Analyzing the effects of 3D printing process per se on the microstructure and mechanical properties of cereal food products

Texture characterization of 3D printed fibrous whey protein-starch composite emulsion gels as dysphagia food: A comparative study on starch type

Texture-modified, multi-nutrient composite foods are essential in clinical treatment for dysphagia individuals. Herein, fibrous whey protein-stabilized emulsion and different crystalline starches (wheat, corn, rice, potato, sweet potato, cassava, mung bean and pea) were used to structure composite emulsion gels (CEGs). These CEGs then underwent 3D printing to explore the feasibility of developing a dysphagia diet. The network of molded CEGs was mainly maintained by hydrophobic interactions and hydrogen bonds. Rice and cassava starches were better suited for structuring soft-textured CEGs. Compared with molded CEGs, 3D printing decreased hydrogen bonds and the compactness of the nano-aggregate structure within the gel system, forming a looser gel network and softening the CEGs. Interestingly, these effects were more pronounced for the CEGs with high initial hardness. This study provided new strategy to fabricate CEGs as dysphagia diet using fibrous whey protein and starch, and to design texture-modified foods for patients using 3D printing.

Improving the Three-Dimensional Printability of Potato Starch Loaded onto Food Ink

This study focuses on improving the 3D printability of pea protein with the help of food inks designed for jet-type 3D printers. Initially, the food ink base was formulated using nanocellulose-alginate with a gradient of native potato starch and its 3D printability was evaluated. The 3D-printed structures using only candidates for the food ink base formulated with or without potato starch exhibited dimensional accuracy exceeding 95% on both the X and Y axes. However, the accuracy of stacking on the Z-axis was significantly affected by the ink composition. Food ink with 1% potato starch closely matched the CAD design, with an accuracy of approximately 99% on the Z-axis. Potato starch enhanced the stacking of 3D-printed structures by improving the electrostatic repulsion, viscoelasticity, and thixotropic behavior of the food ink base. The 3D printability of pea protein was evaluated using the selected food ink base, showing a 46% improvement in dimensional accuracy on the Z-axis compared to the control group printed with a food ink base lacking potato starch. These findings suggest that starch can serve as an additive support for high-resolution 3D jet-type printing of food ink material.

Upcycling imperfect broccoli and carrots into healthy snacks using an innovative 3D food printing approach

Vegetables are healthy foods with nutritional benefits; however, nearly one-third of the world's vegetables are lost each year, and some of the losses happen due to the imperfect shape of the vegetables. In this study, imperfect vegetables (i.e., broccoli and carrots) were upcycled into freeze-dried powders to improve their shelf-life before they were formed into food inks for 3D printing. The rheology of the food inks, color analysis of the uncooked and cooked designs, and texture analysis of the cooked designs were determined. The inks with 50% and 75% vegetables provided the best printability and shape fidelity. 3D printing at these conditions retained a volume comparable to the digital file (14.4 and 14.3 cm3 vs. 14.6 cm3, respectively). The control, a wheat flour-based formulation, showed the lowest level of stability after 3D printing. The viscosity results showed that all the food inks displayed shear-thinning behavior, with broccoli having the greatest effect on viscosity. There was a significant color difference between uncooked and cooked samples, as well as between different formulations. The hardness of the baked 3D-printed samples was affected by the type and content of vegetable powders, where carrot-based snacks were notably harder than snacks containing broccoli. Overall, the results show that 3D food printing can be potentially used to reduce the loss and waste of imperfect vegetables.

