The Change of Bioactive Compounds in some Superior Genotypes of Orange during Maturation Stages Compared to the Commercial Orange (Citrus sinensis) cv. Mars

This research was carried out to investigate the changes in bioactive compounds within four orange-superior genotypes (G3, G4, G5 and G6) cultivated in the north of Iran. These genotypes were harvested at three different maturation stages, with a 30-day interval, and their bioactive compound profiles were compared to those of the commercially grown orange cv. Mars. The study revealed notable changes in various bioactive compounds in response to delayed harvest times. Specifically, as the harvest was delayed, significant increases were observed in vitamin C content, total phenol content (TPC), antioxidant activity, reduced and non-reduced sugar content, total sugar content, hesperidin content, and superoxide dismutase (SOD) activity. Conversely, fruit carotenoid content and titratable acidity (TA) experienced a considerable reduction. Among the studied genotypes, G6 demonstrated particularly elevated levels of carotenoids (0.19 mg 100 g⁻¹ FW), vitamin C (6.29 mg 100 g⁻¹ FW), TPC (4.13 mg 100 g⁻¹ FW), antioxidant activity (5.32%DPPHsc), reduced sugar (3.31 mg 100 g⁻¹ FW), non-reduced sugar (8.04 mg 100 g⁻¹ FW), and total sugar content (3.54 mg 100 g⁻¹ FW) compared to the orange cv. Mars during the second harvest period. Overall, G6, as an orange-superior genotype, harvested on December 10th, presents a promising candidate for early selection in developing early maturing commercial orange cultivars.