Application of Fluorescence Spectroscopy in the Evaluation of Light-Induced Oxidation in Cheese

Abstract

Light-induced oxidation of semihard cheese has been evaluated by fluorescence spectroscopy. The cheese was packaged in two packaging materials and exposed to different storage conditions, which included light/dark storage, oxygen availability, and storage time (0, 4, 7, 14, 21, 42, 70, or 84 days). Fluorescence excitation-emission matrices (EEM) were analyzed by PARAFAC, which gave an estimation of the pure excitation and emission spectra of the fluorophores and the concentrations of these. This analysis showed the presence of components such as tryptophan, tyrosine, vitamin A, fluorescent oxidation products, and riboflavin. Effects of packaging material, light or dark storage, and storage time were seen. However, there was no effect of the oxygen availability on the fluorescence measurements. The score values obtained by the PARAFAC models and chemical and physical measurements were analyzed together by principal component analysis (PCA). The loadings showed a separation of the variables into three groups; the first group was related to oxidation, the second group was related to the degradation of both riboflavin and vitamin A, and the third group was linked to the protein structure.

Measuring Cheese Maturation with the Fluorescence Fingerprint

“…Fluorescence has been used intensively to measure cheese properties such as texture , oxidation (Andersen et al, 2005;Karoui et al, 2007), geographic origin (Karoui et al, 2004) and maturation (Herbert et al, 2000;Mazerolles et al, 2001). The range of research has expanded greatly with the development of front-face fluorescence, where the sample is placed at an acute angle with the incident light and reflected fluorescence is measured, enabling the measurement of turbid and solid samples (Dufour and Riaublanc, 1997).…”

“…The range of research has expanded greatly with the development of front-face fluorescence, where the sample is placed at an acute angle with the incident light and reflected fluorescence is measured, enabling the measurement of turbid and solid samples (Dufour and Riaublanc, 1997). Cheese contains multiple constituents that are fluorescent, such as aromatic amino acids (Mazerolles et al, 2001), vitamin A (Herbert et al, 2000) and riboflavin (Andersen et al, 2005).…”

“…Recently, multiple studies have used the fluorescence fingerprint (FF), also referred to as the excitation-emission matrix (EEM), to acquire more comprehensive information about a cheese sample (Andersen et al, 2005;Christensen et al, 2003). FF is a set of fluorescence spectra acquired at consecutive excitation wavelengths, creating a three-dimensional diagram (Jiang et al, 2010).…”

Calibration, standardization, and quantitative analysis of multidimensional fluorescence (MDF) measurements on complex mixtures (IUPAC Technical Report)

“…chemometrics). Proper use of chemometric data analysis on MDF data requires careful consideration of sample photo-physics and an in-depth understanding of the methods [64,65] and their use [66][67][68][69][70]. The initial and final steps in the implementation of EEM/SFS-based analytical methods generally requires the use of chemometrics, first to assess the reproducibility and robustness of the measurement itself, and second to produce an output in terms of a qualitative result or quantitative value.…”

Multiway chemometric decomposition of EEM of fluorescence of CdTe quantum dots obtained as function of pH

“…The analysis of sets of EEMs obtained as function of selected experimental parameters has been studied by multiway chemometric methods. PARAFAC (parallel factor analysis) [36,37] is a well-established method for the analysis of EEMs [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52]. It allows the decomposition of multiway data arrays in a unique manner allowing robust estimations of the excitation and emission spectra and concentration profiles-this property is known as the multi-order advantage [24].…”