3D printing of egg yolk and white with rice flour blends

Recent research and applications in lipid-based food and lipid-incorporated bioink for 3D printing

Three-dimensional (3D) printing, as an emerging digital production technology, has recently been receiving increasing attention in food processing. It is important to understand the effect of key ingredients of food materials on the printing, which makes it possible to achieve a wider range of structures using few nozzles and to provide tailored nutrition and personalization. This comprehensive review delves into the latest research on 3D-printed lipid-based foods, encompassing a variety of products such as chocolate, processed cheese, as well as meat. It also explores the development and application of food bioinks that incorporate lipids as a pivotal component, including those based on starch, protein, oleogels, bigels, and emulsions, as well as emulsion gels. Moreover, this review identifies the current challenges and presents an outlook on future research directions in the field of 3D food printing, especially the research and application of lipids in food 3D printing.

3D printing of Pickering emulsions, Pickering foams and capillary suspensions - A review of stabilization, rheology and applications

Pickering emulsions and foams as well as capillary suspensions are becoming increasingly more popular as inks for 3D printing. However, a lack of understanding of the bulk rheological properties needed for their application in 3D printing is potentially stifling growth in the area, hence the timeliness of this review. Herein, we review the stability and bulk rheology of these materials as well as the applications of their 3D-printed products. By highlighting how the bulk rheology is tuned, and specifically the inks storage modulus, yield stress and critical balance between the two, we present a rheological performance map showing regions where good prints and slumps are observed thus providing clear guidance for future ink formulations. To further advance this field, we also suggest standard experimental protocols for characterizing the bulk rheology of the three types of ink: capillary suspension, Pickering emulsion and Pickering foam for 3D printing by direct ink writing.

Evaluating the 3D printability of pearl millet flour with banana pulp blends

BACKGROUND

Three-dimensional (3D) food printing is a promising method for developing nutritious snack foods with complex and customized structures. In this study, to develop a pearl millet-based snack formulation, the printability of pearl millet flour (PMF) was assessed, without and with the addition of banana pulp (BP), a natural taste and flavor enhancer, at five different levels (PMF:BP of 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100).

RESULTS

The water activity significantly decreased with increases in the proportion of BP; higher water activity was exhibited at 100:0 (0.99). The BP proportion influences all the color values (redness: 2-11; yellowness: 17-31.87; total color difference: 2-17). All formulations exhibited shear-thinning behavior (n = 0.02-0.49) and higher hardness (0.2-0.4 N), but not all were printable. A significant decrease in adhesiveness (-0.2 to -0.03 N s) and higher storage modulus (2000-6000 Pa) occurred with an increased proportion of BP. Findings from detailed rheological behavior assessment (static, dynamic and three-interval thixotropy tests) better correlated with trends observed during 3D extrusion printing. The highest yield stress was attained (80 Pa) in the 100:0 formulation. From the thixotropy test, more deformation (>80%) and recovery (>100%) were attained by three of the formulations (100:0, 80:20, 60:40). Overall, the best constructs were obtained (based on the visual sensory characteristics) for the 60:40 formulation printed at 600 mm min-1 printing speed and 240 rpm extrusion motor speed through a 1.22 mm nozzle.

CONCLUSION

The findings of this work will provide valuable insights into the development of novel millet-based 3D printed foods. © 2024 Society of Chemical Industry.

Printability and Thermophysical Properties of Three-Dimensional-Printed Food Based on "Cochayuyo" Durvillaea antarctica Seaweed Flour

This research assessed the feasibility of adding Cochayuyo seaweed flour (at 30, 50, and 70% levels) to rice flour-based paste to improve its 3D printing quality. The paste's rheological properties, printing quality, texture profile, thermal properties, and color of 3D-printed foods were explored. Results showed that pastes with Cochayuyo addition exhibited shear-thinning behavior, and viscosity increased with increased Cochayuyo concentration. Viscoelastic properties and a Texture Profile Analysis (TPA) revealed that Cochayuyo improved mechanical strength and made the paste easier to flow, improving printed food's extrudability, fidelity, and shape retention, which was better observed in RC50 and RC70 printed at 15 mm s-1. A differential scanning calorimetry (DSC) analysis showed a partial substitution of rice flour for Cochayuyo flour in the formulation. This increased the onset and melting peak temperatures and reduced the enthalpy of fusion. CIE color parameters a*, b*, and L* showed that Cochayuyo addition increased the color to yellow and red; however, lightness was considerably reduced. Therefore, Cochayuyo flour could have the potential to be used for the manufacture improvement of 3D-printed food with better rheological, mechanical, thermal, printing quality, and nutritional properties, making possible the exploitation of the native Cochayuyo seaweed, which is highly available in Chile.

