Gelatinization properties of rice starches in potassium hydroxide solution was investigated with alkaliviscography. The sample rice starches were purified with detergent from 25 non-glutinous Indica, 3 non-glutinous Japonica, and from 5 glutinous Indica varieties, all of which were grown in the Philippines. The effects on the alkaliviscogram were checked of maturing temperature of rice plants, contamination with immature rice grains, extraction times with detergent, and stored period of sample starch at 25℃ for 9 months. The comparison of each viscogram from 11 rice starches with those of their parents rice starches gave no consistent tendency. Some non-glutinous rice starches showed specific low and flat viscograms, which suggested slow gelatinization of the sample in alkali. On the contrary, glutinous rice starches showed especially high maximum viscosity upon gelatinization. Non-glutinous rice starches are supposed to be grouped into 3 or 4 classes from the standpoint of gelatinization normality of alkali.

25品種のIndica粳米, 3品種のJaponica粳米, 5品種のIndica糯米の澱粉について, それらのアルカリ糊化性に及ぼす試料米の条件, 澱粉の精製条件, 貯蔵条件の影響について検討したのち, 11品種の粳米澱粉のアルカリビスコグラムについてその育種的背景との関係を調べたが, 一定の傾向は見出せなかった. 粳米澱粉のなかには低粘度緩糊化性を示す品種がみられたが, 糯米澱粉は糊化に際して著しく高い粘度を示した. 粳米澱粉の全アルカリビスコグラム図より, その糊化開始アルカリ濃度を基準にすると粳米澱粉は3-4群に分類できるように考えられた.