Identification and Quantification of αS1, αS2, β, and κ-Caseins in Water Buffalo Milk by Reverse Phase-High Performance Liquid Chromatography and Mass Spectrometry

• Published in: Journal of agricultural and food chemistry Vol. 57; no. 7; pp. 2988 - 2992
• Main Authors: Feligini, Maria, Bonizzi, Ivan, Buffoni, Joanna Natalia, Cosenza, Gianfranco, Ramunno, Luigi
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 08.04.2009
• Subjects: alphaS1-casein; alphaS2-casein; beta-casein; Biological and medical sciences; buffalo milk; Food Chemistry/Biochemistry; Food industries; Fundamental and applied biological sciences. Psychology; kappa-casein; mass spectrometry; milk analysis; Milk and cheese industries. Ice creams; molecular weight; protein composition; reversed-phase high performance liquid chromatography; casein; high-performance liquid chromatography; mass spectrometry; Buffalo milk; Water; Milk protein; Casein; Dairy product; HPLC chromatography; Liquid chromatography; Identification; Mass spectrometry; Quantitative analysis
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf803653v

A method for the simultaneous quantitation of αS1, αS2, β, and κ-caseins in water buffalo (Bubalus bubalis) milk using reverse phase high-performance liquid chromatography was developed. The molecular masses of the peaks separated by the described chromatographic protocol were determined by ESI-MS. αS1- and κ-caseins were found to be heteromorphic in several individual milk samples. In particular, αS1-casein showed two peaks with a molecular mass of 23,490 Da and 23,516 Da, and κ-casein showed three peaks with molecular masses of 19,165 Da, 19,177 Da, and 19,247 Da. Only one form for β-casein (24,033 Da) and αS2-casein (22,741 Da) were detected. The mean values of casein fraction concentration observed throughout the individual samples were 8.89 gL−1 with a relative standard deviation (RSD) of 20% for αS1-casein, 5.08 gL−1 with a RSD of 25% for αS2-casein, 20.91 gL−1 with a RSD of 16% for β-casein, and 4.13 gL−1 with a RSD of 24% for κ-casein. Linear and second-order polynomial correlations with total nitrogen were calculated for all casein fractions.