Stabilization of Polymeric Carbohydrate Nitrates From Studies on Starch, Amylose, Amylopectin, and Glycogen

Abstract

Whole starch, an~ylose, amylopectin, and glycogen (polymeric carbohydrates of the a-D-glycosidic linkage type) were nitrated by nitric acid in the presence of phosphoric anhydride and stability properties of the nitrated products were studied. Crude amylose nitrate is more stable than a~nylopectin nitrate and the latter is less stable than the whole-starch nitrate a s judged by the Bergmann-Junk test. The stability of glycogen nitrate is closely similar to that of amylopectin nitrate.Appreciable stabilization of the crude nitrates mas brought about by boiling with slightly allcaline water for long periods (60-70 hours). All stabilized samples were found to possess closely si~uilar stability properties. The Bergmann-Junk values of all examined nitrates ranged from 2.2 to 1.7 mg of nitrogen per gram sample; the latter value seems to represent the maximum stabilization which could be attained for the polymeric carbohydrate nitrates of the a-D-glycosidic linkage type. In the case of cellulose nitrate (6-D-glycosidic linkage type) Bergmann-Junk values of 1 to 1.25 mg of nitrogen were obtained.

The Stability of Dextran Nitrate

“…the stability of the stabilised forms of dextran nitrates (a-D-glucose polymeric carbohydrate nitrates), in comparison with that of a sample taken from the finished form of a stabilised charge of commercial cellulose nitrate containing 13.1 O/o N (P-D-ghCOSe polymeric carbohydrate nitrate), showed clearly that their tendency to thermal decomposition widely differs as judged by the quantitative Bergmann-Junk and the ignition temperature tests (Bergmann-Junk values 2.5 and 1.2 mg N respectively; ignition temperatures 176 and 188 "C respectively). This result finds analogy with the previous data indicating that the nitrates of a-D-glucose polymeric carbohydrates are inherently less stable than those nitrates of 8-D-glucose polymeric carbohydrates[4,8, 111. To explain fully the observed differences in stability of these polymeric carbohydrate nitrates needs, of course, several researches still to be made.…”

“…Hellman et al [4] studied the crystallisation of wheat starch gels using X-ray techniques. Axford and Colwell [ 51 and Mclwer et al [ 6 ] used rheological and Differential Thermal Analysis methods to a similar end.…”