Antioxidant capacity of juice from different papaya (Carica papaya L.) cultivars grown under greenhouse conditions in Turkey

The fruits of Carica papaya L. (Caricaceae) are valuable as food and are also used in traditional medicine. The present study was designed to assess the antioxidant potential of the juices of 3 papaya cultivars (PCJ): Sunrise Solo, Red Lady, and Tainung. The antioxidant capacity of PCJ obtained from fully ripened fruit was determined by the following methods: scavenging of the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), reducing power assay, scavenging of superoxide radicals, 2-deoxyribose oxidation assay, and thiocyanate assay. Total phenolic content (TPC) of PCJ was determined by the Folin-Ciocalteu method. In the DPPH assay (IC50 values), the effect of Sunrise Solo (52.1 ± 1.5 mL PCJ/g DPPH) was better than that of the Red Lady (63.4 ± 2.9 mL PCJ/g DPPH) and Tainung juices (71.8 ± 1.8 mL PCJ/g DPPH). PCJ showed a linoleic acid peroxide scavenging activity that was 5 times higher (during 72 h) than in the negative control but close to that of vitamin E, which served as the positive control. These PCJ antioxidant activities were significantly different from each other (P 0.05). The tested reducing power activity, superoxide anion scavenging activity, and hydroxyl radical scavenging activity were found to follow the order of Sunrise Solo Red Lady Tainung, depending on their concentrations. This study demonstrated that different papaya cultivars have different antioxidant capacities and TPC amounts. Significant correlations were found between antioxidant capacity and TPC, indicating that phenols contribute to antioxidant capacity