Antioxidant Capacity and Food Pathogenic Bacteria Inhibition of Citrus limetta and Citrus reticulata

In this study, phenolic compounds in the juice, seed and bagasse of C. limetta and C. reticulata cultivated in Mexico at two ripening stages were determined, and their antioxidant capacities were evaluated using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2′-azin-bis-(3-etilbenzotiazolin-6-sulfonic acid) (ABTS) and oxygen radical absorption capacity test (ORAC) methods, as well as their antibacterial growth inhibition. We found that bagasse had the highest total phenol content and the highest total flavonoid content. The dominant flavonoid, hesperidin, was observed to be the highest in bagasse. Ascorbic acid was analyzed and C. limetta juice and C. reticulata bagasse had the highest contents. Antioxidant capacity showed variations in both, C. limetta and C. reticulata, juices which had the highest ABTS value; C. limetta juice and C. reticulata bagasse had the highest DPPH value; C. limetta juice and C. reticulata bagasse had the highest ORAC value. C. limetta and C. reticulata extracts showed the bactericidal effect at the range of 4–40 mg/mL, assayed against Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella enterica and Staphylococcus aureus. Overall, ripeness increased total phenol content (TPC), total flavonoid content (TFC), hesperidin content, antioxidant capacity and bactericidal effect. These results may provide useful information for future utilization of C. limetta and C. reticulata