Geographical origin authentication of southern Brazilian red wines by means of EEM-pH four-way data modelling coupled with one class classification approach.

EEM data recorded at different pH values was exploited by MCR-ALS in order to determine qualitative information about Brazilian red wines. In addition, the geographical traceability of wines produced in the Serra Gaúcha (Rio Grande do Sul) was carried out by DD-SIMCA considering 53 samples from the target class and 20 from other producing regions. The fluorescence signal corresponds to 9 EEMs recorded at different pH (3-11), generating four-way data. By MCR-ALS decomposition, eight factors were retrieved and related to typical chemical compounds found in red wine. In addition, the EEM pH data was used to build a one-class classification model, considering that MCR scores and all samples of the target class were properly recognised as belonging to the target class, with maximal sensitivity equal to 1. Samples of the non-target class were also adequately rejected by the model, and the specificity was found to be 0.97.

Optimization of fermentation-relevant factors: A strategy to reduce ethanol in red wine by sequential culture of native yeasts.

Current consumer preferences are determined by well-structured, full-bodied wines with a rich flavor and with reduced alcohol levels. One of the strategies for obtaining wines with reduced ethanol content is sequential inoculation of non-Saccharomyces and Saccharomyces cerevisiae yeasts. However, different factors affect the production of metabolites like ethanol, glycerol and acetic acid by inoculated yeasts. In order to obtain low alcohol wines without quality loss, the aims of our study were: i) to determine optimum conditions (fermentation temperature and time of permanence and initial inoculum size of the non-Saccharomyces population at the beginning of the process, prior to inoculation with S. cerevisiae); ii) to validate the optimized factors; and iii) to assess sensory quality of the wines obtained after validation. Two combinations of yeasts were used in this study: Hanseniaspora uvarum BHu9/S. cerevisiae BSc114 and Candida membranaefaciens BCm71/S. cerevisiae BSc114. Optimization of three fermentation factors that affect to non-Saccharomyces yeasts prior to S. cerevisiae inoculation was carried out using a Box-Behnken experimental design. Applying the models constructed by Response Surface Methodology, the lowest ethanol production by H. uvarum BHu9/S. cerevisiae BSc114 co-culture was obtained when H. uvarum BHu9 was inoculated 48 h 37 min prior to S. cerevisiae inoculation, at a fermentation temperature of 25 °C and at an initial inoculum size of 5 × 106 cells/mL. Lowest alcohol production with C. membranaefaciens BCm71/S. cerevisiae BSc114 was observed when C. membranaefaciens BCm71 was inoculated 24 h 15 min prior to S. cerevisiae at a fermentation temperature of 24.94 °C and at an initial inoculum size of 2.72 × 106 cells/mL. The optimized conditions of the two co-cultures were subsequently submitted to lab-scale validation. Both proposed strategies yielded ethanol levels that were significantly lower than control cultures (S. cerevisiae). Wines fermented with non-Saccharomyces/Saccharomyces co-cultures under optimized conditions were also associated with higher aromatic complexity characterized by the presence of red fruit aromas, whereas wines obtained with S. cerevisiae BSc114 were described by parameters linked with high ethanol levels.

Green and fast determination of the alcoholic content of wines using thermal infrared enthalpimetry.

An innovative use of thermal infrared enthalpimetry (TIE) is proposed for the determination of alcoholic content of red and white wines. Notwithstanding the presence of ethanol in beverages, absolute ethanol was added directly to wines, and the temperature rise caused by the heat of dilution was monitored using an infrared camera. Analytical signals were obtained in only 10 s for four samples simultaneously, and a calibration curve was constructed with hydroalcoholic reference solutions. A linear calibration curve was obtained from 3.0 to 18.0% (v/v) ethanol (R2 = 0.9987). The results showed agreement ranging from 98.2 to 104.0% with 942.06 and 969.12 methods of AOAC. Organic compounds (e.g., sugar) did not interfere in the determinations. The proposed method provided fast results, with a throughput of 480 samples per hour and negligible energy consumption (0.001 kWh). In addition, the consumption of reagents was reduced when compared with conventional method fulfilling green analytical chemistry requirements.

Physicochemical, Antioxidant and Sensory Quality of Brazilian Blueberry Wine.

