Changes in physicochemical properties of egg white and yolk proteins from duck shell eggs due to hydrostatic pressure treatment

Abstract

The shell of the duck egg did not crack after pressure treatments (300 to 500 MPa; 25 degrees C; 10 min) in this study; therefore, the changes of physicochemical properties of egg white and yolk proteins from the intact shell egg by pressure treatment were first investigated and compared with those of pressurized hen liquid eggs. Although the proximate compositions of duck eggs and hen eggs were similar, the moisture and protein contents of hen whole eggs were higher than those of duck whole eggs. The protein contents of duck egg white and yolk were slightly lower than those of hen eggs, and the moisture content of duck egg white was equal to that of hen egg white, whereas that of duck egg yolk was lower than that of hen egg yolk. After pressure treatment at 500 MPa, the results of solubility, sulfhydryl content, surface hydrophobicity, and residual denaturation enthalpy showed that egg white proteins underwent slight but significant unfolding and aggregation, whereas pressure treatments below 500 MPa induced insignificant changes in the physicochemical properties. On the other hand, pressure treatments at 400 and 500 MPa significantly reduced the solubility and residual denaturation enthalpy of egg yolk proteins. However, the native PAGE result showed that pressure treatment up to 500 MPa did not affect the protein components of egg white and yolk. The results showed that the application of pressure treatment on duck shell egg may induce reversible denaturation of both egg white and yolk proteins. The egg white and yolk proteins may be prevented from denaturation after pressure treatment in the presence of the eggshell compared with the absence of the eggshell. As reported in the literature, pressure treatments at 300 to 500 MPa and 25 degrees C would be efficient for decontamination of duck shell eggs. Therefore, based on the consideration for food safety and functional properties, pressure processing can be a good preservation technique for duck shell eggs.

Effects of High Hydrostatic Pressure Processing on Hen Egg Compounds and Egg Products

“…For example, pressures above 450 MPa result in loss of the secondary structure of albumin (Hayakawa and others ) and exposure of buried hydrophobic and SH groups (Iametti and others ). Pressures between 400 and 700 MPa can greatly increase the surface hydrophobicity and exposed SH groups in egg white proteins (van der Plancken and others ; Lai and others ). Studies involving hen egg white lysozyme showed that HHP treatment significantly increased the number of partially unfolded forms of the protein (Nash and Jonas ).…”

“…Eggs are composed of different proteins with high biological, functional, and nutritional properties, and they are used in numerous food products (Lai and others ). Egg white (albumin) is composed of 9% proteins, 0.03% lipids, 0.9% carbohydrates, 0.05% ash, and 90% water (Awade ).…”

Recent Developments in High Pressure Processing of Foods

“…4.7 , Yan et al 2010 ). Lai et al ( 2010a ) studied the effect of HPTs (300-500 MPa, 25 °C, 10 min) on changes in the physicochemical properties of egg white and yolk proteins of duck eggs. HPT at 500 MPa showed that egg white proteins underwent slight but signifi cant unfolding and aggregation, whereas HPT below 500 MPa induced insignifi cant changes in the physicochemical properties.…”

Physicochemical and techno‐functional properties of acid‐aided pH‐shifted protein isolate from over‐salted duck egg (Anas platyrhucus) albumen

“…Several researches reported the effect of processing parameters on egg albumen protein functionalities. For instances, high‐pressure treatment impaired the solubility of albumen proteins due to protein unfolding and aggregation (Lai et al , ). The outlet air temperature and atomisation pressure conditions of spray drying affected the emulsion stability, gelation and foaming stability of resulting dried whole egg powder (Koç et al , ).…”