Albanell E, Cáceres P, Caja G, Molina E, Gargouri A
Universidad Autónoma de Barcelona, Facultad de Veterinaria, Agricultura y Producción Animal, Barcelona, Spain.
J AOAC Int. 1999 May-Jun;82(3):753-8.
Analysis by near-infrared spectroscopy (NIRS) was investigated as a means of predicting quality parameters of ovine milk. Calibration equations were developed with samples of ovine milk obtained from a flock of Manchega and Lacaune dairy ewes at different stages of lactation for a wide variation in milk composition. Prediction equations for milk protein, fat, and total solids content were developed by use of reflection or transflection methods to measure absorbance values. Accuracies of measurements were compared. R2 (squared multiple correlation coefficient) values were satisfactory in most cases. The highest R2 value for milk protein content (0.92) was obtained in transflectance mode with unhomogenized milk. The highest R2 values for fat (0.99) and total solids (0.98-0.96) content were obtained in both a transflectance mode without sample conditioning and in a transflectance mode with milk homogenized at 40 degrees C. To validate the calibration, an independent set of 40 milk samples was used. The best r2 (simple correlation coefficient) values for protein, fat, and total solids were 0.92, 0.97, and 0.92, respectively. The study showed that NIRS is a potentially useful technique for evaluating the composition of unhomogenized ovine milk.
研究了通过近红外光谱法（NIRS）预测羊奶质量参数的方法。利用从一群处于不同泌乳阶段的曼彻格和拉库内奶羊获取的羊奶样本，针对奶成分的广泛变化建立了校准方程。通过使用反射或透反射方法测量吸光度值，建立了牛奶蛋白质、脂肪和总固体含量的预测方程。比较了测量的准确性。在大多数情况下，R2（复相关系数平方）值令人满意。在未均质化牛奶的透反射模式下，获得了牛奶蛋白质含量的最高R2值（0.92）。在未经样品预处理的透反射模式以及在40摄氏度下均质化牛奶的透反射模式下，均获得了脂肪（0.99）和总固体含量（0.98 - 0.96）的最高R2值。为验证校准，使用了一组独立的40个牛奶样本。蛋白质、脂肪和总固体的最佳r2（简单相关系数）值分别为0.92、0.97和0.92。该研究表明，近红外光谱法是评估未均质化羊奶成分的一种潜在有用技术。
