Improvement of solubility, gelation and emulsifying properties of myofibrillar protein from mantis shrimp (Oratosquilla oratoria) by phosphorylation modification under low ionic strength of KCl.

The objective of this study was to investigate the mechanisms of phosphates coupled with KCl (at 0, 0.01 and 0.03 M) affecting gel and emulsifying properties of myofibrillar protein (MP) from mantis shrimp. P NMR showed that phosphate groups were introduced to MP after treatment with sodium pyrophosphate (SPP) or sodium tripolyphosphate (STPP). The incorporation of phosphates enhanced electronegativity and solubility of MP, leading to exposure of hydrophobic groups, especially in the presence of 0.03 M KCl. These changes resulted in increased gel strength, water-holding capacity and elasticity of MP, mainly due to the improved cross-linking of proteins via ionic interaction, hydrophobic interaction and disulfide bonds. Furthermore, the combination of phosphate and KCl contributed to formation of more stable emulsions stabilized by MP with higher emulsifying activity and smaller droplet size. These results indicated that phosphates and low-dose sodium substitutes synergistically improved the processing properties of muscle food.