Ultrasonic characterization of salt, moisture and texture modifications in dry-cured ham during post-salting

For the first time, this study addresses the use of non-destructive ultrasound to monitor ham post-salting. For that purpose, the ultrasonic velocity (1 MHz) and the weight loss of hams were measured regularly every 2 days up to 8 weeks after salting. Additionally, for different post-salting times, internal salt and moisture content and hardness were measured at different locations from the ham surface. The experimental results reflected that the ultrasonic velocity increased as the ham weight decreased (26.1 m/s per kg), showing a satisfactory correlation between both variables (r = 0.95). The ultrasonic velocity was also correlated with the salt and moisture content. However, ham hardness remained fairly constant during post-salting, which confirmed that characteristic textural changes mainly occur during the salting and drying-maturation stages. Thus, the ultrasonic velocity could be a reliable parameter with which to monitor not only overall modifications in ham weight, but also internal changes of moisture and salt content during post-salting in a non-destructive way.