Cultural differences in wine conceptualization among consumers in France, Portugal and South Africa.

Consumers' mental pictures of wine are multifaceted and are shaped by their sensory (taste, smell, visual, sensation) perceptions, in addition to emotional, cultural and extrinsic (brand, price, and awards) influences. This study explores whether consumers from three different wine cultures share mental representations of three wine concepts. Through an online survey, French, Portuguese, and South African wine consumers described their conceptualizations of Wine, Red wine and White wine aroma.

High-throughput plant phenotyping: a role for metabolomics?

High-throughput (HTP) plant phenotyping approaches are developing rapidly and are already helping to bridge the genotype-phenotype gap. However, technologies should be developed beyond current physico-spectral evaluations to extend our analytical capacities to the subcellular level. Metabolites define and determine many key physiological and agronomic features in plants and an ability to integrate a metabolomics approach within current HTP phenotyping platforms has huge potential for added value.

Phenylacetaldehyde real-time release kinetics in wine like model solutions.

The present work shows key possibilities in modelling the kinetics of phenylacetaldehyde formation as a function of sugar, phenolic compounds, metals and sulphur dioxide. The release kinetics were measured online by proton transfer reaction-mass spectrometry (PTR-MS). Phenylacetaldehyde formation was fitted using Weibull models and an activation energy of 73 kJ/mol estimated.

Response surface methodology: A tool to minimize aldehydes formation and oxygen consumption in wine model system.

A response surface methodology was applied to study the effect of precursors on o-quinone and phenylacetaldehyde formation in wine model systems stored at 40 °C during 24 h. The results confirmed that glucose plays an important role in reducing aldehyde formation by inhibiting the formation of o-quinone. The regression equations showed that oxygen consumption followed a 2nd polynomial equation whereas phenylacetaldehyde and o-quinone were best fit with a polynomial function containing quadratic terms.

Genomic and transcriptomic analysis of Saccharomyces cerevisiae isolates with focus in succinic acid production.

Succinic acid is a platform chemical that plays an important role as precursor for the synthesis of many valuable bio-based chemicals. Its microbial production from renewable resources has seen great developments, specially exploring the use of yeasts to overcome the limitations of using bacteria. The objective of the present work was to screen for succinate-producing isolates, using a yeast collection with different origins and characteristics.

Strecker Aldehyde Formation in Wine: New Insights into the Role of Gallic Acid, Glucose, and Metals in Phenylacetaldehyde Formation.

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.

New integrative computational approaches unveil the Saccharomyces cerevisiae pheno-metabolomic fermentative profile and allow strain selection for winemaking.

During must fermentation by Saccharomyces cerevisiae strains thousands of volatile aroma compounds are formed. The objective of the present work was to adapt computational approaches to analyze pheno-metabolomic diversity of a S. cerevisiae strain collection with different origins.

Studying Haloanisoles Interaction with Olfactory Receptors.

In this paper, computational means were used to explain and predict the interaction of several odorant molecules, including three haloanisoles, 2,4,6-trichloroanisole (TCA), 2,4,6-tribromoanisole (TBA), and 2,4,6-trichlorophenol (TCP), with three olfactory receptors (ORs): OR1A1, OR1A2, and OR3A1. As the X-ray structure of these ORs is not known, the three-dimensional structure of each OR was modeled by homology modeling. The structures of these ORs were stabilized by molecular dynamic simulations and the complexes of the odorant molecules with each ORs were generated by molecular docking.

Unravelling the Olfactory Sense: From the Gene to Odor Perception.

Although neglected by science for a long time, the olfactory sense is now the focus of a panoply of studies that bring new insights and raises interesting questions regarding its functioning. The importance in the clarification of this process is of interest for science, but also motivated by the food and perfume industries boosted by a consumer society with increasingly demands for higher quality standards. In this review, a general overview of the state of art of science regarding the olfactory sense is presented with the main focus on the peripheral olfactory system.

Influence of the temperature and oxygen exposure in red Port wine: A kinetic approach.

