塩加減のサイエンス

抄録

The salty taste strength of foods may not necessarily depend on their NaCl contents. The saltiness we feel often varies according to the physical properties of the foods that function in the mouth. However, no clear scientific information has been available up to the present.
With it as a background, we undertook a project research aimed at elucidating the relationship between the NaCl contents of foods and their saltiness. The following foods with different NaCl contents were prepared: egg white gel, 0.4-1.2% NaCl; soy protein isolate gel, 1.0, 2.0% NaCl; soy protein curd (tofu), 0.5, 1.0% NaCl; and agar gel, 0.8, 1.0% NaCl. Sensory tests using well-trained panel members were first carried out with these food preparations to define their saltiness in terms of salty taste efficiency ratio (STER). The tests gave the STER values ranging from 0.58 to 1.10. Physical data were also measured with the foods to obtain several of their parameters involving gelling properties. It was then tried to correlate the physical data with the STER values. We could not find any significant correlation as far as the same food was tested irrespective of its different NaCl content. However, all the foods we prepared were comprehensively submitted to the physical parameter-sensory score analysis, significant relation appeared (R²: 0.83) which were clearly represented by an equation as a function of breaking stress value. It was also suggested that the STER differences were generally larger between foods than within a food having different NaCl contents.
This project research is apparently the first that objectively expresses the saltiness of foods in relation to their physical properties. It would contribute to our scientific aspect on how the proper saltiness for cooking of foods varies depending on the physical properties.