Short communication: Suitability of fluorescence spectroscopy for characterization of commercial milk of different composition and origin

Abstract

Thirteen milk brands comprising 76 pasteurized and UHT milk samples of various compositions (whole, reduced fat, skimmed, low lactose, and high protein) were obtained from local supermarkets, and milk samples manufactured in various countries were discriminated using front-face fluorescence spectroscopy (FFFS) coupled with chemometric tools. The emission spectra of Maillard reaction products and riboflavin (MRP/RF; 400 to 600 nm) and tryptophan (300 to 400 nm) were recorded using FFFS, and the excitation wavelengths were set at 360 nm for MRP/RF and 290 nm for tryptophan. Principal component analysis (PCA) was applied to analyze the normalized spectra. The PCA of spectral information from MRP/RF discriminated the milk samples originating in different countries, and PCA of spectral information from tryptophan discriminated the samples according to composition. The fluorescence spectral data were compared with liquid chromatography-mass spectrometry results for the glycation extent of the milk samples, and a positive association (R(2)=0.84) was found between the degree of glycation of α-lactalbumin and the MRP/RF spectral data. This study demonstrates the ability and sensitivity of FFFS to rapidly discriminate and classify commercial milk with various compositions and processing conditions.

Application of front-face fluorescence spectroscopy as a tool for monitoring changes in milk protein concentrate powders during storage

“…The factor loadings of the first 2 PC of the Maillard emission data fluorescence data sets are presented in Figures 7B. The factor loadings plot of PC-1 showed a broad band from 425 to 440 nm, suggesting the presence and variation of Maillard reaction products in the MPC samples, in agreement with the report by Liu and Metzger (2007) and Ntakatsane et al (2011). They at- tributed positive band of PC-1 at 430 nm to display the accumulation of AGE products during storage of dairy products.…”

“…Discrimination of the MPC powders stored at 25 and 40°C was observed in the similarity maps. The tryptophan maximum emission has been previously reported in most studies in the region between 332 and 343 nm (Dufour et al, 2001;Kulmyrzaev et al, 2005;Ntakatsane et al, 2011), depending on the sample composition, origin, processing, and storage conditions. The changes in tryptophan maximum emission wavelength showed changes in the polarity of the tryptophan residues micro-environment (Liu et al, 2005).…”

Supervision of Food Manufacturing Processes Using Optical Process Analyzers – An Overview

“…A strong correlation (0.95) of hydroxymethylfurfural, as an indicator for the Maillard reaction, and the fluorescence spectra was observed 82. Similarly, tryptophan (excitation 290 nm and emission 300–400) and Maillard reaction spectra (excitation 360 nm and emission 400–600 nm) were taken to discriminate commercial milk of various brands, different composition, and origin by the application of PCA 83.…”

Identification of milk types using two different fluorescence spectroscopy techniques

“…SFS exhibits results of several intrinsic fluorescent compounds (tryptophan, vitamin A, riboflavin and other aromatic amino acids) that present in food and provide the fingerprint spectrum of milk (Genis et al, 2019). In the literatures, there are many applications of fluorescence spectroscopy for the quality determination (Ntakatsane et al, 2011 andVelioglu et al, 2017) or identify of the dairy products (Herbert et al, 2000 andDufour, 2008).…”