Dry Food Processing

Many operations in food industry involve processing of concentrated or even dry materials. Think for example about spray drying processes that convert a concentrated feed into a particulate powder or about milling and air classification operations to manufacture flour ingredients. In an industrial setting many processes are optimised via trial and error approaches with limited knowledge about the dynamic behaviour of the product during processing.

In our group we 1) develop experimental approaches to study and unravel underlying transient phenomena and develop mechanism-based guidelines for process optimisation and 2) develop novel processing concepts that can result in radical breakthroughs in terms of product quality and/or energy efficiency.

Primary focus of our research is on dewatering and drying processes. These processes are responsible for approximately 10% of the total industrial energy use (80 PJ/year). In our research we use a unique approach where we adopt and develop lab-scale approaches such as sessile single droplet drying to study spray drying processes and conductive thin film drying to study drum drying and agitated thin film drying processes. Experimental results are used for model development of physical phenomena responsible for the dynamics of product formation during drying. We also explore new dewatering and drying concepts such as freeze concentration, pre-treatments to increase robustness of living bacteria during spray drying and new drying or related technologies to enhance flavour and nutritional quality of foods during processing.

In addition we investigate radical new processing concepts concerned with processing of concentrated and dry materials:

1) Dry fractionation via combination of milling and dry separation is a tremendous interesting technique to produce protein-enriched cereal and legume ingredients. It not only is inherently more energy efficient compared to wet isolation processes, but it also delivers highly functional ingredients with preserved native properties. Main focus of our current research is investigating new driving forces for dry separation with electric fields and assessment of the unique properties of dry-enriched ingredients.

2) Separation of neutral buoyant particle suspensions or emulsions is conventionally carried out by membrane separation. We investigate a fundamentally different separation principle, called deterministic lateral displacement technology. In this technology the hydrodynamics is controlled such that particles of critical size displace with respect to the fluid flow direction.

3) 3D Food Printing is a rapidly emerging technology with major promise towards making personalised foods and opening perspectives towards novel food concepts that cannot be made with any other technique. However, translating a digital food design into an attractive food product is not that obvious. Therefore, we investigate behaviour of complex food systems in confined geometries and explore new food concepts with 3D food printing.