Supercritical carbon dioxide coextraction of Citrullus lanatus seeds & Citrus aurantium peels: bioactivity profiling and incorporation in oleofoams thereof.

Coextraction of Citrullus lanatus seeds and Citrus aurantium peels (1:1, w/w), two food processing wastes, was performed using supercritical carbon dioxide (scCO2) (345 bar|57 °C|178 min) and pet ether solvents. The major objective of the study was to valorize two fruit processing wastes to obtain a bioactive coextract using a green scCO2 extraction process and further incorporate it into wax-based composite oleofoams. The scCO2 coextraction resulted in better extraction of bioactive compounds such as d-limonene and polyunsaturated fatty acids due to the absence of light and lower temperature of extraction, compared to pet ether. This was reflected in the higher antioxidant activity (7.841 mg TE/g of extract), phenolic (2.861 mg GAE/g of extract) and flavonoid content (0.786 mg QE/g of extract). The fatty acids from the watermelon seed oil bridged the solubility gap between scCO2 and the bioactive compounds. The coextract exhibited high antidiabetic, antiobesity, antimelanogenesis, anti-inflammatory, and antiglycative activity. Wax-based composite oleofoams, incorporating the scCO2 coextract were developed using carnauba, candelilla, and beeswax in the presence of glycerol monostearate crystals. The oleofoams exhibited high oxidative stability, confirming the antioxidant potential of the coextract.