Personalized nutrition with 3D-printed foods: A systematic review on the impact of different additives

Three-dimensional (3D) printing is one of the world's top novel technologies in the food industry due to the production of food in different conditions and places (restaurants, homes, catering, schools, for dysphagia patients, and astronauts' food) and the production of personalized food. Nowadays, 3D printers are used in the main food industries, including meat, dairy, cereals, fruits, and vegetables, and have been able to produce successfully on a small scale. However, due to the expansion of this technology, it has challenges such as high-scale production, selection of printable food, formulation optimization, and food production according to the consumer's opinion. Food additives (gums, enzymes, proteins, starches, polyphenols, spices, probiotics, algae, edible insects, oils, salts, vitamins, flavors, and by-products) are one of the main components of the formulation that can be effective in food production according to the consumer's attitude. Food additives can have the highest impact on textural and sensory characteristics, which can be effective in improving consumer attitudes and reducing food neophobia. Most of the 3D-printed food cannot be printed without the presence of hydrocolloids, because the proper flow of the selected formulation is one of the key factors in improving the quality of the printed product. Functional additives such as probiotics can be useful for specific purposes and functional food production. Food personalization for specific diseases with 3D printing technology requires a change in the formulation, which is closely related to the selection of correct food additives. For example, the production of 3D-printed plant-based steaks is not possible without the presence of additives, or the production of food for dysphagia patients is possible in many cases by adding hydrocolloids. In general, additives can improve the textural, rheological, nutritional, and sensory characteristics of 3D printed foods; so, investigating the mechanism of the additives on all the characteristics of the printed product can provide a wide perspective for industrial production and future studies.

Using waste biomass to produce 3D-printed artificial biodegradable structures for coastal ecosystem restoration

The loss of ecosystem functions and services caused by rapidly declining coastal marine ecosystems, including corals and bivalve reefs and wetlands, around the world has sparked significant interest in interdisciplinary methods to restore these ecologically and socially important ecosystems. In recent years, 3D-printed artificial biodegradable structures that mimic natural life stages or habitat have emerged as a promising method for coastal marine restoration. The effectiveness of this method relies on the availability of low-cost biodegradable printing polymers and the development of 3D-printed biomimetic structures that efficiently support the growth of plant and sessile animal species without harming the surrounding ecosystem. In this context, we present the potential and pathway for utilizing low-cost biodegradable biopolymers from waste biomass as printing materials to fabricate 3D-printed biodegradable artificial structures for restoring coastal marine ecosystems. Various waste biomass sources can be used to produce inexpensive biopolymers, particularly those with the higher mechanical rigidity required for 3D-printed artificial structures intended to restore marine ecosystems. Advancements in 3D printing methods, as well as biopolymer modifications and blending to address challenges like biopolymer solubility, rheology, chemical composition, crystallinity, plasticity, and heat stability, have enabled the fabrication of robust structures. The ability of 3D-printed structures to support species colonization and protection was found to be greatly influenced by their biopolymer type, surface topography, structure design, and complexity. Considering limited studies on biodegradability and the effect of biodegradation products on marine ecosystems, we highlight the need for investigating the biodegradability of biopolymers in marine conditions as well as the ecotoxicity of the degraded products. Finally, we present the challenges, considerations, and future perspectives for designing tunable biomimetic 3D-printed artificial biodegradable structures from waste biomass biopolymers for large-scale coastal marine restoration.

