## 3 Results and Discussion
### Differential Scanning Calorimetry--Phase Transitions and Crystallisation Curves
It was observed in all the DSC diagrams (Figure 13). The second endothermic peak present in all the curves corresponded to the melting of \(\alpha\)-lactose. The third endothermic peak observed in the DSC curves was typical for the melting of \(\beta\)-lactose [50]. [PERSON] et al. [24] determined the DSC curves of infant formula powders with different compositions. Based on the DSC diagrams, the differences in the compositions of the tested powders were observed. Figure 14 presents the DSC cooling curves of the powdered mixtures of the infant formulas and the agglomerates, A1, A2, and A3, obtained from them. The DSC diagrams of all the mixtures with added fatty acid preparations showed the presence of three small exothermic peaks in the temperature range from \(-\)16 to \(-\)46 \({}^{\circ}\)C, with the maximum temperatures at the crystallisation temperatures of the fatty acids from the n-3 and n  
6 groups. A distinct peak characteristic of milk fat was observed for the M1 mixture (Figure 14). The DSC curves of the M2 and M3 mixtures were characterised by very slight peaks at temperatures of \(-\)23.13 and \(-\)40.42 \({}^{\circ}\)C, respectively. In the case of the M2 sample, an distinct exothermic peak at a temperature of \(-\)2.52 \({}^{\circ}\)C was observed in the cooling curve. Distinct exothermic peaks were observed in the DSC cooling diagrams of the M2 and M3 mixtures, with a maximum temperature of \(-\)31.12 \({}^{\circ}\)C. This was due to a significant (34%) share of n-6 fatty acids in these infant formulas. The DSC curves of the M2 and M3 mixtures were characterised by a weak exothermic peak at a temperature of approximately \(-\)76.54 \({}^{\circ}\)C. In the DSC cooling curves, the observed peaks indicated the presence and amount of all the fatty acids that were added or were present in the compositions of the powdered infant formulas. Based on the course and shape of the DSC cooling diagrams, it can be concluded that the M1 mixture and the A1 agglomerate obtained from it included whole milk powder (Tables 1 and 2). The course and shape of the exothermic peak indicated the crystallisation of the milk fat. The weak exothermic peaks observed in the DSC cooling curves indicated the presence of added fatty acids from n-3 and n-6 preparations (Figure 14). The DSC cooling curves for agglomerates A2 and A3 (Figure 14) had a course similar to that of the DSC cooling curve for the M2 mixture. It was observed that the heat flow through the powders was at different levels. Different levels of heat flow were observed for the A2 agglomerate and for the A3 agglomerate. The DSC cooling curves were characterised by three exothermic peaks in the temperature range from \(-\)22 to \(-\)42 \({}^{\circ}\)C. The peaks corresponding to the crystallisation of fatty acids from the n-3 group were much less pronounced than the peaks of the fatty acids from the n-6 group. The addition of the n-6 fatty acid preparation to the M2 mixture and the agglomerates obtained from it was approximately 34% (Tables 1 and 2), as indicated by the intensity of the exothermic peaks at a temperature of \(-\)31.78 \({}^{\circ}\)C (Figure 14). There were no impacts of agglomeration and the use of various wetting liquids on the shape and course of the DSC cooling curves of the agglomerates formed from appropriate mixtures. [PERSON] et al. [22] studied mixtures and powdered infant formulas. They determined DSC cooling curves for mixtures, agglomerates, and coated agglomerates. They indicated that the cooling curves allowed the detection of the presence of added fats. Figure 14: DSC cooling curves of powdered infant formula mixtures M1, M2, and M3 and agglomerates A1, A2, and A3. Figures 15 and 16 present the influences of storage on the thermal properties of mixtures and agglomerates of powdered infant formulas. After a period of six months of storage, the DSC diagrams of the samples were characterised by changes in the shape and course.