Chang Min, Chu Peng-jiao, Xu Ke-xin
National Key Laboratory of Precision Measuring and Testing Techniques and Instruments, College of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2007 Jan;27(1):43-5.
A quick and nondestructive method using near-infrared (NIR) diffuse reflectance spectroscopy to determine the content of protein in milk powder was presented. Twenty-nine kinds of milk powder were selected from domestic different districts. Partial least square (PLS) regression was utilized to build the calibration between the spectra and the protein content with chemical analysis as a reference method. Root mean square error of prediction (RMSEP) of 0. 687% was acquired. With the application of the method of wavelength selection, the number of wavelengths was decreased greatly from 1 558 to 11. The speed was accelerated and the accuracy of the calibration was improved to some extent. In order to reduce the particle size and nonspecific scattering effect, standard normal variate (SNV) and multiplicative scatter correction (MSC) were performed. These two treatments proved useful, and the RMSEP was reduced by 37%. Our results suggested that NIR diffuse reflectance spectroscopy was fast and real-time and could meet the practical measurement accuracy as required for industrial process analysis, providing a new tool for quality control of milk powder products.
提出了一种利用近红外（NIR）漫反射光谱法快速无损测定奶粉中蛋白质含量的方法。从国内不同地区选取了29种奶粉。以化学分析为参考方法，采用偏最小二乘（PLS）回归建立光谱与蛋白质含量之间的校准模型。预测均方根误差（RMSEP）为0.687%。通过波长选择方法的应用，波长数量从1558个大幅减少至11个。分析速度加快，校准精度在一定程度上得到提高。为了减小颗粒大小和非特异性散射效应，进行了标准正态变量变换（SNV）和多元散射校正（MSC）。这两种处理方法证明是有效的，RMSEP降低了37%。我们的结果表明，近红外漫反射光谱法快速、实时，能够满足工业过程分析所需的实际测量精度，为奶粉产品质量控制提供了一种新工具。
