Exploring the Variance of Authentic Skim and Non-Fat Dry Milk Powder Spectra

Abstract

investigated by the Unites States Pharmacopeia (USP) in an effort to develop a successful non-targeted solution for milk powder. A significant challenge to be faced in this study is the normal physicochemical variability of pure milk powders. The existence of these variations will have the effect of widening the boundaries for any potential non-targeted method which may have the effect of decreasing the method’s ability to detect adulterants present at low concentrations. This problem is especially true for NIR diffuse reflectance spectroscopy, with its inherent limitations in the accurate detection of chemical components which are present below approximately 0.1% w /w in a sample matrix. In this report, the variance of NIR spectra from 41 different bovine skim milk powders and non-fat dry milk powders was explored. Spectral data were examined to identify influential sources of variance using princi pal component score trends and spectral signatures in rotated principal component loadings. Chemical analysis of samples of interest was also used to support the interpretations of the rotated principal components.