Changes in Pectin Content of Cabernet Sauvignon Grape Berries During Maturation

Abstract

The total pectin content of Cabernet Sauvignon grapes increased during the period of rapid berry growth following veraison from 6.8 to 10.3 mg uronic acid per berry in samples from Napa and from 4.7 to 8.1 mg per berry in fruit from Lodi. Because the increase in pectin was slower than the berry growth rate, the concentration of pectins decreased during ripening. More than 85% of the total pectin was extracted from the cell wall with EDTA. The proportion of cell wall bound pectin decreased, and water soluble pectin increased during ripening. Although the total pectin content was higher in grapes from Napa, water soluble pectin was higher in grapes from Lodi. These differences suggest that vineyard location has an effect on pectin metabolism during grape berry growth and maturation.