Sudan dyes in adulterated saffron (Crocus sativus L.): Identification and quantification by (1)H NMR.
Saffron, the dried red stigmas of Crocus sativus L., is considered as one of the most expensive spices worldwide, and as such, it is prone to adulteration. This study introduces an NMR-based approach to identify and determine the adulteration of saffron with Sudan I-IV dyes. A complete (1)H and (13)C resonance assignment for Sudan I-IV, achieved by two-dimensional homonuclear and heteronuclear NMR experiments, is reported for the first time. Specific different proton signals for the identification of each Sudan dye in adulterated saffron can be utilised for quantitative (1)H NMR (qHNMR), a well-established method for quantitative analysis. The quantification of Sudan III, as a paradigm, was performed in varying levels (0.14-7.1g/kg) by considering the NMR signal occurring at 8.064ppm. The high linearity, accuracy and rapidity of investigation enable high resolution (1)H NMR spectroscopy to be used for evaluation of saffron adulteration with Sudan dyes.
Laboratory of Chemistry, Department of Food Science and Human Nutrition, School of Food, Biotechnology and Development, Agricultural University of Athens, 75 Iera Odos Str., 11855 Athens, Greece.
Eleftherios A
EA
Petrakis
Institute for Macromolecular Studies, NMR Laboratory, National Research Council, v. A. Corti 12, 20133 Milan, Italy.
Laura R
LR
Cagliani
Laboratory of Chemistry, Department of Food Science and Human Nutrition, School of Food, Biotechnology and Development, Agricultural University of Athens, 75 Iera Odos Str., 11855 Athens, Greece.
Petros A
PA
Tarantilis
Laboratory of Chemistry, Department of Food Science and Human Nutrition, School of Food, Biotechnology and Development, Agricultural University of Athens, 75 Iera Odos Str., 11855 Athens, Greece.
Moschos G
MG
Polissiou
Institute for Macromolecular Studies, NMR Laboratory, National Research Council, v. A. Corti 12, 20133 Milan, Italy. Electronic address: roberto.consonni@ismac.cnr.it.
Roberto
R
Consonni
D001391:Azo Compounds / Q000032:analysis* / Q000737:chemistry; D004396:Coloring Agents / Q000032:analysis* / Q000737:chemistry; D027622:Crocus / Q000737:chemistry; D004340:Drug Contamination; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009284:Naphthols / Q000032:analysis / Q000737:chemistry; D010936:Plant Extracts / Q000032:analysis / Q000737:chemistry; D011522:Protons; D017365:Spices / Q000032:analysis
D001391:Azo Compounds; D004396:Coloring Agents; D009284:Naphthols; D010936:Plant Extracts; D011522:Protons; C024336:1-phenylazo-2-naphthol; C033003:sudan red; C009213:Scarlet Red; C033006:sudan III
(1)H and (13)C NMR; Adulteration; Chloroform-d (PubChem CID: 71583); Quality control; Saffron; Sudan I (PubChem CID: 5858445); Sudan II (PubChem CID: 5354447); Sudan III (PubChem CID: 5379348); Sudan IV (PubChem CID: 5876571); Sudan dyes; qHNMR