Effect Of Different Logistics Temperature On The Quality Of Ponkan Fruits

Citrus ranks second of fruit production in china. Temperature is one of the most important environmental factors affecting fruit decay and quality during postharvest storage. Massive loss is caused by the inappropriate logistics temperature, thus, limiting the development of citrus industry in a certain extent. Appropriate logistics technologies were applied in Ponkan fruit to reduce the loss and maintain the fruit quality, to improve the economic benefits and provide support for the sustained and healthy development of the citrus industry. In the present research, Ponkan (Citrus reticulata Blanco cv. Ponkan) fruit was used as material to investigate the effects of three different logistics temperature (5℃,10℃and15℃) on decay and quality of Ponkan fruit during postharvest storage. The main results are as follows:1. Low temperature (5℃and10℃) can reduce the rot rate and weight loss during logistics and storage of Ponkan fruit, especially for those treated with chemicals. As for the fruit treated with chemicals, the decay rate was higher in fruit stored at15℃than fruit stored at5℃and10℃after10days. However, the shelf life of fruit decreased when the storage temperature decreased. After transferring to the shelf, the decay rate was higher in fruit store at5℃, with3%,8%and5%decay rate after3,5and10days storage, respectively, than those stored at10℃and15℃.2. The effects of three different logistics temperature (5℃,10℃and15℃) on fruit color and taste were investigated. The results showed that CCI value increased more rapidly in fruit stored at higher temperature during the early storage, but there was no significant difference between different temperature treatments when CCI value of fruit reached to6. No significant difference was found in TSS and TA between different temperature treatments, indicating different temperature has little effect on fruit taste in the process of logistics and storage.3. The effects of three different logistics temperature (5℃,10℃and15℃) on total phenolics, total flavonoids and antioxidant activity of fruit were investigated. In the fruit stored for two months, the contents of total phenolics were2.07-2.37mg GAE.g-1FW, the total flavonoids contents were0.21-0.29mg catechin-g-1FW, the antioxidant activity was0.51-0.63mg TEAC-g-1FW and0.89-1.07TEAC-g-1FW measured by DPPH and FRAP, respectively. However, there was no significant difference between different temperature treatments.4. The effects of three different logistics temperature (5℃,10℃and15℃) on bacterial activity on fruit surface, relative electrical conductivity and enzyme activity of fruit were investigated. The CFU value decreased while the logistics temperature decreased. The relative electrical conductivity was increasing in fruit after3-4months storage. The variations of POD and SOD activity were irregular. No significant difference of ethanol and acetaldehyde content was found in fruit stored at different temperatures.In summary, low temperature (5℃and10℃) reduce the rot rate and weight loss of Ponkan fruit during logistics and storage, but had little effects on the fruit taste and nutrition, suggesting that low temperature was more appropriate for logistics and storage of Ponkan fruit.