Comparative Study of Texture Properties, Color Characteristics, and Chemical Composition of Ten White Table-Grape Varieties

The texture, color, and chemical characteristics of 10 white table-grape varieties were compared: Delizia del Vaprio, Matilde, Moscato di Terracina, Panse precoce, Pizzutello bianco, Regina, Regina dei vigneti, Sub lima seedless, Sultanina (or Thompson Seedless), and Vincere. Consumer acceptability of table grapes depends on such factors as visual attributes, chemical constituents, nutritive values, mechanical properties, and, obviously, sensory attributes, which are affected by the cultivar. Notable differences among the studied varieties were found in CIRG (color index of red grapes), solid soluble content, malic acid, hydroxycinnamic acid, and the amount of total polyphenols. However, the mechanical parameters of berries, as determined by texture profile analysis, and berry skin characteristics, evaluated by puncture testing, were the most important properties for the differentiation of varieties. In particular, PCA analysis indicated that hardness, gumminess, chewiness, break skin force, break skin energy, and Young's modulus of elasticity of skin were the best indices with which to characterize the varieties. These results may help viticulture and postharvest professionals recognize the behavior of each variety and thus better respond to the consumer market.