This study investigates the viscosity and creep behavior of peanut protein isolate (PPI) paste incorporated with rice starch (RS) for potential applications in 3D printing. The change in flow properties during the 3D printing was also studied by numerical simulation. The paste exhibited shear-thinning behavior with yield stress. The pressure predicted from the Herschel-Bulkley model showed higher values than those derived from the Power-Law model. The PPI and RS levels had negligible influence on velocity and shear rate; however, they showed greater dependence on the inflow rate. The fractional element model described the creep data well (R2 > 0.9). The addition of PPI resulted in increased viscosity, simulated pressure, and mean extrusion force, with similar effects observed for RS, except at higher PPI levels. Furthermore, the 3D-printed objects revealed that deformations were pronounced at low concentrations of PPI and RS, while resolution suffered when employing higher concentrations of PPI and RS. Using peanut protein isolate, a plant-based high protein ingredient in 3D printing, reduces energy consumption, thereby reducing carbon footprints, offers improved functional properties, and diversifies dietary options by offering an alternative protein source from peanuts. The printing is influenced by the rheological properties of food ink. Thus, knowing the rheological properties of food ink can help researchers and industries to prepare food inks with desired properties. The observations of numerical simulation of this work have the potential to offer practical insights for designing 3D printing systems. In summary, this work has the potential to aid in improving and developing food ink for 3D printing, hence enhancing the performance of extrusion-based 3D food printers. [Display omitted] • Investigation into the potential application of PPI paste incorporated with RS for 3D printing. • Numerical simulation to analyze the change in flow properties during 3D printing. • Modeling of steady-state and creep rheology using viscosity models and fractional element models, respectively. • The addition of PPI resulted in increased viscosity, simulated pressure, and firmness of the paste. [ABSTRACT FROM AUTHOR]