Identifier: TFM:277
Authors: López González, Miguel Ángel
Abstract:
The influence of protein and tartaric stabillity treatments over the final wine quality of wines from Sauvignon blanc, Verdejo and Xarel·lo grape varieties was evaluated in the present study. Microfermentations from the three varieties mentioned above were carried out and then subjected to different combinations of protein stability treatments (bentonite, isinglass, PVPP and vegetal protein) and tartaric stability (cooling stabilization, mannoprotein, potassic bitartarate and carboximethyl celulose). Variables analyzed were chemical variables (total and volatile acidity, pH and alcohol by volume), colour variables (a*, b* and L* components from CIELAB colour space, colour intensity, tonality and Folín index), phenolic content varables (Folín index and total phenolic acids), and fermentative aromas content variables (aromas and off-flavours content). In order to evaluate treatments different data analysis techniques were used: univariate (two factor ANOVA) and multivariate (PCA and two factor MANOVA) techniques. A quality index was calculated for each treatment combination in order to determinate which of the combination was the more suitable for each grape variety studied. The results provided by univariate and multivariate data analysis evidenced the significant influence of tartaric stability treatments over the variables studied and the null influence of protein ones. Quality index calculation determined in a general way that the best combination of treatments were which that uses mannoprotein as a tartaric stabilizer, followed by carboximethyl celulose ones and leaving potassium bitartarate and cooling stabilization in the last place.
Repositori URV