Computed tomography for quantitative determination of sodium chloride in ground pork and dry-cured hams

Seventy-five ground meat and fat samples of pork with varying composition of sodium chloride (0% to 16%), fat (1% to 82%), protein (1% to 46%), and water (13% to 76%) were scanned by X-ray computed tomography (CT) at 110 kV. The dependency of CT value on chemical composition and the linear relationships between sodium chloride (NaCl) and CT value were modeled. When all ground samples were used for modeling and no information of chemical composition was included in the model, the prediction error for NaCl was 2.8%. Adding information on fat or protein content to the model reduced the error to 1.6%. A minimal prediction error of 0.2% for NaCl was found when the variation in chemical composition was strongly reduced. In addition, 22 samples of dry-cured ham lean and fat tissues at different processing stages were CT scanned; their chemical compositions were 0% to 14% NaCl, 1% to 85% fat, 5% to 33% protein, and 7% to 76% water. The NaCl content in dry-cured ham samples was modeled with prediction errors of 0.6% to 2.1%, depending on which chemical component was included in the models. In general, predictions were improved if either the range of concentrations was reduced or information of chemical composition was included in the models. Important sources of error in the models were the reproduction error for ground samples, and for ham samples the analytical errors in determining the chemical composition.