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 without 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 muscle at sarcomere levels caused by pressurization were more severe when freezing occurred. Color, drip loss, and textural properties on the pressurized samples also revealed an additional deleterious influence of freezing. Pressurization alone and pressure-shift freezing resulted unsuitable for muscle preservation.