# Characterization of Thermal Properties of Ruby Chocolate Using DSC, PDSC and TGA Methods
## 3 Results
### Thermogravimetric Characterization  
TGA is a method for the analysis of ingredients and their thermal characteristics. The results for the fat extracted from the RC, presented in Figure 5, were obtained by the use of TGA and DTG in nitrogen (a) and oxygen (b). [PERSON] et al. [10] studied milk fat and cocoa butter in nitrogen flow and observed one transition for each in the ranges 245-420 \({}^{\circ}\)C and 290-460 \({}^{\circ}\)C, respectively. In the RC, there was a mixture of CB and MF. Hence, the TGA curve of the fat extracted from the RC in nitrogen (Figure 5a) gives a clear qualitative profile and shows one step of transition within the range 275-475 \({}^{\circ}\)C. The presence of polymorphic forms of either milk fat or cocoa butter was not observed on the TGA and DTG curves recorded in nitrogen. The presence of oxygen during the TGA  
Figure 5: TGA and DTG curve of fat extracted from ruby chocolate in nitrogen (**a**) and oxygen (**b**). analysis simulates the natural conditions that would affect the sample in the atmosphere. The oxygen affects not only the number of events but also the first release, shifting it to a lower temperature. This phenomenon can be due to quick production of the primary oxidation products, which enhance further decomposition. The TGA and DTG of the oxygen flow for the fat extracted from the RC, presented in Figure 5b, can be divided into three stages. The exact temperature ranges of the thermal events for the decomposition of the fat extracted from the RC in the oxygen flow are presented in Table 5. The first stage is considered to be the most important, and corresponds to the initial phase of the triacylglycerol-cional transitions. [PERSON] et al. [42] analyzed the oxidation behaviour of vegetable and animal fats and suggested that the first stage of thermal decay was the decomposition and oxidation of the mono- and polyunsaturated fatty acids (MUFA and PUFA) as well as the short chains of saturated fatty acids (SFA), which, in the case of the fat extracted from the RC, could especially come from milk fat [43]. The next two stages of the curve represent the decomposition of the trans isomers of fatty acids (more common for milk fat than for cocoa butter) and the saturated fatty acids (SFA). There is a noticeable but not sharp border between the second and third stages of the fat decomposition due to many secondary oxidation products and carbonization processes. The TGA/DTG curves of the RC in nitrogen (a) and oxygen (b) are presented in Figure 6. The measurements of the initial materials (sugar, milk fat, cocoa butter, cocoa liquor), preceding the chocolate measurements, allow the matching of the individual thermal events with specific chocolate ingredients [9,39]. The first stage of decomposition in the nitrogen flow starts at 100 \({}^{\circ}\)C and is related to the loss (<1%) of either citric acid (being added as acidity regulator) or of a small amount of the proteins present in the cocoa liquor. The second mass loss taking place in the range 150-250 \({}^{\circ}\)C is related to small molecular mass polysaccharides. The third one, in the range 250-700 \({}^{\circ}\)C, is the broadest and relates to all the fatty components (cocoa butter, milk fat and cocoa liquor) and the non-organic components. Slightly different thermal characteristics in the nitrogen flow were observed for milk, dark and goat milk chocolate [7,44]. The TGA/DTG curve for goat milk chocolate in nitrogen showed three stages (50-250 \({}^{\circ}\)C, 250-350 \({}^{\circ}\)C and 350-700 \({}^{\circ}\)C) and formed the biggest contribution to the third mass loss event in the whole chocolate. Milk and dark chocolate decomposed similarly in three stages; however, this occurred in different temperatures of 50 to 210 \({}^{\circ}\)C, 210 to 350 \({}^{\circ}\)C and 350 to 700 \({}^{\circ}\)C, respectively [44]. The mass loss within the first stage of decomposition was bigger for the milk and white chocolate than for the dark and goat milk chocolate.