Effects of Different Thermal Treatments on Tenderness and Volatile Flavor Compounds of Beef

The study investigated the effects of different heating treatments like conventional stewing, microwave and ultrasonic assisted stewing on the quality characteristics of beef. The moisture content, water holding capacity, shear force, texture properties, microstructure, volatile flavor and sensory quality of beef samples were analyzed during heating (5, 15, 25 and 35 min). The results showed that the beef samples under water bath heating for 5 min (W₅) reached the highest moisture content (62.9%). The samples under microwave heating for 15 min (M₁₅) got the highest value of water holding capacity (91.8%) and elastic (3.94 mJ), but the relativley lower value of shear force, hardness and chewiness. Moreover, the result of microstructure showed that the muscle fiber structure was relatively loose in samples under microwave heating for 15 min (M₁₅) and ultrasonic-assisted heating for 25 min (U₂₅), which were corresponded to the results of texture properties. A total of 98 kinds of volatile flavor compounds were detected in samples with different heating treatments. Nonanal, eucalyptole, linalool, eugenol and anisole were identified as the mainly flavor substances due to lower threshold. Furthermore, the result of principal component analysis (PCA) showed that different thermal treatments could significantly change the characteristic flavor components of beef. The mainly volatile flavor compounds in W₅, W₁₅ (samples heating with water bath for 15 min), M₅ (samples heating with microwave for 5 min) and U₅ (samples heating with ultrasonic for 5 min) were similar, and that in M₁₅, U₁₅ (samples heating with ultrasonic for 15 min) and W₂₅ (sample heating with water bath for 25 min) were also similar. Further combined with the result of sensory scores, the desirable meat quality could be obtained by microwave stewing for 15 min.