This study investigated the influences of food ingredients; namely, iota-carrageenan (?-carrageenan), sodium alginate and proteins, on viscoelastic properties of flour composites. The entire study was based on the concept of thermodynamic incompatibility between different macromolecules; where each macromolecule is excluded from the volume occupied by the other(s); leading to the phase separation, which can find its use in multi-phase formulated food products. During the first part of the study, mungbean starch in water (10-14.5% w/v) was used as the primary network to provide the three-dimensional matrix stabilized mainly by H-bonds and molecular entanglement of hydrated amylose and amylopectin. The mixed network of gelatinized mungbean starch and fillers; such as rice flour, glutinous rice flour, tapioca starch, ?-carrageenan and sodium caseinate, was altered at different cooking temperature, cooking time and levels of filler substituted or added to yield different degree of network incompatibility. This was to get the insights on factors governing the compatibility of the mixed network; and hence, the rheological properties of mixed structure. It was found that the viscoelastic properties of the mixed gels containing fillers at the level less than, or equal to, one-tenth of total solid was controlled by cooking temperature and cooking time. However, when the mass fraction of the filler was higher than 0.1, the mixed gel characteristics were determined by physicochemical properties of the fillers. In the second part, the rheological characteristics of mixed gels were altered in the presence of ?-carrageenan at different calcium lactate concentration (0-20 mM). The addition of ?-carrageenan (0.1-1.0%), a negatively charged hydrocolloid, increased the degree of incompatibility within the mixed structure. The rheological properties of mixed network, composed of leached amylose and ?-carrageenan in the aqueous phase, as well as the amylopectin remaining in the granular remnants, were regulated by the retardation of starch granule swelling. Increasing the viscosity and/or inducing the gelation of ?-carrageenan (using calcium ion) delayed the leaching of amylose to the aqueous environments. Consequently, the bulk volume occupied by leached amylose, a non-charge macromolecule, was reduced. The effects of ?-carrageenan gel on the induction of thermodynamic incompatibility in the mixed structures were enhanced at higher calcium concentration. Although ?-carrageenan can form thermoreversible gel, the molten carrageenan hindered gelatinization; which, in turn, prevented gelation of flour composites after cooking and could result in macroscopic phase separation. Nevertheless, at appropriate ?-carrageenan, calcium lactate levels, as well as cooking regime, the mixed flour gel characteristics can be designed to be parallel to those of one another regardless of flour or starch sources and/or cooking temperature. The influences of separated phase were investigated in the third part of this study. Results showed that the fracture behaviour of filled gels containing mungbean starch network as the continuous phase and heat-stable alginate beads (diameter approximately 3 mm and contained calcium lactate ranging from 0-100 mM) as the filler, occurred around the beads and not through the beads. Provided that there was no direct involvement of interfacial interactions between the separated phase and the supporting or continuous matrix, the ingredient interactions in the continuous phase would control the textural properties of the mixed network. Results suggested the approach in designing the textural properties of incompatible structure in multi-phase food systems. The possibility of engineering multi-phase food products; such as gluten-free butter cake, protein-rich liquid emulsion containing fiber, as well as carbohydrate-based fat replacer, during conventional unit operations was demonstrated. Overall, this study is the first attempt to explain how to effectively design the textural properties of carbohydrate-based food products by modifying the degree of thermodynamic incompatibility among the macromolecules. However, the complex interplay between the composite