Chemical deacetylation natural xanthan (Jungbunzlauer®)

• Autor(a) principal: Pinto,Ellen P.
• Data de Publicação: 2011
• Outros Autores: Furlan,Lígia, Vendruscolo,Claire T.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Polímeros (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0104-14282011000100011
• topic: Natural xanthan; deacetylation; reaction parameters

With the aim of adapting a method for removal of acetyl groups from xanthan, reactions of chemical deacetylation were carried out with natural xanthan (Jungbunzlauer®) with variations on the following parameters: biopolymer and alkali concentration (sodium and potassium hydroxide). The deacetylation reaction was performed at 25 ºC for three hours. The proposed methodology was efficient to promote the deacetylation reaction. The viscosity of xanthan increased when the alkali concentration was higher in the deacetylation reaction. Xanthan concentration in the solution used in the deacetylation reaction did not influence the solutions viscosity, as similar results in both tested biopolymer concentrations (0.5 and 1%) were obtained for all experiments in different shear rates. Deacetylation reactions at 25 ºC for three hours with sodium and potassium hydroxide in 0.01 mol.L-1 showed a viscosity of 410 and 420 mPa.s at 10 s-1 and acetylation degree 1.3 e 1.4%, respectively.