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Lately, there has been an increasing interest in using plant-derived proteins for wine phenolic fining. Proteins extracted from cereals, potatoes, and legumes have been proposed as effective fining agents, but only those from pea, wheat, and potatoes have been approved for their use in wine. This work aimed at determining the fining ability of quinoa (Chenopodium quinoa Willd.) protein extracts (QP), compared to commercial fining agents, on red wines.The trials compared the performance of QP (30 and 50 g/hL), two potato protein extracts and gelatin, at two different contact times (48 and 96 h), using Petit Verdot, Malbec, and Cabernet Sauvignon wines. Turbidity, total phenolics, precipitable tannins, catechins, and color characteristics were determined. QP reduced the turbidity of all wines in a similar way to commercial fining agents. Both doses of QP significantly reduced tannins and other phenolic measures, including color intensity reductions, in a similar way to commercial fining agents.QP behaved as an effective fining agent that deserves further studies in order to improve its performance and advance its characterization. © 2022 Society of Chemical Industry.

The aim of this work was to characterize and optimize the formation of molecular complexes produced by the association of calcium alginate and reduced glutathione (GSH). The influence of varying concentrations of calcium and GSH on the production of microcapsules was analyzed using response surface methodology (RSM). The microcapsules were characterized by thermogravimetric analysis (TGA-DTG) and infrared spectroscopy (FTIR) in order to assess the hydration of the complexes, their thermal stability, and the presence of GSH within the complexes. The optimum conditions proposed by RSM to reach the maximum concentration of GSH within complexes were a 15% w/v of GSH and 1.25% w/v of CaCl2, with which a theorical concentration of 0.043 mg GSH per mg of CAG complex was reached.

Recently, the use of alternative vessels to oak barrels during winemaking has become increasingly popular, but little is known about their impact on the chemical composition of the resulting wines. To address this issue, a Sauvignon Blanc wine was elaborated from the same grape juice by using cylindrical stainless-steel tanks, oval-shaped concrete vessels, oval-shaped polyethylene vessels, and clay jars in triplicate. Each vessel was used for alcoholic fermentation and the aging of wines over its own lees. Wines elaborated in concrete vessels showed the highest pH and the lowest titratable acidity, most likely related to the observed release of inorganic compounds from the concrete walls. Little effect of the vessels was seen on the wine color and phenolic composition. Wines elaborated in clay jars showed the highest turbidity and the highest content of soluble polysaccharides, while those made using cylindrical stainless-steel tanks showed the highest content of volatile compounds. Despite the observed differences, all of the vessels tested seem suitable for white wine production since every wine showed chemical features that corresponded with the quality standards of Sauvignon Blanc wines. España Universidad de Sevilla, VI Plan Propio de Investigación y Transferencia (Contract number USE-18644-Z)

In this research, the abilities of two polyaniline-based materials (PANI-EB and PANI-ES) were evaluated as potential fining agents to eliminate 2,4,6-trichloroanisole (TCA) and 2,4,6-tribromoanisol...

Treating wines with cation exchange resins allows the reduction of pH and contributes to limiting the formation of tartrate salts by exchanging cations such as potassium with hydrogen ions. This manuscript summarizes the results of a series of laboratory and winery-scale trials performed with the aim of evaluating the ion exchange process and its effects on the chemical composition of the treated samples. The laboratory-scale results showed that both the procedure employed for the activation of resins and the chemical composition of the wines affected the extent of the chemical changes occurring during the treatment. As such, the winery-scale trials showed that the resin-treated wines have significantly lower pH, higher total acidity, less tartrate formation (measured by weight), and a reduced amount of most metals analyzed. Wine samples blended with approximately 20% of cation exchange-treated samples (by volume) showed no signs of tartrate instability when assessed by a quick qualitative cold test.

Thirty-seven red wines from different varieties, origins, and styles were characterized to identify the chemical parameters that better correlate with wine astringency. Principal Component Analysis showed that tannin content was the most important parameter influencing overall astringency and its sub-quality dryness, followed by polyphenolic content, color index and, to a lesser extent, pH and alcoholic degree. Given that astringency is a textural sensation caused by the interaction between salivary proteins and tannins, a comparison between two tannin precipitation assays (i.e., methylcellulose, MCP; and Harbertson-Adams assays, HA) were performed to evaluate their ability as estimators of red wine astringency. Results of the sensory correlations showed that MCP and HA have a different behavior toward intensity of astringency and dryness, mainly influenced by the tannin concentration. HA exhibited a sigmoidal behavior with a better astringency predictive performance at low and mid tannin concentration range, whilst MCP showed a linear behavior with a better performance at high tannin concentration range.

