, Volume 107, Issue 4, pp 546–554 | Cite as

The influence of thickeners of food on the particle size of boluses: a consideration for swallowing

  • Erika Yamaguchi
  • Tetsurou TorisuEmail author
  • Hiroaki Tada
  • Yuichi Tanabe
  • Tadafumi Kurogi
  • Shinya Mikushi
  • Hiroshi Murata
Original Article


The purpose of this study was to examine the influence of thickeners with different levels of thickness on the sizes of particles in food boluses. In medical and nursing care, thickeners are used to make food safe for patients with dysphagia. However, the effect of thickeners on the foods they are added to, especially during swallowing, is still unclear. The bolus particles of 20 healthy volunteers were photographed, and the digital images were used to estimate the sizes of particles in them. Eight test samples with thickeners with different levels of thickness were tested: six grades of thickened carrot juice with raw carrots in it, raw carrot with banana, and raw carrot alone. The particle homogeneity index (HI) and particle size index (SI) just before swallowing were calculated. The viscosities of the liquid part of the test samples were also measured. The number of mastication cycles across the test samples was not significantly different. However, significant differences were found in SI and HI across the test samples: the absolute values of SI and HI tended to rise as the thickness of the test sample increased. The viscosity of the liquid part of the test sample also increased as the thickness increased. The differences in the thickness of food had an influence on the bolus particle sizes just before swallowing.


Cohesiveness Mastication Particle size Swallowing Thickener 



This study was supported by JSPS Grant-in-Aid for Scientific Research (C), Grant number 16K11628.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© The Society of The Nippon Dental University 2019

Authors and Affiliations

  1. 1.Department of Prosthetic Dentistry, Graduate School of Biomedical SciencesNagasaki UniversityNagasakiJapan
  2. 2.Department of Special Care DentistryNagasaki University HospitalNagasakiJapan

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