Chocolate is widely enjoyed in many sweets and foods all over the world. In cocoa butter, fatty acids combine together and give cocoa butter 6 different types of crystals: γ, α, β’(III), β’(IV), β(V) and β(VI). In the industry, the β(V) form that is required, is metastable and gives chocolate its marketable properties. The β(VI) form is also stable but not desirable, because of fat bloom. The objective of this study is to characterize these polytypes by terahertz(THz) spectroscopy. THz spectroscopy is expected to be a new tool in food industry, as THz energy corresponds to collective molecular macro-vibrations. Two chocolates from different factories were inspected with optical microscope, X-ray diffraction (XRD) and THz spectroscopy. Optical microscope showed different surface aspects, XRD showed the same species in the two brands and THz spectroscopy showed different features. These differences may be due to fatty acids combination of chocolate.
References
[1]
Corler, B. (1992) Le chocolat: Fabrication, composition, valeur nutritionnelle, sa place dans l’alimentation humaine. Ph.D. Thesis.
[2]
Fryer, P. and Pinschower, K. (2000) The Materials Science of Chocolate. MRS/Bulletin, 25, 25-29. https://doi.org/10.1557/mrs2000.250
[3]
Loisel, C., Adenier, H., Chaveron, H., Keller, G. and Ollivon, M. (2002) Le blanchissement du chocolat: Mécanismeetprévention. 6ème Colloque de l’Alliance 7/CEDUS, 12 February 2002, 55-65.
[4]
Willie, R.L. and Lutton, E.S. (1966) Polymorphism of Cocoa Butter. Journal of the American Oil Chemists’ Society, 43, 491-496. https://doi.org/10.1007/BF02641273
[5]
Guthrie, S.E., Mazzanti, G. and Idziak, S.H.J. (2005) X-Ray Phase Identification of Chocolate Is Possible without the Removal of Sugar. European Journal of Lipid Science and Technology, 107, 656-659. https://doi.org/10.1002/ejlt.200501178
[6]
Jordens, C., Rutz, F. and Koch, M. (2006) Quality Assurance of Chocolate Products with Terahertz Imaging. European Conference for Non Destructive Technique, Berlin, 25-29 September 2006, Poster 67. http://www.ndt.net/article/ecndt2006/doc/P67.pdf
[7]
Tanabe, T. and Oyama, Y. (2011) Frequency-Tunable Coherent THz-Wave Pulse Generation Using Two Cr:Forsterite Lasers with One Nd:YAG Laser Pumping and Applications for Non-Destructive THz Inspection. In: Krzysztof Jakubczak, K., Ed., Laser Systems for Applications, InTech, Inc., Chap. 6, 119-136. https://doi.org/10.5772/23468
[8]
van Mechelen, J.B., Peschar, R. and Schenk, H. (2006) Structures of Mono-Unsaturated Triacylglycerols. I. The β1 Polymorph. Acta Crystallographica Section B, 62, 1121-1130. https://doi.org/10.1107/S0108768106037074
[9]
van Mechelen, J.B., Peschar, R. and Schenk, H. (2006) Structures of Mono-Unsaturated Triacylglycerols. II. The β2 Polymorph. Acta Crystallographica Section B, 63, 1131-1138. https://doi.org/10.1107/S0108768106037086
[10]
Padilla, F.C., Liendo, R. and Quintana, A. (2000) Characterization of Cocoa Butter Extracted from Hybrid Cultivars of Theobroma cacao L. Archivos Latinoamericanos De Nutricion, 50, 200-205.
[11]
Lord Rayleigh, F.R.S. (1879) XXXI. Investigations in Optics, with Special Reference to the Spectroscope. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science Series 5, 8, 261-274. https://doi.org/10.1080/14786447908639684
[12]
Nishizawa, J., Suto, K., Sasaki, T., Tanabe, T. and Kimura, T. (2003) Spectral Measurement of Terahertz Vibrations of Biomolecules Using a GaP Terahertz-Wave Generator with Automatic Scanning Control. Journal of Physics D: Applied Physics, 36, 2958-2961. https://doi.org/10.1088/0022-3727/36/23/015
[13]
Rigolle, A., Foubert, I., Hettler, J., Verboven, E., Martens, A., Demuynck, R. and Abeele, K.V.D. (2016) Insight in Ultrasonic Shear Reflection Parameters by Studying Temperature and Limonene Influence on Cocoa Butter Crystallization. Innovative Food Science & Emerging Technologies, 33, 289-297. https://doi.org/10.1016/j.ifset.2015.12.004
[14]
Sasaki, T., Sakamoto, T. and Otsuka, M. (2018) Detection of Impurities in Organic Crystals by High-Accuracy Terahertz Absorption Spectroscopy. Analytical Chemistry, 90, 1677-1682. https://doi.org/10.1021/acs.analchem.7b03220
