Kokumi Substance as an Enhancer of Koku: Its Definition

As describe in Chap. 1 , Koku is defined as total sensations that sensed through taste, smell (odor), and texture. The fundamental elements of koku were proposed as complexity, mouthfulness, and lingeringness (continuity). Koku-enhancing substances are divided into three groups: taste-related substances, smell-related ones, and texture-related ones. Taste-related koku-enhancing substances consist of tastants and taste-modulators. Regarding koku-enhancing tastants, monosodium glutamate (MSG), an umami substance, was reported to enhance the thickness, complexity, continuity, and mouthfulness when added to various kinds of soups. Similarly, sugar and salt (NaCl) have been reported to enhance these characters when added to foods. Among the taste-modulating substances, the substances which enhance basic taste and flavor characters such as complexity, mouthfulness, and lingeringness when added to foods although they were tasteless at the concentration tested are referred to kokumi substances. In this chapter, the actions of smell (odor)-related koku-enhancing substances are introduced. Phthtalide compounds identified in celery were reported to enhance the thick and lasting flavors when added to chicken broth. Rotundone identified in fruits and spices enhanced the intensities of complex flavor when added to fruits-flavored beverages. Regarding the texture-related koku-enhancing substances, the additional effect of glycogen to reconstituted scallop extract was described, and indicated that it enhanced the continuity, complexity, fullness and mildness.