Abstract
To make clear the X-ray diffraction pattern of rice starch elaborated from various kinds of rice grains, the GEIGER counter X-ray spectrometer was used under the conditions of Ni/Cu-K, 40 KVP. 15 Ma in the X-ray tube. The results obtained were as follows. 1) In the preliminary experiment on potatoe starch, it was revealed that the spectrometer was a more useful apparatus for charting the X-ray diffraction pattern of starch as compared with the photograph which had been adopted in general for the same purpose. 2) The diffraction patterns of rice starch charted by the spectrometer were hardly different with varieties and qualities, of rice grains. Especially, there were no differences in the d-value and in the intensity of the main peaks in their charts. 3) Judging from the charts, the authors intended that rice starch should be assorted as CA type rather than CB type. For, the peak denoted as the Ist line by the photograph could not be found in any charts made by the spectrometer. 4) A little difference between rice flour and rice starch was found in the X-ray diffraction patterns. The intensity of all peaks on the pattern of rice flour was weaker than that of rice starch, although the d-value did not show any difference between them. 5) To convertβ-type starch into d-type's, 4 % solutions of β-type starch were treated at 50, 52, 54, 56, 58 and 60°C., respectively. As a result of this experiment, the temperature at which rice starch was transformed into the complete or half-finished α-type, was different with varieties and qualities, of rice starch, and this difference seems to suggest that there exist some other dissimilarities in the physico-chemical characters of various kinds of rice starch.
