The chemical composition of grape berries is influenced by various environmental conditions often considered to be representative of a "terroir". If grapes from a given terroir are assumed to reflect ...this origin in their chemical compositions, the corresponding wine should also reflect it. The aim of this work was therefore to reveal the "terroir" expression within the chemodiversity of grapes and related wines, using ultrahigh-resolution mass spectrometry. Grapes and corresponding wines, from two distinct - though very proximate - terroirs of Burgundy were analyzed over three vintages (2010, 2011 and 2012). Ultrahigh-resolution mass spectrometry and ultra-high performance liquid chromatography were used as untargeted and targeted approaches to discriminate complex chemical fingerprints for vintages, classes (wines, skins or musts), and terroirs. Statistical analyses revealed that even if vintages have the most significant impact on fingerprints, the most significant terroir differences are seen in the grapes of a given vintage.
This study investigates the surface and interfacial properties of the different components of a system composed of an agglomerated cork stopper in a glass bottleneck. Each constituting element has ...carefully been examined to unveil its underlying complexity. First, there was no effect of supercritical CO2 pretreatment or particle size on the surface properties of cork particles. The wettability of the binder was also evaluated, showing that the binder can spread relatively well on the surface of cork particles. Second, capillary rise measurements carried out on three different agglomerated corks indicate that the formulation of the agglomerates has no effect on its surface properties. The binder represents only a small fraction of the total stopper volume and is therefore not the major contributor to the surface tension. Third, the two coating agents studied display different behaviors. The first one, composed of a paraffin emulsion, exhibits poorer wettability than the second one, composed of a paraffin and silicone emulsion. However, once the coating agent has solidified on the surface of the stopper, both coatings display similar adhesion with the glass of the bottleneck. Starting with fundamental considerations, and then progressing to a more applicative aspect, has led to a better understanding of the properties of cork-based materials in their use as wine stoppers.
Bisulfite (HSO3 –) is the predominant form of sulfur dioxide, present as free and bound to wine relevant electrophiles under wine acidic pH. While sulfonation reactions of flavanols and thiols have ...been recently reported as key for wine preservation against oxidation, the transient mechanisms and physicochemical parameters responsible for that remain unknown. In the present study, sulfonation reaction kinetics of thiols and flavanols were monitored under simulated wine aging conditions. The reaction products were then characterized by liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis, and their chemical stability during time was determined by 1H NMR spectroscopy. Thiol and flavanol sulfonation reaction yields were both promoted by the presence of iron and oxygen, while their chemical stability was confirmed under the same conditions. The sulfonation derivatives of epicatechin and cysteine were synthesized and quantified in young and aged wines. Higher concentrations were reported for both metabolites in older wines, indicating their participation on the strongly bound sulfur dioxide fraction. These findings offer new prospects for more precise use of sulfur dioxide in winemaking.
Composite films based on chitosan and lignin biopolymers were investigated for their mechanical, barrier, surface, and antioxidant properties and linked to an extensive microscopic analysis of their ...external and internal structure. In particular, the fluorescence properties of lignins were exploited, using two-photon microscopy, to achieve a 3D representation of its distribution within the chitosan matrix. The lignin incorporation generated small aggregates homogeneously distributed in the film. The aggregates slightly weakened the network as reflected by the mechanical properties. Lignin as an antioxidant provided to the film a radical scavenging activity, essentially governed by a surface activity mechanism. Accordingly, the film surface showed a chemical reorganization induced by the presence of lignin as highlighted by surface hydrophobicity and X-ray photoelectron spectroscopy. On the molecular scale, solid state NMR also revealed the absence of covalent bonds between lignin and chitosan and the establishment, but to a small extent, of low energy dipole–dipole interactions. Finally, lignin is a promising compound for a good added-value due to radical scavenging in a chitosan matrix.
The rich diversity and complexity of organic matter found in meteorites is rapidly expanding our knowledge and understanding of extreme environments from which the early solar system emerged and ...evolved. Here, we report the discovery of a hitherto unknown chemical class, dihydroxymagnesium carboxylates (OH)₂MgO₂CR⁻, in meteoritic soluble organic matter. High collision energies, which are required for fragmentation, suggest substantial thermal stability of these Mg-metalorganics (CHOMg compounds). This was corroborated by their higher abundance in thermally processed meteorites. CHOMg compounds were found to be present in a set of 61 meteorites of diverse petrological classes. The appearance of this CHOMg chemical class extends the previously investigated, diverse set of CHNOS molecules. A connection between the evolution of organic compounds and minerals is made, as Mg released from minerals gets trapped into organic compounds. These CHOMg metalorganic compounds and their relation to thermal processing in meteorites might shed new light on our understanding of carbon speciation at a molecular level in meteorite parent bodies.
•Classification of 106 white wines by high, medium, or low antioxidant capacity.•Isolation of 365 molecular markers correlated with high antioxidant capacity.•Putative identification of oxidative ...reaction products.•Elucidation of the importance of CHONS and CHOS compounds in the antioxidant metabolome of dry white wines.•Proposed chemical mechanism explaining differences between DPPH and EPR measurements.
