Orange essential oils (EOs) are valuable by-products with notable beneficial properties, but their extraction from orange waste is often inefficient. To address this, ultrasound pre-treatment was combined with conventional hydro-distillation to improve EO yield, reduce extraction time, and lower environmental impact. This study aimed to optimize ultrasound-assisted extraction of EOs from orange peels, using extraction time and ultrasonic amplitude as key variables. These factors were selected because they strongly influence cavitation intensity and mass transfer, and limiting the optimization to these two parameters simplifies the process, facilitating reproducibility and potential upscaling to industrial applications. The ultrasound-assisted extraction (UAE) method was compared to conventional hydro-distillation (HD) in terms of extraction yield and rate, EO quality, and energy consumption. Using kinetic modeling and Bayesian Parameter Optimization, the effects of ultrasound parameters on maximum extraction rate ( μ ) and EO yield ( C ) were evaluated. Optimal conditions for μ were 100% amplitude for 30 min, while for C , 100% amplitude for 10 min was best. UAE improved both μ and C compared to conventional method, as the largest relative difference (10.5%) was observed after approximately 30 min of extraction, corresponding to a UAE yield of 1.11%, demonstrating that it significantly enhanced the efficiency of the process. Cost efficiency analysis indicated that UAE's higher extraction rate allowed it to surpass conventional hydro-distillation within minutes, peaking at 47 min (1.79 mL € −1 , 5% increase with respect to conventional HD). In conclusion, UAE significantly enhances the yield and speed of EO recovery from orange peels, supporting cleaner production principles by offering a greener, faster, and more energy-efficient alternative to traditional methods for the valorization of citrus waste. The Graphical abstract was created in BioRender. Bodea, I. (2026) https://BioRender.com/oe3hwoj • Ultrasound pre-treatment boosts orange peel essential oil yield and extraction rate. • Combining ultrasound with hydro-distillation reduces extraction time and energy use. • Bayesian optimization identified ideal ultrasound amplitude and time for extraction. • UAE showed 10.5% faster extraction rate than conventional hydro-distillation method. • Green UAE method offers improved efficiency with lower environmental impact.
Bodea et al. (2026) studied this question.