Alternative treatment of particulate food products

Lead University: University of Birmingham

Professor Peter Fryer, Professor Serafim Bakalis, Silvia Keppler

Collaboration: Campden BRI

Craig Leadley, Principal Research Officer in the Department of Food Manufacturing Technologies


The dry heat treatment of flour is commonly done in industry to alter its functionality and to produce very sweet and moist cakes (high ratio cakes). However, little is known about the mechanism and a cake needs to be baked to assess the outcome of the process.

In this study, the dry heat treatment of flour for the production of high ratio cake flour is evaluated in lab-scale experiments and in a novel, pilot plant device (Revtech system). The Revtech system is a continuous thermal process for particulate products, in which particles are conveyed by vibrations up a helical, heated pipe.

Residence time distributions of flour passing through the equipment have been characterised depending of various process parameters. Temperature distributions of the pipe wall, the flour and the air inside the pipe have been investigated.

The effect of heat treatment on flour functionality has been assessed in terms of RVA peak viscosity and results from lab-scale experiments and pilot plant equipment have been compared. In addition, high ratio cakes were baked with flour after heat treatment at different temperatures for different times. Whereas cakes baked with untreated flour collapse, the cake volume increases with increasing heat treatment intensity of the flour.

The findings are relevant to industry in that a method is shown that helps developing a cake flour specification and facilitates the validation of new processing equipment.


  • A method is shown to correlate cake quality with analytical methods
  • A method was developed for the accurate heat treatment of flour
  • Temperature distributions of pipe wall, air, and flour were measured and modelled
  • Residence time distributions were characterised in detail
  • Effects of heat treatment on flour functionality were analysed

Cakes baked with untreated flour (left) and heat treated flour (right)

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