| This paper mainly studied the influence of different doses of gamma irradiation on physiological and biochemical characteristics changes of chestnut, Through which to find the best dose apply to the irradiation preservation both in normal and refrigeration condition,and provided the irradiation preservation with theoretical foundation;The main result were as follows:1. Experiments proved that 0.5 kGy was the best dose for chestnut irradiation preservation both in normal and refrigeration condition,after a period of 20 days in room temperature,the rate of chestnut in completely good condition was kept in 92.10%;Compared with control,the 0.5 kGy treatment group extended the shelf life of chestnut to another 10 days at room temperature. The rate of chestnut in completely good condition was 95% after a refrigeration period of 180 days.2. Low doses (0.3 kGy～0.6 kGy) and 0.8 kGy treatment had an obvious effect on maintaining the moisture of chestnut at room temperature.The highest moisture content was the 0.6 kGy treatment group. High-dose treatment (2.0 kGy) would destroy the chestnut organization and accelerate the dehydration, which was bad for storage at room temperature; As the result at room temperature, The highest moisture content was the 0.6 kGy treatment group in refrigeration condition.3. During the whole room temperature storage period, the reducing sugar content in chestnut organization presented a trend of first increased and then decreased,Which was similar to the changing trend of amylase activity; The influence to chestnut's reducing sugar content might primarily through passivating the amylase,thus reduced the reducing sugar content significantly compared to controls, as shown in the early days (10 days) and late period (30 days), however there was no significant differences between each two treatment groups from 0.3 kGy to 1.0 kGy.4. Results of experiments determining the starch content of chestnut shown that: treatment group 0.3 kGy and 0.4 kGy were both significantly higher than the control groups and the groups from 0.5 kGy to 1.0 kGy. However starch content of the groups from 0.5 kGy to 1.0 kGy was obviously reduced lower than anyother treatment groups;Overall ,irradiation had no significant effect on starch content of Chinese chestnut in refrigeration condition.5. Results of germination experiments shown that: the dose 0.2 kGy could dramatically reduce the germination rate, doses above 0.3 kGy could fully suppress the germination of chestnut. Chestnut buds need a period of latter stage of ripening more than 30 days; Cultivating experiments in dark proved that light is needed in germination of chestnut, thus dark processing could delays or even stop chestnut to bud.6. Experiments of separating microorganism from chestnut and then cultured them in new culture dishes shown that:doses which used in chestnut irradiation preservation 0.3 kGy～1.0 kGy was too low to exterminate the microorganism that separated from chestnut, nevertheless, doses 3kGy and 5kGy had a limited effect on inhibiting chestnut microorganism,a dose higher (25kGy) could kill all of the separated microorganism,but it was far exceed the dose that the chestnut would tolerate which could not been used in irradiation preservation.7. By analyzing the good rate of different maturity chestnut from Long'an which stored at room temperature and cold condition,result shown that:timely to harvest chestnut ahead of time can prolong the shelf life;Doses from 0.4 kGy to 1.0 kGy could damage the immature chestnut easily, which causing a low rate of good chestnut, low doses of radiation was needed in irradiation preservation, dose of 0.3 kGy was best for the immature chestnut. 8. Chestnut Preservation experiments at room temperature for two size level shown that:size of chestnut had no effect on shelf life length; A comparation of good rate on two varieties of chestnut revealed that chestnut from Donglan had better Storage characteristic. |
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