The characterization of suspensions containing microgel particles is important for fundamental research, as well as for the control of industrial processes. Since labile microgel particles with high water capacities in the size range of up to 1 mm can often be found in food systems, and as they are important for the textural properties and also for sensory observation, an effective measurement system was searched for. This measurement system should be applicable during processing and should be able to characterize particles in a low concentrated suspension.

Konrad Weidendorfer and Jörg Hinrichs, University of Hohenheim, Germany, tested a focus beam reflectance measurement (FRBM) technique which works with a rotating laser that focuses on the spacial element of a sample. The measurement method was used for the characterization of the microgel particles in unsheared and mechanically post-processed stirred yogurt.

The reflected laser light was used as the measured raw signal and was evaluated. The particle size distribution of the chord length distribution was not directly determined. It was shown that this can be mathematically converted into the particle size distribution.

• Online Particle Size Measurement in Microgel Particle Suspensions: Principles and Data Analysis
  K. Weidendorfer, J. Hinrichs,
  Chem. Ing. Tech. 2010, 82 (10).
  DOI: 10.1002/cite.201000014