DEUTERIUM EXCHANGE IN STARCHES AND AMYLOSE
In all starch and amylose preparations examined, the hydroxyl hydrogens were shown by weight change to be completely exchangeable with liquid D2O, within an experimental error of 1 or 2%. Samples examined were defatted wheat starch, potato starch, high-amylose corn starch, acid hydrolyzates of amylose with both A and B x-ray patterns, a palmitic acid complex of amylose in helical configuration, and retrograded amylose preparations. Some of the retrograded preparations were soluble in boiling water, and some were insoluble. The insoluble preparations retained their B x-ray diffraction patterns. Deuterated wheat starch was completely exchangeable with water vapor at low relative humidity, and also with liquid methanol, but was not completely exchangeable with liquid ethanol. Inaccessibility to this last solvent was ascribed to lack of penetration. Complete exchange found in all other cases indicated that the A, B, and helical crystal structures have exchangeable hydroxyls and that all or nearly all hydrogen bonds in starch are relatively weak. It appeared that association in retrograded amylose and resistance to redispersion in hot water are mainly effected by the crystalline regions, which would afford the necessary cooperative strength. (auth)
- Research Organization:
- Northern Regional Research Lab., Peoria, Ill.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-16-000461
- OSTI ID:
- 4833657
- Journal Information:
- Journal of Physical Chemistry (U.S.), Journal Name: Journal of Physical Chemistry (U.S.) Vol. Vol: 65; ISSN JPCHA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Linear starch and hexanoic acid complexation evaluated by isothermal titration calorimetry
Electron Spin Resonance of Free Radical formed in Amylose by γ-Irradiation