The increase in accessibility of fused filament fabrication (FFF) machines has inspired the scientific community to work towards the understanding of the structural performance of components fabricated with this technology. Numerous attempts to characterize and to estimate the mechanical properties of structures fabricated with FFF have been reported in the literature. Experimental characterization of printed components has been reported extensively. However, few attempts have been made to predict properties of printed structures with computational models, and a lot less work with analytical approximations. As a result, a thorough review of reported experimental characterization and predictive models is presented with the aim of summarizing applicability and limitations of those approaches. Finally, recommendations on practices for characterizing printed materials are given and areas that deserve further research are proposed.

Additive manufacturing, or 3D printing, has raised interest in many areas, such as the food industry. In food, 3D printing can be used to personalize nutrition and customize the sensorial characteristics of the final product. The rheological properties of the material are the main parameters that impact the 3D-printing process and are crucial to assuring the printability of formulations, although a clear relationship between these properties and printability has not been studied in depth. In addition, an understanding of the mechanical properties of 3D-printed food is crucial for consumer satisfaction, as they are related to the texture of food products. In 3D-printing technologies, each manufacturing parameter has an impact on the resulting mechanical properties; therefore, a thorough characterization of these parameters is necessary prior to the consumption of any 3D-printed food. This review focuses on the rheological and mechanical properties of printed food materials by exploring cutting-edge research working towards developing printed food for personalized nutrition.

The effect of high hydrostatic pressure (HHP) and temperature on composition of non-conventional dietary fiber (DF) sources and functional properties were evaluated. Mango, orange, or prickly pear peels were processed at 600 MPa during 10 min at 22 ℃ and 55 ℃. Total (TDF), soluble (SDF), and insoluble (IDF) dietary fiber, water/oil holding, and retention capacity, solubility, swelling capacity, and bulk density were assayed. An increment in the SDF content was observed due to the effect of pressure with the greatest changes noticed in mango peel, increasing from 37.4% (control) to 45.7% (SDF/TDF) in the HHP-treated (55 ℃) sample. Constant values of TDF after the treatments suggest a conversion of IDF to SDF in mango (38.9%–40.5% dw) and orange (49.0%–50.8% dw) peels. The highest fiber solubility values were observed for mango peel ranging between 80.3% and 83.9%, but the highest increase, from 55.1% to 62.3%, due to treatment was displayed in orange peel processed at 22 ℃. A relationship between DF modifications induced by HHP treatment and changes in the functional properties of the materials was established. Application of HHP opens up the opportunity to modify non-conventional sources of DF and to obtain novel functional properties for different food applications.