Ultrasonic pretreatment of corn gluten meal proteins and neutrase: Effect on protein conformation and preparation of ACE (angiotensin converting enzyme) inhibitory peptides

• Ultrasound pretreatment of substrate/enzyme before prepare ACE inhibition peptides.
• Neutrase activity increased by 8.74% after sonication at 250 W for 15 min.
• ACE inhibition of pretreated at 250 W for 10 min CGM protein increased by 18.27%.
• Protein unfolding of CGM and neutrase after sonication was found.

The impact of ultrasound pretreatment of corn gluten meal (CGM) protein and neutrase on the ACE (angiotensin converting enzyme) inhibitory activity of hydrolysate was studied. The UV–vis differential spectra and fluorescence spectra of the CGM protein and neutrase were determined. The neutrase activity and the ACE inhibitory activity of the CGM protein hydrolysates were analyzed. The highest ACE inhibitory activity was obtained at 10 min hydrolysis when the CGM protein was pretreated at 20 kHz for 10–30 min and at a power of 1000 W. The neutrase activity and ACE inhibitory activity were at their maxima at sonication of 250 W and sonication time of 15 min. The fluorescence and UV differential spectra of the proteins of CGM and neutrase reflected molecular unfolding due to sonication. Sonication of the protein substrate and the enzyme before hydrolysis may be an effective way to enhance the ACE inhibition attributes of the hydrolysate.