Abstract
A total of 24 samples of rice flour were prepared from 16 different types of rice for analyzing the crude protein, amylose, damaged starch and particle size composition. The particle size of all rice flour samples was over 90% at the 200 mesh passage, but the particle size compositions differed among the rice types. Hokuriku 166 showed a higher 300 mesh passage proportion than other rice types and trends of lower damaged starch content. Regarding the physical properties of gluten-mixed rice flour, the farinograph water absorption rate differed among the rice types, showing a correlation to the amylose content. Specific volume and shape of the rice flour bread also differed among the rice types, with the amylose content being related to the viscogram property of the gluten-mixed rice flour. About 25% amylose content of rice flour was estimated to result in the largest specific volume of rice flour bread. Rice flour bread hardness was also correlated to the amylose content. The hardness of all the rice flour breads increased relative to storage time, but the rate of bread hardening differed among the rice types. In the floury and low glutelin rice types, low values of bread hardness and hardening rate were found in comparison with normal rice flour bread which had equivalent amylose and protein contents. Therefore, protein and element composition of the rice appears to affect the bread properties. The amylose rice cultivars containing about 15 to 25% amylose content are the most suitable for baking rice flour bread.
