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Cholesterol determination in egg yolk by UV-VIS-NIR spectroscopy

Puertas, Gema, Vázquez, Manuel
Food control 2019 v.100 pp. 262-268
cholesterol, egg yolk, enzymatic treatment, least squares, models, pasteurization, saponification, spectral analysis, spectroscopy
A quick and cheap method for cholesterol quantification in egg yolk by UV-VIS-NIR spectroscopy was developed. Cholesterol was saponified and extracted from shell egg yolks or pasteurised egg yolks. Spectral data (144 spectra) were obtained from 38 samples. Different transformations of the spectra (smoothing Savitzky-Golay, standard normal variate, multiplicative scatter correction, detrending, baseline correction and first and second derivative) and modelling strategies such as Partial Least Squares (PLS) regression or Principal Component Regression (PCR) were evaluated. An enzymatic method was selected as reference procedure. Cholesterol content quantified was significantly lower in pasteurised egg yolks than in shell egg yolks. Best results were obtained using PLS and first derivative Savitzky-Golay combined with baseline correction, achieving a model with a determination coefficient of 0.93. Total cholesterol quantification was increased with saponification conditions improvements. Results obtained demonstrate that UV-VIS-NIR spectroscopy can be used to determine cholesterol from shell egg yolks or pasteurised egg yolks.