Fourier-transform Raman analysis of milk powder: a potential method for rapid quality screening

• Published in: Journal of Raman spectroscopy Vol. 42; no. 7; pp. 1548 - 1552
• Main Authors: Almeida, Mariana R., Oliveira, Kamila de S., Stephani, Rodrigo, de Oliveira, Luiz Fernando C.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-07-2011; Wiley Subscription Services, Inc
• Subjects: Assessments; Classification; Least squares method; Milk; milk powder; partial least squares discriminate analysis (PLS-DA); principal component analysis (PCA); quality control; Raman; Raman spectroscopy; Screening; Spectra; Spectroscopy
• ISSN: 0377-0486; 1097-4555; 1097-4555
• DOI: 10.1002/jrs.2893

In this work, FT‐Raman spectroscopy was explored as a fast and reliable screening method for the assessment of milk powder quality and the identification of samples adulterated with whey (1–40% w/w). Raman measurements can easily differentiate milk powders without the need of sample preparation, whereas the traditional methods of quality control, including high‐performance liquid chromatography, are laborious and slow. The FT‐Raman spectra of whole, low‐fat, and skimmed milk powder samples were obtained and distinguished from commercial milk powder samples. In addition, the exploratory analysis employing data from Raman spectroscopy and principal component analysis (PCA)allowed the separation of milk powder samples according to type,identifying differences between samples in the same group. Multivariate analysis was also developed to classify the adulterated milk powder samples using PCA and partial least squares discriminate analysis (PLS‐DA). The resulting PLS‐DA model correctly classified 100% of the adulterated samples. These results clearly demonstrate the utility of FT‐Raman spectroscopy combined with chemometrics as a rapid method for screening milk powder. Copyright © 2011 John Wiley & Sons, Ltd.
The novelty of this work is that this is the first investigation concerning the use of Raman spectroscopy in the evaluation of the presence of extraneous constituents in milk powder, such as whey, as well as the identification by chemometric methods of different types of milk, such as whole, low fat, and skimmed milk. These tools allow the quick analysis of milk samples without the use of reagents that are typically necessary for conventional colorimetric or HPLC methods.