5つの濃度のニュートン流体を用いた官能試験による，とろみ液の粘度測定条件（ずり速度）の検討

Shear Rate Evaluation for the Viscosimetry of Thickened Liquids by a Sensory Test Using Five Concentrations of Newtonian Fluids

要旨　目的：臨床的に妥当なとろみ液の粘度測定条件の検討．方法：医療従事者をパネリストとして，5段階の濃度の水飴を粘度が高いと感じた順に並べさせた後，1.4％および0.95％キサンタンガム系増粘剤（XAN）溶液，1.4％グアガム系増粘剤（GUA）溶液について，粘度が近いと感じる水飴を回答させた．試験は水飴の濃度を変え2回行い，計126名の回答を得た．結果：5段階の水飴濃度の識別の正答率は77％であった．5段階の水飴および2段階のXAN溶液を識別できたパネリストでは，ずり速度11sec^-1未満相当の回答はほぼなく，最頻値は1.4％XAN溶液で61〜140sec^-1，0.95％XAN溶液で80〜240sec^-1，1.4％GUA溶液で210〜620sec^-1相当の回答だった．結論：粘度測定条件として，本邦で頻用されてきた3sec^-1ではなく，少なくとも50sec^-1以上が臨床的に意義をもつと考えられた．

Abstract　Objective：The aim of this study is to obtain information for setting a common shear rate for the viscosimetry of thickened liquids. Materials & Methods：The panelists (healthcare professionals involved in dysphagia) drank five maltose syrups, and organized them in the order of viscosity based on their pharyngeal sense. Then, they drank three thickened liquids, i.e., 1.4% and 0.95% xanthan gum (XAN) solutions, and 1.4% guar gum (GUA) solution, and aligned them with the maltose syrups. We carried out the test twice using different concentrations of maltose syrups and obtained 126 answers. Results：Of all panelists, 77% could correctly arrange the five maltose syrups in the order of viscosity. The answers of the panelists who could serialize the five maltose syrups and the two XAN solutions were as follows. There were few answers that corresponded to shear rate of less than 11 sec^-1 for each of the thickened liquids. Meanwhile, most frequently answers corresponded to the shear rates of 61-140 sec^-1, 80-240 sec^-1, 210-620 sec^-1 for 1.4% XAN, 0.95% XAN, and 1.4 GUA solutions, respectively. Conclusion：The common shear rate for the viscosimetry of thickened liquids was not equivalent to the shear rate of 3 sec^-1 historically adopted in Japan；it was at least 50 sec^-1 according to the results of the sensory evaluation.