Properties of Rice Starch Prepared by Alkali Method with Various Conditions

Abstract

The effect of Alkalis on rice starch granule during the alkaline purification of rice starch was studied. By the first treatment of rice powder by diluted aqueous alkaline solution for 3 hrs., 98% of protein, 90% of lipid, 85% of ash in polished rice powder were dissolved and removed by washing. The starch granules prepared by higher temperature and increased washing with alkaline solution had tendencies to increase viscosity rapidly after gelatinization compared with slow increase of viscosity of the ones prepared at lower temperature and lesser alkaline washing. According to our studies, it became clear that less modified rice starch was prepared by one alkaline soaking with stirring for 3 hrs, and followed with water washing. This modified method to use fine rice powder through 100 mesh enabled to shorten the period of rice starch preparation.