High-pressure effects on the molecular aggregation and physicochemical properties of myosin in relation to heat gelation

- Myosin subjected to high-pressure (HP) treatment (≥ 200 MPa) had lower solubility.
- Pressure intensities of 200 MPa and above induced dimerization of myosin molecules.
- Morphologically swollen myosin was observed following HP treatments at 200 & 300 MPa.
- Samples treated at 200 and 300 MPa HP conditions had improved shear-thinning behaviors.
- Relationship between myosin molecular traits and gelation functionalities were proposed.

Myosin was extracted from the M. psoas muscle of rabbits, and dissolved in 0.6 M KCl buffer (pH 6.5). Effects of high-pressure (HP, 100 to 300 MPa, 9 min, 25 °C) treatment on myosin solubility, molecular traits (molecular weight and morphology), flow behavior and strength of heat-induced myosin gels were studied and compared with the untreated controls. Myosin subjected to 200 MPa HP treatment had lower solubility than samples treated at other pressures (P < 0.05). Molecular dimerization and morphological swelling of myosin was observed using gel-permeation chromatography and atomic-force microscopy. Additionally, the shear-thinning behavior of myosin solutions (10 mg/mL) was improved by HP treatment (≥ 200 MPa), and a positive trend in gel-strength enhancement was inferred. It is postulated that significant morphological changes in myosin accounted for changes in its functional properties, by the influence of HP treatment on protein-protein and/or protein-water interactions. There is a relationship between molecular morphology and the coalescing behavior of myosin, since significant changes of both attributes were observed at pressures ≥ 200 MPa.

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