Oxygen exposure may trigger a series of changes that could be detrimental to the quality white wines. This study evaluated the combined effects of sulfur dioxide, glutathione and light exposure on the chemistry and sensory perception of bottled Sauvignon blanc. The wines were manually bottled into clear bottles, closed with low oxygen transfer rate stoppers, and stored for three months, either exposed or protected from light. The wines exposed to artificial light showed higher rates of sulfite loss and oxygen consumption, were significantly darker in color, exhibited significant changes in the concentration of phenolics and volatile compounds, were perceived as less fruity/floral, and had higher nuances of solvent, earthy and honey aromas than the ones protected from light. The treatments with higher amounts of initial sulfites and glutathione were able to delay some of these changes but were less significant than protecting the wines from artificial light.

Fumonisins are a group of mycotoxins found in various foods whose consumption is known to be harmful for human health. In this study, we evaluated the ability of three polymers (Polyvinylpolypyrrolidone, PVPP; a resin of N-vinyl-2-pyrrolidinone with ethylene glycol dimethacrylate and triallyl isocyanurate, PVP-DEGMA-TAIC; and poly(acrylamide-co-ethylene glycol-dimethacrylate), PA-EGDMA) to remove fumonisin B1 (FB1) and fumonisin B2 (FB2) from model solutions and red wine. Various polymer concentrations (1, 5 and 10mgmL-1) and contact times (2, 8 and 24h) were tested, with all polymers exhibiting fumonisin removal capacities (monitored by LC-MS). The impact of all polymers on polyphenol removal was also assessed. PA-EGDMA showed to be the most promising polymer, removing 71% and 95% of FB1, and FB2, respectively, with only a 22.2% reduction in total phenolics.

Botrytis bunch rot (BBR) is a major disease occurring in vineyards worldwide. Its control is still largely based on the use of synthetic fungicide sprayings at predetermined intervals, which often produces negative residues in grapes and wines that may affect the environment and/or human health. To rationalize BBR management, disease risk indicators were developed and evaluated in a set of field experiments carried out between 2010 and 2019 in France and Chile. Key indicators include early grapevine vegetative growth, i.e. ground-based normalized difference vegetation index (NDVI), and the potential berry susceptibility to Botrytis cinerea, which is driven by tannin content in the skin. Under these contrasting weather and cropping conditions, regression analyses, including weather information, showed a highly significant positive correlation between the early NDVI, measured at berry pea size stage, and BBR incidence or severity at harvest, whereas the opposite was demonstrated for tannin content in the berry skin measured at an early herbaceous fruit stage. The exponential relationship between the final disease severity and the early NDVI allowed us to identify a possible threshold NDVI value, i.e. between 0.5 and 0.6, under which the BBR severity should be lower or close to 5% at harvest (BBR tolerance threshold for wine quality). Accordingly, in a leaf-removal vineyard experiment in France, the NDVI level at berry pea size stage was strictly controlled to correspond to three different increasing index values: 0.45, 0.60, and 0.78. Following this increase in NDVI, a significant increase in final BBR severity was noticeable, i.e. 2.4%, 6.6% and 9.9%, respectively. Very interestingly, the NDVI increase was also related to a significant decrease in the tannin content in the skin of herbaceous berries at veraison, from 47 to 22 mg tannin/g skin. All regression analyses explaining BBR development were highly significant, showing the weather conditions before harvest as the primary factor. They also show that some of the disease risk indicators chosen, especially early NDVI, could be used in the future as tools in decision support systems for deciding to spray and/or scheduling optimized fungicide applications during the season.

Since the early 1990s, a meaningful number of reports have been published supporting the idea that wines, especially reds, encompass a series of bioactive compounds, mainly phenolic compounds, which could bring health benefits if consumed with moderation. Beyond any other alcoholic beverage, the beneficial health effect of moderate wine consumption became noteworthy after the "French Paradox" was avowed. Besides similar intake patterns of saturated fatty acids, CVD incident rates were much lower in France than in the rest of Europe; a situation that was attributed to a type of diet that involves the consumption of large amounts of vegetables, fruits, olive oil, and red wine ("the Mediterranean diet"). Based on the above, this drink is a key component of the Mediterranean diet, associated with a lower incidence of cardiovascular diseases, some forms of cancer, and other disorders related with oxidative stress. In this paper, we review and discuss the main benefits attributed to its moderate consumption, examine the phenolics composition, the chemical characteristics of its major antioxidant components, and their relationship with its biological activity. We also summarize the main methodologies used for their identification and quantification, and the measurements of antioxidant activity.

