In this work, the composition of different types of chocolate was studied by using microscopy (optical and confocal fluorescence) and vibrational spectroscopy (Raman) aimed at obtaining more chemical information about this important food. By combining these techniques, it is possible to distinguish different components of chocolate. It was not possible to obtain Raman spectra of dark chocolate due to the presence of fluorescent flavonoids in cocoa particles. However, silver nanoparticles quench this fluorescent signal, and thus it is possible to obtain a surface-enhanced Raman spectroscopy spectrum of dark chocolate. The effect of ultrasound on the crystallization process of cocoa butter was also studied. These samples were also analysed by X-ray diffraction and differential scanning calorimetry. Furthermore, the combination of all these techniques was very useful in the specific analysis of different components of chocolate and could have a high impact in the chocolate industry.
Keywords: Chocolate; Flavonoids; Fluorescent markers; Raman; Red Nile and Rhodamine B; Sonocrystallization; Ultrasound.
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