Abstract
This study optimizes the 3D extrusion printing parameters-water-to-flour ratio (X(1)), temperature (X(2)), and printing speed (X(3))-for raw (RFB) and extruded (EFB) dehulled Andean fava bean flours to maximize print quality and minimize structural defects. A 2(3) central composite design combined with response surface methodology (RSM) was used to identify the optimal conditions for achieving geometric precision, surface homogeneity, and textural stability. Physicochemical analyses showed that extrusion cooking substantially modified the composition and rheology of the flour. Compared with RFB, EFB exhibited lower protein and fiber contents, a higher proportion of digestible carbohydrates, and reduced rheological parameters (τ(0), K, G', G″), which facilitated printing. The evaluation of different parameter combinations revealed notable differences between the two flours, with X(1) and X(2) exerting the greatest influence on print quality. For RFB, the highest desirability (0.853) was achieved at X(1) = 0.806, X(2) = 23.18 °C, and X(3) = 2470.5 mm/min, yielding more uniform and firmer printed structures. In contrast, EFB reached a desirability of 0.844 at X(1) = 1.66 °C, X(2) = 56.82 °C, and X(3) = 1505.43 mm/min, indicating its outstanding geometric accuracy and robustness. In conclusion, raw flour requires higher hydration and lower temperatures to prevent excessive viscosity. In contrast, extruded flour benefits from low water and high temperatures to achieve stable structures and firm textures. These findings demonstrate the feasibility of using Andean fava bean flour in 3D food printing to create nutrient-dense, functional foods with improved printability. This work offers practical applications for developing personalized foods-such as customized meals for individuals with specific dietary requirements-while contributing to sustainable and secure food production. Future research should address long-term storage, post-printing drying methods, and scaling production.