Comparison of Cooked Rice and Starch Paste Properties of Mutant Rice

Abstract

In this study, we compared the characteristics of cooked rice and their starch pastes properties of Nipponbare (parental cultivar) and mutant rice deficient in starch synthase enzyme I (SSI), starch synthase enzyme IIIa (SSIIIa), and pullulanase (Plu). The cooked Nipponbare and SSI- and PUL-deficient rice had a rounded shape similar to that of japonica rice and they did not show a clear fracture point. Conversely, the cooked SSIIIa-deficient rice had a shape that extended vertically similar to indica rice and they showed a clear breaking point. SSIIIa-deficient rice had an extremely low G’ value, which was lower than that of G”, the dynamic viscoelasticity of starch paste, indicating that was a sol and that it did not form a network in the starch paste. The starch paste of SSIIIa-deficient rice had extremely low viscoelasticity, which was similar to that of water. Hence, SSIIIa-deficient rice can be used as functional rice in kayu (rice porridge) or as a stable low-viscosity liquid food.