Performance Comparison of UV and FT-Raman Spectroscopy in the Determination of Conjugated Linoleic Acids in Cow Milk Fat

Abstract

The determination of conjugated linoleic acids (CLA) in cow milk fat was studied by using UV (210-250 nm) and Fourier transform (FT)-Raman (900-3400 cm (-1)) spectroscopy in order to determine the best spectrophotometric technique for routine analysis of milk fat. A collection of 57 milk fat samples was randomly divided into two sets, a calibration set and a validation set, representing two-thirds and one-third of the samples, respectively. All calculations were performed on the calibration set and then applied to the validation set. The CLA content ranged from 0.56 to 4.70%. A comparison of various spectral pretreatments and different multivariate calibration techniques, such as partial least-squares (PLS) and multiple linear regression (MLR), was done. This paper shows that UV spectroscopy is as reliable as FT-Raman spectroscopy to monitor CLA in cow milk fat. The best calibration for FT-Raman was given by a PLS model of seven factors with a standard error of prediction (SEP) of 0.246. For UV spectroscopy, PLS models were also better than MLR models. The most robust PLS model was constructed with only one factor and with SEP=0.288.

Composition of bovine milk fat globules by confocal Raman microscopy

“…Raman spectral data of milk products and compounds are well documented (Bernuy, Meurens, Mignolet, & Larondelle, 2008;Li-Chan, 2007;McGoverin et al, 2009), and lipids of various origins have been extensively studied (Krafft et al, 2005;Weng, Weng, Tzeng, & Chen, 2003). Raman spectroscopy has been applied to the examination of milk fat globules (MFGs), one from bovine milk (Forrest, 1978) and the other one from human milk (Argov et al, 2008), and to the comparative study of bovine milk and bovine milk fat, providing information on the milk fat globule membrane (MFGM) (Larsson, 1976).…”

Characterization of nutritional parameters in bovine milk by Raman spectroscopy with least squares modeling

“…The advantages lie in the ease of use, rapid analysis, and the determination of several parameters with a single measurement. Raman allows simultaneous and automated determination of fat, proteins, and lactose in milk from any animal without pretreatment [22,24,51]. Raman spectroscopy also allows characterization of common adulterations of milk such as lower concentrations of fat and proteins than labeled values.…”

Total and Free Fatty Acids Analysis in Milk and Dairy Fat

“…As NIRS, RS has potential to predict grouped FA, such as total SFA, MUFA, PUFA, CLA and so on. Meurens et al [115] and Bernuy et al [116] demonstrated that Fourier Transform-RS (FT-RS) technique has a great potential in predicting total CLA in cow's milk. Stefanov et al [117,118] showed the capability of RS for direct semi-routine quantification of the individual or grouped trans-MUFA, CLA, odd and BCFA in the milk fat.…”