## 3 Results and Discussion
### MIR Investigations  
MIR spectra of the four mixtures in the spectral zone 3100-600 cm\({}^{-1}\), then the spectral zones 3020-2800 cm\({}^{-1}\) and 1780-1700 cm\({}^{-1}\) at T = 22.0 \({}^{\circ}\)C, are presented respectively in Figure 4a-c.  
[PERSON] et al. [6] showed that CBE exhibits the same vibrational behavior in MIR spectroscopy as CB. It is questionable whether the presence of CBE, which delays chocolate blooming, manifests on MIR spectra. We can distinguish different regions on the spectra shown in Figure 4a. Here, we will focus on the two following regions:  
* the spectral region 3200-2700 cm\({}^{-1}\) corresponding to the v(C-H) stretching mode (Figure 4b)
* the spectral region 1800-1700 cm\({}^{-1}\) corresponding to the v(C=O) ester carbonyl stretching region (Figure 4c). If CBE has the same vibrational behavior in MIR spectroscopy as CB in the mixtures, MIR spectra of \"CB + 0.5 AMF\" and \"CB + AMF + CBE\" mixtures should be identical. Indeed, both of these two mixtures contain one third (1/3) of AMF and two thirds (2/3) of cocoa butter (only CB or a mixture of CB and CBE). In the spectral region 1800-1700 cm\({}^{-1}\) (Figure 4c), it actually seems that there is no notable difference between the spectra of \"CB + 0.5 AMF\" and \"CB + AMF + CBE\" mixtures. The models of MIR spectra of the four mixtures in this spectral region are presented in Figure 4b. In Figure 4a, the spectra obtained for CB, CBE and AMF at room temperature are presented for comparison [6]. We observe four components in total, whose values of  
Figure 4: The 3100–600 cm\({}^{-1}\) MIR spectral range (**a**), the 3100–2800 cm\({}^{-1}\) MIR spectral range (**b**) and the 1770–1710 cm\({}^{-1}\) MIR spectral range (**c**) of the four mixtures: CB + 0.5 AMF, CB + AMF, CB + 0.5 AMF + CBE and CB + AMF + CBE. \(\sigma\) remain almost stable from one mixture to another: 1729 cm\({}^{-1}\); 1735.5 cm\({}^{-1}\); 1743 cm\({}^{-1}\) and 1751 cm\({}^{-1}\). Moreover, it should be noted that the pure compounds also presented these four components for the vibrations v(C=O) (see Figure 5). The values of the peaks of the four mixtures as well as those of the compounds alone are grouped together in Table 2. The values of the peaks in cm\({}^{-1}\) of the mixtures and of the pure compounds are almost identical, except for the component at 1735.5 cm\({}^{-1}\) for AMF which is located at 1739.8 cm\({}^{-1}\). In Table 2, we present the values of the areas of modes with each component. It can be seen that \"CB + 0.5 AMF\" areas and \"CB + AMF + CBE\" mixtures are similar. In conclusion, it would seem that the presence of CBE instead of CB is not visible in MIR spectroscopy in the 1800-1700 cm\({}^{-1}\) area. In Figure 5b, it can be seen that some components have larger areas in some mixtures than in others. It is therefore interesting to comment on the evolution of the intensity and the area of each peak from one mixture to another, using the values of the areas of each component (Table 3). For example, the peak area at 1743 cm\({}^{-1}\) is the highest for \"CB + AMF\" mixture, which contains the most AMF (50%) (area = 26.2 au) and the lowest for \"CB + 0.5 AMF + CBE\" mixture, which contains the least (20% of AMF) (area = 6.1 au). \"CB + 0.5 AMF\" and \"CB + AMF + CBE\" mixtures, which both contain 33% of AMF, have an area of intermediate and almost identical values (area = 13.5 au for CB + AMF + CBE and area = 14.8 for CB + 0.5 AMF). It would therefore seem that the peak at 1743 cm\({}^{-1}\) mainly reflects the vibrations v(C=O) of TGs of AMF. \begin{table}
\begin{tabular}{c c c c c} \hline
**Area (a.u)** & **1729.0 cm\({}^{-1}\)** & **1735.5 cm\({}^{-1}\)** & **1743.0 cm\({}^{-1}\)** & **1751.0 cm\({}^{-1}\)** \\ \hline _AMF_ & 6.0 & 34.0 & 19.0 & 9.4 \\ _CB_ & 8.0 & 6.2 & 2.5 & 1.8 \\ _CBE_ & 8.5 & 6.8 & 3.4 & 1.4 \\ _CB + 0.5 AMF_ & 7.3 & 5.9 & 14.8 & 4.5 \\ _CB + AMF_ & 7.7 & 3.8 & 26.2 & 5.5 \\ _CB + 0.5 AMF + CBE_ & 7.7 & 6.2 & 6.1 & 4.1 \\ _CB + AMF + CBE_ & 7.8 & 6.2 & 13.5 & 4.4 \\ \hline \end{tabular}
\end{table}