Microstructure and rheology of globular protein gels in the presence of gelatin

Abstract

The microstructure and rheological response of globular protein gels (whey protein isolate (WPI) and soy protein isolate (SPI)) in the presence of gelatin (type A, type B and hydrolyzed type A) was investigated. Microstructural information was obtained using a combination of confocal laser scanning microscopy (CLSM) and spin echo small-angle neutron scattering (SESANS). Addition of gelatin led to a coarsening of the globular protein gel structure and to a reduction in storage modulus of globular protein gels. The presence of hydrolyzed gelatin on the other hand did not induce these changes in the globular protein gels. Results were obtained at conditions where proteins only interact via hard body interactions. For these conditions it was concluded that the ratio of molecular sizes is the most important determinant for the occurrence or absence of rheological and microstructural changes in globular protein gels prepared in the presence of gelatin.