The effect of high-pressure homogenization on rabbit myofibrillar proteins in dilute sodium chloride solutions: weak ionic shielding promotes the depolymerisation

The study attempts to determine the effect of ionic strength on the structure and solubility of rabbit myofibrillar proteins (MPs) and improves MPs dissolution in low salt medium. There was a significant effect of ionic strength on the structure and dissolution characteristics of MPs in low salt medium range (0-200 mM NaCl), increased ionic strength led to MPs aggregation and reduced solubility (P < 0.05), while decreased ionic strength weakened charge shielding effect, resulted in stronger electrostatic repulsion and weaker hydrophobic interaction between molecules, thus promoting MPs structural swell and separation between filaments. The modification effect of HPH on the MPs also depended on the ionic strength. Upon HPH, due to the difference in charge shielding effect and hydrophobic interactions, there was a progressive improvement in MPs solubility (from 23.51% to 85.25%) and dispersion stability at 0 mM salt medium (I = 0.0217) while limited increase in solubility at medium higher than 13 mM (from 4.39% to 7.20% at 20 mM). Decreasing ionic strength promoted the depolymerisation of HPH on MPs, inhibited the myosin assembly into filaments after HPH. The modification of ionic strength on the surface charge and hydrophobicity of MPs were further amplified, also contributed to the improved solubility and dispersion stability.