Experts: Johannes Burkard (ETH Zurich)
3D-printed food is already being sold, and offered in restaurants. The combination of 3D printing and food makes it possible not only to create complex shapes for decorative purposes, but also recipes that can be adapted to specific nutritional requirements. Moreover, this technology is a beacon of hope with regard to the recycling of high-value waste from conventional food production. At the present time, 3D food printing is still of little relevance to mass production.
Picture: iStock
The days of 3D printing procedures being limited to plastics are long gone; to an increasing extent, foods are also being produced layer by layer, i.e. additively. In such cases, the printer usually presses a foodstuff in a paste-like preliminary state through a nozzle that can be moved three-dimensionally. The process steps are the same as in industrial 3D printing: from a digital 3D model to layer-by-layer assembly, through to the finished object.
The very different material properties of foodstuffs represent a major challenge for 3D printing. Materials like chocolate, mashed potato or cheese are referred to as ‘natively printable’ because, unlike meat or broccoli, they can be used as a printing material without any preparation processes. Another category is that of novel foods, where derivatives from bacteria, insects or fungi are used to create palatable products.
Current commercial applications often use this technology for decorative purposes. They include the printing of tempered chocolate to make edible 3D objects, or the controlled melting and solidification of sugar to form complex and delicate shapes. Inspired by the concept of flat packaging, as popularised by IKEA with its furniture packaging, pasta has been produced in compact two-dimensional designs that only unfold into the desired 3D shape in boiling water. This approach saves transport costs, just like IKEA’s furniture packaging. Barilla has also developed a 3D printer that chefs and food artists can use to produce personalised pasta shapes. Some firms, particularly in Israel, have begun to experiment with printing analogues of fish and meat. In addition, there are pilot studies aimed at printing food for children, especially fruit and vegetables, in a way that makes them visually and texturally attractive. Using several types of vegetables, a colourful butterfly could be conjured up on the plate, for example.
In the future, the aspect of personalisation will become more prominent. Using 3D printing, food is prepared in such a way that a multitude of products, adapted to the needs of different population groups in terms of taste and consistency, are created from the same resource. This is beneficial to hospitals and health centres, for instance. It helps not only the elderly, but also patients who have difficulty swallowing for medical reasons. Basic research is also looking into the question of how the fat, salt and sugar content of food can be reduced without detracting from the associated sensory experience. With the aid of 3D printing, perception can be specifically manipulated so that novel low-sugar formulations are perceived to be the same as those with normal sugar content.
Food production generates high-value waste, which can be turned into new, ready-to-consume, tasty products by means of 3D printing. In initial trials, surimi from fish waste is being used to print not only imitation crab sticks, but also new edible formulations and forms. This valorisation of residual flows could help to reduce the footprint of the carbon-intensive food industry and simplify nutrition in outer space: In the future, human faeces and urine could be used in a cyclical process as a nutrient medium for algae or duckweed, for instance, which 3D printing could then transform into a highly valuable food source for astronauts and make long-duration missions possible. For this reason, NASA is funding innovations in 3D food printing for long-duration missions, so as to ensure a secure food supply and to provide a multitude of foods from storable ingredients while minimising crew time expenditure and waste.
There is a lot of interest in 3D printing of food. Industrial development is dominated by start-ups, although some large companies are active in the field. The firms are experimenting with the technology, and looking for new markets and unique selling points. They see this technology as an opportunity to attract the attention of potential customers with innovative products.
The differences in foods’ chemical and physical properties mean that not all foods are suitable for 3D printing in their natural state. They also have to retain their shape and appearance, as well as a high level of quality in terms of their ingredients and consistency, during further processing steps such as boiling and baking. This makes it important to gain a better understanding of the technologies’ complexity and characteristics by means of research, so that they can be used optimally. This includes understanding the interplay between printability, possible uses and subsequent processing. In addition, as with all additive manufacturing applications, there needs to be a trade-off between manufacturing time and print quality, which determines throughput and price.
With nature serving as a model, there are attempts to use 3D printing to produce meat analogues and replicate the typical fibrous structure of muscles. However, this is challenging, especially with red meat. Although the first start-ups are already printing steaks from proteins, fat and blood, further development will be necessary to reproduce such complex fibres using additive manufacturing. Only then will printed steaks be able to compete with the original in terms of palatability.
As there is a strong socio-cultural element to food, the success of this technology also depends on consumer acceptance. In the past, a certain aversion to new types of food product has been evident: The smaller the degree of industrial technological processing, the higher the level of appreciation among customers.
This technology offers a multitude of opportunities, ranging from personalisation in healthcare to the creation of novel structures with food, through to the replication of fish and meat. However, the level of technological maturity and consumer scepticism (and thus the lack of economic incentive) are reasons why 3D printing of food is mainly restricted to research and start-ups for the time being. By combining the technology with artificial intelligence though, it might be possible to overcome the technical hurdles in the near future. SMEs will then also be able to use 3D food printing to create new product categories, increase production flexibility and change consumption habits.
One specific example application is described in the article Chocolate from the printer.
