|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1997 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1996 : ¥1,300,000 (Direct Cost : ¥1,300,000)
The gelation mechanism of polysaccharide solutions have been studied by many researchers. However, as is often the case with bipolymers, the interpretation of results is complicated partly because of differences is materials. To obtain fundamental data for the gel fomation, it is desiable to prepare the standared sample. In comformity with this view, we prerared the standared samples of gelforming polysaccharide, gellan gum, and studied their solution properties. Microbial polysaccharide gellan gum, which forms thermoreversible gel in aqueous solutions, is a linear anionic polymer consistion of [(3)-beta-D-glucose-(1,4)-beta-D-glucuronic acid-(1,4)-beta-D-glucose-(1,4)-alpha-L-rahmnos (1)] repeating unit and a carboxyl group in grucuronic acid.
In 1996, extremely pufified sodium type gellan gum (Na-gellan) was prepared from deacetlatylated gellan gum by passing through a column of cation-exchange resin. The conversion of Na salts was checked by measureing the ionic contents and chelate titlation of the sample. The temperature dependence of the solution properties of the Na-gellan was studied by osmometry and viscometry. It was found that the molecular weight of the sample obtained above 36ﾟC was 4.6*10^4 and below 28ﾟC was 9.4*10^4 suggesting association of two molecues below 28ﾟC.Influence of strage on the molecular weight of the samples were also studied.
In 1997, the purified six Na type gellan samples with different molecular weights were-prepared by mechanical grinding and ion-excahnge methods. The molecular weights of the samples determined from osmometry were ranging from 1.7*10^4 to 5.8*10^4.