Porous Architecture in 3D Food Printing: Advances in Formulation, Process Control, and Sustainable Structural Design.

3D food printing offers precise control over the shape, texture, and nutritional profile of edible structures, enabling high customization. A key yet under-explored feature in this field is the internal porous architecture, which significantly affects mechanical strength, texture, and overall functionality. This review examines how ingredient formulation-particularly polysaccharides and proteins-and printing parameters such as temperature, flow rate, velocity, and nozzle diameter influence the formation of inter-strand macropores and intra-strand micropores. Emphasis is placed on pore-generation and stabilization techniques, especially freeze-drying and emulsion templating, which enable the creation of well-defined porous networks. The intentional design of hierarchical porosity-combining both macro- and micro-scale structures-emerges as a promising strategy for producing lightweight, mechanically robust, and sensorially rich food products. These porous architectures can reduce raw material consumption while maintaining consumer appeal, aligning with goals of food sustainability. In this context, porosity is not merely a structural attribute but a critical design variable for optimizing performance and environmental impact. By connecting internal structure with functional outcomes, this review aims to support the development of next-generation 3D-printed foods that are resource-efficient, nutritionally tailored, and aligned with sustainable production practices.