Recent advances on enhancing 3D printing quality of protein-based inks: A review

3D printing is an additive manufacturing technology that locates constructed models with computer-controlled printing equipment. To achieve high-quality printing, the requirements on rheological properties of raw materials are extremely restrictive. Given the special structure and high modifiability under external physicochemical factors, the rheological properties of proteins can be easily adjusted to suitable properties for 3D printing. Although protein has great potential as a printing material, there are many challenges in the actual printing process. This review summarizes the technical considerations for protein-based ink 3D printing. The physicochemical factors used to enhance the printing adaptability of protein inks are discussed. The post-processing methods for improving the quality of 3D structures are described, and the application and problems of fourth dimension (4D) printing are illustrated. The prospects of 3D printing in protein manufacturing are presented to support its application in food and cultured meat. The native structure and physicochemical factors of proteins are closely related to their rheological properties, which directly link with their adaptability for 3D printing. Printing parameters include extrusion pressure, printing speed, printing temperature, nozzle diameter, filling mode, and density, which significantly affect the precision and stability of the 3D structure. Post-processing can improve the stability and quality of 3D structures. 4D design can enrich the sensory quality of the structure. 3D-printed protein products can meet consumer needs for nutritional or cultured meat alternatives.

3D Printing of Materials and Printing Parameters with Animal Resources: A Review

3D printing technology enables the production of creative and personalized food products that meet consumer needs, such as an attractive visual appearance, fortification of specific nutrients, and modified textures. To popularize and diversify 3D-printed foods, an evaluation of the printing feasibility of various food pastes, including materials that cannot be printed natively, is necessary. Most animal resources, such as meat, milk, and eggs, are not inherently printable; therefore, the rheological properties governing printability should be improved through pre-/post-processing or adding appropriate additives. This review provides the latest progress in extrusion-based 3D printing of animal resource-based inks. In addition, this review discusses the effects of ink composition, printing conditions, and post-processing on the printing performance and characteristics of printed constructs. Further research is required to enhance the sensory quality and nutritional and textural properties of animal resource-based printed foods.

Pleurotus ostreatus is a promising candidate of an edible 3D printing ink: Investigation of printability and characterization

The 3D printing (3DP) technology shows great potential in the food industry, but the development of edible ink is currently insufficient. Pleurotus ostreatus (P. ostreatus) emerges as a novel promising candidate. In this study, a mixed ink was obtained by incorporating butter into P. ostreatus. The effects of different ratios of P. ostreatus and butter, as well as the influence of ink steaming were investigated on 3D printed products. The results indicated that all inks of the P. ostreatus system exhibited positive shear-thinning behavior, and the system maintained stable intermolecular hydrogen bonding when P. ostreatus powder concentration was 40 % (w/v). Furthermore, the L* value of the system was elevated for butter adding. The system with steaming exhibited superior stabilized molecular structure compared to the native system, particularly with a steaming duration of 5 min, showcasing its outstanding supporting capacity. This study suggests that P. ostreatus is a promising candidate in 3DP for the development of an edible ink that promotes innovation and nutritional food.

Recent advances in 3D printing properties of natural food gels: Application of innovative food additives

Recent advances in 3D printing technology have provided a new avenue for food manufacturing. However, one challenge in 3D printing food is the limited availability of printable materials that can mimic the properties of real food. This review focused on the various 3DFP methodologies, as well as the reinforcement of natural food gel for improving printing features in 3D printed food. Also covered is the use of hydrogel-based 3D printing in the development of 3D printed food. Different 3D printing techniques can be employed to print hydrogel-based inks, each with its advantages and limitations. 3D printing of food using hydrogel-based inks has potential for customized food products development. In summary, the utilization of hydrogel-based inks in 3D printing offers a promising avenue for the development of customized food products. Although there are still challenges to overcome, such as improving the printability and mechanical properties of hydrogel-based inks, the potential benefits of this technology make it an exciting area of research.

Printability of Nixtamalized Corn Dough during Screw-Based Three-Dimensional Food Printing

This study aimed to analyze the printability of corn-based dough during screw-based three-dimensional (3D) food printing (3DFP) by relating its rheological and mechanical properties to its screw-based 3DFP performance, with the objective of providing insights into the utilization of corn-based dough to produce 3D-printed foods. Screw-based 3DFP was performed using seven corn-based doughs with different nixtamalized corn flour (NCF) and water contents. Afterward, their rheological and mechanical properties were analyzed and associated with their screw-based 3DFP performance. The results showed that stable printability was obtained within a specific range of NCF content in the dough (30-32.5 wt%). Below this range, the 3D-printed foods flattened, while above it, the extrudability of the dough was affected. The printability of the dough was influenced by different rheological and mechanical properties, depending on the stage of the screw-based 3DFP process. During the extrusion stage, the loss tangent at nozzle strain, yield stress, apparent viscosity, and adhesiveness mainly affected the extrudability of the dough. In contrast, the loss tangent at minimum strain, elastic modulus, Young's modulus, and hardness influenced the self-supporting stage. Therefore, it is important to find a balance between all of these properties, where stable extrudability and self-supporting of the 3D structure are achieved.

