## 3 Results and Discussion
### The Composition of Oil and Lactiaseibacillus rhamnus Viability
As the above shows, the type of fatty acids has an ambiguous effect on the viability of probiotic bacteria during the spray drying process. The Thermal Characterization of Oils Using Differential Scanning Calorimetry (DSC) and the Effect of the Melting Temperature of Oils on the Viability Rate of Bacteria Cells After Spray Drying  
The most widely used technique for the thermal characterization of oils is differential scanning calorimetry (DSC). To characterize the thermal behavior of various oil samples, commonly both melting and crystallization heat transfer parameters are used, which requires the intake or release of thermal energy that corresponds to process enthalpy [44]. For the oil samples used in this study, DSC measurements were made to compare the melting and crystallization transition temperatures. For all oil samples, one could observe that the first exothermic peaks are between \(-67.7\) and \(-58.6\)\({}^{\circ}\)C, except for forage oil. In this temperature range, these oils have a tendency to crystallize. No exothermic peak occurred for the forage oil sample as it doesn't release energy to the system, whereas an endothermic peak was obtained for it at a similar temperature at \(-63.70\)\({}^{\circ}\)C. This oil is the only one that begins to melt at such a low temperature, which is due to the slightly different content of specific fatty acids. It has the lowest content of both oleic and linoleic acid (compared to other oils), secondly, it has a relatively high content of vitamin E and the additional presence of \(\gamma\)- linoleic acid (Table 3). As noted above, the highest bacterial cell viability during the spray drying process was observed for both 20% and 30% addition of borage oil (Figure 1). For all oil samples, there are endothermic peaks in the range between \(-31\)\({}^{\circ}\)C and \(-24.7\)\({}^{\circ}\)C which refers to their melting processes. The additional endothermic peaks were observed in other temperatures: for pumpkin oil \(-14.45\)\({}^{\circ}\)C and \(-7.64\)\({}^{\circ}\)C, for borage oil \(-9.61\)\({}^{\circ}\)C and for milk thistle \(-3.89\)\({}^{\circ}\)C (Table 3). [PERSON] et al. [38] performed DSC analysis in the temperature range from 0 \({}^{\circ}\)C to 80 \({}^{\circ}\)C. There were not any endothermic and exothermic peaks for emulsions based on vegetable oils. Similarly in this study, the transition peaks in the temperature range 20 \({}^{\circ}\)C to 100 \({}^{\circ}\)C which is characteristic for the whole spray-drying process have been not observed [38]. [PERSON] et al. [45] spray dried LGG in coacervates formed by whey protein isolate-high melting point fat shortening oil (SO) and gum arabic through complex coaervation. DSC analysis showed that the addition of shortening oil reduced the temperature of particles by increasing the enthalpy of melting during the spray drying process [45]. In general, the thermal properties of different oils can be characterized by various transition temperatures. DSC provides useful information about thermodynamic changes that are associated with the oils transforming from one to another physical state. We have also tried to verify whether the melting temperature of oils and their final content in the system correlate with the viability rate of bacteria cells after spray drying (Figure 4). It was observed that in the case of milk thistle, pumpkin, hemp, and nigella oil, the viability rate of LGG after the drying process with the addition of a smaller (20% wt.) amount of these oils increases with the increase of the melting temperature of these oils, while in the case of a larger amount (30% wt.) of these oils, there is an opposite relation. This indicates that during the spray-drying process, not only the type of oil but also the final content in the system influences the viability rate of bacteria.