Evaluation of ultrasonic-assisted pickling with different frequencies on NaCl transport, impedance properties, and microstructure in pork

The effects of ultrasonic curing with various frequencies on sodium chloride (NaCl) mass transfer in pork muscle and its potential mechanisms were investigated. The results showed that ultrasound curing dramatically increased the NaCl content in pork compared to static curing, especially curing at 26.8 kHz. The binarized images of NaCl penetration in pork visually confirmed that ultrasound enhanced the efficiency of mass transfer. Energy dispersive spectroscopy showed that the distribution of NaCl in pork tissue cured by ultrasound was the densest compared to the static curing. According to impedance analysis and microstructure observation, the structure of cell membranes was damaged to different extents during ultrasound treatments. The potential mechanisms of low-frequency ultrasound accelerated curing are mainly attributed to the action of acoustic cavitation and the sponge effect. Overall, the low-frequency ultrasound is a promising revolutionary technology in the food industry that can speed up the curing process of meat.