Relationship with Rice Taste of Rice Endosperm Glycolytic Enzyme Activity Amount and Viscoelasticity

Abstract

The purpose of this study was to clarify the rice endosperm glycolytic enzyme activity and the viscoelasticity affect the taste evaluation of polished rice of different varieties, production areas, and production years, as an applied study that reflects the actual conditions of rice in circulation. That is, the level of each enzyme activity of various polished rice was quantified, and the differences were examined. In addition, viscoelasticity measurements of cooked rice and a taste evaluation test were carried out. We investigated the relationship between enzyme activity and viscoelasticity with taste, and obtained the following findings. 1. The level of enzyme activity had a high correlation with the hardness of cooked rice and the freshness of polished rice. 2. Among the enzymes, the level of β-galactosidase activity had the highest correlation with taste. 3. The viscoelasticity affected the taste of cooked rice and was particularly highly correlated with the hardness and stickiness of cooked rice. 4. The higher the activity levels of the starch-degrading and cell wall polysaccharide-degrading enzymes, the softer the cooked rice. 5. The results of the taste sensory evaluation test and the index of the “Shokumi Kanteidan” obtained from the appearance, hardness, stickiness, and freshness of cooked rice showed a correlation with the level of enzyme activity and the viscoelasticity.