From Rheology to Reality: A Decade of Protein-Based 3D Food Printing Research

Protein-based food 3D printing has emerged as a key technology for developing sustainable, personalized, and functional products. This review critically analyzes the scientific evolution of the field between 2014 and 2025 through a bibliometric and functional analysis of 590 articles indexed in Web of Science. Data science tools (keyword co-occurrence, thematic maps, and multiple correspondence analysis) were applied to identify trends, emerging themes, and conceptual relationships. The analysis revealed two main lines: one focused on complex emulsions and the other on vegetable formulations optimized with hydrocolloids. The rheological properties and the type of protein isolate prove to be fundamental axes in the formulation of food inks. It was identified that the type of ingredient (hydrocolloids, lipids, enzymes) and their interaction with proteins directly influence the viscosity, elasticity, extrudability, and shape retention capacity of the inks. Additionally, post-processing methods (baking, microwaving, and enzyme treatment) have a significant impact on the texture, stability, and overall acceptance of the final product. From experimental and literature data, unsupervised classification models (K-means, GMM, hierarchical clustering) based on rheological variables (G′, G″, tan δ) were developed, which allowed the identification of three groups of inks with differential behavior, associated with printing parameters such as nozzle diameter, speed, and filling percentage. Visualization by PCA showed how these properties impact extrusion and structural fidelity. These findings underscore the importance of an integrated understanding of formulation, rheology, printing conditions, and post-processing to optimize the quality and functionality of printed foods, representing a key step towards their industrial implementation.