抄録
Sweet potato starch, available commercially, was found to contain originally about 25mg% of the insoluble starch particles (ISSP), which could not be liquefied with bacterial alpha-amylase under the best known liquefaction process and remained as the residue.
Some of the sweet potato starch which is considered to be difficult to liquefy in dextrose manufacture, often contains about 60mg% of this material. The different species of starch are arranged in the increasing order to the ISSP content as follows: potato starch<sweet potato starch<rice starch<corn and wheat starch. The average amount of ISSP content in corn starch is about 229mg%.
By treating the sweet potato starch slurry at 55°_??_60°C, the ISSP content in the slurry was remarkably increased, and when potato starch (16% moisture) was heated in a pressure vessel with live steam of 115°_??_127°C, the ISSP content was increased to about 3000mg%. ISSP content of sweet potato starch was also increased by the liquefaction with bacterial alpha-amylase, when the operation temperature was between 70°_??_80°C.
