Fast screening and secure confirmation of milk powder adulteration with maltodextrin via electrospray ionization-mass spectrometry [ESI(+)-MS] and selective enzymatic hydrolysis.
Direct-infusion electrospray ionization-mass spectrometry [ESI(+)-MS] of several milk powder samples, confiscated by the Brazilian Federal Police, showed ions accounting for sodiated and potassiated molecules of disaccharides (m/z 365 and 381) as well as trisaccharides (m/z 527 and 543), whereas monosaccharide ions were not detected. The trisaccharide ions were not detected in samples of genuine milk powder, raising the suspicion that their presence indicates adulteration by the addition of maltodextrin. In control samples, maltose and maltotriose were hydrolyzed by alpha-glucosidase and not beta-galactosidase, whereas lactose was resistant to alpha-glucosidase but was hydrolyzed with beta-galactosidase. Samples suspected of being adulterated behaved in the same fashion, confirming the presence of maltose and maltotriose or maltodextrin. Direct-infusion ESI-MS is shown therefore to provide rapid screening of milk powder for adulteration with maltodextrin, whereas its combination with selective enzymatic hydrolysis provides highly reliable confirmation for unambiguous results.
Sanvido
Gustavo B
GB
Thomson Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, São Paulo (SP) 13083-970, Brazil.
Garcia
Jerusa S
JS
Corilo
Yuri E
YE
Vaz
Boniek G
BG
Zacca
Jorge J
JJ
Cosso
Ricardo G
RG
Eberlin
Marcos N
MN
Peter
Martin G
MG
D000818:Animals; D006868:Hydrolysis; D008892:Milk / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D000520:alpha-Glucosidases / Q000378:metabolism*
D011134:Polysaccharides; C008315:maltodextrin; D000520:alpha-Glucosidases