Multivariate evaluation of the printing process on 3D printing of rice protein

The combination of printing parameters appropriately improves the printability of 3D-printed foods. In this regard, the present study aims to evaluate the effect of 3D printing process parameters on protein food generation. Printability of a cylinder 3 cm in diameter and 1 cm in height using a protein mixture of rice water and xanthan gum with a ratio of 30:70:0.5 was evaluated in an extrusion printer with an XYZ system. A ½ fractional factorial design was used with three factors: nozzle diameter (1.2 - 2.2 mm), layer height (1.0 - 2.0 mm), and print speed (20 - 50 mm/s). Each combination of factor levels was performed in triplicate for 12 runs plus three central points. Print time (min), sample weight, change in diameter (%), change in height (%), change in volume (%), mass flow rate (mg/s), appreciation (qualitative variable), and textural and rheology characters were obtained as response variables. The linear effects of the factors and combination factors were evaluated by analysis of variance. Additionally, a principal component analysis was performed to visualize the similarity between the observations and the relationship between the variables. The results showed that the layer height and nozzle diameter affect the printing accuracy concerning surface quality, shape stability, resolution, and layer layout. The nozzle with a diameter of 1.7 mm combined with speeds between 35 and 50 mm/s allowed the effects of overextrusion to be overcome, generating a better flow of the material. Low scores in the printability variable were related to low-speed values (20 mm/s) and a high nozzle diameter (2.2 mm), which generated higher deformations in the printed protein cylinder. Additionally, some printing conditions affected the textural and rheological characteristics, which allowed inferring that the capacity of the protein mass to store and recover energy in compression processes is conditioned by the printing parameters.

Mineral bioaccessibility in 3D printed gels based on milk/starch/ĸ-carrageenan for dysphagic people

Dysphagia is a condition that affects the ability to chew and swallow food and beverages, having a major impact on people's health and wellbeing. This work developed gel systems with a customized texture suitable for intake by dysphagic people using 3D printing and milk. Gels were developed using skim powdered milk, cassava starch (native and modified by the Dry Heating Treatment (DHT)), and different concentrations of kappa-carrageenan (ĸC). The gels were evaluated in relation to the starch modification process and concentration of gelling agents, 3D printing performance, and suitability for dysphagic people (following both the standard fork test described by the International Dysphagia Diet Standardization Initiative (IDDSI), and also using a new device coupled to a texture analyzer). Moreover, the best formulations were evaluated for mineral bioaccessibility through simulated gastrointestinal digestion based on INFOGEST 2.0 standardized method. The results showed that ĸC had a dominant effect compared to the DHT-modified starch on gel texture, 3D printing performance, and fork tests. The gels obtained by molding or 3D printing resulted in different behaviors during the fork test, which was associated with the gel extrusion process that breaks down their initial structure. The strategies applied to tailor the texture of the milk did not affect the mineral bioaccessibility, which was kept high (>80%).

Texture modulation of starch-based closed-cell foams using 3D printing: Deformation behavior beyond the elastic regime

3-dimensional printing is a novel processing method used for the design and manipulation of food textures. The systematic characterization and modulation of 3D printed food textures is imperative for the future design of sensory profiles using additive manufacturing. For 3D printed closed-cell food foams, the clarification of the deformation behavior in relation to design parameters is of interest for the processing of customized food textures. For this reason, we studied the deformation behavior of 3D printed and thermally stabilized closed-cell starch-based foams beyond the elastic regime. Periodic spherical bubble configurations at different porosity levels were used to modulate the deformation behavior of the printed foams. From a processing perspective, the integration of in-line thermal stabilization was used to eliminate post-processing and to control the moisture content of the starch-based system. Compression analysis combined with FEM simulations were performed to characterize the strain rate dependency of textural properties, the stress relaxation, and the foam's stress-strain behavior with respect to the design porosity and bubble distribution. Results showed that the stress relaxation is solely dependent on cell wall properties while different stress-strain regimes showed distinct dependencies on design parameters such as bubble size and distribution. Consequently, the precise control of the large deformation behavior of foods using 3D printing is challenging due to the superposition of structural and geometrical dependencies. Finally, through the presented approach, the structure-deformation relations of 3D printed closed-cell food structures are adequately described.

