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

Abstract

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.