The structural rearrangement and depolymerisation induced by high-pressure homogenisation inhibit the thermal aggregation of myofibrillar protein

The effects of heating on the dissolution and aggregation of high-pressure homogenisation (HPH)-treated myofibrillar protein (MP) in low ionic strength medium were investigated in this study. Upon heating, HPH-treated MP (HTMP) had a greater solubility and lower turbidity than control MP (P < 0.05). The rheological measurement exhibited that the thermal aggregation ability of HTMP was hampered due to lower storage modulus (G ') and loss modulus (G ''), except near 50 degrees C. The increased G ' and G '' of HTMP at near 50 degrees C could be attributed to structural rearrangement induced by HPH. The analysis of proteomics indicated that HPH destroyed the cytoskeletal proteins in myofibrillar structure, made MP structure more swollen and flexible, promoted MP rearrangement and formation of oligomers with higher negative charge, which produced stronger steric hindrance and electrostatic repulsion between molecules, thus inhibiting thermally induced MP aggregation. The depolymerisation effect induced by HPH destroyed myosin head and tail portion, hampered the assembly of myosin into filaments and therefore suppressed the formation of strand-type aggregates under heating. The in vitro digestion suggested that the depolymerisation and rearrangement effect significantly improved MP digestibility (P < 0.05) regardless of whether the protein was heat treated or not.

Automated summary

This study investigated the effects of heating on the dissolution and aggregation of high-pressure homogenisation (HPH)-treated myofibrillar protein (MP) in a low ionic strength medium. The results showed that HPH treatment increased the solubility and decreased the turbidity of MP during heating. Rheological measurements indicated that HPH treatment reduced the thermal aggregation ability of MP, except at around 50 degrees C. Proteomic analysis suggested that HPH treatment disrupted cytoskeletal proteins and promoted structural rearrangement of MP, leading to the formation of oligomers with stronger steric hindrance and electrostatic repulsion, thus inhibiting thermal-induced aggregation. Depolymerisation induced by HPH treatment also hindered the assembly of myosin, preventing the formation of strand-type aggregates during heating. In vitro digestion experiments showed that HPH treatment improved the digestibility of MP, regardless of heat treatment.