title: Synthesis of acetylated konjac glucomannan and effect of degree of acetylation on water absorbency.
abstract: Konjac glucomannan was acetylated with acetic anhydride under different conditions to reduce the unusually high water absorbency of native konjac. The dependence of the degree of substitution (DS) on the reaction conditions and the influence of the DS on the water absorbency were investigated. The most efficient method for the acetylation was refluxing konjac in acetic anhydride in the presence of sodium hydroxide catalyst. The water absorbency rapidly decreased with increasing DS. Fully acetylated product was obtained within 12 h, which exhibited 1.0 g/g water absorbency vs the 105.4 g/g absorbency of native konjac. Because of the exponential decrease of water absorbency with increasing DS, a relatively small DS is sufficient to significantly suppress the absorption of water.
authors.affiliation: Biodegradable Polymer Research Center, Department of Plastics Engineering, University of Massachusetts Lowell, One University Avenue, Lowell, Massachusetts 01854, USA.
authors.forename: B
authors.initials: B
authors.lastname: Koroskenyi
authors.forename: S P
authors.initials: SP
authors.lastname: McCarthy
mesh_terms: D000042:Absorption; D000089:Acetic Anhydrides; D000107:Acetylation; D000924:Anticholesteremic Agents / Q000009:adverse effects / Q000138:chemical synthesis / Q000737:chemistry; D003967:Diarrhea / Q000139:chemically induced / Q000517:prevention & control; D006801:Humans; D046911:Macromolecular Substances; D008351:Mannans / Q000009:adverse effects / Q000138:chemical synthesis* / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water
chemical_list: D000089:Acetic Anhydrides; D000924:Anticholesteremic Agents; D046911:Macromolecular Substances; D008351:Mannans; D014867:Water; C031800:acetic anhydride; C022901:(1-6)-alpha-glucomannan