Spectroscopic characterization of low- and non-fat cream cheeses

Low-fat and non-fat cream cheeses were produced with variations in pH (4.4, 4.7, 5.0), salt concentration (0.4%, 0.65%, 0.9%) and fat content (0%, 3%, 6%, 9%). The cheeses were evaluated by four spectroscopic methods; fluorescence spectroscopy, near infrared spectroscopy (NIR), fourier transform infrared spectroscopy (FT-IR) and low-field nuclear magnetic resonance relaxometry (LF-NMR), to identify and describe the variation in cream cheeses induced by the experimental variables. The four methods complemented each other and gave somewhat different information about the products. Only LF-NMR was affected by all three design parameters and showed that high pH and high salt content made the low-fat samples resemble samples with higher fat content, with respect to water mobility. The sensory parameter, creaminess, could be predicted from the spectroscopic measurements, where NIR and FT-IR performed the best in the chemometric models. The spectra measured by these methods contained more information related to creaminess, but the use of a larger number of components indicated that the information was complex.