Volatile phenols, such as 4-ethyphenol (4-EP) and 4-ethylguaiacol (4-EG), are responsible for the Brett character found in wines contaminated with Brettanomyces yeast (i.e., barnyard, animal, spicy and smoky aromas). In these trials, we explore the effectiveness of polyaniline-based compounds (polyaniline emeraldin salt (PANI-ES) and polyanaline emeraldin base (PANI-EB)), for the removal of 4-EP and 4-EG from acidic model solutions and red wine. First, a screening study, performed in an acidified 12% ethanol solution, was used to optimize parameters such as contact time and the amount of polymers required to remove 4-EP and 4-EG. Then, the trapping ability of PANI agents towards 4-EP and 4-EG was evaluated in a model solution containing other wine phenolics that could potentially be trapped by PANI (i.e., gallic acid and 4-methylcatechol). The results of this trial showed that both PANI compounds were capable of removing 4-EP, 4-EG, regardless of the presence of other phenolic compounds present at a much higher concentration. Finally, the capturing ability of PANI was evaluated in a red wine sample containing 5 mgL(-1) of 4-EP, 5 mgL(-1) of 4-EG and 2.03 +/- 0.02 gL(-1) of total phenolics. The results showed that PANI-EB removed significantly more 4-EP and 4-EG than PANI-ES. For instance, a treatment with 10 mgmL(-1) of PANI-EB produced a 67.8% reduction of 4-EP, 50% reduction of 4-EG and 41.38% decrease in total phenols.

The concentration of seventeen metal elements was analyzed in 130 commercial samples of Chilean wines, using flame atomic absorption spectroscopy (AAS) and inductively coupled plasma–mass spectrometry (ICP-MS). The elements analyzed were within the usual concentration ranges previously reported in other wine regions (for example: Fe, 2.08 ± 0.99 mgL-1; Zn, 0.71 ± 0.44 mg L-1; K, 788± 219 mg L-1; and Na, 14.62 ± 8.6 mg L-1). When the metal content of the samples was compared among geographic areas, significant differences in the concentration of K, Na, Mn, Mg, Zn, and Cr were observed (p ≤ 0.05). Moreover, principal component and linear discriminant analyses, used to discriminate wines according to geographic area, obtained adjustments above 90% for white wines and over 70% for red wines.

Ochratoxin A (OTA) is a mycotoxin produced by filamentous-type fungi that contaminates a wide variety of foods and beverages such as wines. In these trials, we evaluated the capacity of the following polymers for the removal of OTA from acidic model solutions and red wine: polyvinylpolypyrrolidone (PVPP), resin of N-vinyl-2-pyrrolidinone with ethylene glycol dimethacrylate and triallyl isocyanurate (PVP-DEGMA-TAIC), and poly(acrylamide-co-ethylene glycol-dimethacrylate) (PA-EGDMA). In acidic model solution, PVP-DEGMA-TAIC and PA-EGDMA polymers removed up to 99.9% of OTA, but their trapping capacity was highly reduced by the presence of competing phenolic substances (i.e. gallic acid and 4-methylcathecol). In real red wine, PA-EGDMA polymer showed the most promising results, with more than 68.0% OTA removal and less than 14.0% reduction in total phenolic. Finally, computational chemistry analyses showed that the affinity between OTA and the polymers studied would be due to Van der Waals interactions.

