Ora-pro-nobis mucilage as a structuring ingredient in 3D printing formulations

3D food printing technology allows for the customization of food textures, shapes, and compositions, but challenges arise from the diverse properties of food matrices. Ink formulations must balance flowability during extrusion with structural stability. This study investigates the potential of Ora-pro-nobis (OPN) mucilage to enhance the structural integrity and printing precision of 3D-printed food by examining its impact on printing precision and rheological behavior. Food inks were formulated with varying proportions of protein (P), OPN mucilage (M), and starch (S), with total solids ranging from 13.7% to 42.7%. Of the formulations tested, seven were deemed printable. All printable inks exhibited non-Newtonian, pseudoplastic behavior. Thixotropic analysis showed that mucilage was crucial in preventing structural collapse after printing. The absence of mucilage (80P0M20S) resulted in the lowest recovery rate (∼25%), while increasing mucilage concentration improved the recovery rate, reaching 96% with 10% of its mucilage solids (70P10M20S). Similar trends were observed in printing accuracy. Reducing mucilage from 10% to 2% in samples 70P10M20S and 70P2M28S decreased printing accuracy from 95.5% to 89.34%, and 73.38% without mucilage (80P0M20S). Incorporating OPN mucilage in formulations enhanced ink elasticity, viscosity recovery rate, and printing accuracy, underscoring its crucial role in 3D food printing.