Separation technology is an important cornerstone in the gentle processing of lupins, explains Nils Engelke
In 2010 – and with no particular fanfare in the media – employees of Germany’s Fraunhofer Institute founded Prolupin GmbH. It began an intriguing success story that, thanks to great innovation and strong partners, was awarded the 2014 German Zukunftspreis (Future Prize).
Partners such as Flottweg were an integral part of this story, because only the latest in separation technology solutions can make possible the processing of lupines on an industrial scale.
Industrial-scale challenge
The greatest challenge for the scientists was to develop a process that could be used to separate the component materials of lupin seeds fully from one another. Until now, despite their many advantages, lupins were not interesting for the consumer nutrition market because bitter materials made them unpleasant to eat. Thanks to the new process, unpleasant odour and taste substances can be identified and removed.
To ensure the sustainable economic success of lupin fractionation, the target yield for all fractions of the seed is over 90%. But how can ‘sensorily neutral’ proteins be obtained from lupins?
First, the grains are shelled and rolled for form extremely thin flakes. Oil is then extracted from the flakes using supercritical CO2. At a pressure of over 74 bar and temperatures greater than 31°C, CO2 takes on liquid-like properties. The majority of the oils and their accompanying materials dissolve in it. The de-oiled flakes are mashed in stirring tanks, then taken to a Flottweg Decanter. The decanter separates the fibre from the proteins. The liquid phase contains bitter compounds, carbohydrates, sugar and other soluble flavouring materials. The liquid phase is currently not used, and is therefore discarded in the wastewater.
The solid phase, however, is pumped into another thank. There, its pH value is increased to render the proteins soluble. From there, the mash is put into another Flottweg Decanter. The centrifuge separates insoluble fibres from the solid phase out of the mixture. These are later used in the animal fodder industry.
The clear phase is place into a final tank and acidified. Since the remaining dry substance is only a small volume, the proteins can be easily separated using a Flottweg Sedicanter. "We decided on the Sedicanter because it combines the advantages of a disk stack centrifuges with those of a decanter. Thanks to its high speed, this machine gets outstanding separation results while simultaneously processing large quantities of solids," says Marc Zillmann, head of Production and Product Development at Prolupin GmbH.
In summary, the processing of lupines is a challenge for people and machines alike. Until a few years ago, it was impossible to use the lupin plant efficiently for the production of food. In particular the separation of bitter materials and fibre at an industrial scale represented a great challenge. With the great spirit of innovation of Prolupin GmbH and the latest separation technology from Flottweg, it is now possible to use lupins economically as a food additive.
For more information, visit www.engineerlive.com/epe
Nils Engelke is with Flottweg.
