Influence of Brettanomyces custersianus upon the activity of Saccharomyces cerevisiae strains during the tumultuous phase of vinification

The aim of this work was to evaluate the influence of Brettanomyces custersianus on the metabolic activity of Saccharomyces cerevisiae during the tumultuous stage of wine production. The Cabernet Sauvignon grape must with the skin was inoculated with individual cultures of Sacch. cerevisiae and with mixed cultures of Sacch. cerevisiae and Br. custersianus. During the 6-day tumultuous phase of fermentation, the highest ethanol production and the highest sugar consumption were obtained with the strains without B. custersianus. Fermentations carried out with the addition of Brettanomyces metabolites, acetic acid and 4-ethylphenol, showed that only the former inhibited the growth of both Sacch. cerevisiae strains used. In some cases, Br. custersianus could affect the rate higher alcohols production and their final concentrations during the tumultuous phase of vinification.

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.

Aplicação da enzima pectinase na vinificação / Application of pectinase enzyme on vinification

As enzimas são substâncias encontradas natural ou artificialmente, capazes de governar e estimular processos químicos. Seu uso no processo de vinificação promove um aumento nos teores dos compostos fenólicos no vinho. O objetivo do presente estudo foi verificar o efeito da enzima pectinase na vinificação da uva niágara rosada. As uvas, safra 2006, foram coletadas e encaminhadas para o laboratório de Bioquímica da Universidade Paranaense, Campus Toledo, dividida em quatro lotes, e sulfitadas com 50,0 mg/L de metabissulfito de sódio. Após, foram realizadas as correções de açúcar para 23,0 ºBrix, seguidos da adição de nutrientes na proporção de 0,2 g/L de fosfato de amônio dibásico por kg de uva e inoculados com a levedura Saccharomyces Cerevisiae seca e ativada (30 mg/kg de uva). O tratamento 1 foi tomado como controle. Ao segundo foram adicionados 2,5 g da enzima pectinase (Ultrazym AFPL da Novozymes); ao terceiro 5,0 g, e ao quarto foram adicionados 7,5 g/100 kg de uva. As microvinificações foram realizadas em triplicata, sendo acompanhadas pelo ºBrix. Finalizada a fermentação alcoólica, o vinho foi decantado, pasteurizado e mantido sob refrigeração. Foram realizadas análises de pH (a 20º C), acidez total (meq/L), acidez volátil (meq/L), SO2 livre (g/L), SO2 total (g/L) e densidade (g/cm³), polifenóis totais, antocianinas, taninos e índices de cor. A enzima pectinase favoreceu a difusão dos compostos fenólicos da película para o vinho. A concentração de 5,0 g de enzima por 100 kg de uva foi a que se mostrou mais adequada.

Enzymes are substances naturally or artificially found which are able to govern and stimulate chemical processes. Its use in the vinification process promotes the increase of the levels of phenolic compounds in wine. The objective of this study was to verify the effects of the enzyme pectinase in the vinification of the Niagara pink grape. The grapes, harvested in 2006, were collected and taken to the laboratory of Biochemist of the Universidade Paranaense, Campus Toledo, divided into four sets, and sulfited with 50.0 mg/L of metabissulfito of sodium. Then, corrections of sugar to 23.0 ºBrix followed by the addition of nutrients in the ratio of 0,2 g/L of dibasic ammonium phosphate per inoculated kg of grape and dry and activated Saccharomyces Cerevisiae yeast (30 mg/kg of grape) were carried out. Treatment 1 was considered control. To the second, 2.5 g of the enzyme pectinase (Ultrazym®, AFP-L, Novozymes do Brasil) were added; 5.0 g to the third, and 7.5 g/100 kg to the fourth. The microvinification had been carried through in third copy, being followed by ºBrix. The wine was decanted, pasteurized and kept under refrigeration after the alcoholic fermentation. Analyses of pH (20º C), total acidity (meq/L), volatile acidity (meq/L), free SO2 (g/L), total SO2 (g/L) and density (g/cm³), total, anthocyanins, polyphenols, tanines, and color indexes were carried out. The pectinase enzyme favored the diffusion of skin phenolic composites to the wine. The concentration of 5.0g enzyme per 100 kg of grape presented to be more suitable.

Efeito de diferentes épocas de desfolha e de colheita na composição do vinho Cabernet Sauvignon / Effect of different defoliation and harvesting times in the composition of Cabernet Sauvignon wine

O trabalho foi realizado em Santana do Livramento. Rio Grande do Sul, com o objetivo de avaliar o efeito de épocas de desfolha e de colheita sobre a composição físico-química do vinho Cabernet Sauvignon. O experimento foi conduzido num fatoriat incompleto, com quatro épocas de desfolha e três épocas de colheita, realizadas em função de uma data ideal de colheita, totalizando onze tratamentos, com três repetições. A intensidade de desfolha foi de aproximadamente 25 por cento. Os vinhos foram elaborados através de microvinificações. Os resultados mostraram que a época de desfolha não afetou de forma significativa a maioria das variáveis analisadas no vinho, à exceçao do álcool, açúcares redutores e extraio seco. A época de colheita, por outro lado, influiu significativamente na maior parte das variáveis, exceto na acidez total e na acidez volátil, o que sugere uma maior influência deste fator sobre a composição e qualidade do vinho.

The fleld work was carried out in Santana do Livramento, State of Rio Grande do Sul, Brazil, aiming to evaluate the effect of defotiation and harvesting times on the physicchemical composition of Cabernet Sauvignon wines. The experimental design was an incompletely factorial with four defotiation times and three harvesting limes at on ideal harvest date with a total of eleven treatments in three replicales. The defotiation intensity was about 25 percent and wines were elaborated in small volumes The results showed that the time of defotiation did not have significam effect on the majority of the variables anatyzed, exception on the alcohot, reducing sugars and dry extract. On the other hand, the harvesting time had a significant effect on almost ali variables, exception to the total and votatile acidities. These results suggests a greater influence of the harvesting time on the composition and quatity of Cabernet Sauvignon wine.