Changes in chemical wax composition of three different apple (Malus domestica Borkh.) cultivars during storage

The effects of year, picking date and storage conditions on the chemical composition of the wax layer of three apple cultivars (‘Jonagold’, ‘Jonagored’ and ‘Elstar’) were investigated by means of GCMS and multivariate statistical techniques. Wax of apples with different surface characteristics also differed in chemical composition. Controlled atmosphere (CA) storage and subsequent shelf life affected wax properties and caused changes in the chemical composition, especially during shelf life. The changes in wax composition of ‘Elstar’, however, were smaller than those in ‘Jonagold’ and ‘Jonagored’, possibly associated with lower diffusion resistance and more limited structural changes of ‘Elstar’ wax. Longer CA storage periods accelerated the changes in wax composition during subsequent shelf life. The components responsible for the changes were mainly the alkane and ester fractions. The secondary alcohol nonacosan-10-ol was particularly important in explaining the changes in wax composition of ‘Jonagold’ during shelf life and its presence could be linked with greater development of greasiness.