Abstract:

The separation and analysis of 17 amino acids in milk protein and soybean protein were conducted by amino acid
analyzer. When the concentrations of amino acids were in the range of 0.025–0.350 μmol/mL, the correlation coefficients
between peak areas and amino acid concentrations were above 0.988, the calibration curves of 17 amino acids all exhibited
good linearity and repeatability. Mean recovery rates and relative standard derivations (RSDs) for 17 amino acids from
spiked samples were in the ranges of 94.2% to 103.1%, and 0.89% to 3.31%, respectively. The linear relationship between
the contents of 6 selected amino acids showing significant differences in the amino acid profiles of the two proteins and the
amounts of added soybean protein was established by adulteration simulation experiments with correlation coefficients above 0.889.
This study has provided a good method for qualitative and quantitative detection of soybean protein adulterated milk.

Key words: amino acid analyzer, adulterated milk, soybean protein isolated, detection