Depth profiling Fourier transform analysis of cheese package using generalized two-dimensional photoacoustic correlation spectroscopy.

Generalized two-dimensional (G2D) photoacoustic correlation spectroscopy was used to detect the migration of protein and fat into the cheese package. The potential of G2D correlation analysis of infrared spectrum to enhance the resolution and interpretation and differentiate the overlapping spectral peaks was demonstrated by depth profiling. Comparison of a pure polymer film not in contact with cheese against the polymer film wrapped on cheese revealed that molecular groups related to protein in cheese adhered to the package film. The detection of fat components from cheese in the package was ambiguous because of the C-H stretch overtone at 2922 cm–1 due to functional groups related to fat and polymer.