Modeling the change in color of mature green tomato during ripening at different storage temperatures based on cumulative ethylene production
Harvesting tomato at the mature green stage is recommended to extend the shelf life. However, a non-uniform color appearance of individual tomatoes at the end of the storage period will occur due to early harvesting. This study aims to analyze the relationship between two important parameters for the determination of the tomato ripening process, ethylene production, and change in color. Batches of 5 tomatoes each were stored at 5, 15, and 25°C for more than 30 days. Color (a* value) and ethylene production were assessed daily. A nonlinear least square method was used to develop a mathematical model estimating the a* value based on Sigmoid function, with cumulative ethylene production as the free variable. The goodness of fit of the proposed mathematical models was evaluated by the coefficient of determination (R2) and root mean square error (RMSE) between the estimated and experimental data. The result showed that 5°C inhibited the ripening process of tomato with the absent of ethylene burst and no red color development until the end of the storage period. On the other hand, tomato stored at 15 and 25°C were undergoing the normal ripening process. Previous research showed that the relationship between a* value and cumulative ethylene production was following the sigmoid function for tomato stored at 25°C. This study found that it is also applicable to other storage temperature as long as the tomato undergoes the normal ripening process. The value of R2 and RMSE for tomato stored at 15 and 25°C were 0.982, 0.989 and 1.889, 1.485, respectively. These values exhibit the proposed model appears to be suitable for describing the change in color of tomato at different storage temperatures based on the cumulative ethylene production.
Ciptaningtyas, D., Kagoshima, W., Iida, R., Umehara, H., Johkan, M., Nakamura, N., Orikasa, T., Thammawong, M. and Shiina, T. (2021). Modeling the change in color of mature green tomato during ripening at different storage temperatures based on cumulative ethylene production. Acta Hortic. 1311, 83-90
tomato, mature green stage, ripening, ethylene, color, modeling, sigmoid function