Optimization of the Extraction Parameters for the Isolation of Bioactive Compounds from Orange Peel Waste

More and more research is being focused on the production of value-adding products from waste materials. Food waste is not only a major global issue, but also an excellent source of bioactive compounds. In this study, the parameters that affect the extraction of the bioactive compounds (polyphenols, ascorbic acid, hesperidin, carotenoids) from orange peels, and their antioxidant properties, were optimized, using a response surface methodology (RSM) (examining the extraction temperature, time, and composition of the extraction solvent). In addition, the effect of two more techniques was examined [ultrasound (US) and pulsed electric field (PEF)], either separately or combined, so as to determine whether they can enhance the extraction of the compounds. From our results, it was apparent that orange peels are an excellent source of many bioactive compounds since the extracts contained hesperidin (16.26 mg/g dw), total polyphenols (34.71 mg GAE/g dw), ascorbic acid (1228.93 mg/100 g dw) and total carotenoids (52.98 μg CtE/g dw)