Study on measurement of milk constituents by NIR analysis

摘要

In this paper an attempt of NIR analysis to measure the milk constituents is introduced. In milk, light is absorbed and scattered simultaneously. The concentrations of each component no longer have linear relationship to the absorbency, but proportional to the absorption coefficient and scattering coefficient. It is necessary to separate the effect of absorption and scattering. Compare with the widely used NIR method, we do not calibrate the prediction model by diffuse reflectance. The calibration is composed by two steps. Firstly, the optical parameters are measured by double integrating sphere; secondly, calibration is made by optical parameters. Concentration of protein and fat are within reasonable range. Fifty samples are acquired for calibration. The experimental result shows a higher prediction accuracy of protein than the intensity calibration method, and a comparable accuracy of fat.