Speaker
Mr
Mikkel Schou Nielsen
(Danish Fundamental Metrology A/S, Lyngby, Denmark)
Description
Extended colloidal networks are found in a variety of multi-phase food systems such as butter, chocolate, cream cheese, whipped creams, ice cream, cheese and yogurt. While composed of many of the same components, these systems display a wide range of mechanical and sensorial textural properties. Thus, focus has been to link the macroscopic properties of the food systems to the 3D microstructure of the colloidal networks. However, since the constituting network elements have submicron sizes, a nano-scale 3D imaging technique would be needed which has been missing so far.
In recent years, a range of non-destructive X-ray phase-contrast imaging methods have been developed at synchrotron facilities and applied to study the microstructure of food products. One of the most recent is ptychographic X-ray computed tomography PXCT which is a quantitative 3D nano-imaging technique. Besides offering a spatial resolution up to 16 nm in 3D, PXCT provides the full 3D electron density distribution of the sample.
We present results of quantitative PXCT applied to a palm kernel oil based oil-in-water emulsion. The 3D structure of the extended colloidal network of fat globules was obtained with a resolution of around 300 nm which was limited by the stability of the sample. In addition, the reconstructed electron density values were within 4% of reference values. Through image analysis of the network structure, the fat globule size distribution was computed and compared to previous findings.
The study demonstrates the potential of applying PXCT for food systems. As PXCT is well-suited for diffraction-limited synchrotron sources such as MAX IV, an increasing availability of this technique is expected in coming years.
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![3D visualization of the extended colloidal network of fat globules in the food emulsion sample.][1]
[1]: http://www.fys.ku.dk/~schou/figures/pxct_food_emulsions/fedtnetvaerk_cropped.jpg
| Topic Area / Session | New X-ray Imaging Modalities for High Quality and Safe Food |
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Primary author
Mr
Mikkel Schou Nielsen
(Danish Fundamental Metrology A/S, Lyngby, Denmark)
Co-authors
Dr
Ana Diaz
(Paul Scherrer Institut, Villigen, Switzerland)
Prof.
Jens Risbo
(Department of food science, University of Copenhagen, Frederiksberg, Denmark)
Prof.
Kell Mortensen
(Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark)
Dr
Merete Bøgelund Munk
(Department of food science, University of Copenhagen, Frederiksberg, Denmark)
Dr
Mirko Holler
(Paul Scherrer Institut, Villigen, Switzerland)
Prof.
Robert Feidenhans'l
(Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark)
