Improving the ability to print complex shapes has been a key focus in the development of 3D food printing. This study evaluated the material properties and printing characteristics of various materials, using the printing data from test models to create a dataset for categorizing, predicting, and validating the special shape printing capabilities of these materials. The primary factors influencing printing performance were the material's mechanical strength, resistance to deformation, and the ‘extrusion expansion’ effect. The print accuracy and support properties of test models of print material can significantly affect its ability to print special shapes. Based on special shape modeling experiments, the printing materials were classified into three categories: gels that could not print either flat or three-dimensional models, gels that could only print flat models, and gels that could print both flat and three-dimensional models. Principal Component Analysis (PCA) and Fisher Discriminant Analysis (with classification accuracies of 98.33% for the training set and 96.67% for the prediction set) confirmed the validity of these classification results. This study established a correlation between the printing characteristics of test models and those of special shape models, aiding in the evaluation of the printability of complex shapes.

Edible robots have edible systems for sensing, processing, and acting on stimuli, which can offer a range of new opportunities for applications in healthcare, environmental monitoring, and the promotion of healthier eating habits. The application of 3D printing technology in the development of edible robots has gained great attention in recent years. 3D printing technology allows for the manufacturing of complex edible robots that fulfil the diverse functions required of such robots. However, the application aspects of 3D printing technology in edible robot development have not been critically reviewed. In this review, the concept of edible robots and research advances are outlined. Furthermore, potential applications of 3D printing technology in the fabrication of bodies, actuators and sensors for edible robots are discussed. Also, new challenges and future trends of 3D printing technology in the fabrication of edible robots are analyzed critically. Overall, the application of 3D printing technology in the field of edible robotics is promising. This review is aimed at providing some guidelines and relevant references for researchers to explore potential applications of 3D printing technology in the development of edible robots.

The rapid development of food additive manufacturing technology provides options for production of innovative high quality personalized food products. Artificial intelligence (AI) helps collect, process, and analyze large amounts of data from the food additive manufacturing process and intelligently manage the printing process to ensure personalization, high quality, and safety of the printed food. This paper reviews and summarizes the potential applications of AI-based food additive manufacturing technologies in food as well as the anticipated challenges and potential solutions. AI can be of great help for pre-processing, processing and post-processing of additive manufacturing. It also guides the design of printing models, selection of smart materials, control of printing process, and possible 4D variations of printed food products. AI-based food additive manufacturing is expected to improve food production efficiency and quality, promote food personalization and nutritional balance, promote transformation of the food industry and provide consumers with healthier sustainable food choices.Industrial relevanceThis review recognizes that the combination of artificial intelligence and food additive manufacturing offers great potential for innovation and sustainable growth in the food industry. AI-based food additive manufacturing has potential applications in food design, print path planning, and food quality control to enable personalization, rapid production, and high-quality manufacturing. The analysis of big data can optimize the formulation of printed food products, intelligently design print paths, improve printing efficiency and precision, and monitor and provide feedback on quality and safety issues during the printing process to ensure food safety while meeting the standards required for food personalization. AI-based food additive manufacturing technology will bring opportunities and changes to the food manufacturing industry, and this integration can drive the digital transformation of the food industry and provide consumers with more diverse and nutritionally balanced food choices.

The practicability of using corn starch and erythritol as initial printing inks for manufacture to children printed products (with high accuracy and special shape) with addition of gelan gum (GG) was investigated. Materials properties and model parameters were applied to improve the printability and printing accuracy of special shape. The results showed that compared with the control group, all materials with hydrophilic colloid additions showed higher hardness, viscosity, rigidity and self-supporting ability. The results had shown that materials with higher GG additions possessed higher obvious viscosity and hardness, while printing inks with 1.5% GG concentration displayed best printing performance. Hydrophilic colloid additions attenuated the syneresis of samples. 3D printed objects using Ink-D (printing ink with GG addition of 1.5%) shown high printing precision with great self-supporting performance and smooth surface texture. Printing experiments revealed that model parameters (such as height and wall thickness) could significantly influence the printing precision and success rate of model with special shape.

