BACKGROUND: Cooking has a great influence on meat tenderness, and we assumed that changes of tenderness in this process resulted from the liberation of actin and associated structural changes. Therefore, in this study, we investigated changes in the microstructure and tenderness when duck breast muscle were cooked to different internal endpoint temperatures (70, 80, 90, 95 °C) by three cooking regimes (conventional cooking, two-stage cooking and three-stage cooking). RESULTS: When duck breast muscle was cooked to an internal endpoint temperature of 70 °C, the three-stage cooking significantly decreased the Meullenet-Owens razor shear force (MORSF) value (P<0.05) and resulted in a longer sarcomere length (P<0.05) compared with the conventional cooking. However, further improvement of the tenderness and an increase in sarcomere length did not occur at higher internal endpoint temperatures. The two-stage cooking regime, with a much longer cooking time below 55 °C, also resulted in a lower MORSF value (P>0.05) and increased sarcomere length (P<0.05) at an internal endpoint temperature of 70 °C compared with the conventional cooking. Significant liberation of actin was also observed in duck meat cooked between 50 and 60 °C. CONCLUSION: The two- and three-stage cooking regimes with initial temperatures of 50-60 °C and endpoint temperature of 70 °C could improve tenderness of duck breast meat, which might be related to the liberation of actin. Three-stage cooking had the great advantages of improving meat tenderness and reducing cooking loss; therefore, this is to be recommended for further application and research.
BACKGROUND: Cooking has a great influence on meat tenderness, and we assumed that changes of tenderness in this process resulted from the liberation of actin and associated structural changes. Therefore, in this study, we investigated changes in the microstructure and tenderness when duck breast muscle were cooked to different internal endpoint temperatures (70, 80, 90, 95 °C) by three cooking regimes (conventional cooking, two-stage cooking and three-stage cooking). RESULTS: When duck breast muscle was cooked to an internal endpoint temperature of 70 °C, the three-stage cooking significantly decreased the Meullenet-Owens razor shear force (MORSF) value (P<0.05) and resulted in a longer sarcomere length (P<0.05) compared with the conventional cooking. However, further improvement of the tenderness and an increase in sarcomere length did not occur at higher internal endpoint temperatures. The two-stage cooking regime, with a much longer cooking time below 55 °C, also resulted in a lower MORSF value (P>0.05) and increased sarcomere length (P<0.05) at an internal endpoint temperature of 70 °C compared with the conventional cooking. Significant liberation of actin was also observed in duck meat cooked between 50 and 60 °C. CONCLUSION: The two- and three-stage cooking regimes with initial temperatures of 50-60 °C and endpoint temperature of 70 °C could improve tenderness of duck breast meat, which might be related to the liberation of actin. Three-stage cooking had the great advantages of improving meat tenderness and reducing cooking loss; therefore, this is to be recommended for further application and research.