Determination of Antioxidant Capacity, Total Phenolic Content and Mineral Composition of Different Fruit Tissue of Five Apple Cultivars Grown in Chile

Carolina Henríquez1*, Sergio Almonacid2, Italo Chiffelle3, Tania Valenzuela3, Manuel Araya4, Lorena Cabezas4, Ricardo Simpson2, and Hernán Speisky5

Apples (Malus domestica Borkh.) have been identified as one of the main dietary sources of antioxidants, mainly phenolic compounds. These compounds vary in their composition and concentration, among cultivars and fruit tissues. In this research, the total phenolic content (Folin-Ciocalteau assay), antioxidant capacity (Ferric Reducing Antioxidant Power, FRAP assay) and mineral composition in three fruit tissues (peel, pulp and whole fruit), of apple cultivars commonly used for dried apple production in Chile, were studied. In addition, the physical-chemical characteristics (dry weight, pH, titratable acidity, soluble solids content and color) were also evaluated. The results indicated that the total phenolic content, the antioxidant capacity, and the mineral composition, of peel were substantially higher than those of whole fruit, and pulp for all the cultivars studied. Among cultivars, ‘Red Delicious’ apple peels have a significantly much higher content of total phenolic (11.6 mg gallic acid equivalents [GAE] g-1 FW) and a higher FRAP (209.9 µmol Fe+2 g-1 FW). Additionally, a high correlation between total phenolic content and antioxidant capacity was found in all the cultivars and fruit tissues analyzed, except in the apple pulp. On the other hand, the physical and chemical composition differed among cultivars and fruit tissues. In conclusion, our results demonstrated that the total phenolic content, antioxidant capacity, mineral composition, and physical and chemical characteristics vary considerably depending on the apple cultivars and fruit tissues analyzed.

Keywords: Folin-Ciocalteau assay, FRAP antioxidant capacity, physical-chemical parameters
1Centro Regional de Estudios en Alimentos Saludables, Gran Bretaña 1093, Valparaíso, Chile. *Corresponding author (carolinahenriquez@creas.cl).
2Universidad Técnica Federico Santa María, Departamento de Ingeniería Química y Ambiental, Av. España 1680, Valparaíso, Chile.
3Universidad de Chile, Facultad de Ciencias Agronómicas, Av. Santa Rosa 11315, La Pintana, Santiago, Chile.
4Universidad de Viña del Mar, Centro de Investigación Agrícola y Ambiental, Agua Santa 110, Viña del Mar, Chile.
5Universidad de Chile, Instituto de Nutrición y Tecnología de los Alimentos, Av. E