Background: Food for the children should be nutritious with attractive shapes, flavors, and colors that distinguish from adult food. Additive manufacturing (AM) can meet the customization needs of children food and provide interesting, nutritionally customized food for them. Scope and approach: This paper reviews and summarizes the applications of AM in food, and presents the potential applications of AM in children food as well as challenges and potential solutions. Key findings and conclusions: As of now, the application of AM in children's food is limited in terms of development of AM technologies, food printing inks, policy and standards. In the future, through breakthroughs in AM technologies, the intelligence of printing materials, and the support of policies and standards, its application in children food can lead to significant innovations to provide high quality children food that cannot be produced by current technologies. The main objective of this review is to identify the potential of AM technologies in manufacturing children's food.

3D printing is a promising technology for food production, capable of producing and developing personalized food products. In recent years, research on the application of 3D printing technology to create easy-to-swallow foods for the elderly with dysphagia has received extensive attention. In this study, we applied dual nozzle 3D printing technology to develop an easy-to-swallow mooncake food using a traditional Chinese food, mooncake, as a model system. We optimized the printing dough ink formulation by setting up soybean oil gradient ex-periments and Arabic gum gradient experiments, and then we applied the optimized dough ink as the crust of the mooncake to produce easy-to-swallow mooncakes. The experimental results show that the addition of 2.5 g of soybean oil and 0.125 g of Arabic gum could improve the texture of the dough product and reduce its hardness and adhesiveness. The mooncake produced with this crust dough ink was rated in the IDDSI texture level four, which met expectations. Therefore, this work provides insights into the development of easy-to-swallow food products.

Following the development trend of intelligentialize and vitalization in the additive manufacturing field, five-dimensional (5D) printing has emerged. 5D printing is a life-active material that changes in the life dimension in the three-dimensional (3D) printed model over time, thus showing favorable changes in structure, performance, or function. In this study, probiotics were used as life materials to explore the feasibility of starch-based gel systems for 5D printing. With the evolution of time, probiotics spontaneously grew and multiplied in the 5D printed model. The number of probiotics in the 100

Glutinous rice flour, the main component of Qingtuan, has increased adhesiveness after gelatinization and hardness after aging; this results in great challenge in swallowing if for patients with dysphagia. Dual nozzle 3D printing has great potential for developing innovative Chinese pastries with fillings that conform to dysphagia diets. In this experimental study, the gelatinization and retrogradation behavior of glutinous rice starch was improved by designing printing inks of optimal properties made with different soluble soybean polysaccharide (SSPS) additions (0%, 0.3%, 0.6%, 0.9%). The internal structure of Qingtuan was modified by adjusting different filling densities (75%, 100%) in combination with the dual nozzle 3D printing. The objective of these tests was to enhance the texture of Qingtuan so that it meets the requirements of International Dysphagia Diet Standardization Initiative (IDDSI). The experimental results showed that 0.9% SSPS addition could effectively reduce the hardness and adhesiveness of the Qingtuan, which met the Level- 6 -soft & bite-sized standard while lower filling density lowers both hardness and adhesiveness.

Background: 3D printing technology, also known as additive manufacturing technology, has the advantages of customization, digitization and personalization. At present, researchers have made significant progress in the exploration of printable materials and the improvement of printing precision in food 3D printing technology, while the use of efficient physical fields in changing printing properties of materials and improving the quality of printed products has not yet been rigorously evaluated.Scope and approach: This paper discusses applications of efficient physical fields for improving the printability and precision of printed food materials. At the same time, efficient physical fields and the combination of efficient physical fields to induce the conversion of 3D printing of products into 4D printing (color, flavor, nutrition, shape changes) are discussed. Moreover, this paper also emphasizes the importance of efficient physical fields for drying and sterilization of 3D printed products.Key findings and conclusions: Pretreatment of printed materials with efficient physical fields can improve their printability and printing accuracy. Meanwhile, the combination of efficient physical fields and efficient physical fields combined with 3D printing technology can quickly realize 4D printing technology. Moreover, efficient physical field drying not only maintains the shape stability of the printed samples, but also protects the active components of the printed samples. Unfortunately, there are few studies on the sterilization of 3D printed samples by efficient physical fields. This paper provides a new ideas for the future study of physical fields combined with 3D food printing technology.

