Rapid quantification of goat milk adulteration with cow milk using Raman spectroscopy and chemometrics

Abstract

As goat milk has a higher economic value compared to cow milk, the phenomenon of adulterating goat milk with cow milk appears in the market. In this article, the potential of Raman spectroscopy along with chemometrics was investigated for authentication and quantitation liquid goat milk adulterated with cow milk. First, the Raman spectra of goat milk and cow milk were examined by principal component analysis (PCA), the results showed that there were differences between the Raman spectra of cow and goat milk, which made quantitative experiments possible. For quantification, three different brands of cow milk and goat milk were selected randomly and adulterated goat milk with cow milk at the proportion of 5%-95%. 342 samples were used for the construction of the partial least square regression (PLSR) model, with 80% for the training set and 20% for the test set. The PLSR model showed the excellent performance for quantifying the level of adulteration, for the prediction set, with a coefficient of determination (R2) of 0.9781, root mean square error (RMSE) of 3.82%, ratio of prediction to deviation (RPD) of 6.8. The results demonstrated the potential of Raman spectroscopy as a rapid, low cost and nondestructive analytical tool for adulteration detection in goat milk.