Thermal Transitions of Salt‐soluble Proteins from Pre‐ and Postrigor Chicken Muscles

Salt‐soluble protein (SSP) was extracted from pre‐ and postrigor chicken muscles at various pH values, and protein thermal denaturation was studied using several techniques. Heating at 1°C/min from 20 to 70°C induced a three‐ to fourfold increase in breast and leg hydrophobicity. Differential scanning calorimetry of breast and leg SSP showed a major transition occurring within the range 55 to 64°C, with the value dependent on rigor state and pH. Protein‐protein association, as measured by turbidity change upon heating, underwent two transitions for leg SSP and two or three for breast SSP. The specific transition temperature and rate were dependent on pH, muscle type and rigor state. However, muscle type and pH had a greater effect than muscle rigor state on SSP denaturation.