Food grade pilot scale strategy for non-thermal extraction and recovery of phenolic compounds from orange peels

The orange peels (OP) derived from orange juice factories consist of several polymers and molecules that could be recovered using a biorefinery approach. This study presents a pilot-scale strategy for the extraction and recovery of phenolic compounds from OP, aiming to demonstrate a sustainable, non-thermal process that operates without the use of solvents and complies with food-grade standards. The extraction process was conducted in a food-grade manner on a 1000 L scale, starting with the enzymatic hydrolysis of pectin in the biomass, followed by ultrasound-assisted extraction (UAE) at 54 W/gslurry and 20 °C. Solid/liquid separation via decanter centrifuge allowed to recover the solution containing the phenolic compounds, that was further purified via sequential cross-flow microfiltration (MF), ultrafiltration (UF) and nanofiltration (NF). The final product was analysed by HPLC-ESI-TOF-MS, revealing an interesting phenolic profile with several potential bioactivities and a total polyphenol content (TPC) of 3.3 g/L. The food-grade analysis confirmed the potential application of the final product in food-related processes, such as food packaging or fortification. This work highlights a scalable and environmentally friendly method to convert agro-food waste into valuable bioactive compounds, aligning with green chemistry principles and zero-waste strategies.