A heat stress application technique for retaining the freshness of fruit during storage.

本研究采用智能控制技术，开发了一种用于水果贮藏保鲜的热胁迫应用技术，并对其实际应用能力进行了检验。研究了温度在5 ~ 45℃范围内对贮藏过程中番茄失水、呼吸和硬度的动态影响。果实的水分损失量和呼吸量随温度升高而增加，但在35℃以上有所下降。当温度恢复到15℃时，40℃热胁迫处理后果实的失水和呼吸持续降低约1周。利用混沌的概念，提出了一种简单、无损的水果硬度测量方法。声学响应是通过用一个小蜂鸣器撞击水果来获得的。首先描述了声响应的吸引子；然后，计算其斜率。吸子的斜率与吸子的硬度有密切关系。这表明，使用吸引子可以在时域上定量评价果实的硬度。首先使用神经网络识别温度影响下水分流失率的动态变化，然后使用遗传算法研究最佳热应力应用，即l步温度设定点的组合，使水分流失率最小化。在6步控制过程中，在15【小于等于】T【小于等于】≦40℃范围内，最优温度操作为{40、15、15、15、15、15、15℃}时间序列。并将最佳温度操作应用于萨摩柑和伊横柑。因此，与番茄相比，观察到水分损失和呼吸的减少更为显著。上述结果表明，在贮藏过程中，最佳热胁迫处理能有效地保持果实的新鲜度，具有足够的实用性。少

In this study, a heat stress application technique for retaining the freshness of fruit during storage was developed using intelligent control techniques and then its capability for practical use was examined.Dynamic changes in the water loss, respiration and firmness of tomato during storage, as affected by temperature in the range of 5-45℃, were investigated. Although the water loss and respiration of the fruit increased with the temperature, they decreased over 35-℃. The water loss and respiration of the fruit after the heat stress application of 40℃ kept lowering for about 1 week when the temperature was returned to the first level (15℃).A simple and non-destructive measurement technique for fruit firmness was developed using the concept of chaos. The acoustic response was obtained by hitting the fruit with a small hummer. The attractor of the acoustic response was first described ; then, its slope was calculated. There was a close relationship between the slope of attractor and fr … More uit firmness. This showed that use of the attractor allowed quantitative evaluation of fruit firmness in the time-domain.The dynamic change in the rate of water loss as affected by temperature was first identified using neural networks, and then the optimal heat stress application, which is the combination of the l-step set points for temperature that minimized the rate of water loss, was investigated using genetic algorithms. Under the 6-step control process and the range of 15【less than or equal】T【less than or equal】≦40℃, the optimal temperature operation was the time series of {40,15,15,15,15 and 15℃}.The optimal temperature operation obtained here was applied to Satsuma mandarin and Iyokan fruit. As the result, more significant reductions of water loss and respiration were observed comparing to the case of tomato.These results suggest that the optimal heat stress application to the fruit is effective for retaining the freshness of the fruit during storage and there is sufficiently the practicability. Less