Middle infrared spectroscopy characterization of ripening stages of Camembert-type cheeses

Mould-ripened soft cheeses like Camembert produced at pilot scale were analyzed in order to evaluate the potential of mid-infrared spectroscopy to follow the ripening phenomena. Two cheese zones (core and under-rind) were analyzed directly and were then fractionated by selective precipitation to obtain more specific parts. Cheese slices and their fractions were analyzed by attenuated total reflectance. Analysis of variance showed the significant absorbance changes on spectra sets, mainly in the regions assigned to the vibrations of alcohol and amide groups. By principal component analysis of spectral data, two different steps of ripening can be described. The spectral studies of other fractions than whole cheese provided no additional information. Using partial least-square regressions-based spectral sets, made it possible to determine ripening day with an error of 1 day.