Prediction of adipose tissue composition using raman spectroscopy: Average properties and individual fatty acids

Abstract

Raman spectroscopy has been used for the first time to predict the FA composition of unextracted adipose tissue of pork, beef, lamb, and chicken. It was found that the bulk unsaturation parameters could be predicted successfully [R2 = 0.97, root mean square error of prediction (RMSEP) = 4.6% of 4 sigma], with cis unsaturation, which accounted for the majority of the unsaturation, giving similar correlations. The combined abundance of all measured PUFA (> or = 2 double bonds per chain) was also well predicted with R2 = 0.97 and RMSEP = 4.0% of 4 sigma. Trans unsaturation was not as well modeled (R2 = 0.52, RMSEP = 18% of 4 sigma); this reduced prediction ability can be attributed to the low levels of trans FA found in adipose tissue (0.035 times the cis unsaturation level). For the individual FA, the average partial least squares (PLS) regression coefficient of the 18 most abundant FA (relative abundances ranging from 0.1 to 38.6% of the total FA content) was R2 = 0.73; the average RMSEP = 11.9% of 4 sigma. Regression coefficients and prediction errors for the five most abundant FA were all better than the average value (in some cases as low as RMSEP = 4.7% of 4 sigma). Cross-correlation between the abundances of the minor FA and more abundant acids could be determined by principal component analysis methods, and the resulting groups of correlated compounds were also well-predicted using PLS. The accuracy of the prediction of individual FA was at least as good as other spectroscopic methods, and the extremely straightforward sampling method meant that very rapid analysis of samples at ambient temperature was easily achieved. This work shows that Raman profiling of hundreds of samples per day is easily achievable with an automated sampling system.

A review of analytical methods measuring lipid oxidation status in foods: a challenging task

“…In line with peroxide values rises, Raman spectra data showed an increase in particular bands and regions of the spectra of oils extracted which could be attributed to alterations in lipids structure. Furthermore, Raman spectroscopy could be an alternative to gas chromatographic fatty acids analysis, since it successfully predicted total unsaturation and individual compounds several meat products [133]. Salmon Raman spectra [134] indicated differences in the fat fraction (as well as in protein fraction) in coldsmoked products.…”

Raman spectroscopy of advanced glycation end products (AGEs), possible markers for progressive retinal dysfunction

“…46 Evidence of the protein content of the POS samples is seen in the sharp band at 1003 cm 1 (phenylalanine), and in the bands in the region 1550-1630 cm 1 , attributable to a variety of aromatic amino acid residues. 44,47 The very strong band around 1455 cm 1 coming from CH x scissoring is present in spectra of all molecules containing hydrocarbon groups such as amino acids or lipid peroxidation products. 46 Comparison of the normalized spectra of non-oxidized and oxidized POS (Fig.…”

Fluorescence suppression using wavelength modulated Raman spectroscopy in fiber-probe-based tissue analysis

“…In the case of chicken, the adipose tissue was dissected from above the chicken breast, all within 48 h of slaughter. 26 Care was taken to ensure that for adipose tissue only the part next to the skin was chosen for the experiment since the fatty acid composition changes across the cross-section of the tissue. 26,27 The Raman signals from all these samples were collected at the ambient temperature of 19 to 21°C.…”

“…26 Care was taken to ensure that for adipose tissue only the part next to the skin was chosen for the experiment since the fatty acid composition changes across the cross-section of the tissue. 26,27 The Raman signals from all these samples were collected at the ambient temperature of 19 to 21°C. For each sample, 20 different spectra were collected to ensure we could obtain reliable statistics.…”