Micro- and Nanotechnology in Food Engineering

Application of micro- and nanotechnology in the production of foods gives us fundamentally new ways to process raw materials to valuable products. These new technologies may contribute to a number of the societal problems that will be important in the coming century: better nutrition for better health, for an ageing population, and to reduce the incidences of (mal)nutrition related diseases. In addition, it can help in making production processes more sustainable. Micro- and nanotechnology may enable us to work with much greater precision and under milder conditions than previous. Separations can be carried out with high selectivity under mild, ambient conditions; conversions can become very selective, while the internal structure of products can be formed with great precision. One may even form product structures that simply were not possible with conventional techniques, and that could be important for the development of healthy products with good sensory properties. Micro-engineered membranes can have fluxes that are three orders of magnitude larger than those of conventional membranes. At the same time the pore size and pore geometry can be exactly designed and created. For these types of membranes it is possible to use a skimming effect to achieve full rejection with membrane pores that are much larger than the particles that are retained. Full-resolution simulation of the dynamics of polydisperse suspensions above such as well-defined membrane indicated that the shear-induced diffusion process responsible for back-transport is more complex than generally thought. It was found possible to use this understanding to completely avoid membrane fouling while achieving full fractionation at very high volume fractions of the dispersed phase. Using micro-engineered microchannels or edge based emulsification (EDGE) microdevices, it is possible to create completely monodisperse emulsions at very low energy input. Especially the EDGE systems were found to be very suitable for scale-up, as there is no interference between droplet forming units, and the droplet detachment, based on Laplace instability, is very stable against pressure differences. Finally, the same type of non-idealities in the dynamics of concentrated suspensions under flow can be used to structure (soft) food solids down to scales below 200 nm. Protein domains of 100 - 200 nm in concentrated suspensions tend to line up under shear flow. Simultaneous, slow enzymatic crosslinking then results in fibrillar protein products that show hierarchical fibrous structure from 150 nm up to macroscopic scales. These examples show that use of micro-and nanotechnology is possible, and suitable for scale up. It will give food engineers the possibility to contribute to the societal challenges on sustainability and health that face us in the 21st century.