Waste reduction in dough processing
Lead University: University of Birmingham
Dr Valentina Stojceska, Professor Savvas TassouProfessor Mark Simmons, Dr Kylee Goode
Warburtons, Finishing Design Services (FDS)
Bread roll manufacturing lines are notoriously less efficient than bread loaf manufacturing lines. This is predominantly due to less efficient dough processing. During dough processing we use a dividing method which is considered wasteful due to the inaccuracy of the weights (55 - 62g range) and through necessary use of processing aids (additional flour and oil) to prevent to dough from sticking.
As such, the objective of this project is to minimise waste from dough processing whilst also eliminating additional flour and oil use. We believe this objective can be achieved by focussing on the application of (i) low pressure extrusion technologies (ii) by developing improved dough transfer technologies and (iii) by the application of low energy surfaces at key dough handling stages (the divider, rounder and pinning operations). Low pressure extrusion technologies have not yet been used successfully to deliver a good quality yeasted dough.
We have used laboratory techniques (contact angle measurement of water and oil on surfaces, physcial removal of dough from surfaces using water, flow and temperature (clean rig), adhesive force of dough determined at 3 different length scales using 2 different applied force variations (micromanipulation (shear pulling of dough from a surface) and uniaxial compression using different contact area with the dough) alongside new pilot scale processing technologies (pumps, screws, extruders and combinations of approaches) for roll dough to assess practical feasibility at industrial scale in the factory.
Successful application of new roll dough processing technologies in the bakery should mitigate the direct cost of the waste, and is estimated to save Warburtons 12% in energy, water and raw material costs.
- A standard bread roll can be produced without additional oil and flour to lubricate dough through the process.
- Dough has a significantly higher level of interaction with stainless steel (SS) than other surfaces tested (polyfluoro coated and silicone based).
- Dough contact area appears significant for all surfaces apart from acetal.
- Cleaning of fresh dough from SS appears optimal at 40°C and is observed as adhesive failure. At 70°C the dough undergoes significant swelling and hydration inhibiting removal.
- Aged dough (24 and 48 h) is easily cleaned from surfaces, also observed as adhesive failure.