Chemical and antioxidant characterization of different apple cultivars in Chile

The apple is one of the most widely consumed fruits in the world owing to its year-round presence and its clear contribution to human health. One of the characteristics of the apples influenced by the cultivar, tissue type (peel or pulp), the mineral nutrition and the climatic zone among others, is their antioxidant activity, which is fundamentally due to their phenol compounds and flavonoid content. Chile is the main apple exporter in the southern hemisphere and the second major exporter at the world level. The present study shows the sugar content and mineralogical characteristics of peel, chemical characteristics of the peel and entire fruit, phenols and antioxidant activity in the peel and the pulp of different apple cultivars in Chile. In terms of sugars in the peel, the concentrations of saccharose and fructose are double that of glucose, with the cultivars Galaxy and Fuji having the highest concentrations. With respect to minerals in the peel, potassium and nitrogen notably have the highest concentrations in all of the cultivars. Proximal chemical analysis showed significantly higher values of crude fibre, proteins and ether extract in the peel than in the complete fruit. Finally, phenol concentrations and antioxidant activity were significantly higher in the peel than the entire fruit or only the pulp. Notably, flavonol concentration in cv. Galaxy was 17 times and in green cultivar (Granny Smith) only 6.7 times as high as in other cvs. In percentage terms, clear differences were observed in the composition of phenolic compounds between the peel and pulp.