Chemical characteristics and antioxidant properties of wheat gluten hydrolysates produced by single and sequential enzymatic hydrolyses using commercial proteases and their application in beverage system

The objective of the study was to determine chemical characteristics and antioxidant properties of wheat gluten hydrolysates (WGH) and utilize the WGH as ingredients in a beverage system. Single (2, 6, 12, and 24 h) and sequential enzymatic hydrolyses (8, 10, and 12 h) were conducted using commercial proteases (Alcalase, Flavourzyme, Protamex, and Neutrase). Yields of all the produced WGH were over 50%. Degree of hydrolysis of the WGH produced by Flavourzyme was the highest, while that of the WGH by Neutrase was the lowest. Sequential enzymatic hydrolysis remarkably decreased the fraction with more than 10 kDa and increased the fraction with less than 500 Da. Contents and composition of free amino acids were affected by the enzyme types and hydrolysis conditions. DPPH radical scavenging activity of the WGH significantly increased with hydrolysis time. The WGH produced by Protamex showed lower turbidity, better thermal stability, and higher solubility, suggesting they may be suitable for beverage development.