Orange Peel Waste Valorization from Bioactive Compound Recovery to Functional and Industrial Applications

Orange and citrus peel, often considered agro-industrial waste, are rich sources of bioactive compounds such as flavonoids, polyphenols, essential oils, and dietary fibers. This review comprehensively discusses the chemical composition and functional properties of orange peel, highlighting enzymatic biotransformation and advanced extraction strategies including ultrasound-, microwave-, and enzyme-assisted techniques. Special attention is given to green extraction approaches using deep eutectic solvents for sustainable recovery of hydrophilic and lipophilic bioactive compounds. The functional applications of orange peel-derived compounds in food, nutrition, pharmaceuticals, cosmetics, agriculture, and industrial materials are also presented, emphasizing their potential in developing eco-friendly biobased products and active food packaging. By integrating chemical profiling, sustainable extraction methods, and multifunctional applications, this review provides a systematic overview of the valorization of orange and citrus peel waste, promoting circular bioeconomy approaches and environmental sustainability.