Characteristics of Enzymatic Hydrolysis of the Wheat Gluten Proteins Treated by Ultrasound Wave

Effects of sonication at 150W and 300W power output on hydrolysis of wheat gluten using two proteinases (Protamex and papain) were evaluated in the present study. Sonication resulted in the increase in amounts of free sulphydryl (SH) of wheat gluten. Significant (P < 0.05) increase in SH contents at 300W power output was found compared with the control and those samples sonicated at 150W power output. Degree of hydrolysis (DH) and protein recovery (PR) of the wheat gluten hydrolysates increased with sonication time and power output. Significant (P < 0.05) increase in DH and PR of the wheat gluten hydrolysate from the sample sonicated by 300W power output was found compared to those sonicated by 150W output. Sonication caused the decrease in the relative percent of the large peptide fractions and increase in the relative percent of the small peptide fractions in the hydrolysates compared to the control. Structure change in insoluble wheat gluten proteins was the principal reason of improvement in their characteristics of enzymatic hydrolysis.