混浊液态食品介质中脂肪的近红外光学特性研究

Study on Near-infrared Optical Properties of Fat in Turbid Liquid Food Materials

脂肪是多数食品中含有的典型且重要的营养成分，同时从光学测量的角度分析，也是决定食品光学特性的重要组成成分。本文对混浊液态食品介质中脂肪在近红外波段的光学特性进行研究。采用牛奶作为基体通过添加稀奶油得到的样品作为复杂液态食品介质的模拟物，应用双积分球技术在10000～6000cm^-1的近红外波段范围测量脂肪含量变化引起的光学特性变化。结果表明，脂肪含量的变化会使吸收系数和散射系数都发生改变，而且散射系数的变化更大。本文的工作为应用近红外光谱技术进行混浊液态食品介质的测量提供了光学上的理论指导。

Fat are typical and important nutrients of many food systems. From a view of optical measurement,the component plays a vital role in the determination of food optical properties. The optical properties of fat in turbid liquid food systems have been studied in the near-infrared region. A biological fluid of raw milk was firstly selected as a matrix and then a simulation sample for complex liquid food systems was created by adding butter oil to the raw milk matrix. The changes of optical properties with the contents of fat were measured by using the double integrating sphere technology in the wavenumber range from 10000 cm^-1 to 6000 cm^-1. The results indicated that the absorbance and scattering coefficients changed with the contents of fat. Moreover, bigger changes of the scattering coefficient were induced by the contents of fat,which showed that the scattering effect cannot be ignored. This study provides valuable theory reference for the measurements of turbid liquid food materials by near-infrared spectroscopy.