By adding this upgrade package, the company claims that bakers will benefit from increased yield, improved crumb quality and shelf life, as well as a reduction in levels of ascorbic acid necessary.
According to the company, the process involves the application of pressure and vacuum to the mixing bowel. In the first instance, air is pumped into the dough by pressurising the bowl. This provides more oxygen, which in turn "enhances the operation" of ascorbic acid as the oxidizing agent.
In the second mixing phase, a partial vacuum controls the size of the bubbles in the dough to refine the crumb structure.
"The pressure and vacuum stages of the cycle can be adjusted so that the full range of structures can be produced, from open-structured breads such as baguettes to pan breads with close and uniform structures," said UK-based APV.
According to the company, the addition of the new package will increase yield as dough is more machineable at a higher water content. It also promises to improve crumb colour and softness, thereby also improving shelf life.
The new capability can be used with all dough mixers in the current Tweedy range, as well as with older machines installed before the introduction of the pressure-vacuum process, said the company.
The upgrade package includes a new mixing bowl and lid clamp, a pressure-vacuum blower and pipework, and strengthening of the mixer frame. The control element involves either a modification package or new customised controls.
"Pressure-vacuum mixing has made a major impact in bakeries throughout the UK and continental Europe, Africa and Australasia. Retrofitting the process will enable bakeries to maintain their competitive edge without the need to replace machinery before the end of its natural life cycle," said APV.
The use of the technique has no effect on traditional process control characteristics, such as flour and weight proportioning, accurate water blending and energy control, all of which remain unchanged, explained the company.
Tweedy mixers are marketed as a complete dough production system, from ingredient weighing to dough delivery to the divider.
The mixers are suitable for bulk fermented, accelerated or mechanically developed doughs, using wheat or wheat and rye flour blends in bread, rolls, hamburger buns and pizza. They are also suitable for pastry and cake making.