Varietal heterogeneity of textural characteristics and their relationship with phenolic ripeness of wine grapes

- Anthocyanin extracbitliy correlated with skin thickness.
- Varietal heterogeneity in textural properties.
- Grape cultivar interacted with puncture position on skin hardness.

The phenolic ripeness of grapes at harvest imparts important functions for high-quality red wine and might be highly related to the textural properties of berries. The textural characteristics of 20 wine grape cultivars were detected by puncture test and textural profile analysis (TPA); and their relationship with phenolic ripeness were determined in this study. Varietal heterogeneity in textural characteristics was clearly observed among the colored and white grapes. Thirteen colored varieties showed marked differences in phenol extractability indices. The cellular maturity index, related to anthocyanin extractability, was highly dependent upon berry skin thickness with a good equation of regression. The multiple correlation coefficient was 0.940. No significant difference in skin mechanical properties and TPA was found between colored and white cultivars. Grape variety showed a significant interaction with puncture position in terms of berry skin hardness for both colored and white berries. Principal component analysis demonstrated differences in textural properties among the wine grape cultivars. Three clear clusters of 20 varieties were differentiated based on the skin hardness at the side of the berry. The results of this study indicated that there are relationships between the textural characteristics of wine grapes, cellular maturity index, and seed maturity index at harvest.