米飯のテクスチャーに関する研究 : 第1報 テクスチャーと食味との関係について

抄録

In order to find out a suitable index for the evaluation of palatability, some experiments on the texture of cooked rice of two japonica varieties (Sasanishiki and Nihonbare) were conducted using a General Foods Texturometer. Measurements were done on the cooked rice of different degree of swelling. The degree of swelling was adjusted by adding different amount of cooking water to the kernels. Mechanical parameters analyzed from the texture profile were hardness, cohesiveness, springiness, chewiness, adhesiveness, viscousness and stickiness as shown in Fig. 1. Hardness, cohesiveness, springiness and especially chewiness were decreased with the increase in swelling. The decreases were remarkable at the range over the swelling degree corresponding to the highest palatability which had been made clear in a sensory test (Fig. 3). On the other hand, adhesiveness, viscousness and especially stickiness were increased with the increase of swelling. These increases were particularly rapid up to the swelling for the highest palatability, but the increment was ceased at higher ranges of swelling (Fig. 4). Product values of chewiness and stickiness peaked at the degree of swelling for the highest palatability (Fig. 5). This value was therefore considered to be an appropriate index for the indication of palatability. Rices of indica variety, paticularly of long grain variety were higher in hardness and chewiness but much lower in adhesiveness, viscousness and stickiness as compared with japonica rices. The values of textural palatability index (TPI) were extremely low in the indica rices. Japanese varieties of high popularlity on the whole showed highest TPI values than unpopular varieties (Table 1). This result seems to suggest usefullness of TPI at least for japanese taste.