ABSTRACT
Before continuing, it should be noted that composite products are not the same as mixed products. The latter term denotes products formed by mixtures of different protein and/or polysaccharide molecules. As long as during product preparation the different macromolecules stay mixed at the molecular scale, the term “mixed products” should be used exclusively. When phase separation takes place, both “mixed products” and “composite products” can be used. For products formed by mixtures of macromolecules and particles, only the term composite products will be used. For gelled systems, nearly all protein gels in food products are mixed gels. One exception is gelatin gels. Examples of mixed gels are acid-and rennet-induced skim milk gels which consist of a mixture of casein molecule, heat-set milk protein gels (containing both different casein and whey proteins), soy protein gels (containing various soy proteins), and gels of meat proteins. The presence of dispersed particles makes such gels composite products as well. The so-called filled gels are composite products consisting of a continuous gel matrix containing dispersed particles (gel-like and non-gel particles as emulsion droplets and air bubbles) that are much larger than the pores in the network.
