Kinetic Effects of KCl Substitution for NaCl in Different Proportions on Lipid Oxidation in Pork

To investigate the effects of KCl substitution for NaCl in different proportions on lipid oxidation in pork processing, 3% or 4% of NaCl, which was partly replaced by 15%, 30%, 45%, or 60% of KCl, respectively, were added to the minced longissimus muscles, then kinetic law of lipid oxidation was studied after treatment at different temperature. The results showed that at a fixed salt content and composition, both the primary and the secondary lipid oxidation rate constants increased with the increasing temperature. At a fixed temperature, lipid primary oxidation rate constants decreased with the increasing of KCl substitution proportion at a 3% salt content, while which first increased and then decreased with the KCl substitution proportion when salt concentration was fixed at 4%, reaching a maximum at 45% of KCl proportion. The Arrhenius equation analysis showed that at 3% salt concentration, the activation energies of both lipid primary oxidation and lipid secondary oxidation increased linearly with the increasing of KCl substitution proportion (P<0.05), while when salt content was at 4%, partial replacement of NaCl with KCl had no significant effect on the activation energies of lipid oxidation (P>0.05). Therefore, partial replacement of NaCl with KCl could improve the lipid oxidation stability in pork linearly with the substitution proportion if total salt concentration is at about 3%, and no significant effect was observed if total salt content was at about 4%.