Gelatin as texture modifier and porogen in egg white hydrogel

In the present study, composite egg white/gelatin hydrogels were produced and their porosity was increased through the subsequent removal of gelatin by leaching into water. The composite gel with 0.5% gelatin showed a higher degree of swelling than did the control gelatin-free sample after 60 min of immersion in an aqueous medium which was ascribed to the formation of capillary channels due to gelatin leaching. The composite gel containing 0.3% gelatin showed the highest water-holding capacity and firmness indices among all samples. Gel porosity decreased with increasing gelatin content. However, after gelatin depletion, higher concentrations of gelatin yielded hydrogels with higher porosity, as confirmed by scanning electron microscopy. Based on Fourier transform infra-red spectroscopy, it was concluded that the count of hydrogen bonds decreased after gelatin depletion. X-ray diffraction analysis indicated that intermolecular interaction between gelatin and egg white proteins had taken place in the amorphous phase.