Perspectives on the history of research on starch Part IV: On the visualization of granule architecture

摘要

Starch has been used over several millennia for a number of different applications. However, research on understanding this substance only spans about three centuries starting with Leeuwenhoek who observed it in 1716. This story of discovery of the molecular structure and architectural makeup of starch is chronicled in a series of six essays of which this is the fourth with a focus on visualizing the granule, its development and architecture. Since the starch granule was visualized initially, researchers focused on the content and composition of the granule and also tried to understand what they saw by way of layers, polarization, and staining properties using a microscope. Two schools of thought prevailed in the 1800s with regards to granule development. Confusion prevailed with respect to terminologies and composition through this period. The first model of the crystallized granule was proposed in the late 19th century and it was not until mid-20th century that the blocklet and crystalline arrangement of starch was understood. However, the crystallinity and helical complex between AM and iodine continued to obscure the source of starch crystallinity during the second half of the 20th century.