## 3 Results and Discussion
### Particle Size Distribution and Surface Morphology of Powders  
The viscosity of solutions subjected to drying is influenced by the type of ingredients used and their concentration. Depending on the viscosity of the solution the average size of powders can be modified. Where together with higher viscosity, one could observe the increase in both: sizes of formed liquid droplets and as a result of final dry powders. High molecular weight materials that promote gelation, can lead to an increase in the diameter of the spray-dried powders [53].  
As shown in Figure 5, one could observe significant differences in the particle size distribution of analyzed powders with both 20% and 30% oil. Materials which are partially insoluble in water and therefore form a suspension tend to form agglomerates when dried [54]. Therefore, for final confirmation of their \"real size\" and examination of surface morphology, we used the additional microscopic observations.  
Figure 5: _Cont._  
Figure 5: _Cont_.  
The reference powder sample has a monomodal particle size distribution, while all powder systems with 20% oil have a bimodal distribution of particles, and powders with 30% oil are mostly trimodal (except pumpkin and milk thistle) (Figure 5). Therefore, such examination of particle size distribution is very important because it confirms the entire range of powder particle sizes.  
The close analysis of powder particles by scanning electron microscopy confirms that the LSD results of the average particle size D4,3 reflect various forms of agglomerates than to the average size of single particles.  
The SEM micrographs in Figure 5 show the surface of various microcapsules with 20% of evaluated oils. The surface morphologies of microcapsules with a higher oil content (30%) were very similar and, therefore, they are not presented in this publication.  
All collected photos generally indicate that capsules are significantly smaller in size than those measured with the LSD technique. Probably during these measurements, the dispersion energy of flow air was too low to overcome the interactions between the microcapsules in powder form. Therefore, it is important to use both D4,3 parameters and analyze whole diagrams of particle size distributions and compare them with observations by scanning electron microscopy (SEM) for accurate and precise real particle size analysis.  
No cracks were noticed on the external surfaces of various particles, which indicated good protection of immobilized probiotics against various gasses, including oxygen and moisture, resulting in high encapsulation efficiencies and good effectiveness of protection, both just directly after the drying process and during long-term storage [55].  
[PERSON] et al. [50] encapsulated _Lbs. rhamnus_ cells by spray drying using 10% (w/w) gum Arabic, 5% (w/w) gum Arabic blended with 5% (w/w) gave truncans/maltodextrin/insulin or trehalose as wall materials. They also observed particles with a partially spherical shape did not show visual fractures or cracks on their surface [50].  
Figure 5: Particle size distribution of powders systems with 20% wt. and 30% wt. and SEM micrographs of spray-dried powders with 20% wt. of different oils.  
Powder particles containing different oils had similar morphology, indicating that the type of oil had no effect on the appearance of the microcapsules. Most of the microcapsules were spherical in shape with dimpled surfaces and sizes in the range from 0.4 to 21 \(\upmu\)m.  
Similar SEM micrographs of the microcapsules containing _L. acidophilus_ NCIMB701748 stabilized in a 3-component carrier based on maltodextrin: whey protein concentrate: D-glucose 60:20:20 (w/w) were obtained by [PERSON] et al. [56]. They observed that the structure of the powder had a partially collapsed spherical shape [56]. According to [PERSON] et al. [57] these irregularities were formed due to the slow film formation during SD of the atomized droplets and uneven shrinkage during the early stages of drying [57].