YAMAMOTO CO., LTD.

Alkaline Degradation Test

What is Alkaline Degradation?

When immersed in a weak alkali solution under the certain set of temperature conditions, milled rice swells and begins to disintegrate as time passes, the degree of which varies depending upon the variety of rice. Little at USDA examined the degree of degradation with a weak alkali solution, taking sixty-five samples of total twenty-five varieties: long, medium and short grain milled rice produced in Texas, Arkansas, Louisiana and California.
The results show that, although there were differences related to cultivation and storage conditions, long grains showed a greater resistance while medium and short grains disintegrated easier.

Testing Method of Alkaline Degradation

The testing method of alkaline degradation was introduced into Japan. According to test results of the National Food Research Institute, Niigata University, Niigata Prefectural Food Laboratory and other testing institutions, indica-type rice from Thailand and Myanmar has greater resistance, while the japonica type disintegrates easier. Those of Spain, Egypt and Taiwan are placed in between the two, while those of Italy, America (California) and China are similar to that of Japan and have a low resistance. Within the japonica type, glutinous rice has higher resistance. The early maturing type has the greatest resistance and the later the planting, the less resistance. Alkali degradation seems to have a high correlation with the characteristics of starch, and is a simple test method that is not affected much by the degree of milling.