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International Journal of Bioprinting 3D-printed diabetic diet

food inks. Each hexagon was assigned a score from 1 to properties of food inks. Right amount of XG enhances
5, with 5 representing the one with highest shape fidelity the extrudability, shear-thinning behavior, and structural
(Table 1). Preliminary tests were conducted to optimize the stability of the food inks. If the XG content is too high, the
ink formulation by evaluating the printability of hexagon food ink is difficult to extrude. If the XG content is too low,
specimens printed with various food ingredients, XG ratios, the food ink may not be able to maintain the structural
nozzle diameters, and fill densities. The compositions and stability. 21,39,40 On the other hand, Ink-M1-3 and Ink-M1-1
printing parameters of the specimens were planned using had similar dryness and water content, except for Ink-M1-1,
the design of experiment methodology. Three specimens which contained 0.45 wt% XG. Due to the absence of XG,
of each ink formulation were printed and evaluated the hexagon printed with Ink-M1-3 appeared damp, and
using the method described in previous publications, 21,34 the extrusion lines tended to spread. The optimized ink
18
and the formulation leading to the highest mean score based on Material-2 (Ink-M2-1) with a printability score of
was considered the optimized formulation in respective 4.46 ± 0.20 did not require the addition of XG to maintain
groups (Tables S1 and S2 in Supplementary File). Three the structural integrity of the 3D-printed object, owing
representative inks, including the optimized formulation, to its high starch and fat content known to enhance the
were selected from each ink material for further analysis. printability 41,42 of food inks (Figure 1D). Ink-M2-2 had a
Among the two types of food inks, Ink-M1-1 and Ink-M2-1 higher water content than Ink-M2-1, resulting in post-
receive the highest scores with a printability score of 4.53 ± print spreading, which led to a printability score of 3.97
0.13 and 4.46 ± 0.20, respectively. Compared to Ink-M1-1 ± 0.17 (Figure 1E). Conversely, Ink-M2-3 had a lower
(Figure 1A), both Ink-M1-2 and Ink-M1-3 exhibited water content than Ink-M2-1, and the resulting structure
inferior printability, scoring 1.55 ± 0.35 (Figure 1B) and 3D-printed with Ink-M2-3 received a printability score of
2.83 ± 0.20 (Figure 1C), respectively. Ink-M1-2 contained 3.09 ± 0.68. The printout exhibited similar characteristics
a higher proportion of Material-1 and a lower amount of to that printed with Ink-M1-2, showing segmented and
XG compared to Ink-M1-1, resulting in a drier consistency twisted extrusion lines (Figure 1F).
that made it more challenging to extrude from the nozzle
during printing. Consequently, the lines extruded with The rheological properties are used to assess the food
Ink-M1-2 appear segmented and twisted, failing to align ink’s ability to produce the desired pattern. The rheological
well with the toolpath to form the desired shape. XG is properties of all six inks listed in Table 1 were characterized
a common food thickener used to adjust the rheological and presented in Figure 2. It was observed that all six inks

Figure 1. Hexagons 3D-printed with the six food inks using a 0.84-mm nozzle for assessing the printability.

Volume 10 Issue 2 (2024) 300 doi: 10.36922/ijb.1862