Rheological characterization of dairy products for high solids drying

Introduction

Within FrieslandCampina, and dairy processing in general, removal of water is a critical step. Typically, water is first extracted using filtration and (falling film, conductive) evaporation. However, at some point the product properties will be become such that the only available option to remove water is (convective) spray drying. This process step is used worldwide to get liquid product to become solid (powder) products.  

One can imagine that this last water is most tricky to get out of the product and convective drying is the most energy intensive dewatering step. In order to minimize the overall energy use and maximize sustainability of the milk drying process, we need to shift the water removal as much as possible to the conductive evaporator, hence move to higher solids spray drying.  

Project description

One of the most critical and difficult aspects during spray drying is the rheological behavior of the product. How does the highly viscous product behave and how does it affect the drying? How can we make droplets that can be dried in a predictable way?  

We want to know how to rheologically characterize the high solids dairy product. What rheological properties relate to droplet break-up and how can we determine these properties? In the end, the hypotheses can be tested on real-life dairy spraying systems.

Techniques
• Capillary Breakup Extensional Rheometer Spectroscopy
• Shear Viscosity Rheometer
• Spraybox with Insitec spray particle size analyzer (available at FrieslandCampina Innovation Centre Pilot plant).

Thesis information
• Thesis work will take place at Food Physics (major part) and FrieslandCampina Innovation Centre, Wageningen (minor part).
• Thesis work is on an industry relevant topic, with an academic level approach.
• Primary supervision by Food Physics department, regular contact with drying experts at FrieslandCampina