Although phenolics are recognized to be related with health benefits by limiting lipid oxidation, in wine, they are the primary substrates for oxidation resulting in the quinone by-products with the participation of transition metal ions. Nevertheless, high quality Port wines require a period of aging in either bottle or barrels. During this time, a modification of sensory properties of wines such as the decrease of astringency or the stabilization of color is recognized to phenolic compounds, mainly attributed to anthocyanins and derived pigments.

Non-targeted and targeted analysis of wild toxic and edible mushrooms using gas chromatography-ion trap mass spectrometry.

Mushrooms are known all over the world both due to the remarkable gastronomic value of some species and for severe intoxications mediated by other species that are frequently difficult to distinguish from the edible ones, by the common user. Therefore, it is important to develop strategies to discover molecules that can identify mushroom species. In the present work, two GC-MS methodologies were applied in the chemical characterization of 22 mushroom species (12 edible, 3 toxic and 7 potentially toxic) - a multi-target procedure to simultaneously determine amino acids (AA), fatty acids (FA) and sterols by previous derivatization procedure with MSTFA, and a Head Space-Solid Phase Microextraction method to determine volatiles.

Application of a high-throughput process analytical technology metabolomics pipeline to Port wine forced ageing process.

Metabolomics aims at gathering the maximum amount of metabolic information for a total interpretation of biological systems. A process analytical technology pipeline, combining gas chromatography-mass spectrometry data preprocessing with multivariate analysis, was applied to a Port wine "forced ageing" process under different oxygen saturation regimes at 60°C. It was found that extreme "forced ageing" conditions promote the occurrence of undesirable chemical reactions by production of dioxane and dioxolane isomers, furfural and 5-hydroxymethylfurfural, which affect the quality of the final product through the degradation of the wine aromatic profile, colour and taste.

Port wine oxidation management: a multiparametric kinetic approach.

Port wine is a flagship fortified wine of Portugal, which undergoes a particularly long aging period, developing a dynamic sensory profile over time, responsible for several wine categories, which is dependent upon the type of aging (bottle or barrel). Therefore, the quality of the product is dependent upon the chemical mechanisms occurring during the aging process, such as oxidation or Maillard reactions. To attain the desired quality management, it is necessary to understand how technological parameters, such as temperature or oxygen exposure, affect the kinetics of the formation of key odorants, such as sotolon.

Untangling the chemistry of port wine aging with the use of GC-FID, multivariate statistics, and network reconstruction.

Chromatography separates the different components of complex mixtures and generates a fingerprint representing the chemical composition of the sample. The resulting data structure depends on the characteristics of the detector used, univariate for devices such as a flame ionization detector (FID) or multivariate for mass spectroscopy (MS). This study addresses the potential use of a univariate signal for a nontargeted approach to (i) classify samples according to a given process or perturbation, (ii) evaluate the feasibility of developing a screening procedure to select candidates related to the process, and (iii) provide insight into the chemical mechanisms that are affected by the perturbation.

Oxidation management of white wines using cyclic voltammetry and multivariate process monitoring.

The development of a fingerprinting strategy capable to evaluate the "oxidation status" of white wines based on cyclic voltammetry is proposed here. It is known that the levels of specific antioxidants and redox mechanisms may be evaluated by cyclic voltammetry. This electrochemical technique was applied on two sets of samples.

Study of major aromatic compounds in port wines from carotenoid degradation.

The carotenoids degradation and the formation of volatiles were examined by simulating Port wine aging. A two year old red Port wine was saturated with oxygen, supplemented with lutein and β-carotene and kept at 60°C during 87h. A similar study was performed in a model wine solution.

Targeting key aromatic substances on the typical aroma of sherry vinegar.

Two gas chromatography-olfactometry (GC-O) techniques were used to screen targeting compounds with an impact on the perceived quality of Sherry vinegar: detection frequency and aroma extract dilution analysis (AEDA). The GC-O study revealed the presence of 108 aromatic notes, of which 64 were identified. Diacetyl, isoamyl acetate, acetic acid, and sotolon reached the highest frequency and flavor dilution (FD) factors.

