カタクリ澱粉の二，三の性質について

Abstract

Some chemical and physical properties of starch prepared from bulbs of katakuri, which were collected in Hokkaido and Iwate, were investigated. The results obtained were as follows; 1) The mean particle size of katakuri starch was 19.9 μm, and was bigger than that of sweet potato starch and smaller than that of potato starch. 2) The susceptibility of katakuri starch granules to hog pancreatin was similar to that of sweet potato starch granules having relatively high susceptibility. By scanning electron micros-copy (SEM), stripe structure and large holes on the surface of katakuri starch granules were observed after attack by pancreatin. The large holes were observed in the early stage of the attack. This was quite different from the case of normal maize starch granules, for which the enzymatic attack usually started with small pits on the surface of the granules and then the pits increased in number and in size during the subsequent enzyme attack. 3) The initiation temperatures for gelatinization of katakuri starch, by photopastegraphy, differential scanning calorimetry (DSC), and Brabender's amylography of 6% concentration, were 44, 47, and 53.5°C, respectively. These temperatures were 10 to 20°C lower than the respective values of kuzu, sweet potato, and potato starches. The enthalpy change, 4H, de-termined by DSC was 3.3 cal/g, which was relatively lower than that of the other three starch-es. The maximum viscosity by Brabender's amylography (6 %) was 900 BU and breakdown was 620 BU. 4) The amylose contents of katakuri starch, determined by amperometric titration and en-zyme-chromatographic method, were 22.1 and 22.6%, respectively. The Fr. III/Fr. II, which was determined by enzyme-chromatographic method, was low in spite of the susceptibility of katakuri starch granules being relatively high. 5) Katakuri starch showed B-type X-ray diffractogram.