“The invention is based on a deep knowledge of what goes on in cooking,” said Di Maio, the study’s lead author and associate professor of materials science at the University of Naples Federico II, via email. “We had fun in the lab.”
The research team, which included a chemical engineer and a graduate student working as a pizzaiolo (pizza maker), used simple ingredients — tap water, iodized sea salt, and flour — and processes to create yeast dough and yeast-free dough that they could compare the two. They even used time-lapse photography to see how the proofing process affected the final structure of both the yeast dough and the unleavened dough.
They measured that the yeast dough became more elastic and increased in surface area by about 20%, while the other doughs hardly changed over time and slightly decreased in surface area.
The researchers’ previous experience proved crucial in compensating for the lack of yeast. Di Maio has studied how bubbles form in polymers, including polyurethane, which is used as a component of paints, varnishes, adhesives and foams. He knew that both bread and polyurethane result from two simultaneous processes, curing and foaming (the formation of a mass of small bubbles).
The researchers placed a tiny yeast-free pizza dough, no larger than a dime, in a hot autoclave. Over the course of a few minutes, they then shifted the pressure levels up and down while dissolving gas into the dough at high pressure. As the autoclave was slowly depressurized, bubbles formed in the dough.
The consistency of the final dough was similar to that of a traditional yeast dough, the study authors said.
“The key to the process is getting the pressure release rate right so that it doesn’t stress the dough, which likes to stretch gently,” Di Maio said in a press release.
“We mainly looked at how dough behaves with and without yeast – how the softness changes during proofing (rising) and how the dough responds to a temperature program during baking,” said Rossana Pasquino, a co-author of the study, in a press release. “This was fundamental to the design of the printing protocol for the yeast-free dough.”
Because the authors allowed the bubbles to form slowly, they weren’t quite as uniform as bubbles in a yeast dough.
Unfortunately, “the project is very immature,” Di Maio said — so you can’t try this at home just yet unless you happen to have an autoclave and a way to blow gas into the pizza dough. But as someone with a yeast allergy, Di Maio hopes the new method can be used for other leavened foods like cakes in the future, “to help people enjoy healthy and tasty food,” he said.
“We will now begin a study of full-size pizza on lab equipment, which should be ready in a few months. After that, depending on the outcome, we would consider selling the idea to companies,” Di Maio added. “I think two years would be enough if everything works and good people get involved.”