Coupled Ultrasound and Microwave-Assisted Extraction of Carotenoids From Citrus clementina Peels and In Vitro Evaluation of Their Biological Activities

This research investigates the optimization of carotenoid extraction from Citrus clementina peels using Ultrasonic-Microwave-assisted extraction (U-MAE) and evaluates their biological activities. The study employs Response surface methodology (RSM) to determine optimal extraction parameters (hexane percentage in hexane/acetone mixture, sonication time, and irradiation time) that yielded the highest total carotenoid content (TCC) with high total antioxidant activity (TAA) and to assess the impact of each parameter on the responses. Additionally, the antioxidant capacity, anti-inflammatory, antidiabetic, and antimicrobial activities were analyzed using in vitro spectrophotometric methods. The results demonstrate a significant positive correlation between hexane percentage and both TCC and TAA. Furthermore, the results revealed that shorter sonication and irradiation times led to important increases in TCC and TAA. Additionally, the study assessed the effect of particle size on TCC and TAA, showing that finer particle sizes resulted in higher carotenoid content and antioxidant activity. The carotenoid-rich extract exhibited robust antioxidant, anti-inflammatory, and antidiabetic activities, as well as notable antibacterial and antifungal properties, suggesting its potential application as a substitute for synthetic counterparts in various industries, including food and pharmaceuticals. Overall, this research provides valuable insights into the extraction and bioactivity of carotenoids from C. clementina peels.