Pectinases: aplicações industriais e perspectivas

Pectic substances are structural heteropolysaccharides that occur in the middle lamellae and primary cell walls of higher plants. They are composed of partially methyl-esterified galacturonic acid residues linked by alpha-1, 4-glycosidic bonds. Pectinolytic enzymes are complex enzymes that degrade pectic polymers and there are several classes of enzymes, which include pectin esterases, pectin and pectate lyases and polygalacturonases. Plants, filamentous fungi, bacteria and yeasts are able to produce pectinases. In the industrial world, pectinases are used in fruit juice clarification, in the production of wine, in the extraction of olive oil, fiber degumming and fermentation of tea, coffee and cocoa.

Efeito da presença e concentração de compostos carbonílicos na qualidade de vinhos

Studies on identification of compounds that make up the aroma and flavor in wines involve research evaluating mainly the influence of terpenes, esters, lactones and alcohols upon these sensory characteristics. However, carbonylic compounds (CC) play an important role concerning the substances that impact aroma to these drinks. Their origin is reported to be linked to the grape's chemical composition, must fermentation or micro-oxidation occurring during storage in barrels. Some CCs, like E-ionone, E-damascenone, siryngaldehyde, can contribute a pleasant aroma and improve the wine quality whereas others are responsible for unpleasant characteristics (acetaldehyde, furfural, 5-hydroxy-methyl furfural, diacetil, E-non-2-enal, etc). A fraction of CCs present is associated with bisulfite ions in the form of hydroxyalkylsulfonic acids. Some of them are stable and play an important role in determining wine quality. The reaction involving the formation of this aduct commonly occurs with CCs of low molar mass, such as formaldehyde and acetaldehyde. The reaction involving CCs with more than three carbon atoms demands further studies.

Análise multivariada de parâmetros físico-químicos em amostras de vinhos tintos comercializados na região metropolitana do Recife

The Brazilian legislation requires analysis of certain parameters to classify a wine and allow its commercialization. Some physico-chemical and some color parameters were determined in this work in samples of different red wines sold in the metropolitan area of Recife. Multivariate analysis comprising principal component analysis and hierarchical cluster analysis was employed to distinguish the analyzed wines. The results for pH, chloride concentration, color parameters and ammonium content were the most important variables for sample classification. It was also possible to classify the wines as soft or dry wines and amongst the soft wines we could determine two out of four winegrowing producers.

Avaliação da composição química de fermentados alcoólicos de jabuticaba (myrciaria jabuticaba)

This work aimed to characterize the chemical composition of samples of alcoholic beverages fermented from jabuticaba produced in five successive crops. Up to 2005 most of the results didn't meet the current legal standards for wines and there was a negative correlation between parameters such as pH and volatile acidity, pH and total acidity, volatile acidity and alcohol content (p<0.01). The implementation of Good Manufacturing Practices and must sulfitation during the 2006 harvest lowered volatile acidity and more than 60% of the samples were in accordance with legislation. Also, a significant improvement in alcohol content was found (p<0.05)

Análise screening de vinhos empregando um analisador fluxo-batelada, espectroscopia UV-VIS e quimiometria

A simple, robust, versatile, high analytical frequency method was proposed to check if a sample of wine is within the range of standards set by the manufacturer, using the UV-VIS spectroscopy, multivariate analysis and a flow-batch analyzer. Two hundred and fifty-two samples of wines were analyzed. The results from the application of Hierachical Cluster Analysis (HCA) to the matrix of the data involving all samples show the formation of fifteen types of wine. A Soft Independent Modelling of Class Analogy (SIMCA) model was constructed and used to classify the samples of the overall forecast. As a result, it is observed that the prediction was performed with a success rate of 99.2% for a confidence level of 95%. This shows that the proposed methodology can be used as an effective tool for classifying of samples of wines.

Otimização e validação de método para determinação de ácidos orgânicos em vinhos por cromatografia líquida de alta eficiência

The organic acids (tartaric, malic, citric, lactic and succinic) are de main components responsible for the acidity in the wine. This method for simultaneous determination of organic acids and interfering peaks in wines can be achieved in 16 min. The sample preceded by a dilution and filtration step. The chromatographic separation required one reversed phase column, isocratic mobile phase (acetonitrila, formic acid in water) and detection wavelength was set at 212 nm. The validation confirmed good repeatability, recovery and application in red and white wines.

