Properties of emu (Dromaius novaehollandiae) albumen proteins

The emu, a flightless bird native to Australia, lays eggs that have different properties than hen eggs: emu eggs begin to coagulate at a lower temperature than do hen eggs, and hard-boiled emu albumen has less gel strength than hen albumen. To investigate the mechanisms behind the differences, three major albumen proteins, ovotransferrin, ovalbumin, and tenp, were analyzed calorimetrically and physicochemically. In the calorimetrical analysis, emu ovotransferrin and ovalbumin exhibited similar thermostability to their hen counterparts. Tenp, a major component of emu but not hen albumen, showed high thermostability. Ovotransferrin, the major protein in emu albumen, produced a softer gel than ovalbumin when denatured in boiling water. Tenp did not coagulate completely in boiling water. The above results suggest the usefulness of emu eggs for processed food production. Changes in the antigenicity of emu ovalbumin during digestion were also examined in vitro.

► Emu ovotransferrin denatures at low temperature then forms a soft gel. ► Tenp protein, an emu albumen specific component, is highly thermostable. ► Emu ovalbumin possesses similar thermostability to hen ovalbumin. ► Emu ovalbumin contains anti-hen ovalbumin antibody cross-reactive peptides.