Numerical study of light scattering and propagation in soymilk: Effects of particle size distributions, concentrations, and medium sizes

Abstract

Understanding light scattering and propagation in soymilk is crucial for the nondestructive evaluation of food qualities of soymilk and its products by near-infrared spectroscopy. We aim to numerically examine light scattering and propagation in soymilk samples with different solid-content properties (particle size distributions and concentrations) and medium sizes. Using the dependent scattering theory, we calculated the light-scattering properties of the samples on the sub-nanometer scale. In contrast, we calculated light propagation on the millimeter scale using the radiative transfer theory. Our numerical results show that the scattering properties of soymilk strongly depend on the solid-content properties, implying a high correlation between the solid-content and scattering properties. The sample with the largest mean diameter and broadest size distribution has the smallest reduced scattering coefficient among the samples, although it has the largest scattering coefficient. We compared the reflected fluence rates in a cylinder and semi-infinite medium. The comparative study shows the finite size effect on light propagation can be negligible at the cylinder radius of more than 2.0 cm. In that case, the light propagation model for a semi-infinite medium is a better choice to provide fast calculations in inverse analysis on the scattering properties. Our findings are essential for further developing near-infrared spectroscopy using scattered light and the physics of light scattering in dense polydisperse media.