Investigating Light Propagation In Full And Skimmed Milk Based On Spectroscopy And Monte Carlo Analysis

Milk quality can be determined through its fat composition. It is important to know the fat composition in milk to ensure consumption of the right product for health reasons. Spectroscopy can be used to study the fat composition in milk. In this paper, light propagation in milk based on visible and near infrared (NIR) spectra is investigated. Samples comprise skimmed and full milk. Full milk shows higher absorbance at visible (VIS) spectra compared to skimmed milk. The analysis on NIR spectra also shows that full milk has higher absorbance peak than skimmed milk due to higher amount of fat globule. Fourier-transform infrared spectroscopy (FTIR) analysis is done to study the chemical compounds such as C=C and O-H in milk samples. Through FTIR, the unsaturated fatty acid and water element in the samples were analyzed. Both milk samples show higher water element than carbon. Numerical modeling based on Monte Carlo method is also done to support experimental results. The modeling results show that full milk has a larger photon count compared to skimmed milk. This is attributed to the large fat globule in full milk that has higher absorbance over skimmed milk. Thus, characterization of milk fat based on spectroscopy techniques can monitor milk adulteration issues, which indirectly gives us guidance on healthy dairy intakes.

KEYWORDS: Absorbance, Transmittance, Milk fat, Monte Carlo, Spectroscopy, Photon count and photon loss.