BACKGROUND Porous plastic tanks are permeable to oxygen due to the nature of the polymers with which they are manufactured. In the wine industry, these types of tanks are used mainly for storing wine surpluses. Lately, their use in combination with oak pieces has also been proposed as an alternative to mimic traditional barrel ageing. RESULTS In this study, the spatial distribution of dissolved oxygen in a wine-like model solution, and the oxygen transfer rate (OTR) of high-density polyethylene tanks (HDPE), was analysed by means of a non-invasive opto-luminescence detector. Also, the chemical and sensory evolutioof red wine, treated with oak pieces, and stored in HDPE tanks was examined and compared against traditional oak barrel ageing. The average OTR calculated for these tanks was within the commonly accepted amounts reported for new barrels. With regards to wine evolution, a number of compositional and sensory differences were observed between the wines aged in oak barrels and those stored in HDPE tanks with oak barrel alternatives. CONCLUSION The use of HDPE tanks in combination with oak wood alternatives is a viable alternative too for ageing wine. © 2014 Society of Chemical Industry

The chemical and sensory effects of storing Sauvignon Blanc in colored bottles and exposing them to artificial light were examined. The colors of the bottles chosen were Dead Leaf Green, Antique Green, Amber, and Flint. The light was provided by fluorescent tubes with a regime of 16 h of exposure during 8 months of storage. The results indicated that the wine's chemical composition was affected by the type of bottle used. The Flint bottle presented the lowest concentration of total phenols. Yellow coloration was not dependent on the bottle color, as the wine in darker bottles (Amber, Antique Green, and Dead Leaf Green) had considerably more yellow color development than the wine in clear bottles. With regard to the sensory analyses performed, a trend showing an increase in color intensity and a decrease in overall aromas depending on the bottle color was observed. The wine's aromatic description changed significantly during its storage under artificial light conditions, demonstrating a decrease in vegetal aromas and an increase in citrus and tropical flavors that was dependent on the bottle color.

Oxygen management is critical to ensure the appropriate development of yeast and avoid its detrimental effects on sensory quality of wine. Oxygen additions during alcoholic fermentation are typically carried out through pump-over operations, which contributions have not been appropriately quantified. In this work, we designed a set of experiments with different pump-over modes (closed, open, and with Venturi) to evaluate oxygen dissolution and consumption during industrial-scale fermentations. Closed pump-overs incorporate negligible amounts of oxygen, while open pump-overs with Venturi incorporate the highest, i.e., 3 mg/L (approximately twice more oxygen than the conventional open pump-overs). A highly heterogeneous vertical distribution of dissolved oxygen was also found, with approx. 80 % of the total concentrated at the top of the tanks. When analyzing oxygen dissolution during the maceration, initial low oxygen levels were encountered in spite of the high free SO2 concentrations (an inhibitor of enzymatic oxidation). We speculate that the latter is due to the high initial CO2 content, which prevents oxygen dissolution during the initial period. In the case of the fermentation stage, the observed low oxygen concentrations are mainly due to elevated yeast activity. We also followed oxygen dissolution kinetics during fermentation by estimating the oxygen dissolution rate and a global consumption constant for different fermentation stages. Our results confirmed the negative impact of CO2 on oxygen dissolution and the elevated yeast biological activity of the tumultuous fermentation, as the main causes for the observed low dissolved oxygen levels. Overall, the present work will help improve the management of oxygen during fermentation and winemaking.

The ability of dendrimers to bind to various target molecules through non-covalent interactions was used to capture water soluble organic reagents, such as tartaric acid (TA), from different matrices, i.e. aqueous solutions and wine samples. The influence of the pH, dendrimer type, generation and feeding concentration on the host-guest complexation of TA was investigated. The maximum binding capacity of TA in aqueous solutions was achieved by amine end-capped dendrimers at pH 5. At extreme pH values of 2 and 11, the binding of TA dropped strikingly, demonstrating the pH-dependency underlying the host-guest interactions. The linear correlation between the maximum binding capacity of TA at pH 5 and the number of primary amine groups on the surface of PAMAM and PPI dendrimers strongly indicated that host-guest complex formation between TA and dendrimers is largely dependent on electrostatic interactions. Molecular simulations confirmed the predominant electrostatic nature of the interactions between TA and the amine end-capped dendrimers and also provided important information on the spatial distribution of TA within the PAMAM G5 dendrimer. All these results designate dendrimers as potential nano-capturing systems for the removal/recovery of TA from complex matrices such as wine, industrial waste or fruit juices.

The organic and mineral components of 20 qvevri wines from selected wineries throughout Europe were evaluated to gain insight into one of the oldest known methods of wine production. The pH, residual glucose, titratable acidity, specific organic acids (acetic, lactic, malic, and tartaric acids), phenolics (total phenolics and anthocyanins in red wines), total antioxidants, and selected minerals (phosphorus, calcium, magnesium, manganese, potassium and zinc) of the samples were measured. The data were compared with previously reported values for conventional wines. Qvevri wines were less acidic than conventional wines, containing higher levels of acetic and lactic acids but lower levels of tartaric acid. They also contained higher levels of antioxidants and total phenolics, the latter up to 10 times more abundant in the white wine varieties than in conventional wines. Despite fermentation in clay vessels, the mineral content of qvevri wines was within the normal reported range, although phosphorus levels were slightly higher. This is the only study that has considered the compositional nature of qvevri wines.

