INFLUENCE OF FLUIDITY OF WATER WITHIN FOOD HYDROGEL ON ITS VISCO-ELASTICITY

为了阐明釜形物的粘弹性随温度升高而降低的原因，本文研究了釜形物作为一种熵弹性体的粘弹性随温度升高而降低的原因。当温度从0 ℃升高到80 ℃时，由于脱水收缩，其重量减少，并且电容和可压出水增加，同时，通过差示红外光谱可观察到的游离水增加。从结果来看，现在出现了一个问题，即粘弹性的降低是由于水的流动性增加。接下来，为了澄清这个问题，在水凝胶模型上测量粘弹性。第一个模型是填充有各种浓度的聚乙二醇600（PEG）的穿孔网球，其被设计为脱水收缩的模型。在提高PEG浓度时，通过力-变形测量获得的该模型的弹性模量和粘度增加。通过应力松弛和蠕变测量获得的瞬时弹性模量和粘度增加。此外，在封闭系统的三种水凝胶模型上测量粘弹性，其中水在其压缩时不从所述封闭系统流出。在所有的情况下，瞬时弹性模量略有增加的抑制水的流动性，虽然粘度并不总是增加。根据结果，可以认为，在食品水凝胶变形时，水在其中流动，并且其粘弹性也受到水的流动性的影响。有一种可能性是，为什么随着温度的升高，kamaboko的粘弹性会降低，这是由于其中的水的流动性增加。

In order to clarify the reason why the visco-elasticity of kamaboko, a sort of entropy elastic body, is decreased with raising temperature is investigated. On raising the temperature of the kamaboko from 0ﾟ to 80ﾟC, its weight was decreased due to the syneresis, and the electric capacity and expressible water were increased, simultaneously, the free water observable by differential IR spectrum was increased. From the results, there arose a now question that the decrease in the visco-elasticity is due to the increase in the fluidity of water.Next, in order to clear this question, the visco-elasticity was measured on the hydrogel models. The first model was a perforated tennis ball filled with various concentrations of polyethylene glycol 600 (PEG), which was designed as a model of syneresis. Upon raising the PEG concentration, the elastic modulus and viscosity of this model obtained by force-deformation measurements were increased. The instantaneous elastic modulus and viscosity obtained by the stress-relaxation and creep measurements were increased. Furthermore, the visco-elasticity was measured on the three hydrogel models of a closed system from which water did not flow out upon their compression. In all the cases, the instantaneous elastic modulus was somewhat increased by the suppression of the fluidity of water, although the viscosity was not always increased. From the results, it is assumed that, upon the deformation of a food hydrogel, water flowed within it, and that its visco-elasticity was also influenced by the fluidity of the water. There may be a possibility that the reason why the visco-elasticity, of the kamaboko is decreased with raising the temperature is due to the increase in the fluidity of water within it.