# The Study of Thermal Properties of Blackberry, Chokeberry and Raspberry Seeds and Oils
## 3 Results and Discussion
### Study of Seeds
#### 3.1.2 Differential Scanning Calorimetry of Seeds  
DSC curves of the heating of blackberry, chokeberry and raspberry milled seeds from \(-70\)\({}^{\circ}\)C to \(160\)\({}^{\circ}\)C are shown in Figure 1. For blackberry and raspberry seeds, the curves are comparable; the chokeberry seeds' heating curve has a different course. Despite the differences, all of the diagrams include four maximum points. Considering blackberry and raspberry seeds, one exothermic and three endothermic peaks are seen on the diagram. An endothermic peak appearing first at \(-40.35\)\({}^{\circ}\)C for blackberry and at \(-40.01\)\({}^{\circ}\)C for raspberry is due to the low-melting fraction of triacylglycerglycerols (TAGs) occurrence. Low-melting fractions generally consist of mono- and polyunsaturated fatty acids. Next, maximum signals and exothermic peaks (overlapping effect) of around \(-38\)\({}^{\circ}\)C represent the thermal transition connected with crystallization of polymorphic forms of TAGs. The endothermic maximums around \(-20\)\({}^{\circ}\)C appear due to middle-melting and high-melting fractions of TAGs which are represented by fatty acids of different structures, containing both unsaturated and also saturated fatty acids. Similar shapes of DSC curves of blackberry and raspberry seeds were reported by [PERSON] et al. (2018). The authors observed the same thermal transitions occurring due to the phase transitions of oil present in seeds and also described a phenomenon of polymorphism of fat in seeds as a cause of specific shape of the diagram in the region of temperatures at \(-50\)\({}^{\circ}\)C to \(-10\)\({}^{\circ}\)C. [PERSON] et al. (2019) reported similar DSC tracings for raspberry oil extracted from raspberry seeds with distinctive transitions correlated to the polymorphism of raspberry seed fat. Moreover, considering the polymorphism phenomenon, it is concluded that the first endothermic peak is a result of the melting of the less stable \(\alpha\) crystal form, and the exothermic signal comes from crystallizing the more stable \(\beta\) form of the oil.  
On the DSC curve for chokeberry seeds, three endothermic peaks are observed. The maximum signal at a temperature of around \(-18\)\({}^{\circ}\)C is present due to middle-melting and high-melting fractions of TAGs containing unsaturated and saturated fatty acids, as well as in the case of blackberry and raspberry seeds.  
The following two peaks at temperatures of around \(137\)\({}^{\circ}\)C and \(140\)\({}^{\circ}\)C occur as a consequence of carbohydrates transformation. Additionally, for blackberries and raspberries at a temperature of \(140\)\({}^{\circ}\)C, an endothermic peak is seen, which is a consequence of the carbohydrates' thermal transition. According to [PERSON] et al. (2018) and [PERSON] et al. (2018), the carbohydrates fractions of raspberry and chokeberry seeds are mainly fiber, so it can be claimed that the signals around \(120\)\({}^{\circ}\)C and \(140\)\({}^{\circ}\)C on the DSC curve come from fiber decomposition.  
Figure 1: _Cont._