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49—THE FRACTIONATION OF STARCH: Part IV—THE AMYLOPECTIN-IODINE REACTION

1949; Taylor & Francis; Volume: 40; Issue: 12 Linguagem: Inglês

10.1080/19447024908660063

1944-7027

R. S. Higginbotham,

Polysaccharides Composition and Applications

The composition and absorption spectra of amylopectin-iodine complexes and glycogen-iodine complexes have been determined for a wide range of iodine concentrations. Provided that the concentration of free iodine is sufficiently high, the amylopectins absorb as much iodine as amyloses do. It is inferred, therefore, that amylopectins absorb iodine partly by a helix mechanism involving chains of iodine molecules and tri-iodide ions, and partly by adsorption of single iodine molecules or single tri-iodide ions. Spectrophotometric data support this view. The proportion of iodine bound by the helix mechanism varies with the total amount of iodine absorbed and with the identity of the amylopectin. These variations may be related to the distributions of branch lengths in the amylopectins.