The changes in both taste and taste components of beef, pork, and chicken during storage were examined.The brothy taste intensity of pork and chicken was significantly stronger after conditioning than before. On the other hand, for beef, there was no significant difference in the brothy taste intensity before or after conditioning. The analysis of major taste componentsshowedthat the levels of free amino acids in all meats were higher after conditioning than before. The differences in the levels of free amino acids before versus after conditioning were large in pork and chicken and very small in beef. Oligopeptide levels were lower in beef after conditioning than before, but they were higher in pork and chicken after conditioning than before. These results corresponded to results of the sensory evaluation studies described above, indicating that free amino acids and oligopeptides contributed to the improvement of meat taste during storage.Flavor is one of the important qualities of meat. Although it has been thought that a period of postmortemaging of meat improves its flavor, consistent results have not been obtained.1~9) This seems to be because the flavor of meat is a result of complex sensations arising from two distinct responses, taste and aroma. There have been few studies to distinguish between taste and aroma in meat.Taste in flavor elements is elicited mainly by water-soluble components. Over a period of postmortem aging, meat shows a gradual change in levels of various chemical components, including free amino acids (FAA),10~18) adenosine S'-triphosphate (ATP) metabolites,5' 19~22) sugars23' 24* and organic acids.24' 25) In this manner, although there are many studies on chemical components in raw meat, the components responsible for the improvement of the taste of meat have not been identified. Chemical components not only in raw meat but also cooked meat should be 2323

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Preference of taste or both aroma and taste between Wagyu (Japanese Black Cattle) beef and imported beef on market was compared to reveal reasons why Wagyu beef is considered to be more palatable than imported beef in Japan. Panelists ate heated beef samples and assessed preference on taste by pinching their noses and both aroma and taste by not pinching their noses. As a result there was no difference in preference on taste between both samples, but in the case of both aroma and taste Wagyu beef was significantly preferred to imported beef. Wagyu beef presented a preferable, sweet and fatty aroma, which was different from the conditioned raw beef aroma, while imported beef did not present such an aroma.Therefore, the existence of such an aroma was presumed to be one of the reasons why Japanese people preferred Wagyu beef to imported beef. We proposed to name this aroma Wagyu beef aroma.The optimum cooking temperature to generate Wagyu beef aroma was found to be 80℃. This aroma was almost absent in Wagyu beef immediately after slaughter. The experiment on additional storage of Wagyu beef slices suggested that a considerable high level of fat-marbling and contact with oxygen were necessary to generate Wagyu beef aroma. On the other hand, an antibacterial agent, chloramphenicol, did not inhibit the generation of Wagyu beef aroma in highly marbled beef stored under air, indicating that a group of bacteria including Brochothrix thermosphacta which is essential for the generation of the conditioned raw beef aroma were not responsible for the generation of Wagyu beef aroma.

Cathepsin B was purified from rabbit skeletal muscle by ammonium sulfate fractionation and successive chromatographies on Sephadex G-75, phosphocellulose, peptide-conjugated Sepharose, DEAE-Toyopearl and Sephadex G-100. The purified enzyme gave a single protein band on SDS/polyacrylamide gel electrophoresis. The enzyme did not abolish the Ca sensitivity of the ATPase activity of myofibrils. The molecular mass of the enzyme was found to be 27 kDa on gel filtration and SDS/polyacrylamide gel electrophoresis. The optimum pH for the hydrolysis of N"-benzoyl-DL-arginine-P-naphthylamide was 6.5. The enzyme was stable in the range of pH 4.5 -5.5. Tetrathionate reacted with thiol groups of the enzyme reversibly so that it stabilized the enzyme. The enzyme was strongly inhibited by iodoacetate, HgC12, antipain, leupeptin, N"-p-tosyl-L-lysine chloromethane and L-tosylphenylalanylchloromethane, but not by pepstatin or trypsin inhibitor.The purification of muscle cathepsin B has already been reported by Schwartz and Bird [I] and Hirao et al. [2]. Schwartz and Bird [l] partially purified the enzyme from rat skeletal muscle and showed that it could degrade myosin. Hirao et al. [2] purified the enzyme to the electrophoretically homogeneous state from monkey skeletal muscle and found that it could degrade myosin and actin. However, in these studies it was not determined at which step of the respective purification process cathepsin B was separated from cathepsin L, which was shown to be present in a crude extract of cathepsin B and to be similar in several properties with cathepsin B in our previous study [3], or whether or not cathepsin L was really excluded from the purified cathepsin B preparation. Therefore, in the present study we established a new method for obtaining rabbit skeletal muscle cathepsin B completely free from cathepsin L, and investigated its properties. MATERIALS AND METHODS MaterialsThe rabbit muscle (longissimus dorsi) was obtained from the carcasses immediately after slaughter and, after removal of fat and connective tissue, it was minced with a meat chopper. Bovine serum albumin, ovalbumin, chymotrypsinogen and cytochrome c were purchased from Boehringer Mannheim Correspondence zo A. Okitani,