| Strawberry fruits are very popular with customers for their abundant vitamin C content and unique flavor. But their commercial and social benefits are restricted due to the short growth phase and limited storage period. So how to improve the storage quality of strawberry fruits and extend their supply time is the very matter to be solved right now. As one of the new efficient irradiation technology, high energy electron beam irradiation is showing significant advantages in food irradiation processing and will be solve the preservation problem of strawberry. This study assessed the sterilization effect and preservation result of electron beam irradiation on'fengxiang'strawberry which had been irradiated at doses of 0.5 kGy,2.0 kGy,3.5 kGy and 5.0 kGy respectively. The mechanism of electrom beam irradiation preservation was presumed based on the nutritional and physiological quality attributes of the fruits. Besides, the parameter of irradiation processing was established, which would theoretically support the utilization of electron beam irradiation on agricultural products preservation.1. Effective sterilization doses of electron beam irradiation The D10 values of bacteria, molds and yeasts on strawberry were 2.27 kGy,2.88 kGy and 4.06 kGy respectively. Therefore, only up to 4.0 kGy doses of electron beam irradiation could meet the sterilization of microbs on strawberry.2. Effective range of electron beam irradiation doses on strawberry preservation Combined the effect of rot inhibition and nutrition keeping of electron beam irradiation, the effective processing dose scale was 2.03.5 kGy, and the highest doses should not overrun 5.0 kGy. When irradiated strawberry fruits were stored at 1820℃with relative humidity of 80%85%, 3.5 kGy dose of irradiation got the best results, which could prolong preservation time to 8 days with rot index be 23.17%, weight loss 4.24%, firmness 0.24 kg·cm-2, soluble sugar 10.74%, titratable acid 0.73%, vitamin C 41.06 mg/100gFW and no significant influence on pericarp color. While stored at low temperature (0.5±0.5℃,RH 85%95%), 2.0 kGy dose of irradiation got the best effect, which could prolong preservation time to 19 days with rot index be 18.31%, weight loss 2.83%, firmness 0.29 kg·cm-2, soluble sugar 12.06%, titratable acid 0.70%, vitamin C 35.84 mg/100gFW and no significant changes on pericarp color.3. Effect of electron beam irradiation on physiological metabolism of strawberry Electron beam irradiation could inhibite respiratory intensity, slow down metabolism activity and therefore maintain most of the nutrients. The feasible irradiation treatment reduced MDA content, delayed relative conductance, kept high SOD activity, low O2- produce rate and low Cx activity, therefore restrained membrane lipid peroxidation, maintained integrality of the membrane structure, delayed softening and finaly kept better quality traits.4. Establishment of electron beam irradiation compound system on strawberry preservation The compound preservation system was consist of 2.0 kGy electron beam irradiation, different concentration of ozone treatment and low temperature storage. The compound system with 90.58 mg·m-3 and 45.29 mg·m-3 ozone treatment showed the best fresh keeping effect, which prolonged preservation period to 30 days and had no rot happened, with the fruits firmness be 0.47 kg·cm-2 and 0.44 kg·cm-2, weight loss lower than 3%, soluble solid content up to 12.36% and 11.9%, titratable acid loss be 36.82% and 53.80%,vitamin C loss 40.21% and 23.53%.
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