Rheological properties image analysis

Methods of objective measurement of cereal foam structures are reviewed, including image analysis, confocal microscopy and x-ray tomography. The analysis of foam structures and their relationship with mechanical and rheological properties is described, and also the relationships between these structures and sensory descriptors such as crispness, crunchiness and texture. The size, shape and anisotropy of bubbles and their cell walls in foams are seen as critical in determining their fracture properties and sensory perception of crispness. Techniques for measuring crispness using acoustic emission and force-deformation profiles are discussed. 

Figure 1.1 showed the links between the formulation, the process and the texture. The first step is to understand how the formulation and process affect the microstructure. This requires microscopy techniques to visualize the ice crystals, air bubbles, fat droplets and matrix and image analysis to quantify their sizes, shapes and locations. The next step is to measure the mechanical, rheological and thermal properties and to relate them to the microstructure. The final stage is to relate these physical measurements to the sensory properties. This chapter describes the techniques used to make these measurements. 

When studying UHMWPE blended with low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), it was found, using analysis of the log-additive rule, Cole-Cole plots, Han curves, and Van Gurp s plot, that the LDPE/UHMWPE blends were miscible in the melt [8]. However, the thermal properties and morphology of the blends were not consistent with the rheological properties. The latter showed liquid-solid phase separation as a result of the different rates of crystallization of LDPE and UHMWPE. However, the rheological properties and electron microscopy images of LLDPE/UHMWPE blends showed... 

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