Crop Diagnostic Study and Its Application : Diagriostic Study on Chemical Characteristics of Rice to Improve the Taste

[摘要] Using the several rice varieties which were produced at the same place and in the same year, the authors have carried out some diagnostic studies concerning the chemical characteristics of polished rice to improve the cooked rice. They have obtained the following results; (1) As far as the sample varieties produced at Furukawa in 1972 are concerned, KOSHIHIKARI contained extraordinary high amount of free amino acids such as glutamic acid, aspartic acid and alanine etc., and other tested varieties followed in the order of SASANISHIKI, TOYONISHIKI, REIMEI and HONENWASE. (2) Glucose, sucrose and maltose were the major three sugars contained in polished rice, but a new sugar, maltotriose, was introduced by trypsin treatment. Much glucose was produced in polished rice by maltase treatment. Trypsin and maltase did not interfere each other even though they were mixed and applied to the polished rice. (3) When trypsin was applied overnight to the polished rice at room temperature, much amount of free amino acids, such ad glutamic acid, aspartic acid, alanine, valine and leucine were released, comparing with the control. The trypsin-treated cooked rice seemed to be apparently improved in the taste, softening the one year-old rice, according to the results of repeated sensory test. (4) The plasticity, one of the physical properties of cooked rice, of both trypsin-treated and the control were compared, using the Parallel Plate Plastometer. The trypsin-treated plot clearly indicated the larger plasticity than the control, and the results of sensory tests mentioned above were proved. The authors hope to develop further the taste-improving technique concerning the safty culture, higher yield, good quality and better taste.

[学科分类] 农业科学（综合）