  Considering the pivotal role of eggs in the food industry and their
nutritional significance, this study employed micro-Raman spectroscopy of eggs,
examining both shells and yolks to assess the quality and freshness of eggs.
Raman spectra were collected at different temperatures and time intervals to
investigate temperature and time effects, potentially indicating Raman peak
reduction due to Maillard reaction and oxidation of proteins and lipids and
carotenoid depletion, respectively. By calculating the ratio of Raman peaks,
lipids, fatty acids, and choline methyl were introduced as biomarkers of
temperature and time. Notable correlations were identified between Raman peaks
and egg quality coefficients, including egg coefficient and peak 1002 cm$^{-1}$
(protein), total weight and 1301 cm$^{-1}$ (Lipids), yolk weight and 2934 and
3057 cm$^{-1}$, total weight with peak 710 cm$^{-1}$, and egg shape index and
peak 3057 cm$^{-1}$. Analysis of eggshells at different time intervals revealed
Raman peak reduction during time, demonstrating Raman's effectiveness in
assessing egg quality from its shell. Using the PLS-DA method, the
classification of eggs at different temperatures and storage times using egg
yolk Raman spectra was performed with 80% accuracy, predominantly influenced by
carotenoid peaks, showing Raman a practical, and non-destructive method for egg
quality and freshness control.
