May 26 2017
MIT researchers are discovering ways to make the dining experience fun and interactive, with food that can alter its shape when water is added.
The researchers, from MIT’s Tangible Media Group, have invented something similar to edible origami, in the form of flat sheets of gelatin and starch that, when submerged in water, instantaneously sprout into 3D structures, including regular pasta shapes such as rotini and macaroni.
The edible films can also be designed to fold into the shape of a flower as well as other unconventional shapes. The researchers wanted to make the most of the films’ culinary potential, and created flat discs that wrap around beads of caviar, similar to cannoli, as well as spaghetti that naturally divides into smaller noodles when soaked in hot broth.
The researchers reported their work in a paper this month at the Association for Computing Machinery’s 2017 Computer-Human Interaction Conference on Human Factors in Computing Systems. They explain their shape-morphing creations as not only culinary performance art, but also a practical technique to minimize food-shipping costs. For example, the edible films could be piled together and shipped to consumers, then morphed into their final shape later, when soaked in water.
We did some simple calculations, such as for macaroni pasta, and even if you pack it perfectly, you still will end up with 67 percent of the volume as air. We thought maybe in the future our shape-changing food could be packed flat and save space.
Wen Wang, Former Research Scientist, Media Lab, MIT
Wang’s co-authors are Lining Yao, lead author and former graduate student; Chin-Yi Cheng, a former graduate student; Daniel Levine, a current graduate student; Teng Zhang of Syracuse University; and Hiroshi Ishii, the Jerome B. Wiesner Professor in media arts and sciences.
“This project is the one of the latest to materialize our vision of ‘radical atoms’ — combining human interactions with dynamic physical materials, which are transformable, conformable, and informable,” Ishii says.
At MIT, Wang and Yao had been exploring the reaction of a variety of materials to moisture. They were working mainly with a specific bacterium that can change its shape, expanding and shrinking in reaction to humidity. Coincidentally, the same bacterium is used to ferment soybeans to create a regular Japanese dish called natto. Yao and Wang speculated if other edible materials could be engineered to transform their shape when exposed to water.
They began experimenting with gelatin, a substance that naturally expands when it soaks in water. Gelatin can expand to varying degrees according to its density — a property that the team exploited in developing their shape-changing structures.
Yao and Wang designed a flat, two-layer film composed of gelatin of two different densities. The top layer is more tightly packed, and thus able to take in more water compared to the bottom layer. When the whole structure is submerged in water, the top layer curls over the bottom layer, forming a gradually rising arch.
The researchers searched for ways to manipulate where and to what degree the structure bends, so that they might form different 3D shapes from the gelatin sheet. They ultimately decided on 3D printing strips of edible cellulose over the top gelatin layer. The cellulose strips naturally absorb very little water, and they discovered that the strips could serve as a water barrier, controlling the quantity of water that the top gelatin layer is exposed to. By printing cellulose in a range of patterns onto gelatin, they could predictably manipulate the structure’s reaction to water and the shapes that it eventually assumed.
“This way you can have programmability,” Yao says. “You ultimately start to control the degree of bending and the total geometry of the structure.”
Designing for a noodle democracy
Wang and Yao built several different shapes from the gelatin films, from macaroni- and rigatoni-like configurations, to shapes that looked like horse saddles and flowers.
To witness how their designs might be used in a professional kitchen, the MIT team took their engineered edibles to the head chef of a top Boston restaurant. The researchers and the chef collaborated and designed two culinary creations: long fettuccini-like strips, made from two gelatins that melt at varying temperatures, causing the noodles to impulsively divide when hot broth melts away certain sections; and transparent discs of gelatin flavored with plankton and squid ink, that immediately wrap around small beads of caviar.
“They had great texture and tasted pretty good,” Yao says.
The team recorded the cellulose patterns and the dimensions of all of the structures they could achieve, and also studied mechanical properties such as toughness, consolidating all this data into a database. Co-authors Zhang and Cheng then constructed computational models of the material’s transformations, which they used to create an online interface for users to prepare their own edible, shape-changing structures.
We did many lab tests and collected a database, within which you can pick different shapes, with fabrication instructions. Reversibly, you can also select a basic pattern from the database and adjust the distribution or thickness, and can see how the final transformation will look.
Wen Wang, Former Research Scientist, Media Lab, MIT
The researchers used a laboratory 3D printer to pattern cellulose onto films of gelatin, but they have outlined techniques in which users can replicate similar effects with more universal methods, such as screen-printing.
We envision that the online software can provide design instructions, and a startup company can ship the materials to your home. With this tool, we want to democratize the design of noodles.
Lining Yao, Former Graduate Student, MIT
This research was funded, partially, by the MIT Media Lab and Food + Future, a startup accelerator sponsored by Target Corporation based in Cambridge, Massachusetts.
Credit: MIT Tangible Media Group