There is a new technology on the block: 3D Printing. The whole concept is such that a number of businesses are trialling the technology to get a better understanding of its power and capabilities. It can be extended to making new human tissues, human prosthetics through to new metals like hard steel or even making a Lamborghini if you really wanted it produced that way.
It is a very exciting new method of digital food production. It applies the process of additive manufacturing to making food. It is coming to the point where we could print out our next meal – in fact, we might order what we like just at the touch of a button or an app from our smartphone which has prepared our meal when we arrive home. With all the creativity in the world, I suspect we will have undreamed of possibilities. People on spaceflights are another example as I write who will be able to take advantage of ‘home’ cooking without suffering the issues of food safety risks.
Another area of commercial interest has to be tailored nutrition. If the consumer knows for example what food is needed to meet their needs for sport, then it is perfectly feasible to imagine that they could produce a series of products to address their requirements. Instead of asking for a ready made sports product, the 3D printer rustles up a protein drink designed for a particular workout but based on the current nutritional status of the recipient.
For some people you might know it as food layered manufacture (FLM). What it isn’t by the way is robotics-based food production
What is 3D food printing all about ?
The process of 3D food printing involves designing a food product using computer-aided design software or scanning a food into the computer. The food is then produced from the image by splitting the designed product into very thin layers.
A set of digitally controlled XYZ-robotics is directed by the layer template to manufacture the food in consecutive layers from the bottom up.
The layers are fused together by phase transitions, chemical reactions which occur during construction or in a separate step following construction.
The 3D food printing process allows the consumer control over colour, texture, shape and nutrition. A number of businesses have made all kinds of foods using this technology from chocolate, sugar and other carbohydrates.
To know more about the physics and all the possibilities, take a look at some of the articles written by Dankar et al., (2018).
Extrusion Based 3D Printing Of Food
I hasn’t taken long to link food extrusion to 3D printing. Extrusion is the most common and probably the simplest of all the 3d printing techniques. In fact it is reckoned that extrusion is the technology involved in creating the food matrix in the first place to manufacture the thin layers. The food ingredients are selectively dispersed through a nozzle or an orifice.
The challenges
The design of a 3D food comes down to three factors:-
- printability
- applicability
- post-processing
The biggest challenge is printing a food with a complex geometry. Designing one depends on the quality of the software used in the first place.
What is really the issue is using food ingredients which can stand up to the stress of such a complex geometry. Lots of food mixes have been tried to understand what the best ingredients and combinations are for the job.
The printing process is limited by the printability of food mixtures. These mixes all have different material properties which include their melting characteristics, the glass transition temperature, thermal behaviour as characterized by enthalpy, gelation and rheology/viscosity. Any issues associated with these values means poor productivity and a smaller choice of materials of 3D printing. The key is finding materials with the optimum characteristics in mind (Godoi et al., 2016).
Some peculiar and almost odd issues have arisen with food printing in other areas. It seems that food samples made this way have a higher than usual microbial concentration when ambient stored. There is also a consumer issue that such food looks overprocessed and clearly is artificial.
What materials can be used ?
The key to success is as much about the technology as it is about the type of materials used. We already mentioned the challenge of creating a complex structure.
One of the growing areas of interest is the use of vegetable proteins such as soy and pea to make interesting structures. It would be possible for example to produce seafood style product using a vegetable protein like pea. The key is creating the striped muscle feature but it has been suggested for a number of years now that 3D printing may well be the way forward given it can produce other meat-mimicked foods.
Chocolate is of course extremely popular and lots of examples using this food are known about.
Traditional food materials which include, vegetables, fruit, meat, rice etc. are not possible to be printed yet. It is possible to create a natural analogue using various hydrocolloids and mixing them with fruit powders so that they have a particular mechanical strength. Meat produced by 3D printing usually relies on something like alginate or agar along with meat puree. Not that long ago scallops and turkey puree was produced using the enzyme transglutaminase to catalyse the formation of covalent bridging bonds between the amino acids glutamine and lysine. The hydrogels formed are structurally stable enough to withstand cooking and frying.
A group at the Indian Institute of Food Processing Technology (IIFPT) in Thanjavur in India have produced fibre-rich printed snacks using mushrooms mixed with wheat flour (Keerthana et al., 2020) and using rice starch (Theagarajan et al., 2020). The same team have made snacks using millets, green gram, fried gram and ajwain seeds. Each nutritious snack took between five and seven minutes to make. A microwave drying process was needed to complete the manufacture. This is a great example of creating a tailored product with an individual’s nutritional requirements.
One group at the College of Agricultural and Life Science, Kangwon National University in South Korea investigated protein and carbohydrate polymer mixes (Oyinloye & Yoon, 2021). In their study they chose a well researched carbohydrate, alginate to mix with pea protein.
They found the best ratio of alginate to pea protein was 80:20 for 3D printing using the three physical factors mentioned earlier. They also examined residual stress in the gel created and established that this was dependent on temperature field and nozzle size.
London’s South Bank University have been using insects in a project called ‘Insects Au Gratin’ to examine the nutritional and environmental aspects of eating insect derived foods. The insect ingredients are mixed with other materials to improve their palatability and ultimatley their acceptance. the insects are made first into a powder which can be mixed with gelling agents, flavouring and water so that the best consistency is obtained.
3D Printing Process Variables
The process variables for a 3D printer to be studied include printing speed from 100 to 1000 mm/min and nozzle diameters between 0.5mm and1.5 mm.
3D Printing And Health
Using 3D printing to solve some of the difficult health issues of the age are worth considering. We know that between 20 and 25% of all people over the age of 50 suffer with swallowing for example. This is also known medically as dysphagia. The Netherlands Organisation for Applied Scientific Research (TNO) has proposed a way to make their food more interesting using 3D printing. Instead of bland puree it is possible to make food more interesting for those who have real chewing issues (Gray 2010).
3D printing And Waste
Leftover food is a suitable material for the technology. Eindhoven University of Technology and a Chinese technology business have been creating foods in this manner. They have produced cracker-like biscuits from sweet potato, rice and other foods.
References
Dankar, I., Haddarah, A., Omar, F. E., Sepulcre, F., & Pujolà, M. (2018). 3D printing technology: The new era for food customization and elaboration. Trends in food science & technology, 75, pp. 231-242 (Article)
Godoi, F. C., Prakash, S., & Bhandari, B. R. (2016). 3d printing technologies applied for food design: Status and prospects. Journal of Food Engineering, 179, pp. 44-54.
Gray, N. (2010), Looking to the future: Creating novel
foods using 3D printing, FoodNavigator.com, viewed
June 6, 2020.
Keerthana, K., Anukiruthika, T., Moses, J. A., & Anandharamakrishnan, C. (2020). Development of fiber-enriched 3D printed snacks from alternative foods: A study on button mushroom. Journal of Food Engineering, 110116. (Article)
Sun, J., Zhou, W., Huang, D. et al. An Overview of 3D Printing Technologies for Food Fabrication. Food Bioprocess Technol 8, 1605–1615 (2015). (Article)
Theagarajan, R., Moses, J. A., & Anandharamakrishnan, C. (2020). 3D Extrusion Printability of Rice Starch and Optimization of Process Variables. Food Bioprocess Technol. (Article)
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