Relation between gel stiffness and water holding for coarse and fine-stranded protein gels

The sensory perception of foods is directly related to gel morphology. The aim of this research was to investigate the relationship between gel water holding and stiffness for gels with a different morphology. Whey protein gels were prepared by varying ionic strength to create fine and coarse-stranded gels. These gels were characterized for their coarseness, stiffness and their water holding capacity. Fine gels were referred to typical coarseness length scale smaller than 0.1 mu m and coarse gels were referred to coarseness length scale larger than 0.1 mu m. Water holding was measured both as a function of time and of applied pressure. Increased gel coarseness length scale in both fine and coarse gels resulted in a larger extent of network deformation at a certain applied force. For fine gels, the coarseness length scale of the gel was shown to determine water removal. In the case of coarse gels, coarseness length scale and stiffness had a counteracting effect, but coarseness length scale was still dominant. These results show that the tuning of coarseness length scale of protein networks independent of stiffness or, the other way round, provides a tool to set the water holding capacity in food gels. (C) 2016 Elsevier Ltd. All rights reserved.