Improving rice quality by enhancing key amylose and amylopectin and their complexation with fatty acids

Lower quality of Chinese rice didn't meet societal demand for high-quality rice. Optimizing starch characteristics (including complexation) enhances rice quality, but the impact of starch-fatty acid complexation remains unclear. Therefore, we used molecular dynamics simulations to explore amylose/amylopectin-fatty acids complexation to elucidate rice quality impact. Results showed that Northeast/East China rice achieved first-grade quality, whereas Central/South/Southwest China rice achieved second-grade. Further analysis revealed 10-40 degrees of polymerization (DP) amylose and 3/2 of A/B₁-chains (3A2B₁-type) amylopectin enhance structural stability (lower energy/root mean square fluctuation (RMSF)) by forming more compact structures (amylose ends/center, amylopectin 2B₁-region), increasing head rice rate and breakdown value, and reducing chalkiness and retrogradation value. These starch structures preferentially complex with specific fatty acids (palmitic/stearic/oleic acid for 10-40 DP amylose, linoleic acid for 3A2B₁-type amylopectin), further tightening their structures. Therefore, boosting 10-40 DP amylose, 3A2B₁-type amylopectin, and their fatty acid complexes improves rice quality, providing a basis for optimization.