Linalool is a monoterpene, which exhibits floral and spicy aromas as well as a variety of pharmacological effects, including antioxidant, anti-inflammatory, and cardiovascular. Wine flavor is highly dependent on the chemical compounds of berries. The objective of this study was to evaluate the concentration of volatile compounds, especially linalool, in grapes (Vitis vinifera L.) ‘Muscat of Alexandria’ grown under different cluster light exposure. Four defoliation treatments were applied at veraison, and changed the light environment at the fruit zone. Severe defoliation (T1): leaves were manually removed from the 1st to the 8th node of each shoot, partial defoliation (T2): leaves were manually removed from the 1st to the 4th, semi-shaded clusters (T3): un-trimmed vines were covered with an 80% shade netting; and (T4) control treatment with non-intervention during season 2014-2015. Free terpenes were extracted using headspace solid-phase microextraction (HS-SPME), and the concentration of volatile compounds was determined using gas chromatography coupled to a flame ionization detector (GC-FID). The study was conducted in two different locations of the Itata Valley in Chile. Linalool concentration was more prevalent in treatments with higher cluster exposure. The treatment with the highest defoliation showed a linalool concentration 40% higher than the control treatment. Higher levels of defoliation in grapevines grown under a traditional farming system result in an increased concentration of volatiles compounds, particularly monoterpenes, where Cerro Verde and Pinihue reached linalool concentrations of 19.1 and 21.7 (g L-1, respectively. These results revealed important differences in the behavior of the synthesis of linalool.

Producción Científica, Measuring the oxygen content during winemaking and bottle storage has become increasingly popular due to its impact on the sensory quality and longevity of wines. Nevertheless, only a few attempts to describe the kinetics of oxygen consumption based on the chemical composition of wines have been published. Therefore, this study proposes firstly a new fitting approach describing oxygen consuming kinetics and secondly the use of an Artificial Neural Network approach to describe and compare the oxygen avidity of wines according to their basic chemical composition (i.e. the content of ethanol, titratable acidity, total sulfur dioxide, total phenolics, iron and copper). The results showed no significant differences in the oxygen consumption rate between white and red wines, and allowed the sorting of the wines studied according to their oxygen consumption rate., Ministerio de Ciencia e Innovación y Ministerio de Economía, Industria y Competitividad (Proyect AGL2014-54602-P, Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. VA124U14, VA028U16), Fondecyt de Iniciación. Grant Number: 1150725

Fumonisins are a group of mycotoxins found in various foods whose consumption is known to be harmful for human health. In this study, we evaluated the ability of three polymers (Polyvinylpolypyrrolidone, PVPP; a resin of N-vinyl-2-pyrrolidinone with ethylene glycol dimethacrylate and triallyl isocyanurate, PVP-DEGMA-TAIC; and poly(acrylamide-co-ethylene glycol-dimethacrylate), PA-EGDMA) to remove fumonisin B

The phenolic compounds of wine contribute to color and astringency, also are responsible for the oxidation state and bitterness. Due the importance of these molecules, different techniques have been used to modulate their concentration such as natural or synthetic polymeric agents. Among the polymeric agents, PVPP is one of the most used, but lacks of selectivity and has a limited pH range. Therefore, the aim of this study was the synthesis of a new polymer, poly(N-(3-(N-isobutyrylisobutyramido)-3-oxopropyl)acrylamide) (P-NIOA), for removal of phenolic compounds, as a potential agent for the fining of wine. The new polymer affinity was studied using HPLC-DAD for different polyphenols using PVPP as a control. The results showed that the new polymer has a similar removal as PVPP, but with lower affinity to resveratrol. The interactions established between polymers and polyphenols were studied using computational chemistry methods demonstrating a direct correlation with the experimental affinity data.

