Broadband Optical Properties of Milk
Broadband Optical Properties of Milk
复制标题
牛奶的宽带光学特性
作者：
Sabrina Stocker;F. Foschum;P. Krauter;F. Bergmann;A. Hohmann;Claudia Scalfi Happ;A. Kienle
乳制品在我们的日常营养中起着重要的作用。作为具有不同种类的颗粒和液滴的混浊散射介质，这些组分的每一次改变都会改变牛奶的散射特性。这项工作的目标是确定的主要散射成分，脂肪滴和酪蛋白胶束的量，通过了解光在均质牛奶和原料奶中的传播。为了提供这些牛奶组分的绝对影响，必须检查组分的几何和光学性质，例如尺寸分布和折射率（RI）。我们用积分球测量法确定了约化散射系数μ s '和吸收系数μ a。利用准直透射装置测量了散射系数μ s。进行尺寸测量以验证脂肪滴尺寸对散射特性结果的影响;此外，两种组分的RI由所述系数确定。这些结果用于确定牛奶组分对散射行为的绝对影响。通过对不同原料奶样品的散射光谱μ s和μ s '进行Mie理论拟合，可以得到脂肪和酪蛋白浓度以及脂肪滴大小的可靠值。通过破坏酪蛋白胶束，可以分离不同散射组分对散射行为的影响。
Dairy products play an important role in our daily nutrition. As a turbid scattering medium with different kinds of particles and droplets, each alteration of these components changes the scattering properties of milk. The goal of this work is the determination of the amount of main scattering components, the fat droplets and the casein micelles, by understanding the light propagation in homogenized milk and in raw milk. To provide the absolute impact of these milk components, the geometrical and optical properties such as the size distribution and the refractive index (RI) of the components have to be examined. We determined the reduced scattering coefficient μ s ' and the absorption coefficient μ a from integrating sphere measurements. By use of a collimated transmission setup, the scattering coefficient μ s was measured. Size measurements were performed to validate the influence of the fat droplet size on the results of the scattering properties; also, the RI of both components was determined by the said coefficients. These results were used to determine the absolute impact of the milk components on the scattering behavior. By fitting Mie theory calculations on scattering spectra μ s and μ s ' from different raw milk samples, it was possible to get reliable values for the concentrations of fat and casein and for the size of the fat droplets. By destroying the casein micelles, it was possible to separate the influence of the different scattering components on scattering behavior.