Elaboration of dimensional quality in 3D-printed food: Key factors in process steps

Three-dimensional (3D) printing has been applied to produce food products with intricate and fancy shapes. Dimensional quality, such as dimensional stability, surface smoothness, shape fidelity, and resolution, are essential for the attractive appearance of 3D-printed food. Various methods have been extensively studied and proposed to control the dimensional quality of printed foods, but few papers focused on comprehensively and deeply summarizing the key factors of the dimensional quality of printed products at each stage-before, during, and after printing-of the 3D printing process. Therefore, the effects of pretreatment, printing parameters and rheological properties, and cooking and storage on the dimensional quality of the printed foods are summarized, and solutions are also provided for improving the dimensional quality of the printed products at each step. Before printing, incorporating additives or applying physical, chemical, or biological pretreatments can improve the dimensional quality of carbohydrate-based, protein-based, or lipid-based printed food. During printing, controlling the printing parameters and modifying the rheological properties of inks can affect the shape of printed products. Furthermore, post-processing is essential for some printed foods. After printing, changing formulations, incorporating additives, and selecting post-processing methods and conditions may help achieve the desired shape of 3D-printed or 4D-printed products during cooking. Additives help in the storage stability of printed food. Finally, various opportunities have been proposed to regulate the dimensional properties of 3D-printed structures. This review provides detailed guidelines for researchers and users of 3D printers to produce various printed foods with the desired shapes and appearances.

Designing future foods: Harnessing 3D food printing technology to encapsulate bioactive compounds

Bioactive compounds (BCs) provide numerous health benefits by interacting with one or more components of living tissues and systems. However, despite their potential health benefits, most of the BCs have low bioaccessibility and bioavailability, hindering their potential health-promoting activities. The conventional encapsulation techniques are time-consuming and have major limitations in their food applications, including the use of non-food grade chemicals, undesired sensory attributes, and storage stability issues. A cutting-edge, new technique based on 3D printing can assist in resolving the problems associated with conventional encapsulation technologies. 3D food printing can help protect BCs by incorporating them precisely into three-dimensional matrices, which can provide (i) protection during storage, (ii) enhanced bioavailability, and (iii) effective delivery and controlled release of BCs. Recently, various 3D printing techniques and inks have been investigated in order to create delivery systems with different compositions and geometries, as well as diverse release patterns. This review emphasizes the advances in 3D printing-based encapsulation approaches, leading to enhanced delivery systems and customized food formulations.

Three-Dimensional Printing Parameter Optimization for Salmon Gelatin Gels Using Artificial Neural Networks and Response Surface Methodology: Influence on Physicochemical and Digestibility Properties

This study aimed to optimize the 3D printing parameters of salmon gelatin gels (SGG) using artificial neural networks with the genetic algorithm (ANN-GA) and response surface methodology (RSM). In addition, the influence of the optimal parameters obtained using the two different methodologies was evaluated for the physicochemical and digestibility properties of the printed SGG (PSGG). The ANN-GA had a better fit (R2 = 99.98%) with the experimental conditions of the 3D printing process than the RSM (R2 = 93.99%). The extrusion speed was the most influential parameter according to both methodologies. The optimal values of the printing parameters for the SGG were 0.70 mm for the nozzle diameter, 0.5 mm for the nozzle height, and 24 mm/s for the extrusion speed. Gel thermal properties showed that the optimal 3D printing conditions affected denaturation temperature and enthalpy, improving digestibility from 46.93% (SGG) to 51.52% (PSGG). The secondary gel structures showed that the β-turn structure was the most resistant to enzymatic hydrolysis, while the intermolecular β-sheet was the most labile. This study validated two optimization methodologies to achieve optimal 3D printing parameters of salmon gelatin gels, with improved physicochemical and digestibility properties for use as transporters to incorporate high value nutrients to the body.

