Study on phase separation in mixed gels and its application to developing foods for persons of advanced age.

制备了两相分散结构不同但成分相同的琼脂/明胶混合凝胶，并对其力学性能进行了研究。琼脂/明胶混合物先在明胶的胶凝温度和琼脂的胶凝温度下搅拌一段时间，然后在明胶的胶凝温度下冷却。用这种方法制备的混合凝胶由琼脂的分散相和明胶的连续相组成。随着分散相含量的增加，混合凝胶的破裂应力减小。在相同组分中，随着分散颗粒尺寸的增大，破裂应力呈降低趋势。这些结果表明，分散相与连续相之间的界面起着Griffith裂纹的作用，混合凝胶的破裂就发生在这个地方。本研究发现，琼脂/明胶混合凝胶的力学性能取决于其内部相分离结构，通过控制其内部结构，我们可以从相同的成分中制备出具有不同质地的混合凝胶。此外，即使一种食物对老年人来说太难吞咽，我们也可以通过加工制作出适合他们的凝胶状食物。

The agar/gelatin mixed gels which had biphase dispersion structure to be different with the same composition were prepared and their mechanical properties were investigated. Agar/gelatin mixture was first kept over the gelling temperature of gelatin and under that of agar with stirring for the selected period, and then cooled under the gelling temperature of gelatin. The mixed gels prepared by this method consisted of a dispersed phase of agar and a continuous phase of gelatin. The rupture stress of mixed gels decreased as the content of a dispersed phase increased. In the same composition the rupture stress showed the lower tendency as the size of dispersed particles became larger. These results suggested that the interface between a dispersed phase and a continuous phase played a role as Griffith crack, and the rupture of mixed gels occurred from that place. In this work, it was found that the mechanical properties of agar/gelatin mixed gels were dependent on internal phase separation structure and that we could prepare the mixed gels which had a various texture from the same composition by controlling their internal structures. Furthermore, even if a food is too hard for persons of advanced age to swallow it, we could prepare a gelatinous food suitable for them by processing.