An evaluation of Raman microscopy for detection of additional MSG in dry soup mix

Main Article Content

N. Çebi
T. Öztürk
C.E. Doğan
O. Sağdıç


monosodium glutamate, Raman, mapping, imaging, DCLS


This article presents Raman chemical mapping application for the detection of adulterant monosodium glutamate (MSG) in dry soup mix. MSG may cause various damages to the health of people. Therefore, there are legal regula-tions for this compound both in Turkish Food Codex and European Union Directives. Most of the times, the main problem is that MSG is added into dry soup products without declaration on the label. Food control mechanisms need effective and real-time monitoring methods to check the reliability of the product labels in order to maintain food safety and alleviate public doubts. In this study, MSG was added into dry soup mix at a concentration (w/w) of 0.1, 0.2, 0.4 and 0.6% and chemical maps were obtained using multivariate data analysis techniques such as direct classical least squares (DCLS) component analysis. MSG was successfully detected and spectral and spatial distribution of the MSG within the commercial and laboratory-prepared dry soup samples was accomplished, with a detection limit of 0.1%. The results obtained were confirmed by a robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique.

Abstract 452 | PDF Downloads 294 HTML Downloads 63 XML Downloads 6


Abeysinghe, C.P. and Illeperuma, C.K., 2006. Formulation of an MSG (Monosodium Glutamate) free instant vegetable soup mix. Journal of the National Science Foundation of Sri Lanka 34: 91–95.
Acebal, C.C., Lista, A.G. and Fernández Band, B.S., 2008. Simultaneous determination of flavor enhancers in stock cube samples by using spectrophotometric data and multivariate calibration. Food Chem-istry 106: 811–815.
Ault, A., 2004. The monosodium glutamate story: the commercial production of msg and other amino acids. Journal of Chemical Education 81: 347.
Aung, H.P. and Pyell, U., 2015. In-capillary derivatization with o-phthalaldehyde in the presence of 3-mercaptopropionic acid for the simultaneous determination of monosodium glutamate, benzoic acid, and sorbic acid in food samples via capillary elec-trophoresis with ultraviolet detectio. Journal of Chromatography A 1449: 156–165.
Beyreuther, K., Biesalski, H.K., Fernstrom, J.D., Grimm, P., Hammes, W.P., Heinemann, U., Kempski, O., Stehle, P., Steinhart, H. and Walker, R., 2007. Consensus meeting: monosodium glutamate— an update. European Journal of Clinical Nutrition 61: 304–313.
Cebi, N., Dogan, C.E., Olgun, E.O. and Sagdic, O., 2018. A sur-vey of free glutamic acid in foods using a robust LC–MS/MS method. Food Chemistry 248: 8–13. foodchem.2017.12.033
Chen, H., Song, Q., Tang, G., Feng, Q. and Lin, L., 2013. The combined optimization of Savitzky-Golay smoothing and multiplicative scatter correction for FT-NIR PLS models. Inter-national Scholarly Research Notices 2013: 642190. https://doi. org/10.1155/2013/642190
Demirhan, B.E., Demirhan, B., Sönmez, C., Torul, H., Tamer, U. and Yentür, G., 2015. Monosodium glutamate in chicken and beef stock cubes using high-performance liquid chromatography. Food Additives & Contaminants: Part B 8: 63–66. 10.1080/19393210.2014.991355
Dhamelincourt, P. and Ramírez, F.J., 1991. Polarized micro-Raman and Fourier transform infrared spectra of L-glutamic acid. Jour-nal of Raman Spectroscopy 22: 577–582. jrs.1250221007
Ekrami, E., Okazi, M., Kang, Q., Zhou, W., Li, Q., Gao, B., Fan, J., Shen, D., Turabik, M., Rojas, F.S., Ojeda, C.B., Pavon, J.M., Lettre, D.P., Patel, K.N., Patel, J.K., Rajput, G.C., Rajgor, N.B., Sahel, K., Perol, N., Dappozze, F., Bouhent, M., Derriche, Z. and Guillard, C., 2010. Analysis of dye concentrations using de-rivative spectrophotometric techniques. Talanta 212: 139–150.
Eksi-Kocak, H., Mentes-Yilmaz, O. and Boyaci, I.H., 2016. Detection of green pea adulteration in pistachio nut granules by using Raman hyperspectral imaging. European Food Research and Technology 242: 271–277.
