From Printer to Stomach: Developments in Printed Food

Authored by Ganga Dripaul

Do you ever wish you could print out a meal in the comfort of your own home? What about printing out fresh foods to solve world hunger? Or to simply eliminate the inconvenience of cooking? The reality of printed food is not entirely far away. Food can be 3D-printed by depositing proteins, lipids, and other components like preservatives and minerals for desired nutritional and physical appearance to create edible 3D-food [1]. Even more, 4D-printing is also being explored to replicate changes in food over time [2]. Printing food allows for personalized customization based on nutrition, visual appeal, or medical conditions like dysphagia [3, 4].

There are several methods to 3D-print an object, including sintering, melting, and light processing. Extrusion is typically used to produce printed food, as it allows the food to be shaped to better replicate real food for recognition and patient comfort [4]. However, extrusion-based printing requires specific ink properties such as strong mechanical properties to maintain structure and shear thinning rheology, otherwise known as the ink’s ability to flow easier when a shear force, like chewing, is applied; essentially rheology relates to the ease of chewing [6]. Thus, the technical requirements for the ink limits the range of food that can be produced. The use of hydrocolloids, however, can modify the rheology of inks to make them usable for printing [5]. Hydrocolloids generally act as a thickening agent within the ink to ensure that once extruded the produced structure can hold a stable shape [6]. If the ink is too liquidy, it results in a mushy, unappetizing puddle of a meal. Although hydrocolloids offer a solution in the improvement of printing and are safe for consumption, they also present a new challenge: they can alter the taste and smell of food by introducing a non-natural flavor that hinders consumer acceptance and satisfaction with printed foods [5]. Thus, using as little hydrocolloid as possible is desired to optimize both taste and printability.

Much of the research on printed food is aimed at modifying food properties to help patients with dysphagia, which is a difficulty in swallowing food, common in both elderly and hospitalized patients [7]. Dysphagia can lead to malnutrition due to reduced food intake and increased risk of choking which can lead to more serious conditions such as aspiration pneumonia and even death [7]. Current solutions of pureeing food for easier consumption can be unappetizing to patients [7]. 3D-printing using freeze-dried vegetable powders can provide a highly nutritional and inexpensive option for patients with dysphagia [7]. However, not all powders are able to easily print and, as mentioned earlier, hydrocolloids are needed to alter their properties. Changing the rheological properties of the 3D-structure changes the way the food flows and deforms for easier consumption. Achieving easier flow is ideal for making the meal easier to swallow, but adding too many hydrocolloids may sacrifice taste to achieve this. The ultimate goal of printed food is to provide a nutritious, appealing, and easily consumed meal.

An additional challenge with 3D-printing food is replicating complex shapes without a mold [2, 7]. Using a mold can better fit the printed food into a shape consumers are accustomed to, but it requires extra manpower for proper casting [6]. Sustainability is also a common goal in printed food research, and unnecessary use of plastics with molds counters that goal [2]. Despite this, mimicking natural food is key to acceptability.

One way that 3D-printed food may be better able to mimic natural food is to have the physical appearance of printed food change with time. 4D-printers use smart materials that react to environmental properties, such as temperature and pH levels [2]. These smart materials deform, change color, flavor, and nutritional value, similar to the way natural food gradually rots over time [2]. 4D-printing is also capable of printing special shapes without a mold, due to the robustness and increased complexity available when using smart materials [2]. Although there are several advantages in the use of 4D-printing, it still faces similar drawbacks: only certain foods are able to print with ease and most do not replicate taste exactly [2]. 

Printed food may be a key solution to food insecurity worldwide. In addition to the physical health benefits of access to healthy food, there are several non-apparent mental health benefits to food security. Food insecurity more than doubles the risk of anxiety and depression [8]. The mental security of knowing where your next meal is coming from provides much needed comfort that improves mental health. 

Printed foods offer a potential solution to the ambitious problem of world hunger and malnutrition. With more research, printed food may become indistinguishable from natural food in terms of taste, look, and feel. 3D-printing can produce nutritional food that is easier to swallow, but is limited by the rheology of the ink. 4D-printing is a step closer to replicating natural food by using materials that account for how food changes over time. Food is essential to human existence and finding methods to reduce food insecurity helps society progress as a whole to improve the quality of life through economic stability, humanitarian improvements, and improved healthcare [9]. Food safety is the first step in securing a safer future. While printed food may seem like something that only exists in sci-fi, it is not infeasible. Advances in technology opens up the possibility of printing food just as easily as we print out papers.

References

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2. Teng, X., Li, C., Mujumdar, A. S., & Zhang, M. (2022). Progress in Extrusion-Based Food Printing Technology for Enhanced Printability and Printing Efficiency of Typical Personalized Foods: A Review. Foods, 11(24), 4111. https://doi.org/10.3390/foods11244111

3. Teng, X., Zhang, M., & Mujumdar, A. S. (2021). 4D printing: Recent advances and proposals in the food sector. Trends in Food Science & Technology, 110. https://doi.org/10.1016/j.tifs.2021.01.026

4. Qiu, R., Wang, K., Tian, H., Liu, X., Liu, G., Hu, Z., & Zhao, L. (2022). Analysis on the printability and rheological characteristics of bigel inks: Potential in 3D food printing. Food Hydrocolloids, 129, 102625. https://doi.org/10.1016/j.foodhyd.2022.102625

5. Sharma, R., Chandra Nath, P., Kumar Hazarika, T., Ojha, A., Kumar Nayak, P., & Sridhar, K. (2024). Recent advances in 3D printing properties of natural food gels: Application of innovative food additives. Food Chemistry, 432, 132196. https://doi.org/10.1016/j.foodchem.2023.132196

6. Nguyen, P. T. M., Kravchuk, O., Bhandari, B., & Prakash, S. (2017). Effect of different hydrocolloids on texture, rheology, tribology and sensory perception of texture and mouthfeel of low-fat pot-set yoghurt. Food Hydrocolloids, 72, 90–104. https://doi.org/10.1016/j.foodhyd.2017.05.035

7. Pant, A., Lee, A. Y., Karyappa, R., Lee, C. P., An, J., Hashimoto, M., Tan, U-Xuan., Wong, G., Chua, C. K., & Zhang, Y. (2021). 3D food printing of fresh vegetables using food hydrocolloids for dysphagic patients. Food Hydrocolloids, 114, 106546. https://doi.org/10.1016/j.foodhyd.2020.106546

8. Fang, D., Thomsen, M. R., & Nayga, R. M. (2021b). The association between food insecurity and mental health during the COVID-19 pandemic. BMC Public Health, 21(1). https://doi.org/10.1186/s12889-021-10631-0

9. Global Food Security. (n.d.). Nation Institute of Food and Agriculture. https://www.nifa.usda.gov/topics/global-food-security#:~:text=Food%20insecurity%20%E2%80%93%20often%20rooted%20in