## 3 Results and Discussion
### Loading Procedure and Restructuring of CM by Thermization  
For loading of disintegrated CM (PEF1 treated), 6 mL of \(\beta\)-carotene solution (c = 1.2 mg/100 mL) were added dropwise to 100 mL CM reentate using a magnetic stirrer for 60 min. Loading procedure was performed in a darkened room under red light. After different incubation times at 60 \({}^{\circ}\)C (t\({}_{\text{therm}}\) = 0, 15, 30, 45 min) for restructuring of CM (thermization), loading effectiveness was monitored by analyzing the \(\beta\)-carotene content (cf. 0) and surface potential of CM (cf. 0). As a control, CM suspension was pumped through the PEF unit, but no PEF treatment was applied (no disintegration). CM remain closed and it can be expected that no \(\beta\)-carotene was incorporated (cf. Figure 6a). For other samples, PEF parameters as determined for disintegration were applied (PEF1, see also Section 3). The corresponding state of CM is depicted in Figure 6b. The results in terms of surface potential and \(\beta\)-carotene content are summarized in Table 1.  
Figure 5: Modification of charge density of CM after PEF application with different pulse widths (15–25 \(\upmu\)s) and electric field strengths (10.7–20 kV/cm), applying a specific energy of 25 kJ/kg and an inlet temperature of 10 \({}^{\circ}\)C, compared to the values of an untreated CM sample (dashed line).  
Figure 6: Schematic diagram of CM state before (**a**) and after PEF treatment (**b**), as well as respective interaction with \(\beta\)-carotene molecules.  
As expected, the surface potential of the PEF1-untreated control sample after 15 min thermization was most negative compared to PEF1-treated samples with incubation times \(\geq\)15 min. The most negative surface potential implies that almost no disintegration took place and the CM were still closed. The negative value can be explained by carboxylate ions at the CM surface, which are densely arranged. As a result, no \(\beta\)-carotene could be incorporated into CM. Additionally, no \(\beta\)-carotene was found for the PEF1-treated sample without thermization (0 min). In this case, CM were disintegrated through PEF1, but due to the missing thermization procedure, CM were not rearranged or closed for incorporation of \(\beta\)-carotene molecules (Figure 6a). A slightly less negative surface potential and no \(\beta\)-carotene was found.  
However, the longer thermization after PEF1 is carried out, the less negative the surface potential is (cf. Table 1). One the one hand, this can be explained by the thermal activity of CM or motion of ions in CM, e.g., Ca\({}^{2+}\) ions, which are more present at the CM surface. On the other hand, diffusion of \(\beta\)-carotene molecules in not-completely disintegrated CM can also influence surface potential, leading to less negative values, as well. The maximum of \(\beta\)-carotene content in CM was found after PEF1 treatment and an incubation time of 30 min. In contrast, the incorporated amount of \(\beta\)-carotene was less after 45 min of incubation. As CM were treated with a higher temperature over a longer period of time, reorganization of CM is affected in a negative way and diffusion of \(\beta\)-carotene is possible (Figure 6b) so that a lesser amount of \(\beta\)-carotene molecules was found.  
As a result, PEF1 treatment can be regarded as necessary for the disintegration of CM, and only in combination with subsequent thermal treatment, can incorporation of \(\beta\)-carotene into CM be realized.