Physical Properties of Food Hydrocolloids

Abstract

The physical properties of food hydrocolloids are a reflection of their inner structure. In this study, we reviewed several methods for examining the inner structure of food hydrocolloids; the percolation model, dielectric analysis, and fractal analysis. In addition, we reviewed the application of food hydrocolloids in developing special foods for patients with dysphagia. The percolation model was effective for describing the behavior of the rheological properties of food hydrocolloids near the sol-gel transition point. The dielectric properties of food hydrocolloids such as bovine serum albumin solution, gelatin solution, and alginate solution were analyzed. Each dielectric relaxation observed was considered ascribable to a different movement of “components” in the electric field among different hydrocolloid systems, thus giving information about the inner structure of the hydrocolloids. Fractal analysis (self-similar structure) is a quantitative analytical method for characterizing many types of disordered shapes. The elastic behavior of the aggregate gels observed on heating globular protein solutions was confirmed to be a reflection of the fractal structure of aggregates in the gels. We investigated the effect of rheological properties of food hydrocolloids on the velocity of the bolus by using ultrasonic pulse Doppler method. Viscosity (μ), dynamic viscosity (η′), and complex viscosity (η^*), were considered suitable indices for liquid-type foods for patients with dysphagia.