Cereal Chem 39:304 - 310.  |  VIEW ARTICLE

Intrinsic Viscosity of Dialdehyde Starch in Alkaline Urea After Reduction with Borohydride.

W. C. Schaefer, J. J. Maurice, C. R. Russell, and C. E. Rist. Copyright 1962 by the American Association of Cereal Chemists, Inc. 

Periodate-oxidized starch, commonly called dialdehyde starch (DAS), was reduced with borohydride at 1.5 C. to minimize alkaline degradation, and dispersed in an aqueous alkaline solvent system. The final solvent system consisted of 0.5N potassium hydroxide containing 25 g. urea per 100 ml. solution. Absence of nitrogen from reduced DAS isolated from dispersion in this system indicated that the pretreatment left no aldehyde groups available for reaction with urea. Intrinsic viscosities of reduced DAS dispersed in this system were significantly higher and were more stable than those obtained without prior reduction. Comparable values were obtained in both systems with less-sensitive starch derivatives, but again, the reduction system gave improved stability.