Advances in the Potential Application of 3D Food Printing to Enhance Elderly Nutritional Dietary Intake

The contradiction between the growing demand from consumers for "nutrition & personalized" food and traditional industrialized food production has consistently been a problem in the elderly diet that researchers face and discuss. Three-dimensional (3D) food printing could potentially offer a solution to this problem. This article reviews the recent research on 3D food printing, mainly including the use of different sources of protein to improve the performance of food ink printing, high internal phase emulsion or oleogels as a fat replacement and nutrition delivery system, and functional active ingredients and the nutrition delivery system. In our opinion, 3D food printing is crucial for improving the appetite and dietary intake of the elderly. The critical obstacles of 3D-printed food for the elderly regarding energy supplements, nutrition balance, and even the customization of the recipe in a meal are discussed in this paper. By combining big data and artificial intelligence technology with 3D food printing, comprehensive, personalized, and customized geriatric foods, according to the individual traits of each elderly consumer, will be realized via food raw materials-appearance-processing methods. This article provides a theoretical basis and development direction for future 3D food printing for the elderly.

Effect of 3D printing conditions and post-printing fermentation on pearl millet fortified idli

BACKGROUND

Three-dimensional (3D) printing is an emerging technology with numerous applications in the development of novel foods to meet personalized and special dietary needs. Using 3D printing, foods with modified textures and consistency can be prepared conveniently. In this work, an indigenous rice-black gram batter was fortified with pearl millet flour and 3D printed in the in-house developed extrusion-based food printer, Controlled Additive-manufacturing Robotic Kit (CARK™). The impact of material supply composition was investigated along with optimization of different printing parameters and an in-depth analysis of post-printing fermentation kinetics was undertaken. The shape changes in the 3D printed constructs during fermentation were analyzed using a pixel-count-based image-processing technique that correlates with the change in surface area.

RESULTS

The addition of millet flour resulted in accelerated fermentation. At 20% w/w level, better printability with higher precision and layer definition was obtained at 800 mm min^-1 of printing speed, 360 rpm extrusion motor speed, and 1.22 mm nozzle diameter with an extrusion rate of 15.57 mm³  s^-1 . The constructs of pearl millet flour (PMF) fortified idli batter have shown good structural stability and creep recovery. Fermentation-assisted shape change was found to be significantly influenced by infill levels. Both raw and steamed constructs with 40% infill showed around 37% lower hardness than 100% infill constructs due to a porous inner structure with reduced expansion in the surface area/volume during fermentation.

CONCLUSION

The results of the study provide insights into the scope of printing fermented foods through the food-to-food fortification approach and textural modification of foods using 3D printing by varying the infill levels. © 2022 Society of Chemical Industry.

3D Printing Approach to Valorization of Agri-Food Processing Waste Streams

With increasing evidence of their relevance to resource recovery, waste utilization, zero waste, a circular economy, and sustainability, food-processing waste streams are being viewed as an aspect of both research and commercial interest. Accordingly, different approaches have evolved for their management and utilization. With excellent levels of customization, three-dimensional (3D) printing has found numerous applications in various sectors. The focus of this review article is to explain the state of the art, innovative interventions, and promising features of 3D printing technology for the valorization of agri-food processing waste streams. Based on recent works, this article covers two aspects: the conversion of processing waste streams into edible novel foods or inedible biodegradable materials for food packing and allied applications. However, this application domain cannot be limited to only what is already established, as there are ample prospects for several other application fields intertwining 3D food printing and waste processing. In addition, this article presents the key merits of the technology and emphasizes research needs and directions for future work on this disruptive technology, specific to food-printing applications.

3D Printed gelatin film with Garcinia atroviridis extract

Active packaging, such as edible film with antibacterial properties, can help extend the shelf life of food. The research aimed to develop a 3D printed gelatin edible film by using glycerol and Garcinia atroviridis extract (GAE). Mechanical properties of gelatin gel, physical, mechanical, and antimicrobial properties of edible film with glycerol and GAE were determined. Water solubility, total colour difference, and elongation of break of gelatin edible film increased as glycerol concentration increased (0-25% w/w), whereas tensile strength and Young's modulus value decreased from 26.5 to 4.64 MPa and 3.04 to 0.13 MPa, respectively. On the other hand, increasing GAE from 1 to 4% (w/w) increases elongation at break from 40.83 to 98.27%, while decreasing edible film tensile strength and gelatin gel hardness value from 8.94 to 6.21 MPa and 1848.67 to 999.67 g, respectively. Using 20% (w/w) glycerol and 4% (w/w) GAE, the best 3D printed film with low tensile strength (6.21 MPa), high elongation at break (98.27%), and antibacterial activity against S. aureus with 7.23 mm zone of inhibition was developed. It seems to have a great potentiality as an active packaging material for 3D printed gelatin edible film.

