The influence of closure permeability, defined by oxygen transfer rate (OTR), on red wine aging is critical for chemical stability and quality. This study investigated the long-term impact of different closures on tannin evolution after 17 years in a red wine blend (70% 'Cabernet-Sauvignon'/30% 'Merlot'), initially aged in oak barrels. While previous studies have evaluated how closures affect tannin concentration and low-molecularweight phenolic compounds, there is limited knowledge regarding their impact on high-molecular-weight tannin evolution by depolymerization. For the first time, we studied the markers of long-term tannin evolution depending on closure permeability, by combining thioglycolysis and UHPLC-UHRMS metabolomics, applied to tannin fractions. Multivariate analysis revealed separation of tannin profiles according to closure type (natural, synthetic, and microagglomerated corks) (45.5% of the variance). Wines sealed with low-OTR closures exhibited more stable tannin evolution and lower oxidation marker levels, from reactions among tannins and with other molecules, including anthocyanins and aroma compounds. In contrast, wines under high-OTR closures displayed faster, more heterogeneous tannin evolution and higher oxidation marker levels. Sensory evaluation revealed that closure type mainly influenced bitterness and sweetness. Overall, these results provide scientific validation of the importance of closure choice and support metabolomics for understanding complex enological processes.

Understanding the long-term evolution of condensed tannins (CTs) in wine remains challenging due to the molecular complexity of aged wines. In this study, an advanced analytical workflow combining tannin-fraction isolation, thioglycolysis, UHPLC-UHRMS with AcquireX™ data-dependent acquisition, and Feature-Based Molecular Networking (FBMN) driven by the t-distributed stochastic neighbor embedding (t-SNE) algorithm was applied for the first time to wines. The studied wines are authentic red wines aged for 17 years. This exceptionally rare sample set, stored under four closures of differing oxygen permeability, provided a unique opportunity to assess the applicability of this workflow for the in-depth structural characterization of condensed tannin evolution markers in a complex wine matrix. Using this approach, 139 evolution markers were annotated. Among these, 122 markers were assigned to levels 2-3, while 17 markers were assigned to level 4. Overall, 72 of the 139 annotated markers were previously unreported, including 55 markers within the levels 2-3 group and 17 within the levels 3-4 group. These markers arose from interactions between tannins and anthocyanins, pyranoanthocyanins, and aromatic aldehydes with high oxidation levels of up to 5. Exploratory univariate (ANOVA) and multivariate statistical methods including Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) revealed correlative trends between marker abundance and closure oxygen permeability within this specific sample set. Overall, this work demonstrates the power of this transferable analytical workflow for comprehensive structural characterization of condensed tannin evolution markers in complex matrix form long-aged red wines and provides new molecular insights into their chemical evolution.

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. Thirteen specific discriminating compounds were found for 24-months-aged wines including CHO, CHNOS and CHOS compounds. Among them, sulfonated flavanols and pyranoanthocyanins were identified and emerged as key molecular markers of wine ageing. This metabolomics analysis also enabled us to identify specific chemical markers of cork oxygen transfer rate (OTR) influence. Analysis revealed specific molecules linked to corks with low and high OTR such as anthocyanins and proanthocyanins respectively. This research enhances our comprehension of intricate chemical changes during red wine ageing and underscores the potential impact of cork OTR on wine composition.

Ion mobility spectrometry (IMS) may improve feature-based molecular networking (FBMN) for annotating polyphenol isomers co-eluted in chromatography. The study aimed to assess the added value of trapped ion mobility spectrometry (TIMS) in metabolomics with FBMN for cocoa polyphenols. Untargeted analyses were performed on black and brown cocoa beans using a UHPLC-TIMS-Q-TOF system, with or without TIMS. The processed data underwent statistical and FBMN analyses. TIMS nearly doubled discriminating features in black beans and increased them by 50 % in brown beans. It separated isomeric dimers, trimers, and C-(O-)glycosides (native or process-derived). The UHPLC-TIMS-HRMS-FBMN resolved these isomers into distinct molecular network clusters. New discriminant phenolics were reported compared to a previous non-IMS study: ethyl-bridged flavanols in black beans and dehydro(epi)catechins, (epi)catechin-C-glycosides, and B-type procyanidin trimer C-glycosides in brown beans. TIMS improved structural information from FBMN, enabling polyphenols isomer identification. This TIMS-based approach can improve the phenolic characterization of cocoa products.

