Evaluation of some physiochemical and antioxidant properties of some Syrian Citrus species

Citrus species have been cultivated throughout Syria as fruit trees, but the antioxidant properties of their fruits have not been fully revealed. The current study aimed to characterize the physiochemical, antioxidant compounds with their antioxidant activities of eight Syrian citrus juices (orange, sour orange, mandarin, lemon, citron, grapefruit, pomelo, and kumquat). The fruits were assayed for pH, titratable acidity, total soluble solids (TSS), ash, reducing sugar content, ascorbic acid, total phenolic compounds, total flavonoid content, carotenoids, and antioxidant activity. Of all Syrian Citrus species, the orange had the highest TSS content (11.8%) and the highest content of ascorbic acid (139.45 mg/100 g). Lemon was dominated by the high amount of carotenoids (77.56 mg β-carotene/100 g). Grapefruit demonstrated the highest content of total phenolic (659 mg GAE/100 g), total flavonoid compounds (326.49 mg quercetin/100 g), and antioxidant activity (87.94%). Pearson correlation analysis revealed that the phenolic compounds were the main contributing compounds.