Effects of high pressure freezing (HPF) on denaturation of natural actomyosin extracted from prawn (Metapenaeus ensis)

•Effects of high pressure freezing (HPF) includes cold and pressure denaturation.•Actomyosin denaturation was related to ice formation paths during HPF.•Freezing-Factors weakened the effects of high pressure on protein denaturation.•HPF caused higher conformation of actomyosin during crystallization period.

Effects of protein denaturation caused by high pressure freezing, involving Pressure-Factors (pressure, time) and Freezing-Factors (temperature, phase transition, recrystallization, ice crystal types), are complicated. In the current study, the conformation and functional changes of natural actomyosin (NAM) under pressure assisted freezing (PAF, 100,150,300,400,500 MPaP−20 °C/25 min), pressure shift freezing (PSF, 200 MPaP−20 °C/25 min), and immersion freezing (0.1MPaP−20 °C/5 min) after pressure was released to 0.1 MPa, as compared to normal immersion freezing process (IF, 0.1 MPaP−20 °C/30 min). Results indicated that PSF (200 MPaP−20 °C/30 min) could reduce the denaturation of frozen NAM and a pressure of 300 MPa was the critical point to induce such a denaturation. During the periods of B → D in PSF or B → C → D in PAF, the generation and growth of ice crystals played an important role on changing the secondary and tertiary structure of the treated NAM.