Effect of Proteases from Bacillus Subtilis and Aspergillus Oryzae on the Tenderness of Beef

Tenderness, the single most important palatability factor affecting consumer satisfaction of beef, is mainly associated with the structural integrity of myofibrillar and connective tissue proteins. One approach to increasing beef tenderness is to significantly reduce the amount of detectable connective tissues without causing extensive degradation of muscle fibers. This purpose may be achieved by controlled proteolysis of targeted proteins by addition of exogenous enzymes. Although enzyme tenderisation of meat has been used for many years, most commonly using enzymes of plant origin such as papain, bromelain, and ficin, previous reports on the effects of enzymatic tenderisation on tenderness of cooked meat have been unsatisfactory. Due to their broad substrate specificity, these enzymes tend to indiscriminately break down the major muscle proteins which often results in an extensive degradation of the meat structure and undesirable flavour and texture (McKeith et al., 1994; Stefanek et al., 2002).