UHPLC-Q-Orbitrap metabolomics of Syrah red wines during bottle ageing: Molecular markers of evolution and cork permeability.

An experiment involving the ageing of Syrah red wine was conducted over a period of 24 months, during which the impact of four different micro-agglomerated corks was examined. An untargeted UHPLC-Q-Orbitrap metabolomics analysis was performed and provided valuable insights into the chemical dynamics of red wine evolution. Forty-three specific discriminating compounds were found for non-aged wines, including various CHO and CHON-types molecules.

Analysis of targeted phenolic ageing markers in Syrah red wines during bottle ageing: Influence of cork oxygen transfer rate.

A Syrah red wine ageing experiment was set up during 24-months and the influence of four micro-agglomerated corks were investigated. Specific phenolic ageing markers were selected and hemi-synthesized: vitisin B, malvidin-ethyl-catechin, and epicatechin-sulfonate. A targeted quantification method of these markers was then developed and validated by using ultra-high performance liquid chromatography - triple quadrupole mass spectrometry (UHPLC-QqQ-MS) operating in MRM (Multiple Reaction Monitoring).

Oxidation of Wine Polyphenols by Electrochemical Means in the Presence of Glutathione.

The oxidation of wine may be beneficial or harmful to its quality. On the one hand, controlled oxidation can lead to the development of desirable sensory characteristics for red wine, such as enhanced color stability. Alternatively, oxidation can lead to white wine browning and a decrease in fruity aromas, and the development of an off flavor and wine polyphenols are also involved.

Impact of phenolic composition and antioxidant parameters on the ageing potential of Syrah red wines measured by accelerated ageing tests.

Fourteen Syrah red wines with different initial composition and antioxidant properties (polyphenols, antioxidant capacity, voltammetric behaviour, colour parameters and SO) were selected. Three different accelerated ageing tests (AATs) were then performed on these wines: thermal test at 60 °C (60 °C-ATT), enzymatic test with laccase (Laccase-ATT) and chemical test with HO (HO-ATT). The results showed high correlations between the initial phenolic composition and antioxidant properties of the samples.

Impact of Acetaldehyde Addition on the Sensory Perception of Syrah Red Wines.

Two experimental Syrah red wines with different polyphenol contents were used to study the impact of acetaldehyde addition on olfactory perception. Free acetaldehyde levels were measured in red wine by Head Space-Gas Chromatography-Mass Spectrometry (HS-GC-MS) to determine the acetaldehyde combination levels for those wines. Significant differences were observed for both sensory threshold and acetaldehyde combination for the wines.

Study of the oxidative evolution of tannins during Syrah red wines ageing by tandem mass spectrometry.

Red wine is a very complex medium in which condensed tannins undergo many modifications during winemaking and bottle ageing. These reactions have an impact on the organoleptic properties. This work aimed to highlight tannins evolution related to wine evolution by studying three vintages of Syrah wines.

UHPLC-Q-Orbitrap /MS identification of (+)-Catechin oxidation reaction dimeric products in red wines and grape seed extracts.

B-type procyanidin dimers and (+)-catechin dimeric oxidation products were analyzed in grape seed extracts and red wines (UHPLC-Q-Orbitrap MS). The different dimers had different fragmentation patterns according to their interflavan linkage position. Oxidation dimeric compounds had a specific fragment ion at m/z 393, missing for B-Type dimers fragmentations.

Identification of adducts between oxidized rosmarinic acid and glutathione compounds by electrochemistry, liquid chromatography and mass spectrometry.

Natural polyphenols are omnipresent and are an integral part of the human diet as well as quinones. Glutathione (GSH) is present in a significant amount inside cells and consequently, GSH conjugates of polyphenols will be encountered in the body. In the current work, voltammetry and liquid chromatography-mass spectrometry were carried out to characterize the reaction mechanism of the electrochemical oxidation of polyphenolic rosmarinic acid (RA) with GSH nucleophiles in aqueous solution.

Red Wine Oxidation Characterization by Accelerated Ageing Tests and Cyclic Voltammetry.

