Effects of Two Pre-Treatment Methods on Functional Properties of Egg White Protein Hydrolysates Obtained by Pepsin

After Egg White Proteins (EWPs) were pre-treated by Conventional Heating (CH) Method and Microwave Irradiation (MWI), respectively, functional properties of protein hydrolysates from egg white hydrolyzed by pepsin was systemically investigated. The results indicated the maximum Degrees of Hydrolysis (DHs) of EWPs pre-treated by MWI could reach 19.81%, which was much more than that of EWPs pre-treated by CH. As the pH increased, the solubility of Egg White Protein Hydrolysates (EWPHs) gradually decreased, but the solubility of EWPHs originated from the proteins pre-treated by MWI was also significantly higher (p<0.05) than the EWPHs derived from the proteins treated by CH at pH 2. The Emulsifying Activity Index (EAI) and Emulsion Stability Index (ESI) of EWPHs exhibited the same trend with the solubility of the EWPHs. The water absorption ability of the EWPHs originated from the proteins pre-treated by MWI and CH, respectively, was higher than crude EWPs, but the former is far better than the latter. The experimental data also showed that MWI could improve the Oil Absorption Capacity (OAC) of EWPHs significantly (p<0.05) compared with CH treatment. The EWPHs had a greater ability to hold water than the FDEW and glycerol, but there were no difference in the WHC between the EWPHs originated from the proteins treated by CH and MWI (p>0.05). According to the experimental results, the EWPHs have potential for use as a natural ingredient for emulsifying and wetting agent.