Protein Solubility as Influenced by Physiological Conditions in the Muscle ^a, ^b, ^c

Abstract

SUMMARY The solubilities of sarcoplasmic and myofibrillar proteins were determined at the time of slaughter, onset of rigor mortis, completion of rigor mortis and 24 hr after death in muscles exhibiting a wide range of physiological conditions during the post‐mortem period. Muscle protein solubility was grossly altered by the conditions of both temperature and pH which existed at the onset of rigor mortis or during the first few hours after death. Sarcoplasmic protein solubility at 24 hr was decreased to 55% of that found at 0 hr in muscle groups exhibiting high temperature and low pH at the onset of rigor mortis. Conversely, only a 17% reduction of sarcoplasmic protein solubility was noted in groups with high pH at onset. Myofibrillar protein solubility ranged from no reduction during the first 24 hr after death when pH remained high at onset to 75% reduction in muscle with low pH and high temperature at the onset of rigor mortis. The 24‐hr pH of the muscle appeared to have only a minor influence on protein solubility. Muscle protein solubility appeared to be one of the major factors affecting the juice‐retaining properties of muscle.