Recovery of Citric Acid from Citrus Peels: Ultrasound-Assisted Extraction Optimized by Response Surface Methodology

The production of citrus juice generates a large quantity by-products, which are often discarded or used for animal feed. However, several studies have shown its richness in valuable compounds, namely organic acids. Thus, this work intended to valorize orange and lime peels as renewable sources citric acid. An experimental design combining five levels the independent variables time (2–45 min), ultrasonic power (50–500 W), ethanol proportion (0–100%) was implemented response surface methodology (RSM) applied optimize extraction process. UPLC-PDA analysis showed that peel presented higher acid content than lime. For peels, yield maximized by sonicating at low 5.8 35.5 min, using only water solvent, respectively. Overall, optimal UAE conditions were defined sustainable from thus contributing valorization upcycling into natural food ingredients.