Sensitivity analysis of membership functions for fuzzy sorting of tomato as affected by storage temperature and duration

In the present study, classification of tomatoes by fuzzy logic and change in classification due to storage conditions were studied. In order to conduct the study, qualitative properties such as color, size and hardness of tomatoes were measured. Tomato samples were sorted by a deigned fuzzy logic system based on fuzzy rules, and compared with the experts. Sensitivity analysis of outputs of membership functions were tested by chi-square statistic. In cool room storage, sensitivity of membership functions started from six-day after storage with change from grade 1 to grade 2. For samples that kept at ambient temperature sensitivity started on third day after storage with the same change in sorted groups as previous tests. The results emphasized that any processing operation or marketing after initial sorting of tomatoes should spend time in a way that does not change the results of the initial classification.