Essentially all of the proteins of chicken breast muscle were soluble in sodium chloride solutions of physiological ionic strength or less and neutral pH. However, there was a critical order of treatment necessary to accomplish this. After removal of those proteins solubilized by homogenizing the tissue 1:10 (w/v) in water, it was necessary to solubilize a fraction of the remaining proteins in moderate concentrations (25-150 mM) of sodium chloride at neutral pH before the remaining proteins could be solubilized in water. Solubilization of chicken breast muscle proteins in water could be prevented or reversed by salt solutions of low concentration, suggesting that most of the solubility was not directly caused by proteolysis. SDS-polyacrylamide gel electrophoresis indicated that removal of specific peptides by moderate concentrations of sodium chloride at neutral pH was correlated with removal of the restriction on the water solubility of the remaining proteins.

This work was designed to test the hypothesis that it is not solubilization of the myofibrillar proteins per se that is required to form good gels at low salt concentrations, but the protein‐containing structures must be disorganized. Gels were made from washed minced chicken breast muscle at 0.15, 0.88, and 2.5% sodium chloride. The gels made with varying salt concentrations were evaluated either at pH 6.0–6.5 or pH 7.0–7.4. Strain values, an indicator of protein quality, were high only at neutral pH in the gels containing 0.15 or 0.88% salt. At 2.5% salt, strain values of gels made at acid pH were superior to those at the low salt concentrations at acid pH, but inferior to gels with 2.5% salt at neutral pH. Poor gels were obtained at 0.15% salt and low pH whether or not there was an intermittent adjustment to neutral pH. A neutral salt wash markedly increased the water content of the mince, suggesting that solubility‐inhibiting proteins were removed. Good quality gels were obtained in the absence of any detectable solubilization of myosin and only minimal solubilization of actin.

Sodium chloride (0.29 M) at pH 7 solubilized about 24% of the myosin of washed, minced chicken breast muscle. At a similar pH, 0.2 M sodium chloride in the presence of 10 mM sodiumpyrophosphate and 10 mM magnesium chloride solubilized almost 60% of the myosin. In spite of the greater solubility of myosin under the latter conditions, when gels were prepared with these concentrations of salt at pH 7, the gels without the sodium pyrophosphate and magnesium chloride were slightly superior in both stress (39.3 kPa vs 28.3 kPa) and true strain (2.3 vs 2.0) values. Gels made at a lower pH (6.1–6.5) made much poorer gels. This was true whether the low pH was obtained naturally in the preparation of the sample or re‐adjusted after bringing the mince to a neutral pH. It appears that conditions of pH and salt content that cause solubilization of myosin at more dilute conditions does not contribute to gel quality, but the neutral pH is an important factor for obtaining good gels at ionic strengths <0.3.