Cellulose and the various starches were dried in vacuum line apparatus, deuterated in liquid deuterium oxide, and dried in the same apparatus. Their accessibility was determined by measurement of the maximum absorbance (a) and the integral absorbance (b) at the wave number of each OH and OD group band on the infrared spectra, and crystallinity was calculated from accessibility. Crystallinity of cellulose showed the reasonable values of 0.66 for (a) and 0.71 for (b). Crystallinity of starches was considerable lower than those by means of the X‐ray diffraction. There are inaccessible regions (so called crystalline fractions) in the starch granules which are not able to be deuterated and, moreover, neither to contain nor to absorb moisture inside. The reason why crystallinity was so low might be attributed to dehydration in the amorphous region at high vacuum.
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NARA et al. (1981) studied this question.