MALDI based identification of soybean protein markers--possible analytical targets for allergen detection in processed foods.
Soybean (Glycine max) is extensively used all over the world due to its nutritional qualities. However, soybean is included in the "big eight" list of food allergens. According to the EU directive 2007/68/EC, food products containing soybeans have to be labeled in order to protect the allergic consumers. Nevertheless, soybeans can still inadvertently be present in food products. The development of analytical methods for the detection of traces of allergens is important for the protection of allergic consumers. Mass spectrometry of marker proteolytical fragments of protein allergens is growingly recognized as a detection method in food control. However, quantification of soybean at the peptide level is hindered due to limited information regarding specific stable markers derived after proteolytic digestion. The aim of this study was to use MALDI-TOF/MS and MS/MS as a fast screening tool for the identification of stable soybean derived tryptic markers which were still identifiable even if the proteins were subjected to various changes at the molecular level through a number of reactions typically occurring during food processing (denaturation, the Maillard reaction and oxidation). The peptides (401)Val-Arg(410) from the G1 glycinin (Gly m 6) and the (518)Gln-Arg(528) from the α' chain of the β-conglycinin (Gly m 5) proved to be the most stable. These peptides hold potential to be used as targets for the development of new analytical methods for the detection of soybean protein traces in processed foods.
Department of Food Safety and Food Quality, Research group Food Chemistry and Human Nutrition, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
Tatiana
T
Cucu
Bruno
B
De Meulenaer
Bart
B
Devreese
D000485:Allergens / Q000032:analysis* / Q000737:chemistry; D000595:Amino Acid Sequence; D015415:Biomarkers / Q000032:analysis / Q000737:chemistry; D059022:Food Safety / Q000379:methods*; D005525:Food-Processing Industry; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D059748:Proteolysis; D012015:Reference Standards; D030262:Soybean Proteins / Q000032:analysis* / Q000737:chemistry; D013025:Glycine max; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000592:standards; D053719:Tandem Mass Spectrometry / Q000592:standards; D014357:Trypsin / Q000737:chemistry
D000485:Allergens; D015415:Biomarkers; D010446:Peptide Fragments; D030262:Soybean Proteins; D014357:Trypsin