Phytochemicals and antioxidant capacity of orange (Citrus sinensis (l.) Osbeck cv. Salustiana) juice produced under organic and integrated farming system in Greece

Organically and integrated produced orange (Citrus sinensis (l.) Osbeck cv. Salustiana) fruits were assayed in terms of fruit characteristics and juice phytochemicals over a period of two years. Fruit size and juice volume were higher under organic farming system. There were not any significant differences concerning either the carbohydrates’ or organic acids’ concentrations of the juice. Similar results were obtained concerning the total phenol, the total o-diphenol and the total flavonoid concentration of the juice, while neither hesperidin nor narirutin differentiated significantly. However, β-carotene concentration was detected in higher concentration in organically produced fruit (0.43 mg L⁻¹). Juice extracted from both integrated and organically produced fruits exhibited similar antioxidant capacity values (based on 2,2-diphenyl-1-picryl hydrazyl and ferric reducing/antioxidant power assays), while correlation analysis revealed the significant contribution of phenolic compounds to antioxidant capacity (r = 0.75–0.86). Most of the amino acids determined were quantified in similar concentration in the juice of both organic and integrated produced fruits (approximately 1600 mg L⁻¹). The present results indicate that integrated oranges cv Salustiana, under the cultivation management implemented in this experiment, present similar antioxidant and nutritional values to the organically produced ones.