Abstract: Starch, a natural polymer material, is increasingly used in the field of food processing. As an industrial raw material, starch has been also widely used in the fields of pharmaceutics, textile, paper and materials. There is a long history of more than 4 000 years since humans began to use starch, but it is only 100 years since its large-scale production and application occurred. This is because the large-scale application of starch in different fields is restricted by some fine microstructural characteristics of natural starch. Elucidating starch structure is a rather lengthy process. This article reviews the current state of the art of the fine microstructure of starch granules. The molecular composition of starch is described and a systematic review of how starch structure is organized at 6 increasing orders of magnitude is presented with special emphasis on double helix structure, super helix structure, sealing plug structure, and particle structure. Finally, the fine microstructural features of starch granules are summarized. This review is expected to provide a theoretical basis for future research on the fine microstructure of starch granules to facilitate the application of starch to the food industry.

Key words: starch, fine structure, double helix structure, superhelical structure