Adulteration analysis of milk protein based on amino acid pattern

To establish a method for identifying of milk protein adulteration based on amino acid pattern. With on sale qualified milk and milk powder as material, flour and starch were used to simulate adulteration. Tryptophan (Trp) , threonine (Thr) , valine (Val) and lysine (Lys) of the samples were determined by pre-column derivation-high performance liquid chromatography (HPLC) to establish amino acid concise patterns for identifying milk protein adulteration. The result indicated that the amino acid pattern of qualified milk was Trp∶Thr∶Val∶Lys=1.0∶2.7∶3.5∶5.4, which was highly anastomosed with the standard one proposed by World Health Organization (WHO) . And the amino acid pattern of qualified milk powder was Trp∶Thr∶Val∶Lys=1.0∶3.0∶4.5∶5.4. The amino acid patterns of adulterate milk and milk powder were significantly different from these of qualified ones. In conclusion, it was feasible to apply amino acid concise patterns of milk and milk powder to analyze milk protein adulteration, and this method could meet the requirements of routine determination and food safety control of dairy.