Study of Index (Model Food) for Thickener Solutions When Users Prepare Them

―Evaluation of Physical Measurements and Non-Oral Sensory Properties―

Abstract

Recently, various thickeners have become commercially available, but the fact that no index (model food) of consistency is indicated on the product label is a serious issue for consumers.

The aim of this study was to establish an index (model food) for thickener solutions when users prepare them.

We reviewed measurements for evaluating the physical properties of thickener solutions and liquid food to examine the correlation with non-oral sensory properties.

To prepare thickened samples, the volumetric amount of each commercial thickener was added to water to make the solution thickness like either a honey or yogurt consistency indicated on the product label.

The difference in sensory properties between the model food (honey or plain yogurt) and the thickened solutions was examined. A sensory evaluation panel compared the viscosities of these samples by tilting the containers, stirring the contents with a spoon, and by pouring the thickened solution from a spoon.

These samples were subjected to physical measurements, including the texture properties of hardness, adhesiveness, cohesiveness, and viscosity at the shear rate of 0.7–50 s^-1.

According to the sensory evaluation data, the honey was considered to have a viscosity that was not similar to that of honey-like thickener solutions. This was because the shear viscosity of physical measurements indicated that honey was Newtonian flow, while most thickener solutions were Non-Newtonian flow. This suggested that honey was not an appropriate model food.

The texture properties of hardness–cohesiveness and hardness–adhesiveness on a two-dimensional plot showed that the Newtonian samples including honey and Non-Newtonian samples were located in the same range and could not be distinguished.

Measurements of not only texture properties but also viscosity at different shear rates are necessary to determine the index (model food) for thickener solutions that are prepared by stirring.