Caracterização espectroscópica multivariada do potencial antioxidante de vinhos

In this work the antioxidant capacity of red wine samples was characterized by conventional spectroscopic and chromatographic methodologies, regarding chemical parameters like color, total polyphenolic and resveratrol content, and antioxidant activity. Additionally, multivariate calibration models were developed to predict the antioxidant activity, using partial least square regression and the spectral data registered between 400 and 800 nm. Even when a close correlation between the evaluated parameters has been expected many inconsistencies were observed, probably on account of the low selectivity of the conventional methodologies. Models developed from mean-centered spectra and using 4 latent variables allowed high prevision capacity of the antioxidant activity, permitting relative errors lower than 3%.

Determination of polyphenol contents and antioxidant capacity of no-alcoholic red grape products (vitis labrusca) from conventional and organic crops

The polyphenol contents and antioxidant capacity of Brazilian red grape juices and wine vinegars were analyzed. Additionally, it was analyzed the human polyphenol absorption and acute effect in plasmatic oxidative metabolism biomarkers after juice ingestion. The organic Bordo grape juice (GBO) presented a higher level of trans-resveratrol, quercitin, rutin, gallic acid, caffeic acid and total flavonoids then other juices and vinegars as well as antioxidant capacity. The plasmatic polyphenol increased 27.2% after GBO juice ingestion. The results showed that juices and vinegars from Brazilian crops present similar chemical and functional properties described in studies performed in other countries.

Comparação do perfil químico entre cachaças de um mesmo vinho destiladas em alambiques e em colunas

Six wines were distilled in two different distillation apparatus (alembic and column) producing 24 distillates (6 for each alembic fraction - head, heart and tail; 6 column distillates). The chemical composition of distillates from the same wine was determined using chromatographic techniques. Analytical data were subjected to Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) allowing discrimination of four clusters according to chemical profiles. Both distillation processes influenced the sugarcane spirits chemical quality since two types of distillates with different quantitative chemical profiles were produced after the elimination of fermentation step influence.

Precision agriculture in Australia: present status and recent developments

A brief account of the present status of Precision Agriculture (PA) in Australia is presented, and areas of opportunity in the grains, sugar and wine industries are identified. In particular, these relate to the use of spatially-distributed experimentation to fine-tune management so as to achieve production efficiencies, reduced risk of environmental impact and enhanced food security, and the management of crop quality through selective harvesting and product streaming. The latter may be an important avenue by which farmers can take a more active role in the off-farm part of agricultural value chains. The important role of grower groups in facilitating PA adoption is also discussed.

Adaptation of "Niagara Rosada" grape must to winemaking by partial cluster dehydration

This study aimed to verify the influence of partial dehydration of "Niagara Rosada" grape clusters in physicochemical quality of the pre- fermentation must. In Brazil, during the winemaking process it is common to need to adjust the grape must when the physicochemical characteristics of the raw material are insufficient to produce wines in accordance with the Brazilian legislation for classification of beverages, which establishes the minimum alcohol content of 8.6 % for the beverage to be considered wine. Therefore, given that the reduction in the water content of grape berries allows the concentration of chemical compounds present in its composition, especially the concentration of total soluble solids, we proceeded with the treatments that were formed by the combination of two temperatures (T1-37.1ºC and T2-22.9 ºC) two air speeds (S1: 1.79 m s-1 and S2: 3.21 m s-1) and a control (T0) that has not gone through the dehydration treatment. Analysis of pH, Total Titratable Acidity (TTA) were performed in mEq L-1, Total Soluble Solids (TSS) in ºBrix, water content on a dry basis and Concentration of Phenolic Compounds (CPC) in mg of gallic acid per 100g of must. The average comparison test identified statistically significant modifications for the adaptation of must for winemaking purposes, having the treatment with 22.9 ºC and air speed of 1.79 m s-1 shown the largest increase in the concentration of total soluble solids, followed by the second best result for concentration of phenolic compounds.

Deficit irrigation in grapevine cv. Syrah during two growing seasons in the brazilian semiarid

Irrigation plays an important role for grape’s yield as well as on its quality for winemaking. Thus, the effects of deficit irrigation strategies on yield and quality of wine grapes cv. Syrah were evaluated in Petrolina, State of Pernambuco, Brazil. Evaluations were carried out throughout the second and third growing seasons, which were from November 2010 to February 2011 (rainy season) and from May to September 2011 (dry season), respectively. Vines were drip irrigated and the experimental design was completely randomized with three treatments and four replications. The treatments were full irrigation (FI), performed according crop evapotranspiration; regulated deficit irrigation (RDI), in which irrigation was interrupted in phenological growth stage of bunch closure, but was occasionally performed according soil water monitoring of the root zone; and deficit irrigation (DI), when irrigation was interrupted from bunch closure to harvesting. Differences on leaf water content among treatments were observed in both growing seasons and RDI and DI treatment plants presented moderate water stress. The number of bunches did not differ among treatments in both growing seasons; however, bunch weight per plant, average bunch weight and soluble solid content were higher in FI treatment during the dry season. Deficit irrigation strategies promoted water saving.