BACKGROUND Sauvignon blanc wines are produced under a wide variety of winemaking conditions, some of which include different fruit-ripening levels, cold soaks and the use of fining agents and inert gases. Anecdotal evidence suggests that sensory variations among these wines may have to do with their phenolic composition and concentration. Therefore the aim of this work was to study the effects of different winemaking conditions typically used in Chile on the phenolic composition and concentration of Sauvignon blanc wines. RESULTS The use of an inert gas (CO2) in winemaking produced differences in the proportion of proanthocyanidin fractions. A higher concentration of flavan-3-ol monomers resulted from winemaking in the presence of inert gas. This condition also produced a higher content of total phenols and low-molecular-weight phenolic compounds. Low doses of polyvinylpolypyrrolidone (PVPP) in the prefermentative treatments produced wines with a higher content of phenolic compounds. Under these conditions a higher content of polymeric proanthocyanidins was observed. CONCLUSION Different winemaking conditions modified the concentration and proportion of proanthocyanidin fractions and the global phenolic composition of the resulting white wines. This should be taken into account by the wineries producing these wines. © 2012 Society of Chemical Industry

Phenolic compounds in Vitis vinifera contribute important flavor, functionality, and health qualities to both table and wine grapes. The plant phenolic metabolic pathway has been well characterized, however many important questions remain regarding the influence of environmental conditions on pathway regulation. As a diagnostic for this pathway's regulation, we present a technique to incorporate a stable-isotopic tracer, L-phenyl-(13)C(6)-alanine (Phe(13)), into grape berries in situ and the accompanying high throughput analytical method based on LC-DAD-MS/MS to quantify and track the label into phenylalanine metabolites. Clusters of V. vinifera cv. Cabernet Sauvignon, either near the onset of ripening or 4 weeks later, were exposed to Phe(13) in the vineyard. Phe(13) was present in berries 9 days afterwards as well as labeled flavonols and anthocyanins, all of which possessed a molecular ion shift of 6 amu. However, nearly all the label was found in anthocyanins, indicating tight regulation of phenolic biosynthesis at this stage of maturity. This method provides a framework for examining the regulation of phenolic metabolism at different stages of maturity or under different environmental conditions. Additionally, this technique could serve as a tool to further probe the metabolism/catabolism of grape phenolics.

A simple, direct injection, electrospray ionization Fourier transform mass spectrometry (ESI FT–MS) method, in combination with multivariate statistics, was used for the characterization and sorting of Chilean wines. 47 commercial red wines labelled as Cabernet Sauvignon, Carmenere, Syrah, and Pinot noir, and 25 white wines of the varieties Chardonnay and Sauvignon blanc were diluted, directly infused into the mass spectrometer, and analyzed in negative ion mode. The signature ions used for statistical analyses were manually filtered out from the signals with m/z ratios over 10%. The results of principal component analysis allowed a good sorting of white wines, but not so in the case of reds. The main three principal components explained 96.82% and 85.65% of the variance for white and red wines, respectively. Instead, linear discriminant analysis, allowed the correct discrimination of 100.00% of white and 95.74% of red samples. The validation of these results using the leave-one-out cross-validation method gave lower percentages of correct classification (76.00% and 61.70% of white and red samples respectively), suggesting that some of the wine samples analyzed might have been blends of more than one variety. Consequently, ESI FT–MS direct injection analysis of wines can be used for sample discrimination, but requires a stronger mathematical model built with spectral information of pure and blended samples before improving the percentages of classification.

β-Carboline imine reductions mediated by Saccharomyces bayanus have been described achieving moderate to good enantiomeric excesses of the amine products. The enantiomeric excesses of the bioreduction showed a dependence on the imine substituents. Compounds presenting C1–C11 aliphatic substituent groups afforded amines with an (S)-configuration, whereas C15 and higher aliphatic- and aromatic-substituted β-carboline imines achieved inversion of the configuration in the final (R)-2 amine products. Based on this data, a model for the Saccharomyces reduction is proposed.

The assessment of wine traceability and authenticity is a critical issue that has gained a lot of interest internationally. Specific quality control programs are mandatory in many countries, including EU and USA, to protect consumers from involuntary mistakes occurring during production, as well as to narrow the possibilities for illegal adulteration practices. The rapid introduction of advanced analytical techniques, employed for the measurement of trace compounds or the simultaneous determination of a wide array of analytes, has been accompanied with the development of more comprehensive approaches for data mining, and data analysis. The prior has lead to improving the means for wine traceability, and discrimination and classification of grapes and wines (mainly in terms of grape varieties, geographical origin and processing conditions). Some of the recent findings on wine typification and authentication herein reviewed, highlight that several challenges need to be solved in order to improve the assessment of wine authenticity and confirm potential mistakes or product adulteration.

