Effects of Ultrasound Treatment on Connective Tissue Collagen and Meat Quality of Beef Semitendinosus Muscle

The effects of low-frequency, high-power ultrasound (40 kHz, 1,500 W) on meat quality and connective tissue collagen of beef semitendinosus muscle were assessed. Beef steaks were sonicated for 10, 20, 30, 40, 50 or 60 min. The effects of ultrasound on exudate yield, water-loss rate, cooking loss, meat tenderness, and connective tissue and collagen properties were assessed. The results revealed that ultrasound increased meat exudate and water-loss rates and reduced Warner-Bratzler shear force values. However, ultrasound had no effect on cooking loss or insoluble collagen content and little effects on collagen content and solubility. The mechanical strength of connective tissue decreased in ultrasound-treated beef samples. Following ultrasound treatment of >= 10 min, muscle fibers shrank, the endomysium was disrupted and the perimysium thickness decreased. Protein aggregates formed in the extracellular space. Low-frequency, high-power ultrasound had significant effects on meat texture and connective tissue properties.