Avaliação da aceitação de vinhos brancos varietais brasileiros através de testes sensoriais afetivos e técnica multivariada de mapa de preferência interno

A aceitação de nove amostras comerciais de vinhos brancos brasileiros, de três diferentes linhas varietais (Riesling, Chardonnay e Gewürztraminer), foi avaliada por 43 consumidores de vinhos brancos nacionais, utilizando a escala hedônica estruturada de nove pontos. Os provadores foram recrutados através de um questionário de avaliação de hábitos de consumo de vinho branco. Duas metodologias distintas foram utilizadas para avaliar os dados obtidos: o Mapa de Preferência Interno (MDPREF) e Análise de Variância (ANOVA) com comparação de médias (teste de Tukey). Os resultados da ANOVA e Tukey indicaram que duas amostras foram significativamente (p < 0,05) melhor aceitas, obtendo médias de aceitação ao redor de 7, na escala hedônica: uma do varietal Riesling e outra do varietal Gewürztraminer, ambas vinhos brancos suaves. A amostra de menor aceitação (média 4,3) foi um vinho branco demi-sec do varietal Chardonnay. As demais amostras obtiveram aceitação intermediária, apresentando médias ao redor de 5, todas referindo-se a vinhos brancos secos ou demi-sec. O MDPREF confirmou os resultados da ANOVA, indicando que a maior preferência por parte dos provadores foi pelas amostras de vinhos brancos suaves, pois 86% dos consumidores convergiram para a região do mapa de preferência onde situavam-se estas amostras. Apenas 14% indicaram sua preferência por vinhos brancos secos ou demi-sec, convergindo para a região oposta do mapa, onde situavam-se as demais sete amostras. Este estudo sugere que vinhos brancos suaves são mais preferidos pelos consumidores brasileiros, do que vinhos brancos secos ou demi-sec.

Perfil sensorial de vinhos brancos varietais brasileiros através de análise descritiva quantitativa

Terminologia descritiva e perfil sensorial de três variedades de vinhos brancos varietais brasileiros (Chardonnay, Gewürztraminer e Riesling) foram desenvolvidos através de metodologia fundamentada na Análise Descritiva Quantitativa (ADQ). Em consenso, a equipe sensorial definiu os descritores, materiais de referência e a ficha de avaliação das amostras. Após treinamento, dez indivíduos foram selecionados para compor a equipe final de provadores, utilizando-se como critérios o poder discriminativo, reprodutibilidade dos julgamentos e consenso do indivíduo com a equipe. Doze termos descritores definindo as similaridades e diferenças entre as amostras foram gerados. A intensidade de cada descritor foi avaliada em cada amostra através de uma escala não estruturada de nove centímetros, com termos de intensidade ancorados em seus extremos. Os dados foram analisados por ANOVA, Teste de Tukey e Análise de Componentes Principais (ACP). Os resultados indicaram moderada variação entre os perfis sensoriais das amostras dos varietais Gewürztraminer e Riesling e pouca variação entre os perfis sensoriais dos vinhos Chardonnay. A ACP separou as amostras em dois grupos: um primeiro grupo caracterizado por vinhos com maior intensidade de doçura, sabor e aroma frutado e corpo, e um segundo grupo de amostras de maior acidez, adstringência, amargor, sabor alcoólico e sabor fermentado.

Discrimination of Brazilian red wines according to the viticultural region, varietal, and winery origin

This work evaluated the physicochemical composition of 171 red Brazilian wines from the 2006 vintage, which were represented by 21 varietals. These wines were produced by 58 Brazilian wineries in different regions of the country, with latitudes varying from 9º to 31º South. Physicochemical wine analysis was performed in the same year and discrimination in the viticultural regions, varietal wines, and wineries was performed by means of the principal component analysis (PCA). The main results show that wines from São Joaquim had higher values of A420, A520, A620, color intensity, total phenolic compounds, anthocyanins, and dry extracts, while those from Toledo had lower values of these variables; those from Vale do São Francisco had higher values of potassium, pH, density, and volatile acidity; from Serra do Nordeste A, they had higher titratable acidity; and from Planalto Superior B, higher hue. Regarding the varietal wines, PCA mainly discriminated the wines produced from the varieties Ancellotta, Teroldego, Egiodola, Refosco, Marselan, Cabernet Sauvignon, Pinotage, Pinot Noir, Malbec, Arinarnoa, Barbera, and Alfrocheiro. In relation to wineries, twenty two of them were discriminated by their higher values of some variables, i.e., three were characterized by color intensity; three by hue; eight by alcohol content; six by potassium, dry extract, density, and pH; and two by titratablel acidity.