抄録
1) One of the recommended method for rice starch preparation by alkalis was proposed by the author's basic studies of rice starch. 2) In order to elucidate the difference of pasting character between classified potato starches, some properties of the starches were investigated by using chemical and enzymatic methods. As the results, there are no differences in the molecular structure among the classified potato starches in terms of blue value, amylose content, beta-amylolysis limit, distribution of chain length and some properties of Nägeli amylodextrin. 3) The more detail of pasting properties among classified potato starches were examined by using cation substituted potato starches. It was confirmed that small granule starch showed higher phosphorus content than large granule starch. In the case of same cation substitution, peak viscosity in amylogram has high corelation with starch granular size. 4) In order to understand classified potato starches in more detail, changes in some Theologi-cal properties, such as flow curves and torque-time dependence, during pasting were observed. And also, changes in pasting properties of classified potato starches were studied by warm water treatment method. 5) In Japan, about 250, 000 tons of potato starches are produced. More than 85% of them are produced in 18 factories belonging to Agricultural Co-operation in Hokkaido Prefecture. We classified roughly these products into 4 types by using Brabender amylography. More-over, we tried to study these products by measurement of starch gel properties. It was showed that Young's modulus of gels is affected by characteristic values in amylogram, starch granular size and potassium content, and that breaking strength of gels is affected by phosphorus content in potato starches. The use of potato starches produced in Hokkaido was speculated from amylograms and starch gel properties.
