The future of 3D food printing: Opportunities for space applications.

Over the past decade or so, there have been major advances in the development of 3D printing technology to create innovative food products, including for printing foods in homes, restaurants, schools, hospitals, and even space flight missions. 3D food printing has the potential to customize foods for individuals based on their personal preferences for specific visual, textural, mouthfeel, flavor, or nutritional attributes. Material extrusion is the most common process currently used to 3D print foods, which is based on forcing a fluid or semi-solid food "ink" through a nozzle and then solidifying it. This type of 3D printing application for space missions is particularly promising because a wide range of foods can be produced from a limited number of food inks in a confined area. This is especially important for extended space missions because astronauts desire and require a variety of foods, but space and resources are minimal. This review highlights the potential applications of 3D printing for creating custom-made foods in space and the challenges that need to be addressed.

Advancements in 3D food printing: a comprehensive overview of properties and opportunities.

3D printing has numerous applications in the food industry that may enhance diversity, quality, healthiness, and sustainability. This innovative additive manufacturing technology has the ability to specifically tailor food properties for individuals. Nevertheless, several challenges still need to be overcome before 3D printing can be utilized more widely in the food industry. This article focuses on the development and characterization of "food inks" suitable for 3D printing of foods. Specifically, the main factors impacting successfully printed foods are highlighted, including material properties and printing parameters. The creation of a 3D printed food with the appropriate quality and functional attributes requires understanding and control of these factors. Food ink printability is an especially important factor that depends on their composition, structure, and physicochemical properties. Previous studies do not sufficiently describe the precise design and operation of 3D printers in sufficient detail, which makes comparing results challenging. Additionally, important physicochemical characteristics utilized in traditional food are not consistently reported in 3D inks, such as moisture content, water activity, and microbial contamination, which limits the practical application of the results. For this reason, we highlight important factors impacting 3D ink formulation and performance, then provide suggestions for standardizing and optimizing 3D printed foods.

An innovative filtration based Raman mapping technique for the size characterization of anatase titanium dioxide nanoparticles.

Characterization of titanium dioxide nanoparticles (TiO2-NPs) is of significant importance in the production quality control, applications and study of their toxicological effects. In this study, we developed a filtration-based Raman mapping technique as a rapid approach for the analysis of different sizes and concentrations of anatase TiO2-NPs. Four different sizes of TiO2 standards: 173, 93, 41, and 8 nm measured by electron microscopy techniques were dispersed using a probe sonicator with sodium pyrophosphate as a dispersing agent. The resulting hydrodynamic diameter measured by dynamic light scattering (DLS) was stabilized at 192, 289, 325, and 360 nm respectively as a negative correlation with the ones by TEM. These NPs were then collected on a 0.1 µm (pore size) filter membrane with a vacuum pump and scanned using a Raman imaging microscope. The result shows that the 100 × objective lens was more capable of detecting the smallest size particles (8 nm) and lowest concentration (0.0004 g L-1) evaluated than the 20 × objective lens. Moreover, at low concentrations (i.e. 0.0004 and 0.004 g L-1), we established a linear correlation between the map area covered by the particles and the particle size measured by TEM. While at higher concentration (i.e. 0.04 g L-1), a positive correlation was established between the particle size and its corresponding Raman intensity. These results demonstrated a successful application of Raman mapping technique in rapid characterization of the size of anatase TiO2-NPs as small as 8 nm, which will facilaite the TiO2-NPs research, production, and applications.

Role of Mucin in Behavior of Food-Grade TiO2 Nanoparticles under Simulated Oral Conditions.

Fine titanium dioxide (TiO2) particles have been used as additives (E171) to modify the optical properties of foods and beverages for many years. Commercial TiO2 additives, however, often contain a significant fraction of nanoparticles (diameter <100 nm), which has led to some concern about their potentially adverse health effects. At present, relatively little is known about how the characteristics of TiO2 particles are altered as they travel through the human gastrointestinal tract. Alterations in their electrical characteristics, surface composition, or aggregation state would be expected to alter their gastrointestinal fate. The main focus of this study was, therefore, to characterize the behavior of TiO2 particles under simulated oral conditions. Changes in the aggregation state and electrical characteristics were monitored using particle size, ζ-potential, turbidity, and electron microscopy measurements, whereas information about mucin-particle interactions were obtained using isothermal titration calorimetry and surface-enhanced Raman spectroscopy. Our results indicate that there was a strong interaction between TiO2 and mucin: mucin absorbed to the surfaces of the TiO2 particles and reduced their tendency to aggregate. The information obtained in this study is useful for better understanding the gastrointestinal fate and potential toxicity of ingested inorganic particles.

Emulsions as delivery systems for gamma and delta tocotrienols: Formation, properties and simulated gastrointestinal fate.

Tocotrienols have been reported to have stronger bioactivities than tocopherols, and may therefore be suitable as a potent source of vitamin E in functional foods, supplements, and pharmaceuticals. However, their inclusion into new products is hindered by their low water-solubility and oral bioavailability. Oil-in-water emulsions (O/W) could provide an adequate delivery system for these bioactive compounds. Tocotrienols were tested in bulk oil and within O/W conventional emulsions (>10µm) and nanoemulsions (<350nm). The emulsions were prepared with medium chain triglycerides (MCT) as an oil phase (5 to 40% wt) and quillaja saponins as a natural surfactant. The gastrointestinal fate of the emulsion-based delivery systems was investigated using a simulated gastrointestinal tract (GIT). The physical properties of the emulsions (color, apparent viscosity) were affected with increased droplet concentration. The lipid phase composition (emulsion type and particle size) had a pronounced impact on the microstructure of the emulsions in different regions of the GIT. At simulated small intestine conditions, the rate of lipid digestion and tocotrienol bioaccessibility decreased in the following order: nanoemulsions>emulsions>bulk oil. These results suggest that emulsions containing small lipid droplets are particularly suitable for delivering tocotrienols.