2016 Volume 20 Issue 1 Pages 11-22
Background and objectives: In terms of the fundamental requirements for food appropriate for dysphagia, the greatest importance is placed on safe physical properties. In 2009, with the aim of safer oral intake, the relationships between the physical properties of food and the physical properties appropriate for dysphagia were clarified by the System for Food for Specified Health Uses of the Japanese Ministry of Health, Labour and Welfare (MHLW), in a document titled “Criteria for acceptability of foods for dysphagia”. In order to achieve the appropriate physical properties, thickening polysaccharides, that is, dietary polysaccharides with the properties of thickening agents, gelling agents, etc. are frequently used. In the case of foods appropriate for dysphagia, the objective of the present study was to replicate physical properties effectively within the range of the criteria for acceptability, using typical thickening polysaccharides, starch-degrading enzyme, and gelling promoter, and to elucidate methods that are readily applicable to the clinical environment.
Materials: The food used was polished rice. The following six types of thickening polysaccharide were used: glucomannan, κ- and ι-carrageenan, xanthan gum, gellan gum, and locust-bean gum. The starchdegrading enzyme used was amylase. The gelling promoter used was non-fat milk powder.
Methods: Dissolved polysaccharides and kayu were mixed together by stirring. A Petri dish was then filled with the mixture, and left undisturbed for 30 min with the temperature within the material maintained at 20±2℃, after which the hardness, adhesivity and cohesiveness were measured using a rheometer, in accordance with the test methods stipulated by the Ministry of Health, Labour and Welfare, and the water separation rate was measured together.
Results: When polysaccharide was used alone, the glucomannan, locust-bean gum, and xanthan gum did not gel. Gellan gum and κ- and ι-carrageenan decreased in cohesiveness with gelation, and were within the reference range, but did not satisfy licensing standard I because the hardness and adhesion increased rapidly and exceeded the upper limits of the reference value. The gellan gum separated, but it was effective in combination with polysaccharide. We effectively formed a gel for the two combinations of xanthan gum and locust-bean gum, and xanthan gum and glucomannan.
Conclusions: Appropriate material properties to utilize the characteristic of polysaccharides and to satisfy the licensing standard, were provided. Starch chain degradation by an enzyme, amylase, is effective for reducing the increase in adhesive property. Bridge formation by supplying cations by non-fat milk powder promotes gelling. Gelling is achieved by combining several polysaccharides that do not gel when added singly, and combining polysaccharides also makes it possible to prevent dehydration. A combination using polysaccharide was effective for reducing water separation.
