The effect of microstructure on the sensory perception and textural characteristics of whey protein/κ-carrageenan mixed gels

The objective of the study was to understand how physical and structural properties of food translate into sensory perception. A range of gels with different structures were developed by combined mechanisms of ion-induced micro-phase separation of whey proteins, whey protein/k-carrageenan phase separation and network inversion. Descriptive sensory analysis was used to assess textural attributes of gels during the oral processing phases of first compression by tongue, first bite, mastication, and post swallow. Large deformation properties and fracture behavior of the gels were determined by uniaxial compression and single-edge notched bend tests. Mechanical properties at varying stages of deformation (before, during and after fracture) and sensory properties at different stages of oral processing (first compression, first bite and after 5-8 chews) followed similar trends based on the change in microstructure. Recoverable energies of gels were in agreement with springiness and compressibility evaluated at first compression in the mouth before biting. Young's modulus together with fracture properties, including critical energy release rate and fracture toughness, varied among different microstructures along with firmness. After the fracture point, the speed of macroscopic breakdown determined the fracture type of the gels, which was related to the degree of fracturability at the first bite. Overall, five out of six microstructures were discriminated in sensory texture properties. It was demonstrated that defined physical and sensorial properties of soft-solid foods can be generated by modifying the gel microstructure through colloidal interactions. (C) 2011 Elsevier Ltd. All rights reserved.