Enhancement of 3D-printability of zucchini puree by rice flour addition

This study explored the feasibility of 3D food printing with zucchini puree-rice flour mixtures, focussing on factors impacting print quality for home-based applications. The effects of printing variables, including fill ratio (25%, 50%, 75% and 100%) and printing bed temperature (65 degrees C, 75 degrees C and 85 degrees C), were assessed on the print quality of the samples, along with rice flour ratio and a freeze-thaw step commonly employed by general consumers. Increasing rice flour content enhanced water retention, leading to improved printability in terms of shape retention and dimensional accuracy. Higher printing surface temperatures promoted starch gelation in the initial layers, resulting in better shape retention and improved print scores at moderate rice flour ratios. The highest print quality, determined by dimensional accuracy and visual observations, was achieved with a rice flour puree ratio of 5:10, printed at a 100% infill ratio and 85 degrees C printing bed temperature. While freeze-thawing the mixtures preserved printability, it weakened the structure, leading to increased syneresis and spreading. Cooking fresh samples at 170 degrees C for 20 min after printing caused surface cracks, whereas freeze-thawed samples retained their smooth surface. Further research is needed to optimise printing parameters, considering typical preparation steps that may be applied to vegetable flour mixtures before and after 3D printing.