Controlled cacao fermentation is limited by traditional methods, hindering understanding of flavour formation dynamics. Therefore, this study investigated the influence of controlled fermentation variables-temperature profile, initial pH setting, and mixing frequency-on cacao flavour development, evaluated through sensory analysis, volatiles analysis, and untargeted metabolomics. Internal pH dynamics were also monitored. A fully controlled fermentation system using stirred-tank bioreactors enabled precise regulation of process conditions. Eight treatments were tested, varying temperature (constant 45 degrees C vs. stepped gradient 35-45 degrees C), initial pH (controlled vs. spontaneous), and mixing frequency. The results showed that temperature and initial pH were the primary drivers of internal acidification and flavour differentiation, while mixing frequency showed negligible effects. Constant-temperature (45 degrees C) fermentation with spontaneous pH produced chocolates with enhanced fruity, nutty, woody, and floral attributes. Conversely, fermentation under a stepped gradient with controlled pH intensified bitterness and astringency. Uncontrolled pH under the same gradient led to chocolates with pronounced acidity and lack of distinctive attributes. Extended fermentation (144-192 h) under spontaneous conditions resulted in off-flavours. Metabolomic and volatile profiles aligned with sensory data, revealing four treatment-specific clusters and identifying peptides and volatiles as candidate biomarkers of cacao quality.

Dimethyl sulfide (DMS) is a volatile sulfur compound that plays a complex role in wine aroma, contributing both positive and negative sensory attributes depending on its concentration. While DMS is known to accumulate during bottle aging through the degradation of precursors such as S-methylmethionine (SMM), this study presents the first evidence that DMS can also be lost through wine closures via a permeation mechanism. In practice, the permeation of DMS through closures was demonstrated using model wines spiked with DMS and aged under accelerated conditions at 35 °C. As DMS was detected only in the ®Tenax tubes placed above bottles containing the spiked model wines, we formally proved that DMS can permeate closures under these conditions and may account for 12 % of initial DMS. In Syrah wines, DMS concentrations increased during bottle aging due to the breakdown of SMM. However, wines sealed with more permeable closures exhibited lower DMS levels compared to those sealed with low-permeability closures, supporting findings from the model wine studies. This previously unreported phenomenon of permeation underscores the significant influence of closure permeability on the aromatic evolution of aged wines.

Feature-Based Molecular Networking approach is widely used to investigate the composition of complex matrices in various fields, particularly in chemistry. In this research, to investigate oxidation markers of condensed tannins in grape seeds, this advanced approach was combined with a depolymerization reaction with thioglycolic acid as a nucleophilic reagent and an intelligent MS/MS data acquisition using AcquireX™ Deep Scan workflow. Through this innovative combined methodology, 104 oxidation markers were highlighted, including 49 previously unreported. MS/MS analysis revealed dimers and trimers, indicating linkages between extension and terminal units, or both, with oxidation levels from 1 to at least 8. These findings enhance understanding of the structural evolution of condensed tannins, which significantly impact the quality and the stability of tannin-containing products. Moreover, this innovative analytical approach, applied here for the first time, can be extrapolated to other complex tannin-containing matrices, notably wines, offering new possibilities for chemical analysis in biomolecule research.

The wine industry aims to reduce pesticide use by utilizing disease-resistant grape varieties, although their oenological potential remains underexplored. This study aimed to evaluate their oenological potential compared to traditional ones. Musts from resistant (Souvignier Gris, Sauvignac, Voltis, and Floreal) and traditional (Chardonnay, Sauvignon Blanc, and Viognier) varieties were fermented at laboratory scale with online CO2 monitoring, and two yeasts were used to study varietal responses to yeast impact. Wines were analyzed for metabolites from central carbon metabolism, aromas (varietal thiols, ethyl esters, acetate esters, and higher alcohols), and phenolic compounds (hydroxybenzoic acids, hydroxycinnamic acids, flavan-3-ols, and flavonols) using (U)HPLC methods. Principal component analysis (PCA) of all variables revealed Souvignier Gris grouped with a Sauvignon Blanc sample, partially due to varietal thiols. PCA of aromas (PC1: 37.7%, PC2: 17.8%) showed that Souvignier Gris and Sauvignac exhibited similar behavior to Sauvignon Blanc. The heat map of 19 phenolics showed Sauvignac and Sauvignon Blanc clustered, with lower phenolic abundance. This preliminary work contributes to a detailed characterization of the oenological potential of these new varieties and constitutes an essential step in identifying which traditional and well-known varieties they resemble. This will then enable the recommendation of cellar itineraries adapted to their profile.

