Future of additive manufacturing: Overview of 4D and 3D printed smart and advanced materials and their applications

In this study, the effects of pH (2.5, 6.5 and 7.8) and potato flake content (15%, 19%, 23% and 27%) on the properties of mashed potatoes (MP) were studied in terms of moisture distribution, rheological properties, texture properties and 3D printing performances. Results showed that the potato flake content was positively correlated with apparent viscosity, storage modulus (G′), and loss modulus (G″), while negatively correlated with tanδ and relaxation time (T2). As the content of potato chips increased, the shape fidelity of MP increased after printing. The addition of citric acid increased MP's apparent viscosity, G′, hardness and gumminess, thus increasing its capacity to be self-supportable performance after deposition, while an opposite trend was observed when sodium bicarbonate was added. A dual-extrusion printer was furtherly used to manufacture a colorful 4D ready-to-eat food in terms of spontaneous color change by using anthocyanin-rich purple sweet potato puree and MP. Results indicated that the color change of MP was significantly correlated with the pH value and the potato flake content. Industrial relevance This work extends the conventional 3D printing of single material to multi-material, and potentially provides a new view on how to produce colorful food products by 4D printing in terms of spontaneous color change of 3D printed multi-material products.

4D printing of mashed potato/purple sweet potato puree with spontaneous color change

4D printing of products based on soy protein isolate via microwave heating for flavor development.

Three-dimensional printing can be successfully applied in the food sector to fabricate 3D foods with complex geometries, customized texture, and tailored nutritional contents. The concrete applicat...

3D Printed Foods: A Comprehensive Review on Technologies, Nutritional Value, Safety, Consumer Attitude, Regulatory Framework, and Economic and Sustainability Issues

Background 4D printing technology has attracted extensive attention in academic and industrial circles since 2013 although commercialization still requires additional research and development. 4D food printing is an extension of 3D printing, which permits customization of new food products. Compared with aerospace, automobile, robotics, biomedicine and materials etc, there are few reviews on 4D food printing. Scope and approach This review shows recent advances in 4D printing technology applied to foods. To adapt current 4D printing technology to foods it is necessary to improve the extrusion printer and develop the necessary software. Aspects of recombination of different food materials and reasons of alterations in color, shape, flavor and nutrition via 4D food printing are discussed critically. The key to the success of 4D food printing and diverse solutions to the corresponding problems are outlined and analyzed. Future prospects for 4D food printing technology are discussed along with research and development needs. Key findings and conclusions At present, 4D food printing experiment is mainly based on soy protein isolate, starch and hydrogels and is realized through material properties, internal structural design and spatial arrangement of recombined food materials. The stimulation factors responsible for causing alteration of 3D printed products include pH, water absorption, microwave and temperature, resulting in deformation, modification of color, flavor and nutritional value. It is noteworthy that 4D food printing is still at research stage. There are opportunities for enhancement in the link between internal structure and stimulation, design of the printer, printing software, printing materials as well as evaluation of the properties of the printed foods.

4D printing: Recent advances and proposals in the food sector

A four-dimensional healthy food product was fabricated, in which 3D printed anthocyanin-potato starch (PS) gel changed its color over time to an attractive color (the 4th dimension). The color changed not only when sprayed the 3D product with different pH solutions but also independently as a response to an internal pH stimulus from another part inside the printed multi-material product. To achieve this, two parts of the gel system were combined, one part was from anthocyanin-PS gel and another part from lemon juice gel. In addition, the color change of anthocyanin-PS gel was also assessed after spraying with different pH solutions at different concentrations of PS and anthocyanin. Color changes were evaluated in terms of lightness (L*), redness (a*), and blueness (b*) using a colorimeter. The color stability of the 4D food product was examined for 24 h after printing. Moreover, a sensory evaluation test was performed to assess the consumer acceptance of the 4D food product. The printed samples sprayed with pH solutions 2, 2.5, 3, and 3.5 showed significant differences (p ≤ 0.05) in color at all PS and anthocyanin concentrations. However, pH samples 4, 4.5, and 5 did not show any visible difference in color after treatment compared to control samples. Furthermore, the color of the 3D printed anthocyanin-PS gel in model (A) gradually changed from purple to red over time during and after the printing process. On the contrary, the 3D printed anthocyanin-PS gel in model (B) did not show any noticeable color change over time after printing. This paper presents a novel application for 4D printing in the food field, which is very important for the food industry to fabricate a healthy product with attractive colors.

Spontaneous Color Change of 3D Printed Healthy Food Product over Time after Printing as a Novel Application for 4D Food Printing

4D printing is a result of 3D printing of smart materials which respond to diverse stimuli to produce novel products. 4D printing has been applied successfully to many fields, e.g., engineering, medical devices, computer components, food processing, etc. The last two years have seen a significant increase in studies on 4D as well as 5D and 6D food printing. This paper reviews and summarizes current applications, benefits, limitations, and challenges of 4D food printing. In addition, the principles, current, and potential applications of the latest additive manufacturing technologies (5D and 6D printing) are reviewed and discussed. Presently, 4D food printing applications have mainly focused on achieving desirable color, shape, flavor, and nutritional properties of 3D printed materials. Moreover, it is noted that 5D and 6D printing can in principle print very complex structures with improved strength and less material than do 3D and 4D printing. In future, these new technologies are expected to result in significant innovations in all fields, including the production of high quality food products which cannot be produced with current processing technologies. The objective of this review is to identify industrial potential of 4D printing and for further innovation utilizing 5D and 6D printing.

Progress in 4D/5D/6D printing of foods: applications and R&D opportunities.

Comparative characterisation of fat fractions extracted from Egyptian and Chinese camel milk

Impact of a novel probiotic Lactobacillus strain isolated from the bee gut on GABA content, antioxidant activity, and potential cytotoxic activity against HT-29 cell line of rice bran

Ahmed Fathy Ghazal

Papers

Spontaneous Color Change of 3D Printed Healthy Food Product over Time after Printing as a Novel Application for 4D Food Printing

Progress in 4D/5D/6D printing of foods: applications and R&D opportunities.

Comparative characterisation of fat fractions extracted from Egyptian and Chinese camel milk

Impact of a novel probiotic Lactobacillus strain isolated from the bee gut on GABA content, antioxidant activity, and potential cytotoxic activity against HT-29 cell line of rice bran

Microwave-induced rapid 4D change in color of 3D printed apple/potato starch gel with red cabbage juice-loaded WPI/GA mixture