The traditional 4D deformation of 3D printed objects has certain limitations, because the deformation they achieve is often singular. Unlike previous 4D deformation studies, we proposed a new method to achieve bidirectional 4D deformation of 3D printed objects and explored the principles that lead to this change. We chose the paste made of coix seeds and purple potato powders as the printing ink, and tested its rheological properties, moisture distribution, and dielectric properties to predict and explain the characteristics of the 4D printing process. A model-based structural design was performed to study the conditions needed to achieve bidirectional 4D deformation. Experiments showed that the local expansion of the microwave-induced printed object was the driving force that led to the deformation. The structure of the deformable component in the model changed the role of this driving force. Different 4D deformation effects can be achieved by adjusting the structure of the model. The experiment also proved that the composition of the printing ink did affect 4D deformation. The purpose of this research is to provide a method to accentuate the 4D deformation effect, so that users can obtain a more appealing visual experience, and such deformation will attract children to consume, which can then be applied to the manufacture of cold food dishes and the production of food for children.

Eating patterns, financial and time constraints, and food availability play a key role in the wide variety of diets followed by young adults. As a result, many young consumers turn to quick and sometimes less healthy low nutrition options from convenience stores. In order to offer healthy and nutritious food, 3D printing can be used to make individualized diet plans and produce meals depending on factors such as age, occupation, and personal choice. In the field of food technology, 3D printing is a well-established additive manufacturing (AM) technology used to produce highly individualized food items. The types of foods that have been manufactured via 3D printing are evolving continuously. Customization of food and environmental sustainability are now possible because of this rapid and risk-free manufacturing approach. Future foods will include alternative proteins, plant-based products, insect protein etc. Current and future generations need healthy alternatives since most ready-to-eat or customized foods lack significant amounts of required nutrients. Due to eating disorders, allergies, or unpredictable eating habits, many young adults, especially those between 18 and 30 years of age, tend to suffer increasingly from malnutrition, obesity, and linked conditions like diabetes. 3D food printing is suitable for meeting this demand for nutritionally packed meals for the youth, which can be used to customize meal plans and meals for people with special diets. This paper summarizes recent studies on 3D printing formulations for future foods especially suited for young people.

4D food printing is an emerging technology developed from 3D printing technology, which allows consumers to have an interactive experience with the food. In this research, soy protein isolate and oat were formulated as printing materials to realize the shape change of 4D printing, using butterfly as a model. The relationships between the shape changing, water loss, and dielectric properties of the materials were explored. The results showed that the printing formula with higher protein content was preferable for the model shape change, due to its higher puffing property under microwave heating, whereas the water loss was the secondary factor causing the shape alteration. In addition, low-field nuclear magnetic resonance and rheology analysis suggested that the higher puffing properties of the soy protein isolate could be caused by its denser microstructure. The 4D-printed butterfly product with lower hardness resulted in a better sensory property.

The practicability of using corn and flaxseed protein as printing inks for manufacture of printed products specifically designed for toddlers as a dysphagia diet with high precision and special shapes with addition of fenugreek gum (FGG) was investigated. 3D printing was used to process grains and dysphagia-compatible food (corn) into a dietary product with attractive appearance which was also easy to swallow. Rheological measurements shown that appropriate amount of flaxseed protein (FP, 0-10 %) can reduce the stickiness and yield strength of printing material. Based on FTIR measurements, FP weakened the hydrogen bond strength of inks, but it was still an important gradient for the formation of the ink suitable for precision 3D printing. The TPA results shown that the addition of FP (0-10 %) remarkably reduced both the stickiness and hardness of the ink. These results shown that compared with the control group, materials with FGG additions possessed higher printing accuracy and self-supporting ability. Ink with 5 % FP content exhibited the best printability and swallowability, while ink with 10 % FP content had the lowest viscosity and hardness, but it was not suitable for 3D printing. 3D printing of objects printed using Ink-C (5%FP and 0.8 %FGG) showed high support characteristic and attractive appearance. According to the international IDDSI testing standards, Ink-C (5%FP and 0.8 %FGG), Ink-E (15%FP and 0.8 %FGG), and Ink-F (20%FP and 0.8 %FGG) were defined as level 5-minced and moist foods.