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Gonzalez-Neves G.,University of the Republic of Uruguay | Gil G.,Instituto Nacional Of Vitivinicultura | Favre G.,University of the Republic of Uruguay | Ferrer M.,University of the Republic of Uruguay
International Journal of Food Science and Technology | Year: 2012

The anthocyanin composition of Tannat red wines obtained with four winemaking techniques was evaluated in different years. The wines were elaborated with traditional maceration (TM), cold pre-fermentative maceration, delayed extraction of anthocyanins and extended maceration. Two vinifications were carried out for each technique, employing 70kg of grapes in each one. The anthocyanin composition of wines was analysed by high-performance liquid chromatography-diode array detection. The results confirm the fundamental role of the grape composition on the anthocyanin composition of the wines. The winemaking had an important effect on the total concentration of anthocyanins and also may modify the anthocyanic profile of wines. The wines obtained with TM had higher or similar content of anthocyanins than those elaborated with the other techniques. Canonical discriminant analysis of data showed that vintage has a greater effect on anthocyanin concentration than winemaking techniques. © 2012 The Authors. International Journal of Food Science and Technology © 2012 Institute of Food Science and Technology. Source

Gonzalez-Neves G.,University of the Republic of Uruguay | Gil G.,Instituto Nacional Of Vitivinicultura | Favre G.,University of the Republic of Uruguay | Baldi C.,University of the Republic of Uruguay | And 2 more authors.
South African Journal of Enology and Viticulture | Year: 2013

The influence of winemaking procedure and grape variety on the colour and composition of young red wines was evaluated. For this purpose, Tannat, Syrah and Merlot wines were elaborated in Uruguay in 2011. Traditional maceration (TM), the addition of pectolytic enzymes (ENZ) and cold pre-fermentative maceration before traditional maceration (CPM) were the alternative procedures of winemaking tested. Two batches of grapes (70 kg each) were employed for each winemaking procedure. Tannat wines had the highest colour intensity, red colour (a*), and anthocyanin, proanthocyanidin and alcohol content, and the lowest luminosity (L*) and pH values. CPM increased the colour intensity and total polyphenol, anthocyanin and proanthocyanidin content in Tannat and Merlot wines. Pectolytic additions enhanced colour intensity and red colour and decreased the luminosity in all wines. Meanwhile, enzyme additions enhanced proanthocyanidin content in all cases. Pectolytic enzyme significantly increased the methanol levels of the wines. Nevertheless, the amounts of this compound are far within maximum acceptable limits. Principal component analysis of the data shows significant separation between the wines of each variety, since the colour and composition are largely related to the cultivar and the vintage, despite the effect of the winemaking procedures. Source

This paper shows the results of a study carried out during four years (2001-2004). Its aim was the characterization of Tannat, Cabernet Sauvignon and Merlot grapes cultivated in the south of Uruguay. The results were evaluated to qualify the enological potential of these varieties of Vitis vinifera L. Typical cultivation situations in the region were included of each variety. The grapes were analysed at harvest for determination of global composition and polyphenolic potential. Tannat grapes presented very different characteristics in relation to other varieties. Tannat had the highest percentage of seeds, berry weight, sugar contents, total acidity, total polyphenols, total anthocyanins, extractable anthocyanins, skin tannins and seed tannins levels. Also, they had the lowest pH values and the highest EA%, corresponding to the lowest extractability of anthocyanins. The effect of vintage on the grape composition was very important, according to the impact of the climatic conditions in the synthesis of quality components of berries. However, the joint consideration of analytical indexes of base composition, polyphenolic potential and structure of the berry allowed a perfect discrimination of samples of each variety. Source

Gonzalez-Neves G.,University of the Republic of Uruguay | Favre G.,University of the Republic of Uruguay | Gil G.,Instituto Nacional Of Vitivinicultura
Food Chemistry | Year: 2014

This work aimed to evaluate the effect of four fining agents on the colour and pigment composition of red wines of Tannat. The wines were analysed 15 days after fining and immediately after separation of sediments and bottling. Colour was evaluated by spectrophotometry and polyphenols were analysed by spectrophotometry and HPLC-DAD. The colour intensity of wine was significantly decreased by bentonite and egg albumin. The most remarkable effects on wine phenolic composition were produced by bentonite and gelatin, which significantly decreased anthocyanin and tannin concentrations, respectively. Results show that each fining agent has very different impact on the wine attributes, and their effects depended as well on the composition of the clarified wine. The use of non-traditional agents of fining, as vegetable proteins, may have less impact on the colour and anthocyanin content of red wines. © 2014 Elsevier Ltd. All rights reserved. Source

Favre G.,University of the Republic of Uruguay | Pena-Neira A.,University of Chile | Baldi C.,University of the Republic of Uruguay | Hernandez N.,University of the Republic of Uruguay | And 3 more authors.
Food Chemistry | Year: 2014

Low molecular weight phenols of Tannat red wines produced by Traditional Maceration (TM), Prefermentative Cold Maceration (PCM), Maceration Enzyme (ENZ) and grape-Seed Tannins additions (ST), were performed and discussed. Alternatives to TM increased wine phenolic contents but unequally, ST increased mainly smaller flavans-3-ol, PCM anthocyanins and ENZ proanthocyanidins (up to 2250 mg/L). However low molecular weight flavan-3-ols remained below 9 mg/L in all wines, showing that there is not necessarily a correspondence between wine richness in total tannins and flavan-3-ols contents at low molecular weight. PCM wines had particularly high concentrations of tyrosol and tryptophol, yeast metabolism derived compounds. The use of grape-seed enological tannins did not increase grape seed derived phenolic compounds such as gallic acid. Caftaric acid was found in concentrations much higher than those reported in other grape varieties. Wine phenolic content and composition was considerably affected by the winemaking procedures tested. © 2014 Elsevier Ltd. All rights reserved. Source

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