Wet and Dry Classification

The beans4feeds project is testing the efficacy bean-starch and -protein as aquaculture and animal feeds. The protein and starch is separated using either a 'wet' or 'dry' classification method. The raw starting material for both classification methods is bean flour produced from milled kernels (dehulled beans).

Dry Classification

“Air classification” (AC), “air fractionation” or “protein enrichment” is a low cost approach using a vertical cyclonic air stream to separate finely ground dry flours.  The larger and heavier starch granules fall lower in the air stream and the smaller and lighter protein bodies are lifted higher. The particulates occupying upper and lower regions of the cyclone are then removed separately to provide protein and starch enriched concentrates. The technique is commercially attractive because it is inexpensive requiring no solvents, acids or water. Pulses such as faba beans and good quality peas are also suited to this process.

Wet Classification

This method also exploits the differences in starch:protein density. and also the facts that the protein component is insoluble in water while the starch may be suspended in water. A centrifuge based protocol eventually yields separate fractions of pure dried bean-protein and -starch. The high purity of the wet classified products distinguishes them from those of dry process - since AC provides a "bean starch concentrate" (BSC), which contains some protein and a 'bean protein concentrate' (BPC), which contains some starch.

These differences in purity determine their relative suitability for processing as feeds and also their other non-food uses.

The economics and sustainability of the approaches will be continually appraised and refined and tested throughout the project as data becomes available.

For more information contact:

• Faba bean meal classification & aquaculture feed manufacturing  
  • Viv Campton, EWOS Ltd.
• Animal feed manufacturing
  • Willie Thomson, Harbro Ltd.
• Non-feed uses 
  • Pete Iannetta, The James Hutton Institute
  • This aspect is  being carried out in collaboration with Abertay University