There is a new technology on the block: 3D Printing. The whole concept is such that a number of businesses are trying out the technology to get a better understanding of its power and capabilities. It can be extended to making new human tissues, cultured meat, 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 (Mantihal et al., 2020; Wu et al., 2023). 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. Cornell University were the first to try 3D printing in designing a food and they produced the 3D printer, fab@home model 1, for printing liquid food (Malone & Lipson, 2007) in the home.
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, baked products 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). The benefits are many fold:-
- low waste generation,
- time-saving,
- good precision,
- high efficiency,
- free design
Most 3D food printing processes only need a single processing step to convert the food into its final form. That is one of the major benefits of the technology and is sometimes a point lost with those developing alternative processing methods. At the moment though there are no true kitchen sized pieces of kit or ones to be used for industrial scale production however it will not be long before search machines become available (Wegrzyn et al., 2012).
Extrusion Based 3D Printing Of Food
It 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
We can expand these design criteria further by outlining the processing steps encountered. There are essentially five steps in the design of a 3D product (Utela et al., 2008):-
- product formulation
- selection of binding method
- selection of binding agent
- the printing process including conditions
- post-processing conditions
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 other issue to bear in mind is whether the structure generated has the ability following any 3D printing to stand up to the rigours of post-processing. The type of extreme processes include baking, boiling and frying.
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). It is critical that there are no particulates that block the nozzle of the printer. That usually means the product to be printed out must be sieved.
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 over processed and clearly is artificial or even ultraprocessed not that this term should put scientists off in their product development.
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. Food inks were one of the first types of food material to be explored on a grand scale but that can now be extended to dough, mashed potato, chocolate, gel-based and comminuted products, even meat and cheese (Dick et al., 2019).
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 (Lanaro et al., 2017). The largest 3D printing company, Stratasys, has been manufacturing a printer for chocolate, and filing patents on processes before developing a commercial machine (United States Patent Application No. 61469305, 2012).
Kim et al., (2017) investigated methylcellulose (MC) as a reference material for simulation of printability. They assessed structures of different thickness from 20 to 80mm. Most interestingly, there was no collapse of the structure. There was a small amount of deformation. They also developed a classification system based on product stability and ease of handling.
Traditional food materials which include, vegetables, fruit, meat as we recognise it, 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.
Yang et al (2018) produced a baking dough gel using sugar (moisture content 0.2% g/g), butter, a low gluten flour, egg and water. Their main interest was how the technology might extrude the dough and whether the structure once formed was stable and retained its structure. In this example, water was the key factor in producing a workable dough suited to printing with because of the viscosity. They also used interestingly a range of sophisticated analytical techniques including laser scanning confocal microscopy (LSCM) to measure protein and fat distribution, low-field nuclear magnetic resonance (NMR) to monitor water distribution, torque rheometer and texture analyser. The dough behaved like a pseudoplastic gel with high extrusion levels, elasticity and good gel strength. The ideal formulation was a recipe of water (29 g), sucrose (6.6 g), butter (6.0 g), flour (48 g) and egg (10.4 g) per 100 g.
A fruit-based snack of relatively good nutrition was developed by Derossi et al., (2018). Any solid particles needed to be mashed through a 0.6-mm sieve to ensure optimal material supply through a nozzle. This has been subsequently used as a good model for assessing the behaviour of 3D printers. They also added pectin which improved flow consistency and restricted phase-separation in the water and ingredient interface during the manufacturing process.
Starch, which is a component of all baked goods, has shear thinning behavior, which is a favourable rheological property for hot extrusion. A research group conducted a study with three different starches from potato, rice, and corn to test the relationship between rheological properties and printability. Results showed all three starches exhibited shear thinning and strain responsiveness, making it suitable for extrusion printing (Chen et al., 2019).
Protein has a significant impact on the texture and microstructure of printed food. The key parameters are isoelectric point and pH. Protein aggregation and gelation are key features in liquid-based printing. Gelatin is a suitable protein molecule to change the viscosity of the feedstock. At higher shear rates, viscosity effects show a decreasing trend (Godoi et al., 2016).
Wheat-based doughs are ideal materials for extrusion printing with optimal extrudability and viscosity (Pulatsu et al., 2020, 2022). Even though they have optimal flowability and rheology for extrusion printing, post-processing properties are vital to understand. These are dough fermentation, leavening and baking processes.
