THE CRYSTALLINE DOMAINS IN POTATO STARCH GRANULES ARE ARRANGED IN A HELICAL FASHION

The structural basis for the physical properties of starches from different botanical sources is still poorly understood. Particularly at the level of the crystalline domains the present knowledge concerning the structure of starch is limited. This paper reports the semi-crystalline structure of potato starch granules by electron optical tomography and by cryo electron diffraction. It is concluded that the crystalline domains in the amylopectin form a continuous network of left-handed helices, which appears as a well-ordered skeleton for the starch granule. This type of super-helical lamellar structure has not been reported before either in natural or in synthetic polymers.