Freeman, M., 2006. Reconsidering the effects of mono-sodium glutamate: a literature review. Journal of the American Academy of Nurse Practitioners 18: 482–486. https://
Gowen, A.A., O’Donnell, C.P., Cullen, P.J., Downey, G. and Frias, J.M., 2007. Hyperspectral imaging—an emerging process an-alytical tool for food quality and safety control. Trends in Food Science and Technology 18: 590–598. tifs.2007.06.001
Kabischt, G. and Klose, M., 1978. A Raman spectroscopic study of aqueous and methanolic tetrame thylammonium chloride solu-tions. Journal of Raman Spectroscopy 7: 311–315. https://doi. org/10.1002/jrs.1250070604
Khampha, W., Yakovleva, J., Isarangkul, D., Wiyakrutta, S., Meevoo-tisom, V. and Emnéus, J., 2004. Specific detection of L-glutamate in food using flow-injection analysis and enzymatic recycling of substrate. Analytica Chimica Acta 518: 127–135. https://doi. org/10.1016/j.aca.2004.05.048
Lau, O.W. and Mok, C.S., 1995. Indirect conductometric de-tection of amino acids after liquid chromatographic sep-aration. Part II. determination of monosodium glutamate in foods. Analytica Chimica Acta 302: 45–52. https://doi. org/10.1016/0003-2670(94)00423-J
McAughtrie, S., Lau, K., Faulds, K. and Graham, D., 2013. 3D optical imaging of multiple SERS nanotags in cells. Chemical Science 4: 3566.
Navarrete, J.T.L., Hernandez, V. and Ramirez, F., 1994. Vibrational spectra of [15 N] glutamic acid and [2H4]glutamic acid. Journal of Raman Spectroscopy 25: 861–867. jrs.1250251104
Peica, N., Lehene, C., Leopold, N., Schlücker, S. and Kiefer, W., 2007. Monosodium glutamate in its anhydrous and monohydrate form: differentiation by Raman spectroscopies and density functional calculations. Spectrochimica Acta—Part A: Molecular and Bio-molecular Spectroscopy 66: 604–615. saa.2006.03.037
Populin, T., Moret, S., Truant, S. and Conte, L.S., 2007. A survey on the presence of free glutamic acid in foodstuffs, with and without added monosodium glutamate. Food Chemistry 104: 1712–1717.
Qin, J., Chao, K., Cho, B.K., Peng, Y. and Kim, M.S., 2014. High-throughput Raman chemical imaging for rapid evaluation of food safety and quality. Transactions of the ASABE 57: 1783– 1792.
Qin, J., Chao, K. and Kim, M.S., 2011. Investigation of Raman chem-ical imaging for detection of lycopene changes in tomatoes during postharvest ripening. Journal of Food Engineering 107: 277–288.
Qin, J., Chao, K. and Kim, M.S., 2013. Simultaneous detection of multiple adulterants in dry milk using macro-scale Raman chemical imaging. Food Chemistry 138: 998–1007. https://doi. org/10.1016/j.foodchem.2012.10.115
Savitzky, A. and Golay, M.J.E., 1964. Smoothing and differ-entiation of data by simplified least squares procedures. Analytical Chemistry 36: 1627–1639. ac60214a047
Schaumburg, H.H., Byck, R., Gerstl, R. and Mashman, J.H., 1969.  Monosodium L-glutamate: its pharmacol-ogy and role  in  the Chinese restaurant syndrome. Science (New York, N.Y.) 163: 826–828. science.163.3869.826
Shannon, M., Green, B., Willars, G., Wilson, J., Matthews, N., Lamb, J., Gillespie, A. and Connolly, L., 2017. The endocrine disrupting potential of monosodium glutamate (MSG) on secretion of the glucagon-like peptide-1 (GLP-1) gut hormone and GLP-1 re-ceptor interaction. Toxicology Letters 265: 97–105. https://doi. org/10.1016/j.toxlet.2016.11.015
Shurvell, H.F. and Bergin, F.J., 1989. Raman spectra of L(+)-glutamic acid and related compounds. Journal of Raman Spectroscopy 20: 163–168.
Skurray, G.R. and Pucar, N., 1988. L-Glutamic scid content of fresh and processed foods. Food Chemistry 27: 177–180. https://doi. org/10.1016/0308-8146(88)90060-X
Yongliang, L., Chao, K., Kim, M.S., Tuschel, D., Olkhovyk, O. and  Priore, R.J., 2009. Potential of Raman spectroscopy and imaging methods for rapid and routine screening of the pres-ence  of melamine in animal feed and foods. Applied Spectros-copy 63: 477–480.
Zhang, L., Henson, M.J. and Sekulic, S.S., 2005. Multivariate data analysis for Raman imaging of a model pharmaceutical tablet. Analytica Chimica Acta 545: 262–278. aca.2005.04.080