Application of NIR spectroscopy and image analysis for the characterisation of grated Parmigiano-Reggiano cheese

Grated Parmigiano–Reggiano cheese holds a valuable market segment and its quality strictly depends on the amount of rind, size, shape of cheese particles and original cheese properties. Textural properties of the rind and inner part of the cheese significantly affect size and shape of grated particles. Rind produces a higher amount of finer and less circular particles than the inner region. Rind content established by European regulation (maximum 18%) is a major issue and could be successfully predicted by multivariate models developed on near-infrared (NIR) spectra. Image analysis (IA) was a suitable method to estimate rind percentage that was found positively correlated to number of particles, total surface covered by particles and circularity. IA and NIR spectroscopy enabled characterisation of the distribution of the particle in dimensional classes and could be used to control the maximum limit of 25% of particles finer than 0.5 mm provided by European regulation.