Currently, Rio Grande do Sul state is the main producer of blueberry in Brazil. Practically all production is commercialized in fresh state and only a small portion is subject to processing. The blueberry wine making process is an alternative to expand the beverage industry and offers to the consumer a value-added product as well as a new market for Brazilian blueberry producers. The objectives of this study were to produce wines from blueberries and to evaluate the effect of deacidification (with calcium carbonate) and chaptalization (with glucose syrup or sucrose) on physicochemical characteristics, antioxidant content, and sensory parameters. Samples were analyzed for total soluble solids, pH, total titratable acidity, total sugar content, alcohol content, monomeric and total anthocyanin, total flavonols, total phenolic compounds and antioxidant activity by DPPH and FRAP methods. The use of calcium carbonate caused a reduction in total titratable acidity, while the use of glucose syrup resulted in wines with low alcohol content. The blueberries wine from Climax and Aliceblue cultivars had higher content of anthocyanin when produced with glucose syrup. The use of calcium carbonate and glucose syrup also provided wines more appreciated by tasters in relation to color. With regard to flavor, George and Aliceblue were the cultivars with lower preference under the control treatments (without carbonate and sugar). The presence of phenolic compounds may have provided a positive influence on wine flavor, once the more preferred wines presented the greater phenolic content.

In-line electrochemical reagent generation coupled to a flow injection biamperometric system for the determination of sulfite in beverage samples.

This work reports an in-line electrochemical reagent generation coupled to a flow injection biamperometric procedure for the determination of SO3(2-). The method was based on a redox reaction between the I3(-) and SO3(2-) ions, after the diffusion of SO2 through a gas diffusion chamber. Under optimum experimental conditions, a linear response ranging from 1.0 to 12.0 mg L(-1) (R=0.9999 and n=7), a detection and quantification limit estimated at 0.26 and 0.86 mg L(-1), respectively, a standard deviation relative of 0.4% (n=10) for a reference solution of 4.0 mg L(-1) SO3(2-) and sampling throughput for 40 determinations per hour were achieved. Addition and recovery tests with juice and wine samples were performed resulting in a range between 92% and 110%. There were no significant differences at a 95% confidence level in the analysis of eight samples when comparing the new method with a reference procedure.

Effect of selected Saccharomyces cerevisiae yeast strains and different aging techniques on the polysaccharide and polyphenolic composition and sensorial characteristics of Cabernet Sauvignon red wines.

BACKGROUND: The objective of this work was to study the effect of two Saccharomyces cerevisiae yeast strains with different capabilities of polysaccharide liberation during alcoholic fermentation in addition to subsequent aging on lees with or without oak wood chips as well as aging with commercial inactive dry yeast on the physical, chemical and sensorial characteristics of Cabernet Sauvignon red wines. RESULTS: The HPS (high levels of polysaccharides) yeast strain released higher amounts of polysaccharides (429 g L(-1)) than EC1118 (390 g L(-1)) during alcoholic fermentation, but the concentration equalized during the aging period (424 and 417 g L(-1) respectively). All aging techniques increased the polysaccharide concentration, but the increase was dependent on the technique applied. A higher liberation of polysaccharides reduced the concentration of most of the phenolic families analyzed. Moreover, no clear effect of the different aging techniques used in this study on color stabilization was found. The HPS wines were better valued than the EC1118 wines by the panel of tasters after alcoholic fermentation. CONCLUSION: In general, the HPS wines showed better physicochemical and sensorial characteristics than the EC1118 wines. According to the results obtained during the aging period, all aging techniques contributed to improve wine quality, but it was difficult to establish the technique that allowed the best wine to be obtained, because it depended on the aging technique used and the period of aging.

Main differences between volatiles of sparkling and base wines accessed through comprehensive two dimensional gas chromatography with time-of-flight mass spectrometric detection and chemometric tools.

The main changes in the volatile profile of base wines and their corresponding sparkling wines produced by traditional method were evaluated and investigated for the first time using headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) and chemometric tools. Fisher ratios helped to find the 119 analytes that were responsible for the main differences between base and sparkling wines and principal component analysis explained 93.1% of the total variance related to the selected 78 compounds. It was also possible to observe five subclusters in base wines and four subclusters in sparkling wines samples through hierarchical cluster analysis, which seemed to have an organised distribution according to the regions where the wines came from. Twenty of the most important volatile compounds co-eluted with other components and separation of some of them was possible due to GC×GC/TOFMS performance.

Detection of abnormal fermentations in wine process by multivariate statistics and pattern recognition techniques.

