| The helical complex formation between iodine and a linear glucan polymer has been the cornerstone of research on starch. The objective of this study was to investigate the interaction of iodine vapor with different branched homo-glucan polymers within the larger context of understanding starch granular architecture. It was hypothesized that crystalline structures within starch granules and branched structure like beta-limit dextrins will not bind iodine because of the physical constraints that would restrict polymer mobility hindering the helical complex formation of iodine with glucan polymers. The different glucan polymers studied included native granules, non granular starches, beta-limit dextrins of the starches, and starch lintners from corn and potato starches, and their waxy counterparts. All of these materials were used to make different branched structures and exposed to iodine vapor for 24 h and the resultant material was evaluated for their absorption spectra and for their X-ray diffraction spectra. Non-granular, lintner and beta-limit dextrins were further characterized using sequential enzymatic hydrolysis. The results are significant and interesting because they highlight the ability of a range of branched homo-glucan polymers to bind iodine; an observation that implies the presence of long enough linear regions that can form an alpha helix without steric hindrances, even in structures like a beta limit dextrin that have very short A-chains. |