Hydroxyl radicals (•OH) seem to have an important role in the oxidation of wine constituents and the production of important electrophilic aldehydes and ketones. In this experiment, glyceraldehyde, a •OH oxidation product of glycerol, recently described in wine, reacts with (+)-catechin, (−)-epicatechin, and malvidin-3-glucoside (Mv3gl), in model solutions, yielding new condensed phenolic compounds. The adduct compounds formed were separated by means of reversed phase liquid chromatography and detected and characterized using UV−vis and electrospray ionization mass spectrometry. Flavanol−flavanol and anthocyanin−flavanol adducts linked with glyceraldehyde yielded compounds with m/z ratios for their main ions, in positive ion mode, of 653.2 for the (+)-catechin dimer or the (-)-epicatechin dimer and 855.5 for Mv3gl/(+)-catechin or Mv3gl/(−)-epicatechin dimers. The possible occurrence of these compounds in wine is suggested, and the potential role of these and related reactions in wine aging is discussed. K...

Simple polyphenols and tannins differ in the way that they contribute to the organoleptic profile of wine and their effects on human health. Very few straightforward techniques to separate red wine nonpolymeric phenols from the polymeric fraction are available in the literature. In general, they are complex, time-consuming, and generate large amounts of waste. In this procedure, the separation of these compounds was achieved using C18 cartridges, three solvents with different elution strengths, and pH adjustments of the experimental matrices. Two full factorial 2(3) experimental designs were performed to find the optimal critical variables and their values, allowing for the maximization of tannin recovery and separation efficiency (SE). Nonpolymeric phenols such as phenolic acids, monomers, and oligomers of flavonol and flavan-3-ols and anthocyanins were removed from the column by means of an aqueous solvent followed by ethyl acetate. The polymeric fraction was then eluted with a combination of methanol/acetone/water. The best results were attained with 1 mL of wine sample, a 10% methanol/water solution (first eluant), ethyl acetate (second eluant), and 66% acetone/water as the polymeric phenols-eluting solution (third eluant), obtaining a SE of ca. 90%. Trials with this method on fruit juices also showed high separation efficiency. Hence, this solid-phase extraction method has been shown to be a simple and efficient alternative for the separation of nonpolymeric phenolic fractions and the polymeric ones, and this method could have important applications to sample purification prior to biological testing due to the nonspecific binding of polymeric phenolics to nearly all enzymes and receptor sites.

Polyvinylpolypyrrolidone (PVPP) is a fining agent, widely used in winemaking and brewing, whose mode of action in removing phenolic compounds has not been fully characterised. The aim of this study was to evaluate the experimental and theoretical binding affinity of PVPP towards six phenolic compounds representing different types of phenolic species. The interaction between PVPP and phenolics was evaluated in model solutions, where hydroxyl groups, hydrophobic bonding and steric hindrance were characterised. The results of the study indicated that PVPP exhibits high affinity for quercetin and catechin, moderate affinity for epicatechin, gallic acid and lower affinity for 4-methylcatechol and caffeic acid. The affinity has a direct correlation with the hydroxylation degree of each compound. The results show that the affinity of PVPP towards phenols is related with frontier orbitals. This work demonstrates a direct correlation between the experimental affinity and the interaction energy calculations obtained through computational chemistry methods.

Porous plastic tanks are permeable to oxygen due to the nature of the polymers with which they are manufactured. In the wine industry, these types of tanks are used mainly for storing wine surpluses. Lately, their use in combination with oak pieces has also been proposed as an alternative to mimic traditional barrel ageing.In this study, the spatial distribution of dissolved oxygen in a wine-like model solution, and the oxygen transfer rate (OTR) of high-density polyethylene tanks (HDPE), was analysed by means of a non-invasive opto-luminescence detector. Also, the chemical and sensory evolution of red wine, treated with oak pieces, and stored in HDPE tanks was examined and compared against traditional oak barrel ageing. The average OTR calculated for these tanks was within the commonly accepted amounts reported for new barrels. With regards to wine evolution, a number of compositional and sensory differences were observed between the wines aged in oak barrels and those stored in HDPE tanks with oak barrel alternatives.The use of HDPE tanks in combination with oak wood alternatives is a viable alternative too for ageing wine.

