## 3 Results and Discussion
### Physical Properties of Algal Pigment Microparticles  
Table 3 shows the colour change of microparticles in comparison with PEG. In comparison with PEG, the L value was reduced while redness slightly increased. Moreover, the yellowness of the powder significantly increased, which is probably linked to encapsulated pigments. As previously reported, chlorophyll a, chlorophyll b and carotenoids are the major pigments that contributed to the photosynthetic performance of _Fucus_[29]. They probably remained on the surface of the microcapsule and gave the final particles their green-brown colour. It is perceptible that after the PGSS process, microparticles became lighter. This effect occurs due to the encapsulation effect, where pigment particles are entrapped into the shell material.  
Results for WAI and WSI showed that the PGSS process improved the solubility of dry extract microparticles in comparison with RAM. The solubility properties of pigment microparticles were similar to PEG properties. This could be related to the loss of structural order, caused by the penetration of water. Another reason for increased solubility could be the reduction of the particle size resulting in increased total surface area (Table 3). WSI values of extract microparticles were very similar to the WSI of pure PEG, indicating that WSI depends directly on the properties of the coating materials, which was also found by [PERSON] et al. [30]. Lower WSI values of RAM encapsulated in PEG could be assigned to the presence of insoluble fibre in algal material. In addition, when WAI and WSI are compared, one trend can be observed where the percentage of water absorption decreases with increased water solubility of the microparticles. However, even though high water solubility is desired for application in the food and pharmaceutical industry, some additional analyses also need to be conducted. According to [PERSON] et al. [31] agglomeration of the encapsulated particles could contribute to a smaller WAI, and subsequently increase WSI.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Micro** & **Dry Matter** & **Mean** & **COLOR** & **\(\Delta\)E** & **WI** & **WAI (g/g)** & **WSI (\%)** \\ \hline PEG & 98.67 & - & - & - & 0.073 & 99.71 \\ \hline RAM+PEG & 98.66 & 24.09 & & 13.34 & 80.59 & 0.490 & 93.32 \\ \hline SCO\({}_{2}\)E+PEG & 99.47 & 16.49 & & 7.97 & 85.84 & 0.097 & 98.71 \\ \hline CON+PEG & 98.92 & 17.68 & & 9.41 & 84.42 & 0.190 & 97.86 \\ \hline WAT+PEG & 98.99 & 17.98 & & 15.92 & 77.96 & 0.195 & 97.64 \\ \hline \hline \end{tabular} \(\Delta\)E—colour change, WI—whiteness index, WAI—water absorption index, WSI—water solubility index, RAM+PEG—raw algal material, SCO\({}_{2}\)E+PEG—extract obtained with supercritical extraction, CON+PEG—dry extract obtained with conventional extraction, WAT+PEG—dry extract obtained with ethanol/water extraction, PEG—polyethylene glycol.  
\end{table}
Table 3: Dry matter and physical properties for pigment microparticles obtained with the PGSS process.  
The final microparticle water content can be utilized to estimate how stable they will be during storage. The final level for all microparticles was below 2%. Results indicate that relatively dry and microbiological stable powders can be obtained by the PGSS process [32].  
The bulk density of the microparticle is a crucial parameter that indicates how effectively the microparticle fits compactly. In handling and processing procedures such as transportation, mixing, compression, and packing, the microparticle's flowability and cohesiveness are crucial [33]. As particle size decreases, the cohesivity of powder should increase. As the forces between the particles weaken, a free-flowing powder has a higher bulk density and is therefore packed more densely [34; 35]. According to flowability data (Figure 6), CON+PEG and RAM+PEG microparticles have excellent flowability, while the flowability properties of WAT +PEG microparticles were fair, and for CO\({}_{2}\)+PEG they were passable.