Performance of hydroxycinnamic esters during white wine vinification

O objetivo deste trabalho foi determinar o conteúdo de ácido caftárico e cutárico em mostos e vinhos brancos, nos vários estágios da vinificação. Foram utilizadas cultivares de uva branca, Chenin Blanc e Sauvignon Blanc (Vitis vinifera) cultivadas em Santana do Livramento, RS, e Niágara (Vitis labrusca), cultivada em Santa Maria, RS, das safras de 1997, 1998 e 1999. O conteúdo desses compostos foi determinado por meio de cromatografia líquida de alta eficiência, na fase de esmagamento da uva, durante a fermentação, e no vinho pronto para o consumo. Concentrações de ácido caftárico foram geralmente mais altas do que as de ácido cutárico, tanto em mosto quanto em vinho. A quantidade média de ácido caftárico no mosto, nas três cultivares, foi de 61,25 mg/L, enquanto no vinho correspondente, foi de 32,10 mg/L, comprovando a diminuição deste composto durante a fermentação. Comportamento semelhante foi observado em relação ao ácido cutárico (22,63 e 9,00 mg/L, respectivamente no mosto e no vinho). Em amostras coletadas seis meses após o engarrafamento, observou-se também uma diminuição dos dois compostos, porém em menor proporção.The objetive of this work was to quantify caftaric acid and cutaric acid in musts and wines during the vinification phases. White grape cultivars Chenin Blanc and Sauvignon Blanc (Vitis vinifera) cultivated in Santana do Livramento, RS, and Niágara (Vitis labrusca) cultivated in Santa Maria, RS, Brazil, were used in 1997, 1998 and 1999. Content of the compounds was determined through high performance liquid chromotography in grape crushing, during fermentation and when the wine was ready to be consumed. Generally, the caftaric acid concentrations were higher than the cutaric acid concentrations, in musts as much as in wine. The average quantity of caftaric acid in must, in the three cultivars, was 61.25 mg/L, while in the corresponding wine it was 32.10 mg/L, proving a decrease of this compound during fermentation. A similar performance was observed for cutaric acid (22.63 and 9.00 mg/L, respectively for must and wine). In samples collected six months after bottling, a decrease was also observed in these two compounds, but in a smaller proportion

Phenolic compounds in Merlot wines from two wine regions of Rio Grande do Sul, Brazil

In Brazil, the grape and wine production takes place mainly in the state of Rio Grande do Sul, and the region "Serra" is known as the traditional wine region. In the last years, new areas have emerged, with emphasis for the Campanha region; the red wines from this region have low acidity, little color intensity, and are wines to drink while young, even when produced from grape varieties such as Merlot and Cabernet Sauvignon. The objective of this study was to evaluate the influence of different maceration types on the phenolic compounds of Merlot wines made with grapes produced in two regions of Rio Grande do Sul, Serra and Campanha, as well as to identify the key differences between the wines produced. The localization of the vineyards seems to have more influence on the wine characteristics than the maceration type. The color due copigmentation was an important aspect in the wines made with short maceration. The effect of extended maceration was different than the expected for the Campanha region wines; the extended maceration increased the extraction of tannins resulting in greater color intensity and a greater amount of anthocyanins. The pH control seems to be a key factor for the Campanha region wines

Copigmentation and color of Brazilian Merlot wines. I. Influence of skin contact time

Aim: To evaluate the impact of maceration time on color, polyphenols and copigmentation of Merlot wines in order to better understand the differences between two important Brazilian viticultural regions, Campanha Gaúcha and Serra Gaúcha, which have not been extensively studied. Methods and results: Merlot grapes (red Vitis vinifera variety) from four vineyards located in the Campanha Gaúcha (n = 2) and Serra Gaúcha (n = 2) regions were harvested, crushed and fermented at the same temperature, with three different maceration times (4, 8 and 15 days). Wines from the 2009 and 2010 harvest were analyzed by spectrometry for phenolic composition and color. The results showed that the origin of the grapes had a higher influence on phenolic composition and color than the winemaking process treatments (i. e., maceration time). Maceration time did not affect copigmentation phenomena, and polymeric anthocyanins had the greatest correlation with color intensity. Conclusion: The maceration time had different effects according to the wines studied. However, more studies will be necessary to identify the characteristics of the grapes and to understand the differences between these two viticultural regions. Significance and impact of the study: One of the regions studied, Campanha Gaúcha, is a new Brazilian viticultural region. There are only few studies on this wine region. So, the results presented here will provide some guidance for the selection of the most appropriate oenological practices for this region

Phenolic compounds in Merlot wines from two wine regions of Rio Grande do Sul, Brazil

In Brazil, the grape and wine production takes place mainly in the state of Rio Grande do Sul, and the region "Serra" is known as the traditional wine region. In the last years, new areas have emerged, with emphasis for the Campanha region; the red wines from this region have low acidity, little color intensity, and are wines to drink while young, even when produced from grape varieties such as Merlot and Cabernet Sauvignon. The objective of this study was to evaluate the influence of different maceration types on the phenolic compounds of Merlot wines made with grapes produced in two regions of Rio Grande do Sul, Serra and Campanha, as well as to identify the key differences between the wines produced. The localization of the vineyards seems to have more influence on the wine characteristics than the maceration type. The color due copigmentation was an important aspect in the wines made with short maceration. The effect of extended maceration was different than the expected for the Campanha region wines; the extended maceration increased the extraction of tannins resulting in greater color intensity and a greater amount of anthocyanins. The pH control seems to be a key factor for the Campanha region wines

Aminoácidos livres e uréia durante a fermentação de mosto de Chardonnay com diferentes leveduras

A análise de aminoácidos e uréia durante a fermentação da cultivar Chardonnay, fermentada com diferentes leveduras, foram os principais objetivos deste trabalho. Os mostos foram coletados em Santana do Livramento, RS, transportados para a UFSM; lá foram divididos em dois lotes aos quais foram adicionadas diferentes leveduras: Saccharomyces cerevisiae Fermol Bouquet e Saccharomyces cerevisiae D47. O aminoácido encontrado no mosto em maior quantidade foi a prolina (327 mg/L) seguido por treonina, arginina e alanina (239 mg/L). A maioria dos aminoácidos foi consumida pelas leveduras, logo após o início da fermentação. A liberação máxima de uréia no meio coincidiu com o máximo de consumo de arginina, que para a levedura Fermol Bouquet foi com 15ºBrix e para a levedura D47 com 11ºBrix. Confirmando a pouca preferência de prolina pelas leveduras, o teor deste aminoácido permaneceu elevado durante o processo fermentativo. Os aminoácidos, arginina, alanina, treonina, serina, ácido aspártico e isoleucina podem ser considerados as melhores fontes de nitrogênio para as leveduras