title: Comparison of different gum-based thickeners using a viscometer and line spread test: a preliminary study.
abstract: OBJECTIVE
  To compare fluid thickeners composed of starch polysaccharide (STA), guar gum-based polysaccharide (GUA), and xanthan gum-based polysaccharide (XAN) with the use of a viscometer and a line spread test (LST) under various measurement conditions.
  
  
  METHODS
  The viscosity of thickened fluid with various concentrations (range, GUA 1%-4%, XAN 1%-6%, STA 1%-7%, at intervals of 1%) was measured with a rotational viscometer with various shear rates (1.29 s(-1), 5.16 s(-1), 51.6 s(-1), and 103 s(-1)) at a temperature of 35℃, representing body temperature. The viscosity of STA showed time dependent alteration. So STA was excluded. Viscosities of GUA and XAN (range of concentration, GUA 1%-3%, XAN 1%-6%, at intervals of 1%) were measured at a room temperature of 20℃. LST was conducted to compare GUA and XAN (concentration, 1.5%, 2.0%, and 3.0%) at temperatures of 20℃ and 35℃.
  
  
  RESULTS
  The viscosities of 1% GUA and XAN were similar. However, viscosity differences between GUA and XAN were gradually larger as concentration increased. The shear thinning effect, the inverse relationship between the viscosity and the shear rate, was more predominant in XAN than in GUA. The results of LST were not substantially different from GUA and XAN, in spite of the difference in viscosity. However manufacturers' instructions do not demonstrate the rheological properties of thickeners.
  
  
  CONCLUSIONS
  The viscosities of thickened fluid were different when the measurement conditions changed. Any single measurement might not be sufficient to determine comparable viscosity with different thickeners. Clinical decision for the use of a specific thickener seems to necessitate cautious consideration of results from a viscometer, LST, and an expert's opinion.
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jae Hyeon
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ho-Geun
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Byung-Mo
authors.initials: BM
authors.lastname: Oh
authors.affiliation: Department of Food and Nutrition, College of Human Ecology, Seoul National University, Seoul, Korea.
authors.forename: Min-Woo
authors.initials: MW
authors.lastname: Lee
authors.affiliation: Department of Food and Nutrition, College of Human Ecology, Seoul National University, Seoul, Korea.
authors.forename: In-Kyeong
authors.initials: IK
authors.lastname: Hwang
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Shi-Uk
authors.initials: SU
authors.lastname: Lee
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Tai Ryoon
authors.initials: TR
authors.lastname: Han
keywords: Deglutition disorders; Diet; Viscosity