Changes of polyphenols, sugars, and organic acid in 5 Vitis genotypes during berry ripening

The concentrations of sugars, organic acids, and polyphenols during berry ripening in 5 grape genotypes were analyzed using HPLC and HPLC-MS to determine which were correlated. Veraison is critical stage during grape berry development, and marks the beginning of ripening. Glucose and fructose accumulated sharply in a 1: 1ratio, though the concentration of fructose was slightly higher than that of glucose at maturation. Malic acid and tartaric acid were the dominant organic acids, and they decreased rapidly during berry ripening. The 5 cultivars contained 28 anthocyanins and 8 other polyphenols. All anthocyanins accumulated and were positively correlated with the sugars and negatively correlated with the organic acids. Hydroxycinnamic acids declined and were positively correlated with anthocyanin contents. Changes in flavanols and flavonols different among the 5 genotypes, with flavonols positively correlated with anthocyanin content, but the flavanols procyanidin B1and epicatechin negatively correlated with anthocyanins content. There were obvious differences in patterns of change of polyphenols among 5 grape genotypes.

The results could be used for improving grape berry quality during ripening and developing a comprehensive database of primary and secondary metabolites in the Vitis for grape breeding.