Effect of Heating Avian Muscle Tissue on Solubility of Nitrogen Fractions and pH Values of Breast and Leg Muscle 1

Sarcoplasmic, myofibrillar, and non-protein nitrogen fractions extracted from chicken leg and breast muscle tissue after heating to 40, 50, 60, 70, and 80 C were compared with non-heated samples. The pH modifications that occurred during heating were also observed. The myofibrillar fraction was more heat-sensitive than the sarcoplasmic proteins with a slight difference in sensitivity occurring between the leg and breast muscle tissues. Both of these fractions were only approximately 10% soluble after heating to 70 C with only slight alterations caused by additional heating to 80 C. The non-protein nitrogen fractions decreased slightly during the heating cycle and remained more than 90% soluble after heating to 80 C. Initially, pH of breast muscle was lower (P < .05) than leg muscle and the breast sample increased in pH more rapidly than the leg sample during the heating cycle.