Cluster classification of dysphagia-oriented products considering flow, thixotropy and oscillatory testing

The present paper proposes an objective classification of commercial thickened food widely used in patients with dysphagia. A total of 34 commercial enteral nutrition products were analyzed (beverages, main courses and desserts) corresponding to 6 different commercial brands. All these products contain different hydrocolloids (i.e., starch, xanthan gum, carrageenans, etc.) as thickeners, in order to get the desired texture. Joint consideration has been made of viscous behavior (flow and thixotropy) and viscoelastic behavior (oscillatory testing). Rheological measurements were fitted to different rheological and empirical mathematical models, and a total of 11 parameters were generated. Based on these parameters and the use of fuzzy clustering and the c-means method, an objective classification of all the products was obtained. Our results correspond to five different classes, one more than the four established by other authors. The five defined classes have been named in a way similar to those most commonly used in the literature. Each class has been defined from the parameters of the centroids generated by the classification method used - thus allowing us to know the common rheological characteristics of any of the products belonging to a given class. (C) 2010 Elsevier Ltd. All rights reserved.