Complex ellagitannin extracts from oak are commonly used to improve wine properties, but their compositions are not well known. The composition of eight commercial oak tannin extracts was characterised using a multi-analytical approach. The concentrations of phenolic compounds evaluated by gravimetric analysis of the fraction adsorbed on polyvinylpolypyrrolidone and by UV spectrophotometry varied from 473 to 776 mg/g and from 334 to 576 mg/g, respectively. HPSEC-UV-dRI analysis showed differences in molecular size distribution. The concentration of sugars and polyols (quercitol), determined as alditol acetates by GC-FID, ranged from 59 to 259 mg/g. Nitrogen compounds determined by Kjeldahl analysis were present in very low amounts. Untargeted metabolomics data highlighted 159 features, including ellagitannins and their derivatives (e.g., formed upon toasting) and other molecules such as lignans and triterpenosides, showing large differences between samples. This work demonstrates the variability in the composition of commercial oak tannin extracts, likely to impact their properties.

Faba beans are promising alternatives to animal proteins due to environmental, food functional and nutritional benefits. However, they are characterised by off-flavours, notably off-notes and bitterness. Research on pulses and pulse-based products has largely focused on the involvement of volatile compounds in off-notes whereas the molecules responsible for pulse bitterness have not been studied as much. To better understand the role of non-volatile compounds in faba bean bitterness, different cultivars and air-classified fractions (flour, starch and protein) were investigated for their taste properties. Firstly, 21 trained panellists evaluated the bitter intensity of gels containing faba bean fractions. Bitter differences were highlighted according to the type of fractions and cultivars. Secondly, an untargeted metabolomics approach based on UHPLC-DAD-HRMS (ultra-high-performance liquid chromatography-diode array detector-high-resolution mass spectrometry) analysis was carried out for profiling the non-volatile content of the fractions. Thirdly, the sensory data was correlated with the metabolomic data resulting in the tentative identification of 42 phytochemical compounds (mainly alkaloids). Fourthly, the bitterness of highlighted compounds was studied using an in vitro cellular-based assay. Linking sensory attributes with the chemical content of pulse-based products allows to target compounds responsible for bitterness to propose strategies improving their flavour and the consumer acceptability.

Polyphenols are responsible for wine colour and astringency, and, as antioxidants, they also have beneficial health properties. In this work, we developed a robust full-scan high-resolution mass spectrometry method for the quantification of 90 phenolic compounds in wine samples (either red, rosé, or white wine), using a UHPLC-OrbitrapTM system. With this method, we could conduct a detailed analysis of phenolic compounds in red, rosé, and white wines with great selectivity due to sub-ppm mass accuracy. Moreover, accessing the full-scan spectrum enabled us to monitor all the other compounds detected in the sample, facilitating the adaptability of this method to new phenolic compounds if needed.

IntroductionThis study aimed to evaluate the color and the discriminating compounds for two types of cocoa beans (black and brown beans) related to 70% dark chocolates of black and brown colors from a previous work of our group.MethodsColor analysis and untargeted high-resolution mass spectrometry-based metabolomic analysis were performed on eight beans of each type. Mass spectral data processing, univariate and multivariate statistical methods were conducted for classification of beans and selection of discriminant features.Results and discussionThe results showed that the color difference already observed for black and brown chocolates preexists in the beans. Black and brown beans had 45 and 50 discriminant features, respectively, of which 16 and 41 were phenolic compounds. Most of them were also previously identified as discriminating compounds for black and brown chocolates. Black beans predominantly contained glycosylated flavanols, ranging from monomers to trimers, with dimers and trimers being A-type procyanidins, along with a phenolic acid (protocatechuic acid), and an O-glycosylated flavonol (quercetin-3-O-glucoside). In contrast, brown beans mostly contained non-glycosylated B-type procyanidins ranging from dimers to decamers, but also dimers and trimers of A-type procyanidins, and a glycosylated and sulfated flavanol ((epi) catechin hexoside-sulfate). These markers may be useful for quality control purposes and may contribute to the selection of beans that yield black or brown dark chocolates.

