Unraveling the Thermal Effects of High-Intensity Ultrasound: A Practical Guide to Acoustic Power Determination and Heat Management.

This study provides a practical guide for determining acoustic power, the actual energy delivered during high-intensity ultrasound (HIUS) processing, which is critical for the effective design of ultrasound-assisted processes. Acoustic energy is fundamental for ensuring precise process scaling and optimization. Additionally, we address a key misconception in the literature, challenging the view that HIUS is a strictly nonthermal treatment. While HIUS has been widely explored for enhancing process efficiency, reducing energy consumption, lowering costs, and minimizing environmental impact in food and beverage processing, its thermal effects have often been overlooked. HIUS is employed in various applications, including the extraction of bioactive compounds, inactivation of microorganisms and enzymes, and modification of proteins and carbohydrates. However, one of the primary challenges in HIUS processing is temperature control, which is essential for maintaining food stability, quality, and safety. Uncontrolled temperature increases can jeopardize these attributes. In this study, we assessed actual temperature conditions during HIUS treatments by analyzing thermal histories and investigating strategies for minimizing heat generation, such as pulsed ultrasound, ice baths, and combining sonication with external heating. We also evaluated the temperature profiles in fluids with varying thermophysical properties. While heat minimization techniques are effective in mitigating excessive heating, failure to account for thermal histories can lead to underestimations of the thermal effects. Accurate temperature monitoring provides critical insights into optimizing process design. Moreover, we observed potential solvent phase changes at the microscale during high-intensity treatments. These findings offer valuable guidance for improving heat management in HIUS applications and propose standardized methods for reporting thermal conditions and energy parameters in studies that utilize this technology.