Science - February 10, 2011

High-speed steaks of the future

A new technology makes it possible to braise a steak in seconds. And it uses very little energy, thanks to minimal heat loss.

Demo of the Nutri-Pulse for Dutch TV
Our own braising steaks stay in their packaging after all; it is still asking too much to expect the prototype Nutri-Pulse oven to prepare a complete meal. But a snack is no problem. Chef Johan Verbon of the Restaurant of the Future on the Wageningen campus has some ready-cut beef for a demonstration of this brand-new technology. He places a slice into a bowl of stock with an electrode underneath it; the bowl is placed in a plastic holder in the machine and covered with a lid that has a second electrode.
Verbon briefly consults Hans Roelofs from the IXL Nederland company and then the door is closed, the knobs are turned and the machine emits an unbroken series of rapid ticking noises, like a clock gone berserk. It sounds as if sparks are flying in there, and indeed, electricity plays a key role in the cooking process. Between the electrodes, the Nutri-Pulse creates a high-frequency pulsing electric field at 3,000 volts. The ticks are the discharges of about ten microseconds each. After a minute the oven is opened. 'Don't take any notice of its looks', says Roelofs. 'It is still a load of electronics with a practical casing'. The moment of truth has come. The slice of meat is done, juicy but not as dark in colour as it would have been if it had simmered in a pan for hours.

Less heat loss
The Nutri-Pulse is based on technology that the OMVE company developed for pasteurizing fruit juice. Curious staff tried it out on other foods and nearly two years later, a spin-off emerged. The further development of the spin-off was entrusted to IXL, under the leadership of Roelofs. He got in touch with Hennie Mastwijk and Jeroen Knol of Wageningen UR Food & Biobased Research, for help with the scientific underpinning for the project and the further development of the electronics and the concept.
'The high voltage is released onto the lower electrode', explains Knol. 'The product between the electrodes serves as a resistor. The high-frequency pulses break open the small channels in the cell walls, speeding up the cooking process in the pan.' It speeds it up considerably. Potatoes are done in seconds, the designers claim; a braising steak takes four minutes instead of three hours. 'What is more, in terms of energy consumption, it is eight times more economical', claims Knol. 'You aim the energy very precisely. In a pan you lose most of the warmth.'
Six hundred steaks in a flash
This is good for the climate and good for busy cooks, especially in canteens and restaurants. That is where the new technology will be most applicable for the time being, Roelofs thinks. 'The big advantage of the Nutri-Pulse is its speed, making it possible to produce on demand. Say you had to serve 600 steaks in an evening: that would take an awful lot of preparation. With the Nutri-Pulse we can prepare a medium rare steak in ten seconds - and the quality is the same.'
But the steak will be done to exactly the same degree on the outside as on the inside, because the braising process is so uniform and the temperature so precise and stable. Will consumers accept that? 'I think so', says chef Verbon. 'And otherwise I'll slap it under the grill for a second.'