Influence of extrinsic operational parameters on salt diffusion during ultrasound assisted meat curing
The present study investigated the effect of geometric parameters of the ultrasound instrument during meat salting in order to enhance salt diffusion and salt distribution in pork meat on a lab scale. The effects of probe size (ø2.5 and 1.3 cm) and of different distances between the transducer and the meat sample (0.3, 0.5, and 0.8 cm) on NaCl diffusion were investigated. Changes in the moisture content and NaCl gain were used to evaluate salt distribution and diffusion in the samples, parallel and perpendicular to ultrasound propagation direction. Results showed that 0.3 cm was the most efficient distance between the probe and the sample to ensure a higher salt diffusion rate. A distance of 0.5 cm was however considered as a trade-off distance to ensure salt diffusion and maintenance of meat quality parameters. The enhancement of salt diffusion by ultrasound was observed to decrease with increased horizontal distance from the probe. This study is of valuable importance for meat processing industries willing to apply new technologies on a larger scale and with defined operational standards. The data suggest that the geometric parameters of ultrasound systems can have strong influence on the efficiency of ultrasonic enhancement of NaCl uptake in meat and can be a crucial element in determining salt uptake during meat processing.