Non-destructive estimation of moisture, water activity and NaCl at ham surface during resting and drying using NIR spectroscopy

This paper describes the ability of near infra-red reflectance (NIR) spectroscopy to predict moisture, water activity (aw) and NaCl content at the surface of dry-cured ham during the process. A Fourier Transform (FT) NIR spectrometer and two probes (on-contact and remote) were tested directly on the surface (gracilis muscle) of 98 hams during the process. The highest precision was achieved when two spectra per sample were used in the predictive model development. The models based on the remote measurement probe yielded acceptable results with determination coefficients (r2) of 0.93, 0.62 and 0.91 and residual predictive deviation (RPD) of 3.74, 1.63 and 3.33 for moisture, aw and NaCl content, respectively. These results show that NIR measurements could be included in the control system of the resting and drying processes to prevent crusting in dry-cured ham.