EFFECTS OF AN ALKALINE ELASTASE FROM AN ALKALOPHILIC BACILLUS STRAIN ON THE TENDERIZATION OF BEEF MEAT

The tenderizing effect of a new alkaline elastase produced by alkalophilic Bacillus sp. strain Ya-B was evaluated on beef meat. We first investigated differences in the hydrolysis of elastin, collagen, casein, and myofibrillar proteins by various enzymes. The elastolytic activity of the new elastase was 60-200 times greater than that of papain and bromelain, which are used as meat tenderizers. This enzyme had greater hydrolyzing activity toward both collagen and elastin but markedly lower hydrolyzing activity toward casein and myofibrillar proteins at a lower pH. We then analyzed the mode of myofibril degradation using SDS-polyacrylamide gel electrophoresis after incubation of intact samples with or without the enzymes. Elastase treatment inhibited the proteolysis of isolated myofibrils, in contrast to papain, which degraded most proteins, especially myosin heavy chain and actin, when the higher concentration ratio of substrate to enzyme was applied at refrigeration temperature. To examine the effect of enzymes on meat tenderness, mechanical hardness was measured with a rheometer. When enzyme solutions were injected into bovine thigh muscle, we found that the force required to cut the muscle fiber was reduced in enzyme-injected samples. These findings suggest that this alkaline elastase is promising as a favorable meat tenderizer.