ABSTRACT

Why do particular nanoscale structures actually form? The answer in simple terms is that the formation is a slow step-by-step process, like the gradual descent into a valley from a mountain. That is, rather than requiring large amounts of energy for their creation, it appears that selfassembled nanoscale structures are formed through a series of optimized processes that utilize the tendency of a system to minimize its overall free energy, thereby minimizing any required activation energies. Therefore the production of specific nanoscale structures for food science and technology must rely first and foremost on an in-depth understanding of the thermodynamically driven self-assembly processes in multicomponent food systems (Manski et al., 2007; Morris, 2006). We require an understanding of both the structural and thermodynamic characteristics of the final self-assembled nanostructures as well as the molecular mechanisms of their formation and degradation. Once this information is available, it can be used to design, stabilize and manipulate nanostructures rationally so as to enhance functionality under the conditions encountered in food manufacture and in product usage by consumers (Murray and Ettelaie, 2004; Graveland-Bikker and de Kruif, 2006; Morris, 2006; Weiss et al., 2006; Manski et al., 2007). Probably most relevant for the case of food colloids is the understanding and development of novel interactions between proteins and polysaccharides, and also between biopolymers and emulsifiers/lipids. Controlling the interactions of particles, droplets and bubbles covered by these mixed ingredients could make possible tailor-made improvements in existing products as well as leading to novel food system formulations (Murray and Ettelaie, 2004; McClements, 2006; Morris, 2006; Dickinson, 2003a,b, 2006a). Table 1.3 sets out the potential impact of the different kinds of physical biopolymer interactions in relation to the phenomena making a major contribution to the nanostructuring of food colloids.