## 3 Results
### DSC Study of Cocoa Butter Extracted from Untroasted and Roasted Cocoa Beans Criollo and Forastero
TGA/DTG Study of Cocoa Beans and Cocoa Butter Extracted from Unroasted and Roasted Cocoa Beans Criollo and Forastero  
Thermogravinetry analysis (TGA) and the first derivative thermogravimetry (DTG) are excellent tools to examine the composition of mixtures, including food. From the TGA curve, the upper use temperature of a material, in the case of this study--fat--can be determined. Beyond this temperature, the material will begin to degrade. Hence, TGA can be applied complementary to DSC to estimate the thermal stability of the material. TGA and first derivative DTG were performed for ground cocoa beans of both species before and after roasting (Figures 3 and 4) as well as for fats extracted from these cocoa beans (Figures 5 and 6). The typical thermogravimetric behaviour of ground cocoa beans of Criollo (Peru) and Forastero (Ecuador) species showed significant diversity between the samples. Figure 3 shows TGA and DTG curves of unroasted and roasted cocoa beans Criollo in nitrogen (a, b) and oxygen (a', b'). For unroasted and roasted cocoa beans Criollo, two main mass losses were detected in the nitrogen atmosphere. The first mass change for unroasted cocoa beans Criollo of 20.39% was observed at temperature range 100-325 \({}^{\circ}\)C and for roasted cocoa beans of 19.89% at temperature range 75-300 \({}^{\circ}\)C. The second mass change for unroasted cocoa beans of 63.39% was observed at temperature range 325-500 \({}^{\circ}\)C and for roasted cocoa beans of 64.22% at temperature range 300-520 \({}^{\circ}\)C. [PERSON] et al. [14] and [PERSON] et al. [24] studied the thermal properties of cocoa liquor. They stated that saccharides in the cocoa liquor were responsible for the first mass loss. The second significant mass loss was attributed to cocoa butter decomposition. The total mass loss for unroasted and roasted cocoa beans Criollo was not observed, the amount of the residues were 15.86 and 14.69%, respectively. This phenomenon can be explained by the high content of inorganic ingredients with high stability. The significant differences between unroasted and roasted cocoa beans have not been observed. Four stages of combustion on TGA and DTG curves for unroasted and roasted cocoa beans Criollo in oxygen were observed. First mass change for unroasted and roasted cocoa beans Criollo of 27.99 and 25.88%, respectively, was observed. In the case of unroasted and roasted cocoa beans Criollo, certain stages of mass changes took place in the following order: second mass loss of 35.23 and 37.68%, third mass change of 14.73 and 15.12% and fourth mass loss of 18.59 and 18.29%. All the mass changes were characterized by the same temperature ranges: first--150-275 \({}^{\circ}\)C; second--275-375 \({}^{\circ}\)C; third--375-450 \({}^{\circ}\)C and fourth--450-525 \({}^{\circ}\)C (Figure 3a',b'). According to [PERSON] et al. [14] and [PERSON] et al. [24], cocoa liquor is a mixture of cocoa butter, cocoa powder, cocoa solid, antioxidant flavour and mineral compounds. They determined the thermal properties of dark chocolate ingredients in the air and oxygen atmosphere. In the case of the courses of DTG diagrams of unroasted and roasted cocoa beans Criollo the differences were observed. The DTG curve of roasted cocoa beans Criollo was characterized by a more distinct course than the DTG curve of unroasted cocoa beans Criollo. The roasting process causes the structure of cocoa beans has changed. Figure 3: Thermogravimetry (TGA) and DTG curves of ground Criollo (Peru), unroasted (**a**) in nitrogen (**a**\({}^{\prime}\)) in oxygen and roasted (**b**) in nitrogen and (**b**\({}^{\prime}\)) in oxygen. Figure 4: TGA and DTG curves of ground Forastero (Ecuador), unroasted (**a**) in nitrogen (**a’**) in oxygen and roasted (**b**) in nitrogen and (**b’**) in oxygen. Figure 5: TGA and DTG curves of fats extracted from cocoa beans Criollo (Peru), unroasted (**a**) in nitrogen (**a**) in oxygen and roasted (**b**) in nitrogen and (**b**) in oxygen.