Rice noodle quality is structurally driven by the synergistic effect between amylose chain length and amylopectin unit-chain ratio

Chewiness, slipperiness, and rapid rehydration are satisfactory qualities for rice noodles. These qualities are dependent on rice starch structure. However, the synergistic effect of fine structure of amylose (AM) and amylopectin (AP) on rice noodle quality remains unclear. In this work, six rice varieties, three from early indica and three from late indica, with similar amylose content for each pair were analyzed to assess the synergistic effects between AM and AP fine structures. The results showed that the combination of amylose long-chains and a low amylopectin unit-chain (APC) ratio favored the maintenance of relatively intact starch granules, resulting in a higher die expansion ratio and improvement of the mechanical properties of rice noodles (Hardness varied from 403 g to 1627 g). Meanwhile, higher die expansion was associated with a larger rehydration ratio. These results suggest that the synergistic effect between AM and AP fine structures significantly affects rice noodles' quality. [Display omitted] •Rice starch with similar amylose content yields rice noodles of different quality.•Rice noodle diameter is related to the long-chain amount of amylose and amylopectin.•A low amylopectin unit-chain (APC) ratio helps to maintain starch granule integrity.•Evaporation of more intergranular water shortens rice noodle rehydration time.•Long-chain amylose and low APC ratio synergistically improve rice noodle quality.