Effects of hydrolysis degree and type of protease on antioxidant activity and functionality of egg white protein hydrolysates

Enzymatic hydrolysis of egg white proteins has shown great potential to improve their functional properties such as increased solubility, stability, and digestibility, and to reduce protein allergenicity while still retaining their nutrition value. However, the enzymatic hydrolysis process is still poorly defined and difficult to control at the industrial scale resulting in peptide mixtures poorly characterized and with unpleasant bitter taste that make them unsuitable for human consumption. Thus, the hydrolysis reaction must be carefully controlled in order to produce new value-added egg white hydrolysates with improved properties and specialized functionality. In this paper egg white protein solution was hydrolysed with several enzymes using both, one-step and two-step hydrolysis. The hydrolysate was then tested on antioxidant activity, flavour, solubility, digestibility emulsifying activity, foaming capacity and stability. All protein hydrolysates showed higher solubility and digestibility than intact proteins, especially at pHs near isoelectric point of egg white proteins. Moreover, all hydrolysates had better functional properties, except emulsifying activity, than the native protein solution.