Extraction and Preliminary Characterization

In only one instance, namely, Borassus flabellifer, has there been any report of decomposition leading to altered D-mannose D-galac-tose ratios caused by purification through the copper complexes, and it seems likely that this was due to fortuitous fractionation.37 

A method for purifying certain neutral polysaccharides by precipitation in borate buffer with cetyltrimethylammonium bromide was developed by Stacey and coworkers,118 but it does not appear to have been used for the isolation of galactomannan gums. It has, however, been claimed119 that guar gum and locust-bean gum can be separated by carefully controlled precipitation of the cetylpyridinium bromide complexes by 0.1 M sodium hydroxide. Guar gum is precipitated between pH 7.0 and 8.3, and locust-bean gum between 8.6 and 9.3. 

As mentioned previously (see Section 11,2 p. 255), those galac-tomannans having D-mannose D-galactose ratios approaching unity must, of necessity, possess, at the most, a narrow range of D-man- 

When gum is extracted from seeds in which the mucilage exhibits a broad range of species differing in D-mannose and D-galactose composition, the D-mannose D-galactose ratio of the product obtained depends very much on the method of extraction used. Thus, if cold 

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Thomas, M. Thibault, J. F. (2002). Cell-wall polysaccharides in the fruits of Japanese quince Chaenomeles Japonica) extraction and preliminary characterization. 

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