Phenolics, which play a crucial role in determining
the sensory and nutritional quality of fresh apples, are an
essential part of the human diet and are of considerable
interest due to their antioxidant properties. Among the
polyphenolic compounds found in apples, more than 50 %
are procyanidins (tannins), responsible for the pungent
and bitter taste of the fruit. The rest of the biologically
active structures are phenolic acids, dihydrochalcones,
quercetin glycosides, and anthocyanins. The main phenolic
acid in apples is chlorogenic acid and among dihydrochalcones
dominates phloridzin and phloretin-xyloglucoside.