Characterization of buffalo milk by 31P-nuclear magnetic resonance spectroscopy

We report a 31P nuclear magnetic resonance (31P-NMR) investigation of buffalo milk, milk ultrafiltrate, and phospholipids from milk fat; for comparison corresponding data were also acquired for cow milk samples. In buffalo milk samples, we identified glycerophosphorylcoline, glycerophosphorylethanolamine and inorganic orthophosphate resonances, together with a broad peak assigned to serylphosphate residues of casein. Buffalo milk ultrafiltrate showed the presence of several phosporous signals, and ten of them (inorganic phosphate, phosphocreatine, glycerophosphorylcoline, glycerophosphorylethanolamine, N-acetylglucosamine-1-phosphate, glucose-6-phosphate, galactose-1-phosphate, phosphorylethanolamine, phosphorylcoline, and glycerol-1-phosphate) were unambiguously identified by addition of pure standards. In phospholipids fractions from buffalo milk, we clearly identified phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, sphingomyelin, and phosphatidylinositol. A preliminary estimation (mol%) of each phosphorylated compound was obtained. By comparing 31P-NMR data from milk samples from buffaloes and cows, we concluded that these milks are rather similar as far as the phosporous distribution in small molecules is concerned.