Jiang et al., (2024) investigated different gluten contents of a bread dough. Firstly, the rheological properties of the dough closely correlated with the dough’s ability to be 3D printed. Fermentation and the baking process were not so closely correlated if at all. The most suitable gluten content was 13% for both printing, leavening and baking.
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 ultimately 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.
Fish surimi is an excellent food material for this type of process (Wang et al., 2018). A surimi slurry can be devised which is optimised for printing with. The addition of 1.5g/100g of NaCl is significant in this study. In this study they analysed the properties of the surimi manufactured. The most important feature was that the surimi easily flowed from the printer nozzle which then became viscous on deposition.
Lipton et al. (2010) used transglutaminase and bacon fat as additives to make printable scallop and turkey meat-puree.
Cheese is altered by 3D extrusion printing but it is still possible to produce processed cheese. Cheese hardness is lowered as is its melting properties (Le Tohic et al., 2018). The changes are wrought as in all 3D processing by exploiting the shear and heat forces.
The techniques used to modify food materials for extrusion in particular include:-
- flow enhancers that alter viscosity and improve lubrication
- addition of carbohydrates to increase water hydration capacity which inhibits the swelling of other particles (Kim et al., 2018)
- gel modification by weakening the structure using the addition of sodium chloride.
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. Derossi et al., (2018) in their study looked at print speed and flow on the kinetics and microstructure of the health. They reduced the print speed by 30% without compromising the product’s structure. Adjusting the printing flow affected the structural characteristics of the food.
The kinetics of the printing process can be modeled using a 1st-order rate equation:-
H(t)/H∞ = 1 – exp[-ktn]
where H(t) and H∞ are the height of the printed snack after time t and at the end of the printing process respectively and k and n are coefficients. The index n is dimensionless and defines a shape factor. The reciprocal of k (1/t) is the ‘location factor’. (Derossi et al., 2010).
In the Wang study of 2018, the optimum printer design for fish surimi was a 2.0 mm nozzle diameter, 5.0 mm nozzle height, 28 mm/s nozzle moving speed and 0.003 cm3/s extrusion rate.
Rheological properties of the material being printed are the most important factors. Principally, the properties that determine whether the substance can be successfully extruded from a nozzle, are storage modulus, loss modulus, viscosity, and yield stress (Jiang et al., 2022).
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.
Current Commercial Suppliers of 3D Food Printers
In recent years there has been a flurry of releases of 3D printing equipment. These include brand and trade names such as Foodini™ by Natural Machines, Foodjet™ by De Grood Innovations, Foodform™ 3D by RIG, Chefjet™ and CocoJet™ by 3D Systems, Stratasys, Choc Creator™ by Choc Edge, by FlowFocus, Imagine3Dprinter™ by Essential Dynamics, and Replicator™ by Makerbo, and Myocusuni (Sun et al., 2015).
Conclusion
3D printing is developing as a significant answer to many food development problems. The main areas of interest are those foods which are relatively liquid but become solid with time such as chocolate, baked foods etc. It is a precision tool for which the scope has to be fully explored. It is also widely used in many industries and with time, the machinery will become cheaper and more widely available.
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)
Derossi, A., Caporizzi, R., Azzollini, D., Severini, C. (2018) Application of 3D printing for customozed food. A case on the development of a fruit-based snack for children. J. Food Eng. 220 March pp. 65-75 (Article)
Derossi, A., Caporizzi, R., Paolillo, M., & Severini, C. (2021). Programmable texture properties of cereal-based snack mediated by 3D printing technology. Journal of Food Engineering, 289, 110160.
Derossi, A., De Pilli, T., & Fiore, A.G. (2010). Vitamin C kinetic degradation of strawberry juice stored under non-isothermal conditions. LWT – Food Science and Technology, 43, pp. 590-595
Dhal, S., Anis, A., Shaikh, H. M., Alhamidi, A., & Pal, K. (2023). Effect of mixing time on properties of whole wheat flour-based cookie doughs and cookies. Foods, 12(5), pp. 941.
Dick, A., Bhandari, B., & Prakash, S. (2019). Post-processing feasibility of composite-layer 3D printed beef. Meat science, 153, pp. 9-18 (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 (Article).
