Baking of 3D printed purple sweet potato and pumpkin powder mixture: Effects of 3D printing filament diameter and baking method on water transfer and Young's modulus during baking

Abstract

Water variation in post-processed 3D-printed foods with different 3D printing filament diameters (3D-PFD) critically affects their final quality. In this research, a purple sweet potato and pumpkin powder mixture (PPM) were utilized as the 3D printing ink and printed under different 3D-PFD. The printed samples then underwent oven and microwave baking. A temperature-dependent diffusion model and a Young's modulus model were applied to analyze water transfer during baking. The results inferred that the effective water diffusivity (D_eff) increased with the increment of the previous 3D-PFD and baking temperature. The D_eff during baking demonstrated distinct ranges across the 3D-PFD. For example, when the samples were printed under the 3D-PFD values of 1.2 mm and 0.8 mm, the D_eff values in the subsequent oven baking ranged from 2.20 × 10⁻⁹-2.25 × 10⁻⁹ m² s⁻¹ and 4.78 × 10⁻⁹ -4.87 × 10⁻⁹ m² s⁻¹, respectively. Meanwhile, the D_eff value of microwave baking was higher than that of oven baking. Moreover, the Young's modulus of the baked 3D-printed PPM sample exhibited a positive correlation with both the previous 3D-PFD and deformation degree during baking, as well as a negative correlation with its water content. These findings highlight the important role of 3D-PFD and post-processing methods on the final quality of 3D printed foods.