Thermal Characteristics of Ground Pectoralis Secundus Turkey Muscle

Thermal conductivity and diffusivity of ground turkey pectoralis secundus muscle were investigated using a line-source apparatus modified to allow determinations upon the sample during transient heating. Samples (51.5g) were heated in a water jacketed cylinder at and to end points of 77, 95, 113, 131, 149, 167, and 185^oF and subjected to holding times of 0 or 15 min. The relationship between thermal properties and moisture factors including total moisture, cooking loss, and expressible moisture index was investigated.

Thermal conductivity values were similar for samples heated at and to temperatures between 77 and 167^oF but tended to decrease for those at 185^oF. Holding times did not affect thermal conductivity values. There tended to be close agreement among values for a given end point and these were within ranges reported in the literature.

Total moisture gradually decreased for turkey heated to temperatures that ranged from 77 to 149^oF. Thereafter a pronounced decrease in total moisture occurred as end points increased. A significant increase in cooking loss was noted between samples heated to 77 and 95^oF (P < 0.001) , to 113 and 131^oF or 149^oF (P < 0.01) , and to 149 < 167 < 185^oF (P < 0.05) . Expressible moisture indexes for 77 and 95^oF samples were similar and decreased slightly at 113^oF. A pronounced decrease occurred for samples at 131^oF. With further increase in temperature, little difference was observed. Expressable moisture indexes were similar for the 149, 167, and 185^oF end points. Holding time had little if any effect on all parameters measured.