The large number of conjugated double bonds and hydroxyl groups is responsible for their antioxidant activity (AOA). Polyphenols represent a group of secondary metabolites with aromatic ring(s) bearing one or more hydroxyl moieties. In Germany, they are the most popular type of fruit with an annual consumption of 25.9 kg per person. Apples are one of the most important fruit sources of dietary polyphenolic compounds in the Western diet, due to the fact that they are consumed widely and are available throughout the year. Polyphenols are the most abundant antioxidants in the human diet and the major part of antioxidants in apples, rather than essential nutrients such as vitamin C. Antioxidants have become even more a focus of research due to increased exposure to ROS.

Through a variety of antioxidant ingredients, apples have been associated with reduced risks of degenerative and cardiovascular diseases, which are considered to be caused by oxidative stress, especially by free radicals and reactive oxygen species (ROS). The polyphenolic content (HPLC data) of the flesh differed significantly between old (29 ± 7 mg/100 g) and new (13 ± 4 mg/100 g) cultivars, and the antioxidant capacity of old apple cultivars was up to 30% stronger compared to new ones.Īpples ( Malus domestica) have a growing scientific interest because many investigations have demonstrated their beneficial effects on human health. The calculated relative contribution of single compounds indicated flavonols (peel) and vitamin C (flesh) as the major contributors to the antioxidant capacity, in all cultivars investigated. Quercetin glycosides (203 ± 108 mg/100 g) were the main polyphenols in the peel and phenolic acids (10 ± 5 mg/100 g) in the flesh. Twenty polyphenolic compounds were identified in all investigated apples by HPLC analysis. The in vitro antioxidant capacity was determined by total phenolic content (TPC) assay, hydrophilic trolox equivalent antioxidant capacity (H-TEAC) assay and hydrophilic oxygen radical absorbance (H-ORAC) assay. The polyphenolic profiles of old and new apple cultivars ( n = 15) were analysed using high-performance liquid chromatography (HPLC) with diode array detection (DAD). Polyphenols are antioxidant ingredients in apples and are related to human health because of their free radical scavenging activities.

Apples by Frank Browning