Relationship between the Physical Properties of Rice Gruel Containing Heated Carrots, and Oral Sensation

Abstract

In the present study, we prepared rice gruel samples including model solid pieces of food with different physical properties, and studied the correlations between the physical properties and the oral sensation which is indicative of the ease of eating. For the model solid pieces of food, we used heated carrots (diced into 5 mm cubes), the physical properties of which had been varied by changing the conditions of heating. The heated carrots were mixed into the rice gruel samples (called “mixed rice gruel”) so that the carrots accounted for 20% of the weight of the rice gruel. In terms of the physical properties, we studied the rupture properties of a single grain of the basic rice gruel and the rupture properties of a single grain of the heated carrot, and also measured the texture properties of the mixed rice gruel. Sensory evaluation was employed for examining the oral sensation which is indicative of the ease of eating. All measurements were made using samples heated to 45℃ and 20℃. There was no correlation between the hardness of the texture properties of the mixed rice gruel and the firmness obtained from the sensory evaluation. The firmness showed high correlations in the rupture properties of a single grain of the rice gruel and a single grain of the heated carrot. At a sample temperature of 45℃, no significant differences were found between the basic rice gruel and the mixed rice gruel in the sensory evaluation of the ease of eating. On the other hand, at a sample temperature of 20℃, the mixed rice gruel was more firm than the basic rice gruel, and showed a residual feeling in the mouth after swallowing. Thus, the inclusion of heated carrots in the rice gruel appeared to have an effect on the ease of eating at a sample temperature of 20℃. The outcome of the present study indicated the necessity of studying the correlations between the physical properties of a single grain of the rice gruel and a single grain of the heated carrot as solid pieces of food, in addition to measuring the texture properties of the mixed rice gruel.