Abstract
The properties of starch granules prepared from tochinomi (Japanese horse chestnut) and hishinomi (water chestnut) were examined. The average sizes of tochinomi and hishinomi starch granules were determined by polarized-light micrography to be 13.7 × 10.8μm and 19.5 × 14.1 μm, respectively. The susceptibility of these two starches to porcine pancreatin in a 24-h reaction was approximately 70% of that of normal maize starch. The solubility and the swelling power of both starches were slightly lower at 70°C, but considerably higher at 80°C and 90°C than those of normal maize starch. Photopastegraphy and differential scanning calorimetry (DSC) showed that the initiation temperature for gelatinization of hishinomi starch (66.2°C and 70.5°C) was 10 degrees higher than that of tochinomi starch (55.9°C and 58.7°C). Amperometric titration and gel chromatography indicated that the amylose contents of the tochinomi and hishinomi starches were 26.4-25.9% and 23.4-23.8%, respectively. The Brabender amylogram (6% concentration) of tochinomi starch showed a comparatively high peak viscosity (570 BU) and large breakdown, while that of hishinomi starch showed that its breakdown was almost zero and its viscosity increased, especially on cooling. Tochinomi starch showed a Cb type of X-ray diffraction pattern, while hishinomi starch showed a Ca type.
