Abstract
Five newly developed rice (aromatic Sari-queen, low amylose Dohoku 43, high amylose Hoshiyutaka, giant grain Ochikara, and high yield Habataki rice) were studied. To determine the properties of the flour and starches of the newly developed rices, swelling power and solubility, photopastegraphy, viscography and starch gel texture were examined. The stability during storage at a low temperature was determined by measuring the water syneresis ratio and the whiteness of the starch gel. The swelling power of rice starch at 90°C ranged from 17 to 26. Hoshiyutaka had the lowest, and Ochikara the highest values. Dohoku 43 and Nipponbare were difficult to swell. Sari-queen showed a high maximum viscosity, a high viscosity in the cooling step and a large breakdown, i.e., low heat stability. Hoshiyutaka, which showed a viscosity curve similar to that of the corn starch, can be used in foods by taking advantage of its gelling properties. Hoshiyutaka and Sari-queen were high in firmness of starch gel, and the firmness was increased when stored at a low temperature. The Nipponbare gel was soft, and the Dohoku 43 gel, intermediate in softness. In this third study, the gelatinization and retrogradation properties, gel texture and stability of the flour and starches of newly developed rice were determined. Forth coming studies will look at how the varied properties of the flour can be used for many kinds of cooking and processing, including couscous and traditional Japanese sweets and cakes (Dango and Uiro).
