On applying softening techniques using microorganisms and enzymes to low-quality meat produced in Japan from culled dairy cattle, on improving techniques to promote decomposition of the hardening factor, connective tissue protein, and to control enzyme activity as well as to effectively use the treated meat, we report the results of our investigation. When comparing meat quality between culled dairy cattle (C.D.C.) and fattening cattle (F.C.), both meat and fat of culled dairy cattle were significantly inferior to those of fattening cattle in terms of color tone. In the case of culled dairy cattle, cooking markedly increases the ratio of meat hardness. Meat hardness is largely the result of a qualitative factor of connective tissue rather than a quantitative factor. Based on observation by electron microscope, changes of the perimysium structure due to aging was assumed to be the main cause of increasing hardness.

Examination of crude enzymes naturally existing in various fermented foods found soy sauce lees and malted rice to have strong activity and a sufficient tenderization effect. Concurrently, this revealed how enzyme activity affected the production of decomposed protein and its taste. Moreover, it clarified how protein decomposed during treatment.

Examination of available food ingredients showed that raw bovine serum proved effective in controlling inhibiting the activities of enzymes produced from malted rice.

Our promising results are now under consideration for practical application and are expected to be used in meat processing for dried meat products or as an ingredient in soups, stews, or curries.