ANTIOXIDANT, ACE INHIBITORY ACTIVITIES AND FUNCTIONAL PROPERTIES OF EGG WHITE PROTEIN HYDROLYSATE

The antioxidant, angiotensin-I-converting enzyme (ACE) inhibitory activities and functional properties of egg white protein hydrolysate (EWPH) prepared by papain under different concentrations and pH were investigated. The antioxidant activity of EWPH increased with increasing concentration and decreased at the alkaline pH value (P < 0.05), while pH did not affect the ACE inhibitory activity of EWPH (P > 0.05). Hydrolysis significantly enhanced the functional properties of egg white proteins (P < 0.05). EWPH had an excellent solubility (>93%) over a wide pH and possessed interfacial properties (emulsifying and foaming properties), which were governed by the concentration and pH. These results suggest that EWPH may be useful ingredients in food and nutraceutical applications with potential bioactive properties. PRACTICAL APPLICATION More recently, it has been recognized that many peptides that are released in vitro or in vivo from food proteins are bioactive and have regulatory functions in humans. Furthermore, enzymatic hydrolysis can modify and even improve the functional characteristics of proteins for different applications. Egg white proteins are widely used as functional and nutritional ingredients in food products and their hydrolysates obtained by protease treatment are water soluble and have high nutritional value. China is the largest producer of egg, which makes up about 40% of the total egg production in the world. But the human consumption of egg products was less than 2% of the total egg consumption. Therefore, the study on the combined biological activity and functional properties of egg white protein hydrolysate as affected by concentration and pH can provide a theoretical basis for the deep processing of egg.