Simultaneous determination of ketoacids and dicarbonyl compounds, key Maillard intermediates on the generation of aged wine aroma.

The aim of this work was the simultaneous determination of both ketoacids and dicarbonyl compounds in wine. To detect ketoacid compounds in wine, a method based on the quinoxaline derivatives by the reaction with diaminobenzene, currently employed to detect alpha-dicarbonyl compounds, was developed. The quinoxaline derivatives were detected by RP-HPLC with UV detection, which allows the determination of the major dicarbonyl compounds in wine: glyoxal, methylglyoxal, diacetyl and pentane-2,6-dione, and the quinoxaline/quinoxalinol derivatives of alpha-keto-gamma-(methylthio)butyric acid and beta-phenylpyruvic acid (intermediate ketoacid compounds of methional and phenylacetaldehyde) were simultaneously detected by a fluorescence detector.

Carotenoid, chlorophyll, and chlorophyll-derived compounds in grapes and port wines.

Carotenoids and chlorophyll-derived compounds in grapes and Port wines were investigated by HPLC-DAD and HPLC-DAD-MS (ESP+) analysis. A total of 13 carotenoid and chlorophyll-derived compounds are formally reported in grapes, 3 are identified for the first time, pheophytins a and b and (13Z)-beta-carotene, and 3 others remain unknown. In Port wines 19 compounds with carotenoid or chlorophyll-like structures are present, 8 still unidentified.

A case study of molinate application in a Portuguese rice field: herbicide dissipation and proposal of a clean-up methodology.

This study was designed to monitor molinate losses in surface and underground waters during Ordram application in a rice field situated in central Portugal. Water samples were collected from different sites, before, during and about one month and a half after Ordram application. Molinate quantification was based on a solid-phase microextraction (SPME) method followed by gas chromatography with flame photometric detector (GC-FPD) analysis, and led to the conclusion that the herbicide was dissipated in the environment, reaching levels as high as 3.

3-Hydroxy-4,5-dimethyl-2(5H)-furanone levels in fortified Madeira wines: relationship to sugar content.

The maturation of Madeira wines usually involves exposure to relatively high temperatures and humidity levels >70%, which affect the aroma and flavor composition and lead to the formation of the typical and characteristic bouquet of these wines. To estimate the levels of sotolon [3-hydroxy-4,5-dimethyl-2(5H)-furanone] and their behavior over time, 86 aged Madeira wines samples (1-25 years old), with different sugar concentrations, respectively, 90 g L(-)(1) for Boal, 110 g L(-)(1) for Malvazia, 25 g L(-)(1) for Sercial, and 65 g L(-)(1) for Verdelho varieties, were analyzed. Isolation was performed by liquid-liquid extraction with dichloromethane followed by chromatographic analysis by GC-MS.

Identification of key odorants related to the typical aroma of oxidation-spoiled white wines.

The oxidative degradation of white wines rapidly leads to a loss of their sensorial qualities. The identification of the most important descriptors related with oxidation-spoiled wine was performed by a trained sensory panel. The terms selected were "honey-like", "farm-feed", "hay", and "woody-like".

Influence of some technological parameters on the formation of dimethyl sulfide, 2-mercaptoethanol, methionol, and dimethyl sulfone in port wines.

Volatile sulfur compounds of 15 young port wines and 12 old port wines were determined. As there is a great difference in the pool of sulfur compounds between the two groups of wines, an experimental protocol was performed to determine which technological parameter (dissolved O(2), free SO(2) levels, pH, and time/temperature) was related with the formation/consumption of these compounds. Four sulfur compounds were selected for this purpose: dimethyl sulfide, 2-mercaptoethanol, dimethyl sulfone, and methionol.

Heterocyclic acetals from glycerol and acetaldehyde in Port wines: evolution with aging.

In Port wine, isomers of glycerol and acetaldehyde acetals have been found at total contents ranging from 9.4 to 175.3 mg/L.