Grape varieties

The addition of exogenous glycosidases enhance greatly aromas in wines in relation with the aromatic potential of grape varieties. Tastings confirm that the improvement is obvious for red and for white wines. Wines are always judged more fruity and more intense. 

Classification of wines according to the grape variety succeeds better, in general, because there are many more typical bouquet components (several hundreds) than mineral and trace elements being typical for the origin of wine. The organic compounds can be analyzed easily and reliably by Headspace Solid-Phase Microextraction Capillary Gas Chromatography and afterwards used for classification (De la Calle et al. [1998]). An example... 

Fig. 8.12. Representation of the both first discriminant functions df vs df2 obtained by discriminant analysis (MVDA) of 65 German wines from five wine-growing regions according to six different grape varieties by means of 58 features (bouquet components)...

Fig. 8.13. Discriminant analysis of 36 wines from the wine-growing region of Alzey according to four grape varieties (see above) by means of 58 features...

Danzer K, De la Calle D, Thiel G, Reichenbacher M (1999) Classification of wine samples according to origin and grape varieties on the basis of inorganic and organic trace analysis. Am Lab 31 26... 

Mane C, Souquet JM, Olle D, Verries C, Veran F, Mazerolles G, Cheynier V and Fulcrand H. 2007. Optimization of simultaneous flavanol, phenolic acid, and anthocyanin extraction from grapes using an experimental design application to the characterization of champagne grape varieties. J Agric Food Chem 55(18) 7224—7233. 

The amounts of analytes are compiled in Table 2.74. The results indicated that the concentration of polyphenols in red wines depends on both the grape variety and on the exogenous factors. The validation parameters of the method were good, the recoveries were in each case over 98 per cent, the coefficients of variation were between 1.3 per cent and 4.3 per cent, and the limit of detection ranged from 10/rg/l to 0.1mg/l. It was stated that the method is suitable for the determination of silbene compounds and quercetin in red wines [194],... 

Fedrizzi, B., Magno, F., Badocco, D., Nicolini, G., and Versini, G. (2007). Aging effects and grape variety dependence on the content of sulfur volatiles in wine. J. Agric. Food Chem. 55,10880-10887. 

Perez-Magarino, S., Ortega-Heras, M., Cano-Mozo, E., and Gonzalez-Sanjose, M. L. (2009). The influence of oak wood chips, micro-oxygenation treatment, and grape variety on colour, and anthocyanin and phenolic composition of red wines. /. Food Compos. Anal. 22, 204-211. 

Compound Impact of grape variety Source in grape Impact of yeast Role of yeast/bacteria ... 

Alvarez et al. [73] compared the performance of LDA and ANNs to classify different classes of wines. Metal concentrations (Ca, Mg, Sr, Ba, K, Na, P, Fe, Al, Mn, Cu and Zn) were selected as chemical descriptors for discrimination because of their correlation with soil nature, geographical origin and grape variety. Both LDA and ANNs led to a perfect separation of classes, especially when multi-layer perceptron nets were trained by error back-propagation. 

Figure 2. Protein pherograms (disc electrophoresis) of different grape varieties (harvest 1971). The separation distance was redrawn to a 10 cm scale. Scale Rf-values, Arrows Main bands common to all varieties.

The literature indicates that most studies pertaining to amino acids have been devoted to grape varieties of the species V. vinifera. In general, investigations have shown that grape varieties of the species V. vinifera and V. labrusca are qualitatively similar in amino acid composition. However, the concentrations of amino acids vary over a wide range, and the varietal effect is significant (83, 93, 94, 95, 96, 97, 98, 99, 100). 

---