Insights into multiscale structures of starch to illuminate their relationship with taste quality of rice

Multiscale structures of starch and their interactions with proteins are key factors in determining taste qualities of rice. This study explored six high-quality rice cultivars to uncover the factors contributing to superior eating quality. It was revealed that high-quality rice featured large starch granules, and size distributions were positively correlated with breakdown viscosity but negatively correlated with cool paste viscosity. The proportion of fb₂ chains (DP 25-36) in amylopectin was positively correlated with peak viscosity and negatively correlated with cohesiveness of cooked rice. Conversely, the proportion of fb₃ chains (DP ≥ 37) was negatively correlated with hot paste viscosity. Gelatinization temperatures had negative correlation with fa chains (DP 6-12), while positive correlation with fb₁ chains (DP 13-24). Fourier transform infrared spectroscopy and Raman spectroscopy revealed that the enhanced hydrogen bonding interactions within starch-protein complexes strengthened gels and resulted in higher peak viscosities. These findings provide new perspectives for breeding high-quality rice cultivars.