Consumers‘ quality perception and preference of tomatoes were measured during the whole process of eating. Words expressing the features of palatable and unpalatable tomatoes were collected and 91 pairs of words were selected to formulate the evaluation sheet for sensory evaluation. Fifteen kinds of tomatoes were chosen for test samples, at Tokyo Ohta Fruit and Vegetable Market, from those produced in various areas under the name of Momotarow, the most popular original kind in Japan. Panel was consisted of 307 university students. Each panelist was given a whole fresh tomato and evaluated the 91 items according to the process of eating, i.e., looking, holding, peeling, biting, tasting, and swallowing, using seven-point scales. Principal component analysis was applied both for mean average scores of 15 samples and individual scores of total 307 samples. Results in both cases showed that the total variance was mainly explained by two components. PC1 was related to taste (sweet, sour and umami), texture and flavor in the mouth. PC2 was related to ripeness. Multiple regression analysis showed that the total evaluation of tomatoes was mostly explained by the properties perceived in the mouth and only a small amount by those perceived through visual and tactile senses.
The subjective umami intensity of Umamate-100, which is “compound natural seasoning”, was compared with that of monosodium glutamate. The subjective umami intensity of Umamate-100 solution containing soy sauce was also compared with that of monosodium glutamate. The effect of Umamate-100 on saltiness of 0.6w/v% NaCl solution was examined. The results were as follows; (1) The threshold values of Umamate-100 and monosodium glutamate were 0.0518 w/v% and 0.0325w/v%, respectively. (2) The subjective umami intensity of 0.0578w/v% of Umamate-100 solution containing 0.5w/v% NaCl was equivalent to that of 0.0452w/v% of monosodium glutamate containing 0.5w/v% NaCl. (3) The subjective umami intensity of 0.0482w/v% of Umamte-100 solution containing 0.5w/v% NaCl and 1.0w/v% soy sauce was equivalent to that of 0.0452w/v% of monosodium glutamate containing 0.5w/v% NaCl and 1.0w/v% soy sauce. (4) Saltiness of 0.6w/v% NaCl solution was weaker than that of 0.6w/v% NaCl solution containing 0.0622w/v% Umamate-100. This result suggested that Umamate-100 is effective in reducing the amount of salt in cooking.