Viscoelastic properties of starches and flours from two novel rice mutants induced by gamma irradiation

Storage and loss moduli (G′ and G″) of rice starch and flour pastes dependent on temperature and frequency were characterized from two starch mutants (waxy mutant GM077 and white-core mutant GM645) and their parent Guangluai 4 (GLA4). The values of G′ and G″ for rice starch and flour pastes decreased with the increase in temperature during heating. GLA4 contained the highest amylose content and exhibited the highest values in both G′ and G″, while the waxy mutant GM077 that had the lowest amylose content showed the lowest values in G′ and G″. During the cooling process, GLA4 and GM645, with higher amylose content, presented more significant increase in values of G′ and G″, indicating that amylose played an important role in intermolecular entanglement and gel network formation. G″ showed sharper increase than G′ as a function of frequency for both starch and flour pastes. Results observed in the current study will be of use to rice breeders and allied industries to meet the diversified demands for quality improvement of food products.