Characterization of rice flour and pastes with different sweeteners for extrusion-based 3D food printing

This work aims at investigating the impact of commonly used sweeteners-sugar and jaggery on 3D printability of rice flour (RF) paste. The physicochemical characteristics of rice flour suitable for 3D food printing have been investigated. Three mixes, rice flour with water (M₁ : RF-50.86%, water-49.14%), rice flour with sugar and water (M₂ : RF-36.75%, sugar-14.10%, water-49.14%) and rice flour with jaggery and water (M₃ : RF-36.75%, jaggery-14.10%, water-49.14%) were compared on 3D printability based on visual inspection and properties supporting 3D printability and shape retention. The effect of the three mixes was characterized on color, rheological, thixotropic, and handling properties. Out of the three mixes, M₃ is found to have the best printability characteristics with shear thinning behavior, yield stress of 157 Pa, flow stress of 121 Pa, and extrusion force of 6.62 kg.

Effect of Steaming as Postprocessing Method on Rice Flour and Jaggery 3D Printed Construct

In this study, the 3D printing of a traditional South Indian snack, “sweet pidikollukattai” has been attempted. The mixing properties of the rice flour used and thermal characteristics of the paste (rice flour, jaggery, and water) have been reported. The traditional form of the product (control) was compared with the 3D printed product, which has been postprocessed by steaming at different time durations (S1-5, S2-10, S3-15 min). A comparative evaluation of the proximate analysis, colour, weight, dimensional measurement, texture profile analysis, and sensory characteristics was done for all samples. No significant difference was observed in colour, proximate composition, weight, and dimensional variation between the 3D printed samples and the control sample. Texture profile analysis revealed that the S2 score is comparable to the control sample. S2 also scored higher on the sensory scale compared to other samples. It was concluded that the 3D printed sample of the recipe, steamed for 10 min, has better acceptability compared to other samples.

Current Trends in the Production of Probiotic Formulations

Preparations containing probiotic strains of bacteria have a beneficial effect on human and animal health. The benefits of probiotics translate into an increased interest in techniques for the preservation of microorganisms. This review compares different drying methods and their improvements, with specific reference to processing conditions, microorganisms, and protective substances. It also highlights some factors that may influence the quality and stability of the final probiotic preparations, including thermal, osmotic, oxidative, and acidic stresses, as well as dehydration and shear forces. Processing and storage result in the loss of viability and stability in probiotic formulations. Herein, the addition of protective substances, the optimization of process parameters, and the adaptation of cells to stress factors before drying are described as countermeasures to these challenges. The latest trends and developments in the fields of drying technologies and probiotic production are also discussed. These developments include novel application methods, controlled release, the use of food matrices, and the use of analytical methods to determine the viability of probiotic bacteria.

Defects in 3D/4D food printing and their possible solutions: A comprehensive review

3D food printing has recently attracted significant attention, both from academic and industrial researchers, due to its ability to manufacture customized products in such terms as size, shape, texture, color, and nutrition to meet demands of individual consumers. 4D printing, which is a technique that allows evolution of various characteristics/properties of 3D printed objects over time through external stimulation, has also been gaining more attention. In order to produce defect-free printed objects via both 3D and 4D printing, it is necessary to first identify the causes of defects and then their mitigation strategies. Comprehensive review on these important issues is nevertheless missing. The purpose of this review is to investigate causes and characteristics of defects occurring during and/or after 3D food printing, with a focus on how different factors affect the printing accuracy. Various techniques that can potentially minimize or eliminate printing defects and produce high-quality 3D/4D printed food products without the need for time-consuming trial and error printing experiments are critically discussed. Guidelines to avoid defects to improve the efficiency of future 3D/4D printed food production are given.

