Abstract

To develop a optimized method for educing the errors associated with the estimation of portion size of foods, fuzzy-dta processing of portion size was performed. Cooked-rice was chosen as a food item. The experiment was conducted in two parts. First, to study the conceptions of respondents to bowl size(large, medium, small), 11 bowls of different size and shape were used and measured the actual weights of cooked-rice. Second, to study the conceptions of respondents to volume(1, 1/2, 1/3, 1/4), 16 different volumes of cooked-rice in bowls of same size and shape were used. Respondents for this study were 31 graduate students. After collecting the data of respondents to size and volume, fuzzy sets of size and volume were produced. The critical values were calculated by defuzzification(mean of maximum method, center of area method). The differences of the weights of cooked-rice in various bowl size and volume between the critical values and the calculated values by average portion size using in conventional methods were compared. The results hows large inter-subject variation in conception to bowl size, especially in large size. However, conception of respondents to volume is relatively accurate. Conception to bowl size seems to be influenced by bowl shape. Considering that the new fuzzy set was calculated by cartesian product(bowl size and volume), bowl shape should be considered in estimation of bowl size to make more accurate fuzzy set for cooked-rice portion size. The limitations of this study were discussed. If more accurate data for size and volume of many other food items are collected by the increased number of respondents, reducing the errors associated with the estimation of portion size of foods and rapid processing will be possible by constructing computer processing systems.

Keywords

• portion sizc cstimation;
• fuzzy-data processing