(1) The degree of hydrolysis both of sweet potato starch (phosphorus content 0.018-0.022%) and white potato starch (phosphorus content 0.06-0.08%) by the various kinds of the saccharifying amylases reached to the same level around 97-98%. The liberation of phosphoric acid from sweet potato starch when treated with sacchari-fying amylases obtained from Rhizopus and Asp. niger were. almost on the same level of 45-50%, but when treated with Endomyces-Saccharifying amylase it was around 25%. The results of white potato starch were almost same to that of sweet potato starch, but the phosphate liberation by Rhizopus-Saccharifying amylase was a little higher than that of Asp. niger-saccharifying amylase.(2) The second hydrol obtained from sweet potato starch by the treatment of saccharifying amylases and had a high percentage of phosphorus content showed an almost same degree of hydrolysis with that of the first hydrol. Concerning to the liberation of phosphoric acid, Asp.niger-saccharifying amylase showed the highest (70-80%), Rhizopus-saccharifying amylase followed and Endomyces-saccharifying amylase had very low activity about a half of the other amylases to sweet potato and white potato starch.(3) It was revealed that the saccharifying ratio had a tendency to be high in parallel with the liberation ratio of phosphorus acid when forth hydrol (phos-phorus content 0.030-0.045 %) was resaccharified with saccharifying amylases. Forth hydrol obtained by Endomyces-amylase showed higher saccharifying ratio when re-saccharified with saccharifying amlases than that obtained with the other kinds of the amylases. On the contrary lower saccharifying ratio was obtained when the forth hydrol of Asp. niger-amylase was re-saccharified.(4) The conclusions of this paper were as follows : Phosphatase activity of Endomyces-saccharifying amylase was low in comparison with activities of the other two kinds of amylases and amylases which contained higher phosphatase activity was most suitable for re-saccharifying purpose.

View full abstract

This is a review succeeding the former one by S. KAWAMURA (1957) covering the years 1947-1956. The main sections, concern (1) general, (2) sweetpotato starch, (3) potato starch, (4) cereal starches, (5) waste disposal, and (6) manufacture of foods and feeds in relation to starch industries. 392 references.

View full abstract

Iodine affinity (I. A.) values of potato of starch (P. S.) and corn starch (C. S.) were estimated by three different types of the automatic titration and the results were compared with each other. (1) The apparatus reported previously of the automatic amperometric titration for I. A. estimation was partly improved. (2) The shape of the amperometric titration curve of P. S. was found to be different from that of C. S.. The difference might be due to a structural difference of amylopectin components of these starches. (3) The potentiometric titration for I. A. estimation was also carried out automatically. The same I. A. value (3.6) was obtained by the two titration methode for P. S., but for C. S. the value obtained by the potentiometric method (4.6) was slightly higher than the one by the amperometric method (4.3). (4) The sample of C. S. used contained an unidentified substance which affected considerably the potential value of the initial reaction mixture. (5) The I. A. value of starch was also calculated from the curves of the automatic photometric titration. The values obtained were widely varied with titration conditions; they were always higher than those estimated by the above two methods, and became higher as the concentration of starch decreased.

View full abstract

[in Japanese]

View full abstract