Original article: Prediction of the colour and polyphenolic composition of the young red wines from the phenolic potential of the grapes

Abstract

The phenolic potential of the grapes of Tannat, Cabernet Sauvignon and Merlot produced in the south region of Uruguay was analysed in four years. The grapes of Tannat had the highest total phenolic richness (A280 = 80.0), total anthocyanin potential (ApH1 = 2540 mg L )1 ) and extractable anthocyanin potential (ApH3.2 = 1269 mg L )1 ), although there were important differences between the years. Representative winemaking of each vineyard was carried out. The differences verified in the grapes phenolic indexes were related to the colour and polyphenolic composition of the wines. The correlations between the phenolic indexes of the grapes and the colour and polyphenolic composition of the wines were very high. The estimation of the polyphenolic richness and the extractability of the anthocyanins of the grapes allow to improve the management of the winemaking and the prediction of the chromatic characteristics and the global polyphenolic composition of the wines.

Modifications in Chemical, Physical and Mechanical Properties of Nebbiolo (Vitis vinifera L.) Grape Berries Induced by Mixed Virus Infection

“…The phenol extractability indexes were: cellular maturity index (EA%) and seed maturity index (Mp%) (Rio Segade et al, 2008;Gonzáles-Neves et al, 2010). The latter index was determined by taking into consideration the average ratio (TAR) between the total phenols (expressed as absorbance at 280 nm) and the total anthocyanins of the skin (expressed as g/L) equal to 70 (Cagnasso et al, 2008).…”

“…However, the chemical composition of the cell wall of the grape skin may affect its mechanical resistance to releasing anthocyanins (Ortega-Regules et al, 2006). Currently, the cellular maturity index or extractability index (EA%) (Gonzáles-Neves et al, 2010), mechanical properties of the whole berry (springiness, chewiness and gumminess) (Zouid et al, 2010) and skin mechanical characteristics (skin break force and thickness) (Rolle et al, 2009;Rio Segade et al, 2011) are the best parameters for reliably obtaining a direct estimate of phenol compound extractability. Two other factors related directly to resistance against splitting, berry rot and plant diseases are berry skin hardness and thickness (Lang & During, 1990;Gabler et al, 2003).…”

Effect of cold pre-fermentative maceration on the color and composition of young red wines cv. Tannat

“…Control wines were made with classical fermentation on skins (maceration in simultaneous with alcoholic fermentation) for 7 (in 2007) or 8 days (in 2006, 2009 and 2010), according to the polyphenolic potential of grapes at harvest (González-Neves et al 2004, 2010b. Two pumping over followed by punching the cap were carried out daily along the skin contact.…”

“…This variety, very rich in pigments and tannins, is very well adapted to the ecological conditions of the country and produces wines of outstanding qualities. Application of CPM in this variety could be interesting because this practice may contribute to obtain highly colored wines with moderate astringency (González-Neves et al 2010b, 2013.…”

Spectra evolution over on-vine holding of Italia table grapes: prediction of maturity and discrimination for harvest times using a Vis-NIR hyperspectral device

“…In case of phenol content, lowest performances were observed in prediction, in particular a value of 0.41 for R in calibration and 0.36 in prediction, the same results were published by Kemps et al (2010), in which the value of correlation (R) in calibration ranged between 0.36 to 0.60 for various grape varieties. González-Neves et al (2010) reported a value of (R 2 ) of 0.98 for total phenols in validation model using red grapes Graciano. Similar results were generated in a study conducted by Nogales-Bueno et al (2014) in which the results of R 2 values of 0.89 for red grapes, 0.80 for white grapes, and 0.77 for global models, were reported.…”