Tenderization of semitendinosus muscle using high intensity ultrasound

Semitendinosis muscle specimens, approximately 2.54 cm thick and weighing 200 grams, were exposed to high intensity ultrasound for periods of 0, 2, 4, 8, 16 minutes. Four specimens were used at each period for a total of 20 specimens. A magnetostrictive transducer produced CW ultrasound at a frequency of 25.9 kHz in a stainless steel tank filled with degassed saline. The semitendinosus meat specimens were cut either cross-sectionally or longitudinally to the muscle fibers. The cross-sectional cuts of the meat specimens were exposed to the ultrasound for periods of 2, 4 and 8 minutes while the longitudinal cuts were exposed for periods of 2,4,8 and 16 minutes. Control specimens of both cross-sectional and longitudinal cuts were also placed in the tank without ultrasound for periods of 2, 4, 8 and 16 minutes. Tenderness was measured (under blind conditions) by Warner-Bratzler shear force by removing six 1.3 cm diameter cores from each meat sample. For the samples exposed for 2 and 4 minutes, there was a statistically significant decrease in Warner-Bratzler shear force, which indicates an increase in tenderness for these specimens. These results suggest that high intensity ultrasound is capable of tenderizing meat as assessed by an objective shear force measurement.