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Effect of Oil Content on the Printability of Coconut Cream
ink. The mass of the collected oil was weighed using a chewiness index. All TPA measurements were conducted
weighing balance. All measurements were conducted in at 25 ± 0.1°C on duplicate samples.
duplicates. The formula of oil separation ratio used was
as follows: 2.6. Statistical analysis
Oil separated All experimental data were expressed as mean ± standard
Oil separationratio =
Amount of oil added deviation with triplicate measurements. Data were
subjected to one-way analysis of variance (ANOVA)
2.3. Rheological characterization through Tukey’s test at 5% significance level using
statistical software (Minitab, Pennsylvania, USA).
Rheological measurements of coconut cream inks were
conducted using an oscillatory rheometer (Discovery 3. Experimental design
Hybrid Rheometer DHR-2, TA Instruments, Delaware, 3.1. Selection of materials
USA) with stainless steel parallel plates with a diameter
of 40 mm at a truncation gap of 1000 mm. Shear-thinning We selected coconut cream and coconut oil as an example
tests were conducted by applying a stepwise shear rate of our demonstration. Coconut cream contains both
ramp of 0.01–100 s . Stress sweep measurements were coconut oil and protein which provide good nutritional
−1
conducted with a logarithmically increasing shear stress value to human health . The proteins present in coconut
[36]
at a constant frequency of 1 Hz over the range of 0.1– cream act as an emulsifier that allows the dispersion of
2000 Pa. Excess food material was removed before the oil in the food system. Coconut oil, in contrast, contains
measurements to prevent edge effect. All rheological primarily saturated fatty acids that is 70% medium-chain
measurements were conducted at 25 ± 0.1°C in triplicates. fatty acids (MCFA), which are metabolized differently
compared to long-chain fatty acids (LCFA) commonly
2.4. DIW 3D printing found in human diets such as vegetable oils and dairy fat .
[37]
An extrusion-based DIW printer (SHOTmini 200 Sx, Consumption of LCFA would lead to the accumulation
Musashi Engineering, Inc., Tokyo, Japan) was used of fatty deposits within the artery walls that increase the
[38]
to perform 3D printing. The printer was placed in an risk of hypertension and cardiovascular diseases . The
enclosed box to maintain a sterile environment. All 3D metabolism of MCFA is quicker than that of LCFA. The
models were obtained from a public repository of 3D metabolic process converts fats into energy; the reduced
printable models, Thingiverse, and imported to Slic3r deposition of fats in the body tissues decreases the risk
[35]
of heart diseases . It was also reported that coconut
[39]
for slicing of the model into layers and generation
of G-code. The generated G-code was converted to oil possesses antioxidant properties that could boost the
[40]
MuCAD V (Musashi Engineering, Inc., Tokyo, Japan) immune system as well as prevent and treat infections .
code through a written Python script and loaded to the Coconut cream and coconut oil also serve as good
alternatives to existing vegetable oils such as canola oil.
DIW printer. All food inks were loaded into a 50-mL luer As such, coconut oils and creams are expected to offer
lock dispensing syringe fitted with 22 G (Birmingham potential advantages in healthcare. Despite potential
Gauge) nozzle. The standoff distance between the nozzle advantages in healthcare, to the best of our knowledge,
and substrate was adjusted to the layer thickness, 0.2 mm, 3D printing of coconut cream has not been shown in the
with a height feeler gauge. Both printing speed and previous studies.
dispensing pressure were kept constant at 15 mm/s and
0.050 MPa, respectively, throughout the printing process. 4. Results and discussion
All printings were conducted at room temperature.
4.1. Phase separation of coconut cream ink
2.5. Texture profile analysis
Initially, we studied the phase separation of the mixture
The texture profile analysis (TPA) was conducted on the 3D of the coconut cream and the coconut oil. We formulated
printed samples using a 10-kg load texture analyzer (CT3 the coconut cream base with coconut cream powder with
Texture Analyzer, Brookfield, USA). The printed samples different weight concentrations of water, and pandan
were placed at the center of the fixture base table before extract (Figure 1A). A fixed concentration of pandan
the measurements. All TPA measurements were conducted extract (0.2% w/w, with respect to coconut cream
with a probe with a diameter of 38.1 mm at pre-test speed powder) was added to the mixture to color the sample and
of 2.0 mm/s, test speed of 2.0 mm/s, post-test speed of observe the phase separation of the oil. Then, we added
2.0 mm/s, trigger force of 5.0 g, and compression strain varying weight concentrations of coconut oil (% w/w,
of 45% to determine the following textural properties: (i) with respect to coconut cream base) to the base. The oil
Hardness, (ii) adhesiveness, (iii) cohesiveness, and (iv) separated from the mixture was collected and weighed. As

116 International Journal of Bioprinting (2021)–Volume 7, Issue 2