Abstract
1. Intending to throw light on the structure of set meat, influences of urea and guanidine hydrochloride (abbrev. G-HCl), well-known protein denaturants which are deemed to cleave the hydrogen-bond, on setting phenomenon of horse mackerel meat have been studied. The amounts of added reagents are conveniently expressed in terms of mole concentration of the solutions. which would be formed when the reagents are dissolved completely in water present in the meat. 2. Urea makes the meat set in concentrations between 0.75 and 1.0 mol. and produces a jelly with high elasticity and strength in concentrations between 1.5 and 2.0 mol. but a friable one beyond 2.5 mol. When water has been added to the meat, the strength of the jelly formed decreases markedly with the increase of water content, and in lower concentrations of urea, the meat does not set and separation of water is observed (Fig. 1). 3. G-HCl behaves in the same way as urea does. But the former is effective in lower concentrations than the latter. Thus the minimum concentration of G-HCl to cause the meat set lies between 0.2-0.3mol. When the concentration increases beyond 0.7-1.0mol., a friable jelly is formed (Fig. 2). 4. Friable jellies produced by urea and G-HCl are quite different from those by I-and CNS- in their properties as well as in the course of formation, as shown in the above table and Fig. 3. 5. The fact that the protein denaturants produce friable jellies. through jellies with high elasticity and strength, seems to suggest that formation of network structure is a factor as im-portant as hydration of the protein in setting phenomenon of fish meat.
