Molecular Chain Structure of Starch with Superior Molding Processability

Abstract

This study provides fundamental insights into improving the moldability of rice batter. To clarify the effects of amylose content and molecular weight on batter properties, three experiments were conducted. First, rice flours with varying amylose contents were blended, and their bread-making properties were evaluated. The results revealed that higher amylose content increased the storage modulus (G’) during heating, thereby enhancing the bread’s expansion ratio. Second, the viscoelastic properties of natural starches were measured. Adding amylose to glutinous rice starch significantly increased G’ in the temperature range of 25°C to 65°C. Third, enzymatically synthesized amylose with different molecular weights was employed to assess viscoelasticity. High-molecular-weight amylose markedly improved G’ in the same temperature range as the second experiment, showing a clear dependence on amylose concentration. These results demonstrate that G’ during heating plays a crucial role in the expansion properties of rice flour dough, and this characteristic is determined by both amylose content and its molecular weight.