Mastication Characteristics of Cooked Rice Prepared from High-quality Cultivars

The objective of this study was to clarify whether the natural mastication behavior of Japanese who habitually consume rice changes among high-quality rice cultivars or not. A newly developed cultivar in Yamagata Prefecture, "Yukiwakamaru", as well as "Haenuki", "Tsuyahime", and "Koshihikari" were selected. Rice samples were produced in Yamagata city in 2017, milled, cooked, and served under the same conditions. The cooked rice samples had similar amylose and protein contents, moisture, and specific volume. Instrumentally measured textural parameters of a grain of cooked rice were also similar when grain size was considered. Electromyography (EMG) from both masseter and suprahyoid muscles was recorded during natural mastication of nine-g rice samples by eleven healthy subjects. More than fifty EMG variables were examined and none differed significantly among cultivars. The results suggest that the texture of cooked rice prepared from high-quality cultivars is similar and does not significantly influence the natural mastication behavior.