Optimal Control of Fruit Responses During Storage As Affected by Temperature

摘要

Lower temperature is usually effective to reduce the quality loss of fruits during storage. It is, however, difficult to accomplish the qualitative improvement of the fruit by only the low temperature. In this study, a more effective control technique for temperature that minimizes the water loss and respiration of the fruit was explored using intelligent approaches. The control input is the storage temperature, and the control outputs are two fruit responses (the water loss and respiration rates). A decision system consisting of neural networks and genetic algorithms allowed an optimal value (8-step set points of temperatures) to be successfully determined. Under the range of 15 to 40℃, an optimal value was the combination of the highest temperature and the lowest, like a (40, 40, 15, 15, 15, 15, 15 and 15℃). Especially, a temperature operation that first raises to the high level and then drops to the lowest level in the given range significantly reduced the water loss and respiration of the fruit, and their values became lower than those in the case of maintaining at the lowest and constant level. Under the range of 5 to 40℃, however, it was the combination of only the lowest temperatures. This operation is the same as a conventional cold-storage manner. These results suggest that a flexible control of the environment based on the fruit responses is better than a conventional constant-value control law in order to maintain the fruit quality.