Characterization of casein lactosylation by capillary electrophoresis and mass spectrometry

• Published in: European food research & technology 2006-02, Vol.222 (3-4), p.467-471
• Main Authors: Steffan, W, Balzer, H.H, Lippert, F, Sambor, B.C, Bradbury, G.W, Henle, T
• Format: Article
• Language: English
• Subjects: alpha-casein; Analytical chemistry; beta-casein; Biological and medical sciences; Capillary electrophoresis; chemical reactions; Dairy products; dried milk; Electrophoresis; food composition; Food industries; Fundamental and applied biological sciences. Psychology; furosine; Ionization; Ions; kappa-casein; lactose; lactosylation; Maillard reaction; Mass spectrometry; milk; Milk and cheese industries. Ice creams; processed cheeses; Processed foods; protein binding; Scientific imaging; Urea
• ISSN: 1438-2377; 1438-2385
• DOI: 10.1007/s00217-005-0177-9

Capillary electrophoresis (CE) and mass spectrometry have been used to verify the formation of lactosylated casein variants. CE was performed in a hydrophilically coated capillary at low pH and in the presence of urea. Lactosylated α-casein, β-casein, and κ-casein migrate shortly after the unmodified proteins. Evidence for casein lactosylation was obtained by electrospray ionization-mass spectrometry (ESI-MS). Lactosylated β-casein can be monitored not only in milk and milk powders but also in the complex protein mixture of processed cheese. The formation of lactosylated β-casein A1 and A2 during heating of processed cheese was found to correlate with the furosine content. Consequently, CE of casein may be a possible method for directly assessing the extent of the early Maillard reaction in dairy products.