Antioxidant Activities and Phenolic Composition of Apple Peel, Core and Flesh Extracts on Selected Apple Cultivars

Phenolic antioxidants have multiple benefits to human health. Polyphenols are responsible for the antioxidant activity in apples. Antioxidant activities were assessed using the ferric reducing/antioxidant power (FRAP) and 2,2-dipheny l-1-picrylhydrazyl (DPPH) radical scavenging assays in different cultivars and different parts of apples grown in China. The phenolic compounds and antioxidant activities differed significantly among the four apple cultivars. Guoguang had the highest phenolic concentration and antioxidant activity and Golden Delicious had the lowest. The peels had the highest total phenolic and flavonoid contents followed by the cores and flesh. Anthocyanins were detected only in red apple peels. Peel and core had greater antioxidant activities than apple flesh. FRAP values were inversely correlated with phenolic contents, whereas no clear relationship could be observed between DPPH values and phenolic contents. The higher levels of phenolic compounds and antioxidant activities of apple peels and cores than flesh may be of technological interest as a valuable source of antioxidants.