In order to obtain information on the oxidative behavior of red wines, oxygen consumption rates and electrochemical changes (cyclic voltammetry) were measured for nine red wines subject to three different accelerated ageing tests: chemical (with hydrogen peroxide), enzymatic (with laccase from ), and temperature (at 60 °C). Oxidative behavior depended both on the wine sample and accelerated ageing test type. A good correlation was observed between electrochemical parameters of charges for reference/non-oxidized wines, in accordance with their antioxidant capacity, and the variation of charges after enzymatic and temperature tests, meaning that cyclic voltammetry could be used in order to predict these two oxidation tests and reflect the wine sensitivity towards respective oxidation targets.

Unambiguous NMR Structural Determination of (+)-Catechin-Laccase Dimeric Reaction Products as Potential Markers of Grape and Wine Oxidation.

(+)-Catechin-laccase oxidation dimeric standards were hemi-synthesized using laccase from in a water-ethanol solution at pH 3.6. Eight fractions corresponding to eight potential oxidation dimeric products were detected.

Polyphenolic Characterization of Merlot, Tannat and Syrah Skin Extracts at Different Degrees of Maturity and Anti-Inflammatory Potential in RAW 264.7 Cells.

(1) Background: Both sensory quality and healthy attributes of grapes used for winemaking are closely related with the polyphenolic composition of their skins. (2) Methods: In this study, the polyphenolic characterization (flavan-3-ols, procyanidins, flavonols, stilbenes, anthocyanins) was investigated by ultra performance liquid chromatography coupled to a triple quadrupole mass spectrometer (UPLC-QqQ-MS). Skins from Merlot, Tannat, and Syrah red grape varieties cultivated in the south of France at different stages of ripening in 2018 were used.

Voltammetric Behavior, Flavanol and Anthocyanin Contents, and Antioxidant Capacity of Grape Skins and Seeds during Ripening (, , and ).

Skin and seed grape extracts of three red varieties (Merlot, Tannat, and Syrah) at different stages of ripening were studied for their total phenolic content (TPC) by using the Folin-Ciocalteu assay and for their total antioxidant capacity (TAC) by using spectrophotometric and electrochemical assays. Flavanol and anthocyanin compositions were also investigated using Ultra Performance Liquid Chromatography coupled with Mass Spectrometry (UPLC-MS). Results showed that seeds had the highest phenolic content and the highest antioxidant potential compared to skins at all stages of ripening.

Red Wine Oxidation: Accelerated Ageing Tests, Possible Reaction Mechanisms and Application to Syrah Red Wines.

Wine oxidation and ageing involve many complex chemical pathways and reaction mechanisms. The purpose of this study is to set up new and reproducible accelerated red wine ageing tests and identify chemical oxidation or ageing molecular markers. Three accelerated and reproducible ageing tests were developed: a heat test (60 °C); an enzymatic test (laccase test; a chemical test (hydrogen peroxide test).

Multimethod Approach for Extensive Characterization of Gallnut Tannin Extracts.

Gallotannins extracted from gallnuts are commonly added to wine to improve its properties. They consist of mixtures of galloylester derivatives of glucose. However, their composition and properties are not well-established.

[Estimation of urea distribution volume in hemodialysis patients].

Background: On-line urea clearance estimation, currently available on some dialysis monitors, makes it possible to calculate the dialysis dose Kt and thus allows to estimate Kt/V for each session, providing an estimation of urea distribution volume (V) at equilibrium assumed equal to total body water.

Methods: Three methods suitable for routinely estimating V, using the anthropometric Watson formula (V(Wat)), the body composition monitor (BCM) device (Fresenius Medical Care) based on bio-impedance analysis (V(imp)) and the indirect estimation (V(Daug)) obtained from measurement of Kt/(Kt/V)(sp) ratio respectively are compared during 25 dialysis sessions in 15 patients to a direct estimation (V(DDQ)) obtained by direct quantification of dialysis (DDQ) considered as the gold standard in hemodialysis patient..