Increase in esterase activity during maturation of Malus pumila fruit

In a range of dessert cultivars of Malus pumila, the esterase in the fruit showed a rise in activity during the period of fresh weight gain. This was the case when activity was expressed on a protein or a fresh weight basis. Both fruit which matured at 100 days after anthesis, and fruit which matured later, showed a similar rate of increase. However, a cultivar used for processing rather than eating showed a much reduced rate of esterase increase.