Bioactive compounds, antioxidant activity, and maturation effects in bitter and sweet orange juices

Bitter oranges (Citrus aurantium) and sweet oranges (Citrus sinensis) are commercially important citrus fruits with distinct uses and characteristics. Bitter oranges, primarily used as a flavoring agent, are rich in bioactive compounds, while sweet oranges dominate global citrus juice production. This study evaluated bitter orange juice at three maturation stages, comparing its physical, chemical, and bioactive properties with pasteurized pear orange juice (C. sinensis). Parameters assessed included water activity, pH, total titratable acidity, total soluble solids, maturation index, vitamin C content, total phenolic (TP) content, total flavonoid (TF) content, and antioxidant activity. The results showed that the vitamin C content in bitter oranges decreased with ripening but remained comparable to pear orange juice in the ripe stage. TPs and TFs were highest in pasteurized pear orange juice, reflecting the stability of these compounds during thermal processing. The antioxidant activity varied significantly across bitter orange maturation stages, with intermediate fruits demonstrating the strongest capacity. However, the maturation stage had limited influence on the antioxidant activity compared to pear orange juice. Bitter orange juices, despite being less commercially prominent, offer distinct bioactive advantages and antioxidant potential. Future research should explore optimizing maturation and processing methods to enhance the nutritional and functional properties of bitter orange juices.