Investigation of the stability of freeze-dried apple chips over a
period of one year showed that the levels of quercetin derivatives
were significantly influenced by storage temperature and storage
time. It is assumed that enzymatic and non-enzymatic reactions are
responsible for the degradation. Storage under moderate temperature
conditions was associated with better preservation of quercetin
glycosides. Enriched apple chips stored at 20 C for 12 months
still showed significant levels of quercetin derivatives