This study aimed to evaluate the effects of sous vide cooking (SV) on beef tenderness and its underlying potential mechanism. Beef semimembranosus (SM) were subjected to SV treatments at 45 °C, 55 °C and 65 °C for 4 h. Compared with control samples (CK, cooked at 75 °C until a core temperature of 72 °C was attained), SV treatment significantly promoted the release of cathepsin B and cathepsin L from lysosomes and decreased the shear force of beef SM (p < 0.05). In comparison with CK, samples treated with SV had more hydrolysis of myosin heavy chain and obtained higher myofibrillar fragmentation index, collagen solubility as well as longer sarcomere length (p < 0.05). The current study showed that the proteolysis of myofibrillar protein and collagen induced by cathepsin B and cathepsin L, and the limited longitudinal shrinkage together contributed to the improvement of beef tenderness upon SV.
Keywords: cathepsins; protein proteolysis; sous vide; tenderness.