采用便携式近红外光谱仪, 结合偏最小二乘回归法, 研究了牛奶脂肪、 蛋白质和干物质含量的测定方法, 建立了近红外漫反射定量分析模型。 结果显示, 脂肪、 蛋白质和干物质模型相关系数(R2)分别为0.98, 0.95, 0.98, 建模集标准残差(RMSEC)分别为0.187, 0.105, 0.217, 验证集标准残差(RMSEP)分别为0.187, 0.120, 0.296, 相对分析误差(RPD)分别为5.02, 2.60, 3.20。 同时探讨了各成分间的相关性, 发现脂肪与干物质间具有很好相关性(R2=0.921), 因此可通过脂肪模型预测来计算干物质含量, 提高了干物质的检测精度。 研究表明, 采用便携式近红外漫反射模式可为牛奶成分的现场检测提供一种无损、 快速的新方法。

Near infrared diffuse reflectance spectroscopy calibrations of fat, protein and DM in raw milk were studied with partial least-squares (PLS) regression using portable short-wave near infrared spectrometer. The results indicated that good calibrations of fat and DM were found, the correlation coefficients were all 0.98, the RMSEC were 0.187 and 0.217, RMSEP were 0.187 and 0.296, the RPDs were 5.02 and 3.20 respectively; the calibration of protein needed to be improved but can be used for practice, the correlation coefficient was 0.95, RMSEC was 0.105, RMSEP was 0.120, and RPD was 2.60. Furthermore, the measuring accuracy was improved by analyzing the correction relation of fat and DM in raw milk. This study will probably provide a new on-site method for nondestructive and rapid measurement of milk.