A COMPARISON OF HEAT-INDUCED CHANGES OF INTRAMUSCULAR CONNECTIVE TISSUE AND COLLAGEN OF BEEF SEMITENDINOSUS MUSCLE DURING WATER BATH AND MICROWAVE HEATING

The main objective of this study was to characterize the thermal properties of intramuscular connective tissue (IMCT) and collagen in beef semitendinosus (ST) muscle from Chinese yellow bulls during water bath and microwave heating. Beef ST muscle was heated to internal endpoint temperature of 40, 50, 60, 70, 80 and 90C by water bath and microwave oven, respectively. The results indicated that insoluble collagen contents of microwave-heated meat were higher than water bath heated except for 90C, and showed significant differences at 80 and 90C (P < 0.05). Mechanical strength of IMCT showed significant difference (P < 0.05) at 60C between water bath- and microwave-heated meat. Perimysial portion content of microwave-heated meat was significantly higher than water bath heated at 60, 70, 80 (P < 0.05) and 90 degrees C (P < 0.01), and endomysial portion content showed a gradual decrease during heating. A heating temperature of 60C was critical, and affects the maximum shrinkage temperatures (Tmax) of IMCT for both heated meat. With the increase in heating temperature, granulation changes of IMCT and disorderly changes of collagenous fibers arrangement have resulted.