Honey, the 3D print – I mean, dessert – is ready!

Cooking devices that incorporate three-dimensional (3D) printers, lasers, or other software-driven processes may soon replace conventional cooking appliances such as ovens, stovetops, and microwaves. But will people want to use a 3D printer-even one as beautifully designed as a high-end coffee maker–on their kitchen counters to calibrate the exact micro- and macro-nutrients they need to stay healthy? Will 3D food printing improve the ways we nourish ourselves? What sorts of hurdles will need to be overcome to commercialise such a technology? 

Columbia mechanical engineers are working to address these challenges in Professor Hod Lipson’s Creative Machines Lab. In a new Perspective article published today by npj Science of Food, lead author Jonathan Blutinger, a postdoctoral fellow in the lab, explores these questions and more, discussing with Professor Christen Cooper, Pace University Nutrition and Dietetics, the benefits and drawbacks of 3D-printed food technology, how 3D-printed food compares to the “normal” food we eat, and the future landscape of our kitchens.

Food printing technology has existed since Lipson’s lab first introduced it in 2005, but to date the technology has been limited to a small number of uncooked ingredients, resulting in what many perceive as less than appetising dishes. Blutinger’s team broke away from this limitation by printing a dish comprising seven ingredients, cooked in situ using a laser. For the paper, the researchers designed a 3D-printing system that constructs cheesecake from edible food inks — including peanut butter, Nutella, and strawberry jam. The authors note that precision printing of multi-layered food items could produce more customisable foods, improve food safety, and enable users to control the nutrient content of meals more easily. 

“Because 3D food printing is still a nascent technology, it needs an ecosystem of supporting industries such as food cartridge manufacturers, downloadable recipe files, and an environment in which to create and share these recipes. Its customisability makes it particularly practical for the plant-based meat market, where texture and flavor need to be carefully formulated to mimic real meats,” Blutinger said. 

To demonstrate the potential of 3D food printing, the team tested various cheesecake designs, consisting of seven key ingredients: graham cracker, peanut butter, Nutella, banana puree, strawberry jam, cherry drizzle, and frosting. They found that the most successful design used a graham cracker as the foundational ingredient for each layer of the cake. Peanut butter and Nutella proved to be best used as supporting layers that formed “pools” to hold the softer ingredients: banana and jam. Multi-ingredient designs evolved into multi-tiered structures that followed similar principles to building architectures; more structural elements were needed to support softer substrates for a successful multi-ingredient layered print. 

“We have an enormous problem with the low-nutrient value of processed foods,” Cooper said. “3D food printing will still turn out processed foods, but perhaps the silver lining will be, for some people, better control and tailoring of nutrition–personalised nutrition. It may also be useful in making food more appealing to those with swallowing disorders by mimicking the shapes of real foods with the pureed texture foods that these patients–millions in the U.S. alone–require.” 

Laser cooking and 3D food printing could allow chefs to localize flavors and textures on a millimeter scale to create new food experiences. People with dietary restrictions, parents of young children, nursing home dieticians, and athletes alike could find these personalised techniques very useful and convenient in planning meals. And, because the system uses high-energy targeted light for high-resolution tailored heating, cooking could become more cost-effective and more sustainable. 

“The study also highlights that printed food dishes will likely require novel ingredient compositions and structures, due to the different way by which the food is ‘assembled,’ ” said Lipson. “Much work is still needed to collect data, model, and optimise these processes.”

Blutinger added, “And, with more emphasis on food safety following the COVID-19 pandemic, food prepared with less human handling could lower the risk of foodborne illness and disease transmission. This seems like a win-win concept for all of us.”

A Recipe for 3D-Printing Food

3D-printing food could address global challenges in food supply and nutrition. But there are hurdles involved in adapting additive manufacturing to produce edible materials.

In Physics of Fluids, from AIP Publishing, University of Ottawa researchers Ezgi Pulatsu and Chibuike Udenigwe identify a range of factors that affect the print quality and shape complexity of food created with additive manufacturing. Accounting for these features can increase food quality, improve control, and speed up printing.

Additive manufacturing of food involves designing (3D shapes and their geometric codes), pre-processing (food ink preparation), manufacturing (deposition of layers to create shapes), and post-processing (baking, boiling, cooking, freezing, frying, or drying). Each step is an opportunity to create innovative foods.

Changing the printing patterns and ingredients of the initial mix or paste can affect the food’s matrix and microstructures and therefore its texture.

The flow of that mix in additive manufacturing is also crucial and is sometimes encouraged or discouraged by controlling ingredients and process conditions.

“Extrusion-based 3D printing is the most applicable technique for food,” said Pulatsu. “It involves a syringe loaded with a food paste – such as puree, dough, or frosting – being forced out of a nozzle by direct (pushing the plunger) or indirect force (compressed air).”

Creating a stable continuous flow is the first step to successful printing, so designed shapes can be produced by layering stringlike material in a controlled way.

“Once a layer is deposited, we no longer want it to flow; otherwise, it will destroy the shape we created,” said Pulatsu.

Post-processing – through baking, boiling, cooking, freezing, frying, or drying – physically and chemically transforms the food’s micro- and macromolecules and leads to various textures and tastes. At the same time, the shape should be conserved or carefully controlled.

“We also have other mechanisms of creating food structures via different 3D-printing techniques,” Pulatsu said. “For example, material jetting uses liquid binders deposited on powder to form self-supporting layers, and liquid inks that harden after deposition can also be used.”

One way to make additive manufacturing more efficient for the food industry is by establishing a printing path (a series of computer-controlled movements), which is often skipped for food applications.

“Future studies should explore the cost efficiency of different technologies in terms of build time, where shape complexity and toolpath strategies – which involve the printing path, moving head speed, and nonprinting movements – are also considered,” said Pulatsu. “Food is essential to living, and it’s becoming more critical due to the increasing global population and environmental changes. Therefore, novel foods and matrices should be designed in consultation with chefs, food scientists, and engineers, and in line with current needs.”