Gelation characteristics of muscle proteins from pale, soft, exudative (PSE) pork

Thermally induced protein gels were made by using extracted salt-soluble proteins from normal pigs and stress-susceptible pigs determined to have pale, soft, exudative (PSE) muscle. Effects of heating rates (17,39 and 93° C/h) at various protein concentrations (23, 34, 48 and 54 mg/ml) were evaluated. Gel strength of PSE extracts was 45% of the controls at equivalent protein concentration. Gel strength of normal and PSE-muscle protein gels from the first compression curve increased with increasing protein concentrations at all heating rates; however, gel strength was greater for slow heating rates than for fast heating rates in both PSE and normal samples. Percent water loss was greater for PSE extracts than for controls at the same protein concentration. Losses of 47% and 36% for PSE and controls, respectively, were observed at a a protein level of 54 mg/ml protein. There was no heating rate effect on water losses in either case. Protein loss was less, for both PSE and control, at low protein concentrations than at high protein content in the range studied. Slow heating rates resulted in less protein loss, for both PSE and control, whereas faster heating rates gave greater protein losses in the exuded water.