Changes of antioxidant content in fruit peel and flesh of selected apple cultivars during storage

The aim of this preliminary research was to evaluate the level of glutathione, ascorbic acid and the activity of glutathione and ascorbate related enzymes (glutathione reductase and ascorbate peroxidase) in apple peel andflesh during cold storage. Four cultivars of apples: 'Jonagold', 'Sampion', 'Gloster' and 'Elise', were tested. Samples of apple tissues from cold storage were collected in October, November and December at 30-day intervals, frozen in liquid nitrogen and stored at -85 °C. The content of soluble reductants depended on cultivar, part of fruit and storage period. Total glutathione and ascorbate content in the peel was 2 and 6 times higher respectively, compared to their content in the flesh. Glutathione level increased in November and decreased in December both for the peel and flesh. Amounts of ascorbic acid in the flesh was nearly the same during storage while its concentration increased in the skin. The level of glutathione reductase activity generally increased during the tested period. Ascorbate 6 peroxidase activity did not significantly change between the tested cultivars and during storage.