Three multivariate statistical techniques (Multiway Principal Component Analysis, Multiway Partial Least Squares, and Stepwise Linear Discriminant Analysis) and one artificial intelligence method (Artificial Neural Networks) were evaluated to detect and predict early abnormal behaviors of wine fermentations. The techniques were tested with data of thirty-two variables at different stages of fermentation from industrial wine fermentations of Cabernet Sauvignon. All the techniques studied considered a pre-treatment to obtain a homogeneous space and reduce the overfitting. The results were encouraging; it was possible to classify at 72h 100% of the fermentation correctly with three variables using Multiway Partial Least Squares and Artificial Neural Networks. Additional and complementary results were obtained with Stepwise Linear Discriminant Analysis, which found that ethanol, sugars and density measurements are able to discriminate abnormal behavior.

Influence of Candida pulcherrima Patagonian strain on alcoholic fermentation behaviour and wine aroma.

The use of selected Saccharomyces and non-Saccharomyces strains as mixed starters in winemaking would have advantages over the traditional spontaneous fermentation, producing wines with predictable and desirable characteristics. The aim of this study was to evaluate the impact of metabolic interactions between Patagonian indigenous Saccharomyces cerevisiae MMf9 and beta-glucosidase producer Candida pulcherrima V(6) strains on alcoholic fermentation behaviour and wine aroma Three inoculation strategies, simultaneous, sequential and final, were assayed at laboratory-scale fermentations using Muscat d'Alexandrie grape juice as substrate. The fermentation and yeast growth kinetics as well as the physicochemical and the sensory quality of wine were evaluated. Results evidenced that the sequential inoculation is the most adequate strategy of strains combination. The kinetic behaviour of sequential fermentation was similar to a successful spontaneous fermentation and its wine showed differential aromatic quality as evidenced through PC analysis using physicochemical and aromatic composition data. This wine presented the highest total concentration of higher alcohol, esters and terpenols and the strongest fruity and floral aroma.

Fate of ochratoxin A content in Argentinean red wine during a pilot scale vinification / Evolución del contenido de ocratoxina A en vinos tintos argentinos durante el proceso de vinificación a escala piloto

The aim of this work was to evaluate the fate of ochratoxin A (OTA) content from must to wine during the red wine making process in a pilot scale vinification. The study was done using musts obtained from two red grape varieties (Bonarda and Tempranillo) artificially contaminated with two OTA levels. A duplicate set of tanks of 100 l each was established for each must (Bonarda and Tempranillo). The fermentations were initiated by inoculation of two Saccharomyces spp. strains having different fermentation performance. The must from the Tempranillo variety was spiked with 6 μg/l of OTA while that from the Bonarda variety with 0.3 μg/l of the toxin. Samples were collected at different stages of the process. Performance of the alcoholic and malolactic fermentations was monitored. Titratable and volatile acidity, pH, ethanol, sugar and SO2 concentrations were determined following standard methods proposed by the Office International de la Vigne et du Vin (OIV). OTA analysis was done by HPLC. Detection and quantification limits were 0.01 and 0.1 ng/ml, respectively. The OTA levels during the vinification trials dropped to an average of about 86.5%. The type of Saccharomyces strains used showed no effect on toxin reduction.

El objetivo del presente trabajo fue evaluar la evolución del contenido de ocratoxina A (OTA) en mostos durante un proceso de vinificación a escala piloto. Se utilizaron mostos de dos variedades de uvas tintas (Bonarda y Tempranillo) contaminados artificialmente con dos niveles distintos de OTA. El ensayo fue llevado a cabo por duplicado en tanques de fermentación de 100 l cada uno. La fermentación se inició mediante la inoculación de dos cepas de Saccharomyces spp. con diferentes características fermentativas. El mosto de la variedad Tempranillo fue contaminado con 6 μg/l de OTA y el mosto de la variedad Bonarda con 0,3 μg/l de la toxina. Se colectaron muestras durante los diferentes estadios del proceso de vinificación. Se estableció el avance de dicho proceso sobre la base de la evolución de las fermentaciones alcohólica y maloláctica. Se determinó la acidez total y volátil, el pH y el contenido de etanol, de azúcar y de SO2 siguiendo los protocolos estándares propuestos por la Oficina Internacional de la Vid y el Vino (OIV). El contenido de OTA se evaluó por HPLC. Los límites de detección y cuantificación fueron 0,01 y 0,1 ng/ml, respectivamente. Los niveles de OTA disminuyeron alrededor del 86,5% al final del proceso de vinificación. El tipo de cepa de Saccharomyces spp. utilizada no tuvo efecto sobre la reducción de OTA.

Differential absorption of metals from soil to diverse vine varieties from the Valley of Tulum (Argentina): consequences to evaluate wine provenance.