4-ethylguaiacol (4-EG) is one of the important compounds responsible for the "Brett character" (i.e. spicy and smoky aromas) found in wines contaminated with Brettanomyces yeast. In this trial, the ability of polyaniline-based materials (PANI-EB and PANI-ES) was tested as a potential fining agent for the removal of 4-EG in wine. First, a screening study was developed in order to determine the binding capacity of 4-EG by PANI materials in 12% ethanol solution. Then, the capturing ability of PANI against 4-EG was evaluated with a solution containing gallic acid (GA), 4-methyl-catechol (4-MC), in which the concentration of the phenolic compounds were maintained as in the real wine. The results obtained showed that the retention percentage varied between 0 to 100% (4-EG), 13.81% to 72.32% (GA), and 0 to 17.39% (4-MC), depending on the interaction time and amount of the PANI used. Finally, the capturing capacity of PANI-EB and PANI-ES against 4-EG was evaluated in a real win e sample containing originally 3.10 ± 0.13 mg L-1 of 4-EG and 2.55 ± 0.10 g L-1 of other total phenolic compounds. The analyses performed indicated that PANI-EB is more effective in removing 4-EG than PANI-ES, with retention percentages varying between 36 and 50%.

Microoxygenation (MOX) is a winemaking technique used with the aim of enhancing certain chemical and sensory wine features. Theoretically, by infusing small volumes of oxygen in a continuous way, the quality of the product may improve and the hazards of oxygen buildup and uncontrolled oxidation are avoided. However, the effects produced by discontinued air exposure, at rates comparable to MOX, have not been reported. Therefore, the aim of this trial was to evaluate the chemical effects of an alternative oxygenation protocol, based on weekly wine aerations, compared to conventional MOX (postmalolactic fermentation). For most of the variables analyzed, the periodic aeration treatment produced effects that were equivalent to conventional MOX (e.g., a reduction in the concentration of free anthocyanins and an enhancement in polymeric pigments).

In this research, we determined the chemical composition of 37 Vitis vinifera cv. Carmenere wines and established their antioxidant capacity (AC). A set of 26 measurements of chemical species potentially related to AC, including phenolic compounds, free and combined sulfites and iron, copper and manganese were obtained for each wine. The AC was estimated by DPPH and ORAC-FL methods. Statistical analyses showed good correlations between chemical profiles and AC values (DPPH ρ 2 = 0.90 and ORAC-FL ρ 2 = 0.87). The main chemical markers contributing to AC were the fraction of color given by free and copigmented anthocyanins (39.1%) for DPPH and gallic acid (30.7%) for ORAC-FL. These are a good indication of the complexity of the wine matrix, and the wide variety of substances possibly contributing to AC.

Volatile species with thiol functions are important contributors to the flavour of a wide variety of wine types. However, in spite of their importance, their fate during winemaking has not been fully elucidated. In this work, the iron-catalysed reaction between 3-sulfanyl-1-hexanol, catechol-containing phenolics, and sulfurous acid, under in vitro aerobic conditions was evaluated by means of electrospray ionisation mass spectrometry (ESI-MS). The results indicate that a direct addition reaction between the thiol and some of the phenolics tested, and between sulfite and some of the phenolics may occur, thus contributing evidence of a possible route of thiol losses in wines.

After the progress made during the genomics era, bioinformatics was tasked with supporting the flow of information generated by nanobiotechnology efforts. This challenge requires adapting classical bioinformatic and computational chemistry tools to store, standardize, analyze, and visualize nanobiotechnological information. Thus, old and new bioinformatic and computational chemistry tools have been merged into a new sub-discipline: nanoinformatics. This review takes a second look at the development of this new and exciting area as seen from the perspective of the evolution of nanobiotechnology applied to the life sciences. The knowledge obtained at the nano-scale level implies answers to new questions and the development of new concepts in different fields. The rapid convergence of technologies around nanobiotechnologies has spun off collaborative networks and web platforms created for sharing and discussing the knowledge generated in nanobiotechnology. The implementation of new database schemes suitable for storage, processing and integrating physical, chemical, and biological properties of nanoparticles will be a key element in achieving the promises in this convergent field. In this work, we will review some applications of nanobiotechnology to life sciences in generating new requirements for diverse scientific fields, such as bioinformatics and computational chemistry.

The title imine bioreduction proves to be an attractive alternative to catalytic asymmetric reduction reactions employing Noyori catalysts.