## 3 Results
### Rheological Properties  
From the shape changes of the flow curves of the HHP-treated blood plasma suspensions shown in Figure 1, it can be concluded that HHP treatment induced changes in the rheological properties of the blood plasma.  
The flow index (n) values (Figure 1d) clearly indicate that the control and the samples treated at 300, 400, 450 and 500 MPa exhibit dilatational (shear-thickening) rheological behavior. Dilatational rheological behavior means that the viscosity of the material increases with an increasing shear rate [38]. The flow index of the sample treated at 500 MPa already shows a decrease, but the extent of this decrease is not significant. The sample treated at 550 MPa also has dilatational properties, but this sample is more like Newtonian fluids and significantly different from the other samples showing dilatational rheological properties, as well as from the sample treated at 600 MPa. Presumably, pressure treatments up to 550 MPa caused reversible changes in protein structures and molecular interactions. This led to increased viscosity and flow resistance [33; 39]. The sample treated at the highest pressure is significantly different from the other samples and already exhibits pseudoplastic rheological behavior. In the case of this sample, the sample was already characterized by larger aggregates. In this sample, protein unfolding and aggregation disrupted the structural network, facilitating molecular alignment and reducing viscosity under shear  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Pressure** & **L*** & **a*** & **b*** & \(\Delta\)E* \\
**Levels [MPa]** & & & & \\ \hline
0 & 52.83 \({}^{\text{a}}\)\(\pm\) 1.27 & 0.22 \({}^{\text{a}}\)\(\pm\) 0.03 & 3.22 \({}^{\text{a}}\)\(\pm\) 0.16 & 0 \\
300 & 34.18 \({}^{\text{b}}\)\(\pm\) 1.16 & 0.86 \({}^{\text{b}}\)\(\pm\) 0.03 & 2.87 \({}^{\text{b}}\)\(\pm\) 0.08 & 18.66 \\
400 & 36.24 \({}^{\text{b}}\)\(\pm\) 0.88 & 0.81 \({}^{\text{b}}\)\(\pm\) 0.04 & 2.65 \({}^{\text{b}}\)\(\pm\) 0.14 & 16.60 \\
450 & 38.50 \({}^{\text{cd}}\)\(\pm\) 0.84 & 0.72 \({}^{\text{c}}\)\(\pm\) 0.07 & 2.49 \({}^{\text{b}}\)\(\pm\) 0.06 & 14.35 \\
500 & 38.24 \({}^{\text{cd}}\)\(\pm\) 1.35 & 0.41 \({}^{\text{d}}\)\(\pm\) 0.09 & 2.56 \({}^{\text{c}}\)\(\pm\) 0.07 & 14.60 \\
550 & 41.12 \({}^{\text{de}}\)\(\pm\) 1.32 & 0.43 \({}^{\text{e}}\)\(\pm\) 0.04 & 2.58 \({}^{\text{c}}\)\(\pm\) 0.05 & 11.74 \\
600 & 44.14 \({}^{\text{e}}\)\(\pm\) 1.25 & \(-\)0.47 \({}^{\text{e}}\)\(\pm\) 0.05 & 2.62 \({}^{\text{c}}\)\(\pm\) 0.08 & 8.73 \\ \hline \hline \end{tabular}  
* Different letters show significant differences (\(p<0.05\)).  
\end{table}
Table 1: The changes in the average values of the color (L*: lightness; a*: redness; b*: yellowness) of the HHP-treated blood plasma suspension and its color differences (\(\Delta\)E*) compared to the control sample.  
stress [40]. The \(y\)-axis intercept of the flow curve gives the yield stress (\(\tau_{0}\)) and provides information on whether a minimum shear stress value is required for the material to start flowing. Examining the yield stress values, it can be concluded that a slight decrease was observed in the sample treated at 300 MPa, and then higher values again characterize the samples treated at different pressure values. There is also a clear trend in the consistency coefficient (K) values, as samples treated at 550 and 600 MPa are significantly different from other samples and from each other, characterized by a higher consistency coefficient value. From this, we can conclude that the apparent viscosity values in these samples are also higher than in the control and in the samples treated at pressures lower than 550 MPa.