Effect of low-frequency alternating magnetic field on the rheological properties, water distribution and microstructure of low-salt pork batters

The effects of different intensities of low-frequency alternating magnetic fields (LF-AMF) modification on gel characteristics, rheology, water distribution, secondary structure and microstructure were investigated. The results showed that application of LF-AMF exhibited a significant improvement of the water-holding capacity, gel strength, color, textural properties and acceptability of low-salt pork batter gels (P < 0.05). When the LF-AMF intensity reached 0.6 mT, the low-salt pork batters had the highest WHC, L*, gel strength, hardness, springiness, gumminess and chewiness and acceptability (P < 0.05). During the temperature (sample heated from 20 to 80 °C) and frequency (0–10 Hz) sweep, the storage modulus G′ first increased and then decreased with increasing of LF-AMF intensity. Low-field nuclear magnetic resonance (LF-NMR) showed that LF-AMF at an intensity of 0.6 mT shortened the T2 relaxation time of pork batter gel and increased the proportion of immobilized water. Fourier transform infrared spectroscopy (FTIR) showed that LF-AMF treatment significantly induced an increase of β-sheet structure and reduction of α-helix content in pork batter gels (P < 0.05). Scanning electron microscopy (SEM) results suggested that LF-AMF contributed to the formation of pork batter gels with a more uniform and orderly network structure.