Viability Study on the Use of Three Different Gels for 3D Food Printing.

Three-dimensional food printing is one of the modern techniques for food customization. The difficulty of this technique lies in the formulation of new matrices. These new formulations must have good extrusion characteristics and, at the same time, maintain the structure once printed. These qualities are related to textural and rheological properties. Printability studies are those whose objective is to know the above properties. Some authors have correlated printability with rheological and physicochemical parameters. The aim of this study was to characterize three gels to test prediction models and to determine the most important rheological and textural parameters (G', G″, Tanδ, maxF, average) in printability. The formulations studied were bovine gelatin (4%) with kappa-carrageenan (0.5%) (Gb + K), porcine gelatin (5%) plus iota-carrageenan (2%) (Gp + I), and methylcellulose (4%) (MC). The samples were characterized by an oscillatory test for the rheological properties and an extrusion test for the textural properties. In addition, the density was obtained to apply the predictive models and correlate the rheological and textural parameters to determine their influence. Gp + I and Gb + K showed higher values of maximum force in the extrusion test than MC, but MC had less deviation in the mean force during the test. All the samples showed a predominantly elastic behavior and damping factor (Tanδ) between 0.14 (Gb + K) and 0.37 (MC). It was observed that the tangent of the phase angle (Tanδ) had a large positive influence on the maximum and average force studied in the extrusion tests. The sample results did not match 100% with the predictions made from the models. It was possible to print samples that were higher in height without obtaining deformations over time of more than 5%. Further work is needed to optimize models and parameters for more accurate prediction.

Fiber Enrichment of 3D Printed Apricot Gel Snacks with Orange By-Products.

Concern about food waste has become a major global concern. The waste generated by the agri-food industry poses an environmental challenge. However, the development of 3D printing technology offers an opportunity to address this problem. By incorporating food waste into inks, it can create personalized food tailored to individual needs. The aim of this study is the valorization of orange by-products (OBP) in 3D printed gels to obtain a final product in the form of a fiber-enriched snack. Gelatin gels were printed with different concentrations of apricot pulp (30, 50, and 70%) and OBP was added. These gels were subjected to a freeze-drying process. The rheology of the gels before and after printing, the printing precision, and the post-treatment of the freeze-dried product, including color, shear force, and the presence of bioactive compounds, were evaluated. The addition of OBP resulted in an increase in the elasticity (997-1242u) of the samples and improved the printability of them. However, an increase in the hardness (173-184u) was observed in the freeze-dried samples. The use of OBP not only improves the printability of the gels but also enables obtaining fiber-enriched snacks, which could contribute to the reduction in food waste and the promotion of healthy and sustainable food.

Impact of Apricot Pulp Concentration on Cylindrical Gel 3D Printing.

The process of 3D food printing is a rapidly growing field that involves the use of specialized 3D printers to produce food items with complex shapes and textures. This technology allows the creation of customized, nutritionally balanced meals on demand. The objective of this study was to evaluate the effect of apricot pulp content on printability. Additionally, the degradation of bioactive compounds of gels before and after printing was evaluated to analyze the effect of the process. For this proposal, physicochemical properties, extrudability, rheology, image analysis, Texture Profile Analysis (TPA), and bioactive compounds content were evaluated. The rheological parameters lead to higher mechanical strength and, thus, a decrease in elastic behavior before and after 3D printing as the pulp content increases. An increase in strength was observed when the pulp content increased; thus, sample gels with 70% apricot pulp were more rigid and presented better buildability (were more stable in their dimensions). On the other hand, a significant (p < 0.05) degradation of total carotenoid content after printing was observed in all samples. From the results obtained, it can be said that the gel with 70% apricot pulp food ink was the best sample in terms of printability and stability.