Sugar and acid concentrations in 98 grape cultivars analyzed by principal component analysis

Abstract

A total of 98 grape cultivars were studied for content and composition of organic acids and sugars in grape juice during two consecutive years. Glucose and fructose were the predominant sugars in grape berries and ranged from 45.86 to 122.89 mg mL −1 , and 47.64 to 131.04 mg mL −1 , respectively, in two years. Sucrose was present at trace amounts in most cultivars, but two cultivars of hybrids between Vitis labrusca and V. vinifera contained large amounts of sucrose. Tartaric acid content in berries, varying from 1.57 to 9.09 and 1.54 to 9.05 mg mL −1 , respectively, in two years, was significantly higher than malic acid, which ranged from 0.38 to 6.05 and 0.36 to 7.06 mg mL −1 , respectively, in two years. Moreover, significantly higher total soluble sugars and fructose and lower total acids and malic acid were found in cultivars from hybrids between V. labrusca and V. vinifera than those in V. vinifera cultivars, and wine grapes had higher total sugars and acids than table grapes from V. vinifera. Principal component analysis (PCA) indicated that genotypic correlations among sugar and acid contents were stable and the first three PCs accounted for about 82% of total variance in both years. PC1 was highly connected with glucose and fructose contents, and sucrose was an important contributor to the variance for PC2, as well as for PC3. PC2 and PC3 were highly connected also with organic acids, but the contributor to variance differed from one year to the next. Tartaric acid was the main contributor to variance in 2003, and malic acid was important in 2004 for PC2 and PC3. In a scatter plot of the score values of all genotypes projected to the PC1 and PC2 plane, three groups of cultivars tend to cluster based on their genetic background or purpose of use. The cultivars of hybrid V. labrusca and V. vinifera were represented by high sugars, especially sucrose, and low acids. Among the cultivars of V. vinifera, wine grapes were found in general to have more sugars and acids than table grapes. The composition of sugars was stable in grape berries between the two years, while acids were sensitive to climate changes. Finally, the different responses of malic and tartaric acids to climate change is discussed.

Profiling of primary metabolites in grapes of interspecific grapevine varieties: sugars and organic acids

“…The lowest and the highest contents of total sugars were found out in the cvs Riesling and Hibernal (190.31 g/l and 244.49 g/l, respectively). Liu et al (2006) found out in 98 cultivars the range of glucose content within the limits of 45.86 g/l and 122.89 g/l while the content of fructose ranged from 47.64 g/l to 131.04 g/l.…”

A Sugar-Inducible Protein Kinase, VvSK1, Regulates Hexose Transport and Sugar Accumulation in Grapevine Cells

“…The involvement of VvSK1 in the control of sugar compartmentation was further strengthened by the fact that cells overexpressing VvSK1 accumulate twice more Glc and three times more Suc than the control, whereas the starch content remains unaffected. Sugar levels of suspension cells significantly differ from those in berries, where monosaccharide concentrations can reach 1.5 M, whereas Suc is poorly detectable (Fillion et al, 1999;Liu et al, 2006). In this context, the role of VvSK1 on sugar transport and accumulation in grape berries has to be further investigated by altering VvSK1 expression in berries.…”

Varietal Comparison of The Chemical, Physical, and Mechanical Properties of Five Colored Table Grapes

“…Moreover, nutritive and functional properties are becoming more and more important in determining consumer choice, even if the classical parameters such as soluble solids concentration (SSC), acid contents, SSC/acid ratio and skin color are still the main quality parameters in table grapes. [2][3][4][5][6][7][8] In particular for colored grapes, skin color is a quality factor of fundamental importance, since sight is the first of the senses to be used, and visual appreciation is decisive in the choice. [9] The total content of anthocyanins and the proportions between them, dependent mainly on the cultivar, [10] determine the final coloration of the grape skin.…”