Color is a major quality trait of rosé wines due to their packaging in clear glass bottles. This color is due to the presence of phenolic pigments extracted from grapes to wines and products of reactions taking place during the wine-making process. This study focuses on changes occurring during the alcoholic fermentation of Syrah, Grenache and Cinsault musts, which were conducted at laboratory (250 mL) and pilot (100 L) scales. The color and phenolic composition of the musts and wines were analyzed using UV-visible spectrophotometry, and metabolomics fingerprints were acquired by ultra-high performance liquid chromatography−high-resolution mass spectrometry. Untargeted metabolomics data highlighted markers of fermentation stage (must or wine) and markers related to the grape variety (e.g., anthocyanins in Syrah, hydroxycinnamates and tryptophan derivatives in Grenache, norisoprenoids released during fermentation in Cinsault). Cinsault wines contained higher molecular weight compounds possibly resulting from the oxidation of phenolics, which may contribute to their high absorbance values.

High-quality dark chocolates (70% cocoa content) can have shades from light to dark brown color. This work aimed at revealing compounds that discriminate black and brown chocolates. From 37 fine chocolate samples from years 2019 and 2020 provided by Valrhona,8 dark black samples and 8 light brown samples were selected. A non-targeted metabolomics study was performed based on ultra-high performance liquid chromatography-high resolution mass spectrometry/mass spectrometry experiments, univariate, multivariate, and feature-based molecular networking analyses. Twenty-seven overaccumulated discriminating compounds were found for black chocolates. Among them, glycosylated flavanols including monomers and glycosylated A-type procyanidin dimers and trimers were highly representative. Fifty overaccumulated discriminating compounds were found for brown chocolates. Most of them were B-type procyanidins (from trimers to nonamers). These phenolic compounds may be partially related to the chocolate colors as precursors of colored compounds. This study increases the knowledge on the chemical diversity of dark chocolates by providing new information about the phenolic profiles of black and brown chocolates.

In the context of climate change, faba beans are an interesting alternative to animal proteins but are characterised by off-notes and bitterness that decrease consumer acceptability. However, research on pulse bitterness is often limited to soybeans and peas. This study aimed to highlight potential bitter non-volatile compounds in faba beans. First, the bitterness of flours and air-classified fractions (starch and protein) of three faba bean cultivars was evaluated by a trained panel. The fractions from the high-alkaloid cultivars and the protein fractions exhibited higher bitter intensity. Second, an untargeted metabolomic approach using ultra-high-performance liquid chromatography–diode array detector–tandem–high resolution mass spectrometry (UHPLC–DAD–HRMS) was correlated with the bitter perception of the fractions. Third, 42 tentatively identified non-volatile compounds were associated with faba bean bitterness by correlated sensory and metabolomic data. These compounds mainly belonged to different chemical classes such as alkaloids, amino acids, phenolic compounds, organic acids, and terpenoids. This research provided a better understanding of the molecules responsible for bitterness in faba beans and the impact of cultivar and air-classification on the bitter content. The bitter character of these highlighted compounds needs to be confirmed by sensory and/or cellular analyses to identify removal or masking strategies.

Flavour scalping in wine is a well-known phenomenon that is defined as the sorption of flavour compounds on wine closures. While the impact of closure type was the object of several studies, no research has addressed the impact of wine closure permeability on flavour scalping. For that purpose, the adsorption of volatile sulphur compounds (VSCs) on four micro-agglomerated wine cork closures was investigated by soaking them in model and Shiraz wines for 7 days. From a kinetic point of view, most of the VSCs were quickly scalped after 1 h of soaking, and this effect increased after 6 h until reaching a plateau. Most importantly, no significant impact of the closure on the kinetics and adsorption rates of the VSCs was found. As to the quantitative aspects, VSC sorption on closures accounted for 1% to 5% of the initial VSCs present in the wines only, meaning that the impact was negligible under oenological conditions.

