Protein denaturation and structural damage during high-pressure-shift freezing of porcine and bovine muscle

Pork and beef muscles were subjected to 200 MPa and -20 degreesC with or wi thout water freezing. Both tissues responded to the treatment with similar behavior. Protein denaturation was greater when freezing occurred. Pressure -induced cold denaturation was complete for actin and very considerable for myosin and other muscle proteins. Connective proteins remained practically unaltered by pressurization and/or freezing. Structural changes in the mus cle at sarcomere levels caused by pressurization were more severe when free zing occurred. Color, drip loss, and textural properties on the pressurized samples also revealed an additional deleterious influence of freezing. Pre ssurization alone and pressure-shift freezing resulted unsuitable for muscl e preservation.