issue: Macrowine 2021

Type: Article

Authors

Graziano Guella

Biorganic Chemistry Lab/Dept. of Physics/University of Trento,Federico Bonaldo1, Fulvio Mattivi2, Daniele Catorci*, &, Panagiotis Arapitsas3, Graziano Guella1, * 1  Bioorganic Chemistry Laboratory, Department of Physics, University of Trento, Trento, Italy; 2 Department of Cellular, Computational and Integrative Biology – CIBIO and C3A, University of Trento, Trento, Italy; 3 Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), San Michele all’Adige, Italy; * D. Catorci passed away on June 27th, 2020

Contact the author

Keywords

flavonoids; chemistry of polyphenols; h/d isotopic scrambling; reaction mechanism

Citation

Related articles…

Profiling and evaluating wine lees by-products from various yeast strains against grapevine pathogens

Wine lees are the sediment that settles at the bottom of wine barrels, tanks, or bottles during the winemaking process and represent the second most significant by-product of wineries.

Read More

Distribution analysis of myo and scyllo-inositol in natural grape must

s it is well known, myo and scyllo-inositol are two characteristic sugars of grape must and, for this reason, their quantification has been proposed to control the authenticity of the concentrated and rectificated grape must.

Read More

For a phenomenology of terroir. A consumers’ perspective

This study investigates the notion of terroir by applying a phenomenological approach, focusing on the subjective experience of consumers. We will consider how terroir is described by consumers in order to gauge their subjective viewpoint and understand their way of describing and defining this spatiality.

Read More

AGEING BOTTLED WINES SUBMERGED IN SEA: DOES IT IMPACT WINE COMPOSITION?

Aging wines is a common practice in oenology, which in recent years has undergone some innovations. Currently, we are witnessing the practice of aging bottled wine in depth, immersed in the sea or in reservoirs, for variable periods of time, but so far, little is known about the impact of aging in depth on the physicochemical properties, of wines.
The objective of this work was to evaluate the impact of this practice on the physicochemical characteristics, in particular to verify changes in the volatile composition of wines bottled and subsequently immersed in depth. A red wine from Cabernet Sauvignon was bottled and a set of bottles were submerged from July to February (2020), another set of bottles were submerged from February to September (2020) and another set was kept in the wine cellar. Bottles from each set were analyzed (in triplicate) in July 2021.

Read More

Preserving wine typicity in a climate change scenario: Examples from the Willamette Valley, Oregon

Aims: Wine typicity is defined as a reflection of varietal origins, cultures and traditions of the wine. These aspects are many times also extremely important when considering a wines quality. However, as climate change occurs the typicity of wines may also change. With the long history of winemaking it is possible to define a wines typicity and how it has changed as climate alters. 

Read More