Study on Differences of Milk Proteins by Liquid Chromatography-Mass Spectrometer

The peptide mass fingerprinting differences of whey ((alpha-La) and (beta-Lg)) and caseins (alpha(s)-CN, beta-CN, kappa-CN) components by enzymatic hydrolysis of milk protein from the Southern water buffalo compared with goat and Holstein milk were analyzed by using the LTQ Orbitrap XL mass spectrometer with high resolution. The results showed that peptide mass fingerprinting differences of a-La amino acid mutation in Southern water buffalo and Holstein milk whey protein were lower than that in the goat milk whey protein. However, the differences of beta-Lg amino acid mutation in Southern water buffalo and Holstein milk whey protein were higher than that in the goat milk whey protein. In contrast, compared with the three different milk-producing species, the amino acids sequence differences of caseins (alpha(s)-CN, beta-CN, kappa-CN) changed more significantly than that in the whey protein, which indicated that the peptide mass fingerprinting differences of milk protein were especially impacted by the species variety.