Advances and prospective applications of 3D food printing for health improvement and personalized nutrition

Three-dimensional food printing (3DFP) uses additive manufacturing concepts to fabricate customized designed products with food ingredients in powder, liquid, dough, or paste presentations. In some cases, it uses additives, such as hydrocolloids, starch, enzymes, and antibrowning agents. Chocolate, cheese, sugar, and starch-based materials are among the most used ingredients for 3DFP, and there is a broad and growing interest in meat-, fruit-, vegetable-, insect-, and seaweed-based alternative raw materials. Here, we reviewed the most recent published information related to 3DFP for novel uses, including personalized nutrition and health-oriented applications, such as the use of 3D-printed food as a drug vehicle, and four-dimensional food printing (4DFP). We also reviewed the use of this technology in aesthetic food improvement, which is the most popular use of 3DFP recently. Finally, we provided a prospective and perspective view of this technology. We also reflected on its multidisciplinary character and identified aspects in which social and regulatory affairs must be addressed to fulfill the promises of 3DFP in human health improvement.

Investigation of 4D printing of lotus root-compound pigment gel: Effect of pH on rapid colour change

The feasibility was investigated of 4D printing of lotus root gel compounded with a pigment that responds to pH change and alters colour. The pigment comprised of a combination of anthocyanins and lemon yellow; it was used in gel preparation for printing. The flowability and self-support properties of the lotus root-pigment gel were studied to evaluate its 3D printing performance. The gel viscosity decreased with the increase of printing temperature over the range 40, 50, and 60 °C. The gel with a ratio (lotus root powder/compound pigment) of 0.35 extruded smoothly and maintained high formability at temperatures below 60 °C. The pH response of compound pigment enabled the printed sample to change colour from reddish/yellowish to green after spraying with NaHCO₃. The a* and b* values decreased significantly (p < 0.05) after spraying for 1 min. The gel with ratios of 0.30 and 0.35 achieved rapid colour change both superficially and internally. Through several different model designs (apple, Christmas tree, letters, and Chinese characters), high-quality 4D printing could be realized without problem. Thus, lotus root gel can be mixed with suitable pigments in correct proportion for 4D printing at appropriate temperature to ensure good flowability.

Three-Dimensional Printing Using a Maize Protein: Zein-Based Inks in Biomedical Applications

The use of three-dimensional (3D) printing for biomedical applications has expanded exponentially in recent years. However, the current portfolio of 3D printable inks is still limited. For instance, only few protein matrices have been explored as printing/bioprinting materials. Here, we introduce the use of zein, the primary constitutive protein in maize seeds, as a 3D printable material. Zein-based inks were prepared by dissolving commercial zein powder in ethanol with or without polyethylene glycol (PEG400) as a plasticizer. The rheological characteristics of our materials, studied during 21 days of aging/maturation, showed an increase in the apparent viscosity as a function of time in all formulations. The addition of PEG400 decreased the apparent viscosity. Inks with and without PEG400 and at different maturation times were tested for printability in a BioX bioprinter. We optimized the 3D printing parameters for each ink formulation in terms of extrusion pressure and linear printing velocity. Higher fidelity structures were obtained with inks that had maturation times of 10 to 14 days. We present different proof-of-concept experiments to demonstrate the versatility of the engineered zein inks for diverse biomedical applications. These include printing of complex and/or free-standing 3D structures, tablets for controlled drug release, and scaffolds for cell culture.

Trends in functional food development with three-dimensional (3D) food printing technology: prospects for value-added traditionally processed food products

One of the recent, innovative, and digital food revolutions gradually gaining acceptance is three-dimensional food printing (3DFP), an additive technique used to develop products, with the possibility of obtaining foods with complex geometries. Recent interest in this technology has opened the possibilities of complementing existing processes with 3DFP for better value addition. Fermentation and malting are age-long traditional food processes known to improve food value, functionality, and beneficial health constituents. Several studies have demonstrated the applicability of 3D printing to manufacture varieties of food constructs, especially cereal-based, from root and tubers, fruit and vegetables as well as milk and milk products, with potential for much more value-added products. This review discusses the extrusion-based 3D printing of foods and the major factors affecting the process development of successful edible 3D structures. Though some novel food products have emanated from 3DFP, considering the beneficial effects of traditional food processes, particularly fermentation and malting in food, concerted efforts should also be directed toward developing 3D products using substrates from these conventional techniques. Such experimental findings will significantly promote the availability of minimally processed, affordable, and convenient meals customized in complex geometric structures with enhanced functional and nutritional values.