3D food printing improves color profile and structural properties of the derived novel whole-grain sourdough and malt biscuits

Presentation of foods is essential to promote the acceptance of diversified and novel products. This study examined the color profile, browning index (BI), and structural properties of 3D-printed and traditional biscuits from whole-grain (WG) sourdough and germinated flours. The processed flours and composite/multigrain flours comprising cowpea sourdough (CS) and quinoa malt (QM) were used to prepare the snacks, and their structural characteristics were determined. Compared with the traditional biscuits, the 3D-printed biscuits showed considerable distinction in terms of consistent structural design and color intensities. The in-barrel shearing effect on dough biopolymers, automated printing of replicated dough strands in layers, and expansion during baking might have caused the biscuits’ structural differences. The composite biscuit formulations had a proportional share of CS and QM characteristics. The 80% CS and 20% QM printed biscuit had a low redness and BI, increased cell volume, average cell area, and total concavity. The 60% CS and 40% QM printed snack showed improved lightness and yellowness, increased average cell elongation, and less hardness. The 3D-printed composite biscuits may be recommended based on their unique structural characteristics. Such attributes can enhance the acceptability of printed foods and reinvent locally prepared meals as trendy, sustainable, and functional foods.

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.

Towards the creation of personalized bakery products using 3D food printing

Bakery products with interesting color, shape and texture have been created using 3D food printing. Current research focuses on the development of new formulations and the optimization of the printing and post-printing treatment processes, in order to obtain high-quality 3D-printed bakery products. Knowledge about food rheology is useful for the development of dough formulations with good 3D-printability. Additives such as hydrocolloids could improve the printability of dough, and novel ingredients are introduced via 3D printing to produce functional bakery products with potential health benefits. One of the main future promises of 3D printing lies in its ability to produce bakery products that are personalized in terms of sensorial properties and nutritional composition, in order to meet the preferences and dietary requirements of individual consumers. This chapter addresses the most recent developments in 3D-printed bakery foods and highlights some important research topics to further advance this field.

Control of starch-lipid interactions on starch digestibility during hot-extrusion 3D printing for starchy foods

The nutritional design of personalized starchy foods has become a research hotspot in the field of food science. Driven by the immense functional and nutritional implications of starch-lipid binary interactions, this study is aimed at designing starch digestibility by controlling the interaction between starch and glycerol monostearate (GMS)/stearic acid (SA) using a hot-extrusion 3D printing (HE-3DP) environment. The results indicated that the thermal shear force in the HE-3DP environment promoted hydrophobic interactions between starch and lipids, forming a V-type starch-lipid complex with a compact and ordered structure, thus enhancing enzymatic resistance. Compared with GMS, SA with linear hydrophobic chains was inclined to compound with starch to form a more ordered structure. Interestingly, the slowly digestible starch (SDS) and resistant starch (RS) content reached 25.06% when the added SA content was 10%. Besides, correlations between the structural parameters and digestibility were established, which provided crucial information for designing nutritional starchy food systems using HE-3DP.

Three-dimensional printed personalized drug devices with anatomical fit: a review

OBJECTIVES

Three-dimensional printing (3DP) has opened the era of drug personalization, promising to revolutionize the pharmaceutical field with improvements in efficacy, safety and compliance of the treatments. As a result of these investigations, a vast therapeutic field has opened for 3DP-loaded drug devices with an anatomical fit. Along these lines, innovative dosage forms, unimaginable until recently, can be obtained. This review explores 3DP-engineered drug devices described in recent research articles, as well as in patented inventions, and even devices already produced by 3DP with drug-loading potential.

KEY FINDINGS

3D drug-loaded stents, implants and prostheses are reviewed, along with devices produced to fit hard-to-attach body parts such as nasal masks, vaginal rings or mouthguards. The most promising 3DP techniques for such devices and the complementary technologies surrounding these inventions are also discussed, particularly the scanners useful for mapping body parts. Health regulatory concerns regarding the new use of such technology are also analysed.

SUMMARY

The scenario discussed in this review shows that for wearable 3DP drug devices to become a tangible reality to users, it will be necessary to overcome the existing regulatory barriers, create new interfaces with electronic systems and improve the mapping mechanisms of body surfaces.