Apple juices are important source of polyphenolic compounds, correlated with antioxidant activities.
Apples and apple juices showed antioxidant activities when tested both in vitro and in vivo; the effects have been attributed to the polyphenolic constituents, such as flavan-3-ols, including monomeric (catechins) and polymeric (procyanidins), hydroxycinamics acids, dihydrochalcones, flavonols and anthocyanins.
The total phenolic content in apple juice was in a range of 0.02 – 0.1% of juice. Catechin and procyanidins are a major class of apple phenolics, representing more than 80% of the total content.
In apple juice, vitamin C activity represented a minor fraction of the total antioxidant activity, with chlorogenic acid and phloretin glycosides as the major identifiable antioxidants.
In epidemiological research some specific flavonoids are associated with protection against ageing diseases.
This might due to their action as antioxidant. Free radicals may attack biomolecules (lipids, proteins, DNA) which can be prevented by antioxidants.
In one study, pure fruit juice, including apple juice inhibited reactive oxygen species generation for up to 90 min after their consumption by 10 healthy young men (J. Med Food.2005;8[1]:41-46).
In addition, 600g of whole apples also acutely reduced oxidative stress levels in six healthy male volunteers.
Antioxidants in apple juice