Stiffening in gels containing whey protein isolate

Gels made only from whey protein isolate (WPI) stiffened over the first few days of storage, after which the textural properties remained nearly constant. However, protein gels containing WPI microparticles, at the same total protein content, stiffened over a longer period than those without microparticles. This stiffening was suggested to be the result of rearrangement of crosslinks in the gel. Addition of particles induces additional effects leading to water distribution between the protein particles and continuous phase. The stiffness change over time was different for gels made from a mixture of locust bean gum and xanthan gum containing microparticles. The stiffness of matrix gel and of gels containing 20% (w/w) microparticles was rather stable over time; microscopy analysis of these gels showed that particle size was constant after 72 h storage. Nevertheless, changes were observed in small deformation; this might be the consequence of slow rearrangements within the protein particles