Effects of Ultrasound Pretreatment and Ageing Processing on Quality and Tenderness of Pork Loin

Tenderness is a primary indicator of meat quality, which directly influences consumer acceptance of the meat. Ultrasound can effectively increase the tenderness of red meat, such as pork and beef, by breaking up muscle fibers and connective tissues through mechanical force, thus making it a basis for physical tenderization of meat to improve meat quality. In this study, ultrasound (2200 W, 15 kHz) was applied in the processing of pork loin to explore the influences of varying treatment durations (0-6 minutes) and posttreatment aging durations (0-2 days) on the tenderness, texture profile, physical and chemical qualities (myofibrillar fragmentation index, or MFI, and rate of marinade absorption), and sensory evaluation (9-point hedonic scale) of meat. The results indicated that ultrasonic treatment (2200 W) for 6 minutes can effectively tenderize the meat by increasing the MFI to 15.1%, lowering the hardness in texture profile analysis (TPA) to 87.6%, and reducing shear force to 87.9%. Moreover, if pork loin is allowed to age for 48 hours following 6 minutes of ultrasonic treatment, shear force can be further reduced to 72.3%. The sensory evaluation scores for texture, tenderness, and overall acceptance of pork loin increased with the elongated ultrasonic treatment.