## 3 Results and Discussion
### MIR Investigations

Table 2: Areas of the components of MIR spectra for C=O carbonyl group for CB, CBE, AMF and mixtures. Figure 5: The MIR carbonyl stretching region (1770–1710 cm\({}^{-1}\)) fitted by Lorentzian curves of CB, CBE and AMF (**a**) and of the four mixtures (**b**): CB + 0.5 AMF, CB + AMF, CB + 0.5 AMF + CBE and CB + AMF + CBE, at room temperature. The solid lines represent the components fitted by Lorentzian functions. We observe an identical phenomenon for the peak at 1751 cm\({}^{-1}\): its area is the most intense for \"CB + AMF\" mixture (area = 5.5 au), and the least intense for \"CB + 0.5 AMF + CBE\" mixture (area = 4.1 au). For the other two mixtures containing the same percentage by mass of AMF, we observe similar areas for the peak at 1751 cm\({}^{-1}\): area \(\approx\) 4.5 a.u. Thus, it would seem that the peak at 1751 cm\({}^{-1}\) would be represented over all the vibrations v(C=O) of TGs of AMF. These results are consistent in comparison with the area of the peaks at 1751 cm\({}^{-1}\) and 1743 cm\({}^{-1}\) between CB, CBE and AMF taken individually: the areas of these two peaks are very important for AMF taken alone (respectively 9.4 and 19.0 au) unlike CB and CBE (respectively 1.8 and 2.5 au for the CB and 1.4 and 3.4 for CBE) (see Table 3). The peak at 1735.5 cm\({}^{-1}\) has an almost identical area from one mixture to another, except for \"CB + AMF\" mixture where the area is lower. However, it is the mixture which contains the least cocoa butter (equivalent or not): 50% of (CB + CBE), against 67% for \"CB + 0.5 AMF\" and \"CB + AMF + CBE\" mixtures and 80% for \"CB + 0.5 AMF + CBE\" mixture. It would therefore seem that the peak at 1735.5 cm\({}^{-1}\) would mostly represent the vibrations v(C = 0) of TGs of CB and CBE. Since the peak at 1729 cm\({}^{-1}\) was used to carry out the normalization, we will not be able to comment on its evolution. In the 3200-2700 cm\({}^{-1}\) zone corresponding to the elongation vibration v(C-H) of TGs, MIR spectra of the four mixtures are shown in Figure 4b. In Figure 6, the modeling of MIR spectrum of \"CB + 0.5 AMF + CBE\" mixture is presented by Lorentzian functions with the same modeling method used for the spectral zone 1800-1700 cm\({}^{-1}\). If we apply this modeling method to each of the spectra of the four mixtures, we find that all the mixtures have the same eight components: a very weak peak at 3005 cm\({}^{-1}\); a defined but weak peak at 2957 cm\({}^{-1}\); a fine and intense peak at 2915 cm\({}^{-1}\) with two shoulders on either side, at 2926 and 2902 cm\({}^{-1}\); a very weak peak of intensity at 2872 cm\({}^{-1}\) and then a fine and intense peak at 2849 cm\({}^{-1}\) with a shoulder at 2852 cm\({}^{-1}\). We find the same peaks observed for CB, CBE [14] and the AMF. The assignments of these peaks are shown in Table 3[18]. From Figure 4b, it seems that we do not observe a difference in vibrational behavior between the mixtures for this spectral zone. In conclusion, CBE TGs have the same vibrational behavior in MIR spectroscopy as CB TGs in mixtures. This is not very surprising, since the study of CB alone and CBE alone did not reveal any vibrational differences in MIR [14]. On the other hand, the detailed study of spectra in MIR spectroscopy in the spectral zone 1800-1700 cm\({}^{-1}\) allows us to know the major contribution of one of the elements of the mixtures for three vibrational modes: the peaks at 1751 and 1743 cm\({}^{-1}\) are predominantly sensitive to AMF while the peak at 1735.5 cm\({}^{-1}\) is sensitive to CB and CBE. \begin{table}
\begin{tabular}{c c c} \hline
**Wavenumber cm\({}^{-1}\)** & **Intensity** & **Assignation** \\ \hline
2849 & (s) & \(v_{s}(CH_{2})\) \\ \hline
2852 & (sh) & \(v_{s}(CH_{2})\) \\ \hline
2872 & (sh) & \(v_{s}(CH_{2})\) \\ \hline
2902 & (sh) & \(v_{s}(CH_{2})\) \\ \hline
2915 & (s) & \(v_{s8}(CH_{2})/v_{s}(CH_{3})/v_{s8}(CH_{3})\) \\ \hline
2926 & (sh) & \(v_{s8}(CH_{2})\)