Gray, N. (2010), Looking to the future: Creating novel foods using 3D printing, FoodNavigator.com, viewed June 6, 2020.
Jiang, Q., Wei, X., Liu, Q., Zhang, T., Chen, Q., Yu, X., & Jiang, H. (2024). Rheo-fermentation properties of bread dough with different gluten contents processed by 3D printing. Food Chemistry, 433, 137318.
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)
Kim, H. W., Lee, J. H., Park, S. M., Lee, M. H., Lee, I. W., Doh, H. S., & Park, H. J. (2018). Effect of hydrocolloids on rheological properties and printability of vegetable inks for 3D food Printing. Journal of Food Science, 83(12), pp. 2923-2932.
Kim, H. W., Lee, I. J., Park, S. M., Lee, J. H., Nguyen, M.-H., & Park, H. J. (2019). Effect of hydrocolloid addition on dimensional stability in post-processing of 3D printable cookie dough. LWT, 101, pp. 69-75.
Lanaro, M, Forrestal, D.P., Scheurer, S, Slinger, DJ, Liao, S., Powell, S.K., et al., (2017) 3D printing complex chocolate objects: platform design, optimization and evaluation. J Food Eng. 215 pp. 13–22 (Article)
Malone, E., & Lipson, H. (2007). Fab@ Home: the personal desktop fabricator kit. Rapid Prototyping Journal, 13(4), pp. 245-255.
Mantihal, S., Kobun, R., & Lee, B. B. (2020). 3D food printing of as the new way of preparing food: A review. International Journal of Gastronomy and Food Science, 22, 100260
Matas, A., Igual, M., García-Segovia, P., & Martínez-Monzó, J. (2022). Application of 3D printing in the design of functional gluten-free dough. Foods, 11(11), 1555.
Niane, M. L., Rouaud, O., Ogé, A., Quéveau, D., Le-Bail, A., & Le-Bail, P. (2024). Optimization of the temperature profile of cake batter in an ohmic heating–assisted printing nozzle for 3D food printing applications. International Journal of Food Engineering, (0)
Pulatsu, E., Su, J. W., Kenderes, S. M., Lin, J., Vardhanabhuti, B., & Lin, M. (2022). Restructuring cookie dough with 3D printing: Relationships between the mechanical properties, baking conditions, and structural changes. Journal of Food Engineering, 319, 110911 (Article).
Severini, C., Derossi, A. & Azzolini, D. (2016). Variables affecting the printability of foods: preliminary tests on cereal-based products. Innovative Food Science and Emerging Technologies. (Article)
Sun J, Peng Z, Zhou W, Fuh JYH, Hong GS, Chiu A (2015) A review on 3D printing for customized food fabrication. Procedia Manuf. 1 pp. 308–319 .
Sun, J., Zhou, W., Huang, D. et al. (2015b) An Overview of 3D Printing Technologies for Food Fabrication. Food Bioprocess Technol 8, pp. 1605–1615 (Article)
Theagarajan, R., Moses, J. A., & Anandharamakrishnan, C. (2020). 3D Extrusion Printability of Rice Starch and Optimization of Process Variables. Food Bioprocess Technol. (Article)
Utela, B., Storti, D., Anderson, R., & Ganter, M. (2008). A review of process development steps for a new material systems in three dimensional printing (3DP). Journal of Manufacturing Processes,
10, pp. 96-104
Wang, L., Zhang, M., Bhandari, B., & Yang, C. (2018). Investigation on fish surimi gel as promising food material for 3D printing. Journal of Food Engineering, 220, pp. 101-108 (Article).
Wegrzyn, T.F., Golding, M., & Archer, R.H. (2012). Food layer manufacture: A new process for constructing solid foods. Trends in Food Science & Technology, 27 (2), pp. 6
Wu, H., Sang, S., Weng, P., Pan, D., Wu, Z., Yang, J., … & Liu, L. (2023). Structural, rheological, and gelling characteristics of starch‐based materials in context to 3D food printing applications in precision nutrition. Comprehensive Reviews in Food Science and Food Safety, 22(6), pp. 4217-4241 (Article).
Yang, F., Zhang, M., Prakash, S., & Liu, Y. (2018). Physical properties of 3D printed baking dough as affected by different compositions. Innovative Food Science & Emerging Technologies, 49, pp. 202-210.
Leave a Reply