Effects of Hardness, Taste and Amount of Low-Gel-Strength Agar on Swallowing in Young and Elderly Subjects

Abstract

Low-gel-strength agar (LGSA), which has recently been developed as a material close to gelatin in its physical properties, was used in this study to prepare samples for evaluating the factors facilitating swallowing. The subjects were assigned to two groups of 20 healthy young persons (22.1±1.7 years) and 12 healthy elderly persons (72.2±3.3 years). The physical properties of each sample were measured with a creep meter. The hardness of the tasty samples [sweet (saccharose), salty (NaCl), and sour (citric acid)] was a little higher than the samples without taste. The sensory evaluation at swallowing was assessed in respect of the LGSA concentration (hardness), taste and amount of the sample. The healthy young subjects reported that a 1.1% LGSA concentration, sweet taste, and 5.0 g amount, produced a sample that was pleasant in the oral cavity, facilitating swallowing. The healthy elderly subjects evaluated only a sweet taste, as facilitating swallowing. The results of the sensory evaluation and physical properties suggest that relative hardness (a 1.1% concentration of LGSA), sweet taste, and 5 g amount resulted in samples that were pleasant in the oral cavity, thus facilitating swallowing.