Performance evaluation of self-assembled dual-frequency ultrasound-assisted devices and their application in the extraction of angiotensin-converting enzyme inhibitors from fish scales

This study proposed a self-assembled dual-frequency (28/68 kHz) ultrasound-assisted (UA) system with high hydrolysis efficiency that was developed and evaluated. This study also focused on UA's synergistic hydrolysis of decalcified fish scales in combination with various commercial proteases, with angiotensin-converting enzyme (ACE) inhibitory activity serving as an evaluation criterion. Simultaneously, response surface methodology (RSM) was employed to optimize the current process conditions of obtaining high yields of ACE inhibitors. The performance of the self-assembled dual-frequency UA with a sound pressure density of 0.10 W/g water produces lower component warming, albeit with a slight reduction in media temperature, and better power conversion and power loss rates than commercially available (35/53 kHz) devices. This study also showed that the RSM optimal conditions for the hydrolysis of fish scales were 0.78 mg/mL alcalase/flavoenzyme, dual-frequency UA treatment duration of 99.53 min, and output power of 181.26 W to achieve an ACE inhibitory activity of 97.55 %. Moreover, the hydrolyzed products have a certain degree of antioxidant ability. Based on all the results, the optimized production procedure of dual-frequency UA in this study demonstrated the potential for producing hydrolyzed fish scales, thereby contributing to enhancing the product's ACE inhibitory activity. • Developed a dual-frequency ultrasound-assisted (UA) device with better performance. • Optimized oscillator layout and device indices with stable sound pressure density. • Energy conversion and degradation rates outperform those of a commercial product. • Optimal conditions for dual-frequency UA enzyme hydrolysis by RSM design.