Long Amylose and Amylopectin Branches Modulate the Textural and Cooking Qualities of Rice Noodles

ABSTRACT

Rice noodles are a popular gluten‐free and hypoallergenic staple product. The textural quality of rice noodles is primarily influenced by amylose content. Alongside the amylose content, the chain length of amylose and the unit‐chain ratio of amylopectin also synergistically influence the texture properties of rice noodle. However, the effects of starch fine structure, especially the fine structure of amylopectin including the long branches of amylopectin, on rice noodle properties remain obscure. In the present work, the fine structure and physicochemical properties of starch from twelve rice varieties, as well as the textural characteristics of rice noodles made from these rice samples, were analyzed. Starch fine structure was characterized using Wu–Gilbert biosynthetic mode. Correlation's analysis revealed that a higher proportion of long amylose chains with a peak around DP = 1600 imparts a chewy, gummy, and resilient texture to the rice noodles, while reducing stickiness. Similarly, the long amylopectin chains (DP>65) were found to enhance the firmness and springiness while mitigating adhesiveness. Conversely, the diameter of cooked rice noodles increased when the amylopectin branches (DP<30) became shorter, which could be ascribed to the less entanglement of the shorter chains. Furthermore, specific physicochemical properties, such as low starch solubility, water absorption index, and crystallinity parameter ( I _max ), of starch were identified as effective criteria for selecting cultivars that yield rice noodles with desirable hard, chewy, gummy, and resilient texture.