Microwave-Assisted Extraction of Carotenoids from Orange and Mango Peels Using Green Coconut Oil versus Solvent-Based Methods

This study was designed to compare and determine the effects of microwave-assisted green extraction (MAE) and conventional extraction (CE) techniques on the carotenoid content, polyphenolic compounds, and antioxidant activities of mango and orange peels. The MAE was carried out using coconut oil as a green solvent, while the CE involved solvents such as Hexane:Acetone (2:1), Ethanol:Water (20:1), Ethyl acetate:Petroleum ether (1:1), 100% Hexane, and 100% Acetone. Results showed that the total carotenoid content (TCC) obtained from MAE (19.27 ± 0.08 µg/g for orange peels and 25.85 ± 0.08 µg/g for mango peels) was significantly higher (p < 0.05) than those from all conventional methods, with the highest CE values being 16.62 ± 0.09 µg/g and 17.55 ± 0.28 µg/g, respectively. Polyphenol contents ranged from 6.39 ± 0.23 to 27.54 ± 0.06 mg GAE/g for orange peels and 5.44 ± 0.08 to 19.51 ± 0.06 mg GAE/g for mango peels, with MAE yielding approximately 1.7-fold higher values compared to the best-performing CE. Furthermore, total antioxidant capacity (TAC) of the carotenoid extracts from MAE (46.94 ± 0.15 and 37.20 ± 0.15 mg AAE/g for orange and mango peels, respectively) was significantly greater (p < 0.05) than those obtained from CE. In addition to enhancing the quality and yield of carotenoids extracted from mango and orange peels, MAE demonstrates clear environmental advantages. These findings highlight the potential of microwave-assisted green extraction as a sustainable method for recovering valuable bioactive compounds from fruit peels for use in functional foods, nutraceuticals, natural colorants, and cosmetic formulations.