Influence of shear during enzymatic gelation of caseinate–water and caseinate–water–fat systems

Solidification, emulsification and application of shear were combined to induce diversity and heterogeneity in the micro- and macrostructure of concentrated caseinate-based food matrices containing a dispersed fat phase. The products were evaluated with selected parameters from small-scale and large-scale deformations and confocal scanning laser microscopy. Sodium caseinate (10–30% w/w) was solidified with transglutaminase during mixing in a Brabender Do-Corder mixer, and palm fat (15% v/v) was emulsified either simultaneously during crosslinking, or after crosslinking. In absence of fat, granular caseinate structures were obtained. Adding fat prior to solidification and mixing resulted in strong homogeneous gels. Adding fat after solidification yielded protein granules surrounded by a concentrated fat phase. The structures were weaker and more brittle, and showed less strain hardening than the systems without fat, even though the linear viscoelastic properties were hardly different from the materials obtained by adding fat prior to mixing and solidification.