Curdlan gels preparation

A wide and 1000-1500 A long (Fig. 11D), in which striat-ions are not so clear as in the renatured and 60°C-set preparations. X-ray studies of the oriented curdlan gels showed that the heat treatment at temperatures above 120°C(autoclaving) caused a... 

The X-ray evidence favours a model for the curdlan gel based on triple-stranded molecules. This structure is present in both the gel prepared from aqueous suspension and from alkali solution. The alkali gel contains the proposed seven-fold triple-stranded model (Figs. 7 and 14a) which converts to the more symmetric six-fold triple helix by annealing (Figs. 6 and 14b). This... 

Spectra of aqueous solutions and gels were recorded at room temperature in fused-sillca vacuum UV cells 25y-200u in path-length. For solutions of amylose complete spectra were obtained within 20 min of autoclaving to eliminate the effect of retro-gradation. Gels of curdlan were prepared directly in a VUCD cell by heating a 20 mg/ml aqueous suspension to 95 C. 

Gels of curdlan can also be prepared by neutralizing an aqueous NaOH solution of this polysaccharide. For the system we have studied, a 0.5 M NaOH solution containing 5% curdlan was subjected to dialysis against water to yield a gel. Under these conditions curdlan would be present as random-coil rather than triplex structure before gelation. A CP/MAS NMR... 

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