Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011-3080, USA.
Ultrason Sonochem. 2010 Jun;17(5):939-46. doi: 10.1016/j.ultsonch.2010.01.013. Epub 2010 Jan 29.
The effects of ultrasound on corn slurry saccharification yield and particle size distribution was studied in both batch and continuous-flow ultrasonic systems operating at a frequency of 20 kHz. Ground corn slurry (28%w/v) was prepared and sonicated in batches at various amplitudes (192-320 microm(peak-to-peak (p-p))) for 20 or 40s using a catenoidal horn. Continuous flow experiments were conducted by pumping corn slurry at various flow rates (10-28 l/min) through an ultrasonic reactor at constant amplitude of 12 microm(p-p). The reactor was equipped with a donut shaped horn. After ultrasonic treatment, commercial alpha- and gluco-amylases (STARGEN 001) were added to the samples, and liquefaction and saccharification proceeded for 3h. The sonicated samples were found to yield 2-3 times more reducing sugars than unsonicated controls. Although the continuous flow treatments released less reducing sugar compared to the batch systems, the continuous flow process was more energy efficient. The reduction of particle size due to sonication was approximately proportional to the dissipated ultrasonic energy regardless of the type of system used. Scanning electron microscopy (SEM) images were also used to observe the disruption of corn particles after sonication. Overall, the study suggests that both batch and continuous ultrasonication enhanced saccharification yields and reduced the particle size of corn slurry. However, due to the large volume involve in full scale processes, an ultrasonic continuous system is recommended.
研究了在频率为 20 kHz 的间歇式和连续流动式超声系统中，超声对玉米浆糖化产率和颗粒尺寸分布的影响。制备了 28%（w/v）的玉米浆，并使用类空化号角在各种振幅（192-320 µm（峰-峰（p-p）））下进行间歇式超声处理 20 或 40 s。通过以 10-28 l/min 的各种流速将玉米浆泵入超声反应器中，在恒定的 12 µm（p-p）振幅下进行连续流动实验。该反应器配备了环形号角。超声处理后，向样品中添加商业α-和葡糖淀粉酶（STARGEN 001），并进行 3 h 的液化和糖化。与未超声对照相比，超声处理的样品产生的还原糖增加了 2-3 倍。尽管连续流动处理释放的还原糖比间歇式系统少，但连续流动工艺的能量效率更高。无论使用哪种系统，由于超声处理导致的颗粒尺寸减小与耗散的超声能量大致成正比。还使用扫描电子显微镜（SEM）图像观察了超声处理后玉米颗粒的破坏情况。总的来说，该研究表明，间歇式和连续超声处理均能提高糖化产率并减小玉米浆的颗粒尺寸。然而，由于全规模过程涉及的体积较大，建议使用超声连续系统。
