Phenolic characterization of four different red varieties with “Caíño” denomination cultivated in Northwestern Spain

In this work, these four red varieties were characterized in terms of phenolic composition. Thus, the anthocyanin accumulation and the extractability evolution during ripening were compared. The extractability assays were carried out using similar pH conditions than those involved in winemaking process. Furthermore, seed phenolic maturity was determined in order to obtain information about the tannin aggressiveness. These parameters are of great importance not only for the varietal differentiation but also for the planning and management of winemaking process. On the other hand, the anthocyanin distribution was determined because it permits the assessment of varietal differentiation, being it considered as a taxonomic characteristic.
Total anthocyanin concentration was significantly greater for Caíño Longo variety, while extractable anthocyanin content for this variety was similar than that corresponding to Caíño Astureses variety. Furthermore, the lowest total and extractable anthocyanin concentrations were associated with Caíño Redondo and Caíño da Terra cultivars. Thus, the extraction facility showed good skin ripeness grade only for Caíño Astureses variety. Furthermore, the seed ripeness resulted to be particularly incomplete for Caíño Astureses and Caíño Redondo varieties, which indicates their worse adaptation to the “terroir”. Malvidin glucoside was the majority anthocyanin in all the varieties studied, excepting the Caíño da Terra variety. The Caíño Longo cultivar showed results statistically higher, while the Caíño da Terra cultivar presented the lowest values of this compound.