Dimethyl sulfide (DMS) is a flavor compound, characteristic of the truffle aroma in red wines, and is well-known to be a fruity exhauster. DMS comes from the degradation of dimethyl sulfide potential (DMSP) during winemaking. Up to now, little is known about the role of the closure on the DMSP degradation during ageing. For that purpose, the effect of four micro-agglomerated wine cork closures was studied on the DMS/DMSP equilibrium, along with six other volatile sulfur compounds (VSC), was investigated in six Shiraz wines. After three months of accelerated bottle ageing, DMS levels increased significantly in all bottles. The most permeable closures induced a lesser accumulation of DMS, suggesting that DMS could be dependent on the redox status of the wine. At the same time, the DMSP decrease was proportional to the permeability of the closures. For the first time, a possible implication of closure permeability on DMSP degradation was observed.

Rosé wines show large color diversity, due to different phenolic pigment compositions. However, the mechanisms responsible for such diversity are poorly understood. The present work aimed at investigating the impact of fermentation on the color and composition of rosé wines made from Grenache, Cinsault, and Syrah grapes. Targeted MS analysis showed large varietal differences in must and wine compositions, with higher concentrations of anthocyanins and flavanols in Syrah. UV-visible spectrophotometry and size exclusion chromatography data indicated that Grenache and Cinsault musts contained oligomeric pigments derived from hydroxycinnamic acids and flavanols which were mostly lost during fermentation due to adsorption on lees. Syrah must color was mainly due to anthocyanins which were partly converted to derived pigments through reactions with yeast metabolites with limited color drop during fermentation. This work highlighted the impact of must composition, reflecting varietal characteristics, on changes occurring during fermentation and consequently wine color.

The color of rosé wines is extremely diverse and a key element in their marketing. It is due to the presence of anthocyanins and of additional pigments derived from them and from other wine constituents. To explore the pigment composition and determine its links with color, 268 commercial rosé wines were analysed. The concentration of 125 polyphenolic compounds was determined by a targeted metabolomics approach using ultra high-performance liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC-QqQ-MS) analysis in the Multiple Reaction Monitoring (MRM) mode and the color characterised by spectrophotometry and CieLab parameters. Chemometrics analysis of the composition and color data showed that although color intensity is primarily determined by polyphenol extraction (especially anthocyanins and flavanols) from the grapes, different color styles correspond to different pigment compositions. The salmon shade of light rosé wines is mostly due to pyranoanthocyanin pigments, resulting from reactions of anthocyanins with phenolic acids and pyruvic acid, a yeast metabolite. Redness of intermediate color wines is related to anthocyanins and carboxypoyranoanthocyanins and that of dark rosé wines to products of anthocyanin reactions with flavanols while yellowness of these wines is associated to oxidation.

Dehydrodicatechins resulting from (epi)catechin oxidation have been investigated in different foods and natural products, but they still offer some analytical challenges. The purpose of this research is to develop a method using ultra-high performance liquid chromatography coupled with trapped ion mobility spectrometry and tandem mass spectrometry (UHPLC−ESI−TIMS−QTOF−MS/MS) to improve the characterization of dehydrodicatechins from model solutions (oxidation dimers of (+)-catechin and/or (−)-epicatechin). Approximately 30 dehydrodicatechins were detected in the model solutions, including dehydrodicatechins B with β and ε-interflavanic configurations and dehydrodicatechins A with γ-configuration. A total of 11 dehydrodicatechins B, based on (−)-epicatechin, (+)-catechin, or both, were tentatively identified in a grape seed extract. All of them were of β-configuration, except for one compound that was of ε-configuration. TIMS allowed the mobility separation of chromatographically coeluted isomers including dehydrodicatechins and procyanidins with similar MS/MS fragmentation patterns that would hardly be distinguished by LC-MS/MS alone, which demonstrates the superiority of TIMS added to LC-MS/MS for these kinds of compounds. To the best of our knowledge, this is the first time that ion mobility spectrometry (IMS) was applied to the analysis of dehydrodicatechins. This method can be adapted for other natural products.