Great differences in antioxidant properties exist between 56 apple cultivars and vegetation seasons.

The contents of ascorbate, thiols, and phenolic compounds and antioxidative enzyme activity were measured in the apple peel of 56 genotypes after harvest in two vegetation seasons, 2003 and 2004. The main reason of great interest in these bioactive compounds is their well-established physiological role in all living systems. The biggest differences between tested genotypes were noted for ascorbate peroxidase and glutathione reductase (GR) activity, followed by total ascorbate, phenolics, and glutathione concentration; the least difference was observed in the case of catalase.