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Preparation of protein particles by CO2 drying

Recently, the design of protein particles has become of interest, as they can be used as a protein source in the design of protein-rich foods. In this project, we create protein particles of micron size by a two-step emulsification method. With this method, the protein source and protein concentration can be varied to obtain protein particles with different properties, such as size, internal protein content, and the appearance of the particles, as can be seen in the figure.

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The method involves the emulsification of a protein solution (water phase) in an oil phase containing PGPR as an emulsifier to obtain a water-in-oil emulsion. After the water-in-oil emulsion is heated, the proteins aggregate and a protein particle is obtained. To obtain pure protein particles, the oil and the PGPR have to be removed. One way is to wash the protein emulsion multiple times to wash away the oil. However, this method is often not efficient and some oil and PGPR remains on the surface of the proteins. Moreover, it is very difficult to obtain the particles as a powder.

Here, we will investigate a novel technique, which is known as CO2 drying. The advantages of this technique is that all hydrophobic material (such as the oil and the PGPR) can be removed and the protein particles will be obtained as a dry powder. We will focus on different parameters of the drying technique and the properties of the dried powder in terms of its composition. When the composition has been determined, the powder will be used to characterize the rheological properties of powder solutions.

Research topics (1 MSc student)

  • Efficiency of CO2 drying to prepare protein particle powder.


  • CO2 drying. This will be performed at Feyecon in Weesp.
  • Rheology
  • Chromatography / Dumas: Oil, PGPR and protein concentration
  • Light scattering: particle size determination


  • Ability to work independently
  • Interest and affinity to use different techniques
  • Have an interest to perform part of the thesis within a company