We report the effect of vine variety on the absorption of metals from soil and follow the variety from wine through juice, verifying which metals could be used to assess wine provenance. Eleven metals were determined by atomic absorption spectroscopy in 32 soils, 16 grapes juices, and 18 wines sampled from a single vineyard having four red grape varieties (Cabernet Sauvignon, Bonarda, Malbec, and Syrah). The K nearest neighbor method allows us to distinguish among different soils, juices, and wines. Linear discriminant analysis affords descriptors to point out differences, mainly Mg, Mn, Ca, K, and Na. Data analysis evidenced that some elements have equivalent concentrations in soil, juice, and wine, while others did not. Canonical analysis shows good correlation between grape juice and wine with their provenance soil. We suggest using Mg as a marker of wine provenance, while Mn could be used to evaluate differences between wine varieties associated with plant physiology.

Taqman real-time PCR for the detection and enumeration of Saccharomyces cerevisiae in wine.

Saccharomyces cerevisiae is the main yeast species responsible for wine fermentation; however, its presence during maturing or barrel-ageing can sometimes result in a reduction in the quality of wine by refermentation. In this work, we developed a quantitative real-time PCR (QPCR) for the rapid detection and quantification of S. cerevisiae in wine. The primers and the hydrolysis probe (TaqMan) were designed from the sequence of a DNA fragment present only in S. cerevisiae and absent in other wine yeasts obtained from an RAPD-PCR analysis. The QPCR developed was highly reproducible, allowing the specific detection and quantification of this yeast in artificially contaminated wines, with a detection limit of 78 CFU/mL. Furthermore, the usefulness of the QPCR developed was evaluated through the quantification of the yeast in wine samples obtained from vineyards, confirming the quantitative capacity of the method. The methodology developed was specific, fast and a sensitive tool for the detection and enumeration of S. cerevisiae cells in wine.

Fate of ochratoxin A content in Argentinian red wine during a pilot scale vinification.

The aim of this work was to evaluate the fate of ochratoxin A (OTA) content from must to wine during the red wine making process in a pilot scale vinification. The study was done using musts obtained from two red grape varieties (Bonarda and Tempranillo) artificially contaminated with two OTA levels. A duplicate set of tanks of 100 I each was established for each must (Bonarda and Tempranillo). The fermentations were initiated by inoculation of two Saccharomyces spp. strains having different fermentation performance. The must from the Tempranillo variety was spiked with 6 microg/I of OTA while that from the Bonarda variety with 0.3 microg/I of the toxin. Samples were collected at different stages of the process. Performance of the alcoholic and malolactic fermentations was monitored. Titratable and volatile acidity, pH, ethanol, sugar and SO2 concentrations were determined following standard methods proposed by the Office International de la Vigne et du Vin (OIV). OTA analysis was done by HPLC. Detection and quantification limits were 0.01 and 0.1 ng/ml, respectively. The OTA levels during the vinification trials dropped to an average of about 86.5%. The type of Saccharomyces strains used showed no effect on toxin reduction.

Diversity of Saccharomyces strains on grapes and winery surfaces: analysis of their contribution to fermentative flora of Malbec wine from Mendoza (Argentina) during two consecutive years.

Spontaneous fermentations are still conducted by several wineries in different regions of Argentina as a common practice. Native Saccharomyces strains associated with winery equipment, grape and spontaneous fermentations of Malbec musts from "Zona Alta del Río Mendoza" region (Argentina) were investigated during 2001 and 2002 in the same cellar. Low occurrence of Saccharomyces on grapes and their limited participation during fermentation were confirmed. Strain sequential substitution during fermentation was observed. Between 30% and 60% of yeast population at the end of fermentation was coming from yeasts already present in the winery. A stable and resident Saccharomyces micro-flora in the winery was confirmed. It exhibited a dynamic behaviour during season and between years. Commercial strains were found during fermentation in different percentages, but their presence on winery equipment was low. The present work represents a first approach to winery yeast and spontaneous fermentation Saccharomyces population dynamics in an important viticultural region from Argentina that has never been characterized before. The results obtained have an important significance for the local industry, showing for the first time the real situation of the microbial ecology of alcoholic fermentation in an industrial winery from Mendoza, Argentina.

Avaliaçäo da eficiência de degustadores de vinhos através da análise multivariada / Evaluation of efficience of wine tasters group using the multivariate analysis

A avaliaçäo sensorial realizada por um grupo de degustadores utilizando critérios objetivos é uma das maneiras mais eficazes de apreciar a qualidade de um vinho. Este trabalho descreve metodologia para testar a homogeneidade e a eficiência de degustadores, levando em consideraçäo um conjunto de 23 variáveis simultaneamente, utilizando-se o potencial das análises multivariadas