To further investigate the degradation of the quercetin derivatives,
the apple peel extract was heated at different temperatures
as dry powder and solubilized in vacuum impregnation fluid.
At 50 C (Tables 4 and 5), the total quercetin content was slightly
reduced after 15 h in solution (7%) and in the dry power (10%). In
contrast, a strong degradation of quercetin monoglycosides was
found at 95 C, resulting in a slight increase of quercetin aglycone
(Tables 4 and 5). The highest reduction at 95 C was found for
quercetin-3-O-arabinoside in the dry powder extract, as well as in
the vacuum impregnation fluid