Abstract:

To reveal the structural characteristics of different kinds of potato starches, the semi-crystalline struc-ture, crystalline morphology, amylose content, relative molecular mass and molecular conformation of ten kinds ofpotato starches were systematically analyzed by means of small-angle X-ray scattering, polarizing microscopy, X-raydiffraction and gel permeation chromatography coupled with multi-angle light scattering. The results show that thegranules of the ten kinds of potato starches are of different semi-crystalline structures, for instance, Long 3 posse-sses the minimum semi-crystalline lamellae thickness and the most orderly double-helix alignment, while Qing 2 andQing 6 possess the maximum semi-crystalline lamellae thickness. All the starches are multi-crystal systems withthe same B-type crystalline structure but with different crystallinity and amylose content. Moreover, it is found thatthe weight-average molecular mass of Feiwuruita, Qing 5 and Qing 8 are relatively larger, and that Qing 5 in DMSOexhibits in the form of random coil, while the rest are all in a spherical form. All of the above-mentioned structuredifferences in different scales provide basic data for the development of potato starches for special processing.

Key words: potato starch, variety, semi-crystalline lamellae, crystalline morphology, amylose content, molecularconformation