LAUSR

AbstractDouble helical polysaccharide, xanthan samples with varying molar mass were thermally denatured and renatured in dilute solutions. Both the weight average molar mass, which was determined by size exclusion chromatography (SEC), and viscosity average molar mass decreased after denaturation and renaturation for samples with an initial molar mass of 106 g mol−1, but those for the samples with an initial molar mass of 105 or 107 g mol−1 decreased only slightly. Although the double helices of xanthan only partially dissociated into single chains, the molar mass distribution estimated by SEC did not broaden drastically by the denaturation and renaturation. These results can be explained by the formation of hairpin structures by the single chains, which are restricted to xanthan with a molar mass of 105 g mol−1 by the strain of the hairpin loop, and for xanthan molar masses of 107 g mol−1 by the incomplete dissociation of its long polymer chains.Double helical polysaccharide, xanthan samples with varying molar mass were thermally denatured and renatured in dilute solutions. The molar mass decreased after denaturation and renaturation for samples with an initial molar mass of 106 g mol−1, but those for the samples with an initial molar mass of 105 or 107 g mol−1 decreased only slightly. A model explaining this molar mass dependence of the denaturation and renaturation behaviors was proposed based on the experimental results.