Dual-frequency multi-angle ultrasonic processing technology and its real-time monitoring on physicochemical properties of raw soymilk and soybean protein

To improve the soybean protein content (SPC), flavor and quality of soymilk, the effects of dual-frequency ultrasound at different angles (40 + 20 kHz 0 degrees, 40 + 20 kHz 30 degrees, 40 + 20 kHz 45 degrees) on physicochemical properties and soybean protein (SP) structure of raw soymilk were mainly studied and compared with the conventional single-frequency (40 kHz, 20 kHz) ultrasound. Furthermore, the intensity of the ultrasonic field in real-time was monitored via the oscilloscope and spectrum analyzer. The results showed that 40 + 20 kHz 45 degrees treatment significantly increased SPC. The ultrasonic field intensity of 40 + 20 kHz 0 degrees treatment was the largest (8.727 x 10(4) W/m(2)) and its distribution was the most uniform. The emulsifying stability of SP reached the peak value (233.80 min), and SP also had the largest particle size and excellent thermal stability. The protein solubility of 40 + 20 kHz 30 degrees treatment attained peak value of 87.09%. 20 kHz treatment significantly affected the flavor of okara. The whiteness and brightness of raw soymilk treated with 40 kHz were the highest and the system was stable. Hence, the action mode of ultrasonic technology can be deeply explored and the feasibility for improving the quality of soymilk can be achieved.

Automated summary

The study investigates the effects of dual-frequency ultrasound at different angles on the physicochemical properties and soybean protein structure of raw soymilk, compared to conventional single-frequency ultrasound. Different treatments showed varying impact on soybean protein content, emulsifying stability, particle size, thermal stability, and solubility. The findings suggest that ultrasound technology can effectively improve the quality of soymilk.