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A system able to evaluate the texture of dry-cured ham inline at the industry would be very useful to ensure and certificate the final quality of the product. Near infrared spectrometry (NIRS) have shown potential for the prediction of texture and pastiness defect (García-Rey et al., 2005) which are known to be related to the proteolysis index of the sample. Salt and water contents are also relevant parameters. The present study is aimed at identifying the NIR spectral bands that characterise dry-cured ham proteolysis. Prediction ability for proteolysis index, salt and water contents determination using different spectral regions has also been analysed. To do so, spectra from 125 dry-cured ham samples, with a wide range of proteolysis index, and with salt and water contents not correlated to this proteolysis index, were acquired using a high-performance Fourier Transform NIR spectrometer (Bruker Optik, Germany). Different mathematical pre-treatments were used to analyse the spectra and develop the predictive models. Regression coefficients of proteolysis index model using raw and normalized spectra show high negative values between 1680 and 1690 nm which corresponds with the absorption peak of amide group (CONH2) characteristic of proteins. Degradation of proteins occurring during proteolysis produces a decrease on this absorption band, as previously reported in cheese (Malegori et al., 2021). Predictive errors for the proteolysis index models developed using the complete spectra and this specific spectral range were 1.622 and 1.379% respectively. Salt and water contents could also be predicted with an error of 0.263 and 0.539%, respectively. These results show potential usefulness of this technology at the industry to estimate texture/ripening level of dry-cured ham from the measurement of proteolytic degradation level in combination with salt and water contents. However, more experimental work is needed to define their threshold values to define the different texture types.
