Influence of storage on the molecular weight of tetramethylammonium-type gellan gums

• Published in: Carbohydrate polymers Vol. 30; no. 2; pp. 145 - 148
• Main Author: Ogawa, Etsuyo
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 1996; Elsevier Science
• Subjects: Applied sciences; Biological and medical sciences; Exact sciences and technology; Food additives; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; gums; Natural polymers; Physicochemistry of polymers; polysaccharides; Starch and polysaccharides; Textural agent; Second virial coefficient; Long term variation; Food additive; Experimental study; Number average molecular weight; Polyelectrolyte; Natural gum; Microbial origin; Ionic strength; Storage stability; Oside polymer; Aqueous solution; Saline solution; Quaternary ammonium polymer
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/S0144-8617(96)00091-4

The number average molecular weights M ̄ n and the second virial coefficients A2 for tetramethylammonium-type gellan gums (TMA-gellans) were obtained in aqueous tetramethylammonium-chloride at 40 °C by osmometry. The TMA-gellans were prepared from two types of gellan gum (gellan-1 and gellan-2), supplied from different companies. M ̄ n and A 2 obtained from the TMA-gellan sample, prepared from gellan-1 in 1992, almost agree with those obtained from the sample prepared from the same gellan-1 in 1994, suggesting that gellan-1 has not deteriorated during the two-year period. Even if the values of M ̄ n of the two TMA-gellans prepared from two types of the gellan gums are very close, their aqueous solutions have different A 2 values at the same added salt concentrations. This could be interpreted as a partial difference in the chemical structure, e.g. the number of charged carboxyl groups in the two types of gellan gum.