Effects of Ultrasound on a Glycin–Glucose Model System—A Means of Promoting Maillard Reaction

Effects of ultrasound on pH, intermediate products, browning, glycin and glucose contents, reducing power, and antioxidant activity of a glycin–glucose solution were examined. Results showed that the ultrasonic treatment at the intensity of 17.83 W/cm2 for 50 min resulted in the increases of the solution’s absorbance at 294 and 420 nm and the antioxidant activity from approximately 0% to 2.40%, 1.19%, and 18.62%, respectively. At the same time, 21% reduction in glycin and 92% in glucose were observed. Gas chromatography/mass spectrum analysis showed that the ultrasonic treatment induced a Maillard reaction in the model system producing substances including 2,5-dimethyl-pyrazine, trimethyl-pyrazine, (Z)-9-octadecenamide, 1,2-benzenedicarboxylic acid, and mono (2-ethylhexyl) ester. This study indicated that ultrasound, especially at higher intensities, could potentially be employed as a means to promote the Maillard reaction in the glycin–glucose solution.