The chemical composition and functionality of molecular fractions associated with dry white wines oxidative stability remain poorly understood. In the present study, DPPH assay, electron paramagnetic resonance spectroscopy (EPR) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) were used to explore the chemical diversity associated with the antioxidant capacity (AC) of white wines. AC determined using the DPPH assay and EPR were complementary and enabled differentiation of wine samples into groups with low, medium, and high AC. Mass spectra variations associated with global DPPH- and EPR-derived indices enabled identification of 365 molecular markers correlated with samples with high AC, of which 32% were CHO compounds including phenolic and sugar derivatives, 20% were CHOS and 36% were CHONS compounds including cysteine-containing peptides. This study confirmed the importance of CHONS and CHOS compounds in the antioxidant metabolome of dry white wines. Knowledge about these compounds will enable better understanding of the oxidative stability of white wines and therefore aid in achieving optimum shelf life.
•Yeast derivatives were tested for their antioxidant activity in model wine.•Glutathione co-accumulated compounds have significant antiradical activity.•Yeast derivatives can be clustered based on ...nucleophilic fingerprint.•Chemical oxidation is used to monitor nucleophiles evolution by UHPLC–MS.•Glutathione accumulation process enhances the whole nucleophiles potential.
Maintaining wine oxidative stability during barrel ageing and shelf life storage remains a challenge. This study evaluated the antioxidant activities of soluble extracts from seven enological yeast derivatives (YDs) with increased glutathione (GSH) enrichment. YDs enriched in GSH appeared on average 3.3 times more efficient at quenching radical species than YDs not enriched in GSH. The lack of correlation (Spearman correlation ρ = 0.46) between the GSH concentration released from YDs and their radical scavenging activity shed light on other non-GSH compounds present. After 4-methyl-1,2-benzoquinone derivatization, UHPLC–Q-ToF MS analyses specifically identified 52 nucleophiles potentially representing an extensive molecular nucleophilic fingerprint of YDs. The comparative analysis of YD chemical oxidation conditions revealed that the nucleophilic molecular fingerprint of the YD was strongly correlated to its antiradical activity. The proposed strategy shows that nucleophiles co-accumulated with GSH during the enrichment of YDs are responsible for their antioxidant activities.
Significance The composition of 170-y-old champagne samples found in a shipwreck in the Baltic Sea constitutes a remarkable and unprecedented example of long-term combinatorial chemistry, which can ...occur in such sealed 750-mL microlaboratories. Multiple analytical tools, including metabolomics, metallomics, and sensory analysis, were combined to characterize the molecular diversity of these champagnes having aged in close-to-perfect conditions at the bottom of the sea. The analyzed champagnes retained intrinsic features allowing us to shed light on the winemaking practices in use in the middle of the 19th century. Therefore, this archeochemistry approach enabled us to rewrite a piece of our cultural heritage.
Archaeochemistry as the application of the most recent analytical techniques to ancient samples now provides an unprecedented understanding of human culture throughout history. In this paper, we report on a multiplatform analytical investigation of 170-y-old champagne bottles found in a shipwreck at the bottom of the Baltic Sea, which provides insight into winemaking practices used at the time. Organic spectroscopy-based nontargeted metabolomics and metallomics give access to the detailed composition of these wines, revealing, for instance, unexpected chemical characteristics in terms of small ion, sugar, and acid contents as well as markers of barrel aging and Maillard reaction products. The distinct aroma composition of these ancient champagne samples, first revealed during tasting sessions, was later confirmed using state-of-the-art aroma analysis techniques. After 170 y of deep sea aging in close-to-perfect conditions, these sleeping champagne bottles awoke to tell us a chapter of the story of winemaking and to reveal their extraordinary archaeometabolome and elemental diversity in the form of chemical signatures related to each individual step of champagne production.
The DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay is an easy and efficient method commonly used to determine the antioxidant capacity of many food matrices and beverages. In contrast with red wines, ...white wines are poorer in antioxidant polyphenolics, and the more hydrophilic sulfur-containing compounds in them may contribute significantly to their antioxidant capacity. The modification of the classical DPPH method, with a methanol-buffer and the measure of EC
(quantity of sample needed to decrease the initial DPPH concentration by 20%) has shown that sulfur-containing compounds such as cysteine (0.037 ± 0.003), glutathione (0.054 ± 0.003) or methanethiol (0.104 ± 0.003) appeared to bear antioxidant capacity comparable to well known phenolic compounds, such as catechin (0.035 ± 0.003), caffeic acid (0.057 ± 0.003) and ferulic acid (0.108 ± 0.003), respectively. In the case of white wines, the comparison with REDOX-sensory scores showed that results from this modified DPPH assay are strongly correlated with sensory attributes (r = 0.73,
< 0.1). These results provide an unprecedented illustration of the important contribution of these sulfur-containing compounds to the radical quenching ability of white wines.
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