Evaluation of Food Texture by Bioinstrumentation

Abstract

Aims:　Human ingestion of foods of different textures can be directly quantified using bioinstrumentation (e.g. tongue pressure sensor and throat microphone). This research aimed to investigate the relationship between textural properties and bioinstrumentation measurements for various foods used in nursing care.　Methods:　Tongue pressure during ingestion of 10 g of food specimens was measured by an ultra-thin sensor sheet with five measuring points attached to the hard palate. Swallowing sound was recorded using an IC recorder with a throat microphone. For in vivo measurements, 28 different food products used in nursing care that can be broken up (crushed) only by tongue pressure were used. Eight healthy dentate subjects were instructed to eat each sample freely while tongue pressure was measured and to then swallow the whole amount at once while swallowing sound was recorded. Tongue pressure signals were divided into squeezing and swallowing parts for analysis. Nine out of the 28 food products were evaluated using the visual analog scale (VAS). The correlation between the parameters obtained from in vivo measurements and the VAS value of sensory evaluations were then tested using cluster analysis and main component analysis.　Results and Discussion:　Three parameters (obtained from swallowing sound, tongue pressure during squeezing and tongue pressure during swallowing) correlated with the VAS value of sensory evaluation. When the first and second principal components calculated from three parameters in bioinstrumentation for the 28 food products were graphed, each plot could be roughly classified according to“The classification of modified diet for dysphagic persons in 2013 of the Japanese Society of Dysphagia Rehabilitation”. We suggest that these methods may facilitate the objective profiling of food textures on the basis of human’s squeezing and swallowing tongue pressurization.