| Bluberry,Ericaeeae,Vaccimum spp,are popular because of their sweet taste,rich nutrients and strong health care functions.Due to the thin cortex and soft and juicy flesh,the postharvest breathing metabolisru is strong.Blueberries are placed at room temperature(25?±5?)for 2 to 4 days,and low temperature(2?±2?)for 7 to 10 days.,seriously restricting the development of the blueberry industry.Electron beam irradiation is a physical processing method that prolongs the shelf life of fruits by killing harmful microbes on the surface and inside of foods,inhibiting physiological changes.In this paper,we designed different nradiation dose gradients of 0.0kGy(not irradiated as control).1.0kGy,1.5kGy.2.0kGy,2.5kGy,3.0kGy to analyze the killing of bacteria,mold and yeast in blueberry fruit during cold storage.The effect of extinction and the effect of different doses of electron beam irradiation on the quality,physiological and functional characteristics of frozen blueberry fruit storage.1.Electron beam irradiation treatment in the dose range of 1.0 to 2.5 kGy significantly reduced the number of bacteria,mold and yeast microorganisms,and was significantly positively correlated with the irradiation dose.The D10 values of bacteria,mold and yeast in blueberries were 1.54 kGy.1.69 kGy and 2.40 kGy,respectively.After refrigerating for 105 d,the nunber of microbes in the 1.5-3.0kGy irradiated blueberry group was significantly lower than that in the control group,but there was no significant difference between the four irradiated groups.2.Irradiation treatment significantly reduced the rate of rot of blueberries throughout the cold storage period(105 d).At the end of storage,the weight loss rate of the 1.5-3.0kGy irradiation group reached 30%,but the rot rate was less than 8%.Although it lost the value of fresh food.it still has processing value.The fresh-keeping period of 1.5-3.0kGy irradiation group can reach 60d,the decay rate is less than 5%,and the weight loss rate is about 15%.At the same time,each irradiation treatment group effectively delayed the decrease of the brightness(L value)of the blueberry peel and inhibited the color change of the peel(a value and b value)compared with the control group.3.Irradiation treatment had no significant effect on the hardness of blueberries during the pre-storage period.After storage for 30-60 days,the fruit hardness of the 2.0kGy irradiation group was significantly higher than that of the control group.In the late storage period,the 1.5-3.0 kGy irradiation group inhibited the degradation of TSS and soluble sugar,but had no significant effect on the pH value of the fruit.4.Within 45 days of storage,the content of anthocyanin and total phenol in the irradiated treatment group was significantly higher than that int the control group,especially in the 1.5kGy irradiation group,and the highest in the 3.0kGy irradiation group.The DPPH free clearance rate of each irradiation treatment group was significantly higher than that of the control group,and the 2.0kGy group had the best effect.The irradiation treatment of 5.2.0?3.0kGy significantly increased the PPO activity of the fruit,but the dose of 1.0?1.5kGy had no significant effect on the PPO activity.In the later stage of storage,the POD activity of the 1.5?2.0kGy irradiation group was significantly higher than that of the control giroup and other irradiation treatment groups;the PG activity of the 1.5?2.5kGy irradiation group was significantly lower than that of the control group;the pre-storage period,1.5?The Cx enzyme activity of the 2.5Gy irradiation group was significantly lower than that of the control group,and the softening was delayed.In summary,the 1.5kGy?2.0kGy dose electron beam irradiation treatment can significantly reduce the number of bacteria,mold and yeast in the blueberry fruit during the cold storage process.The quality and physiological characteristics of blueberry are kept optimal.which can prolong the preservation of blueberries.The period is 45d and the cold storage period is 90?105d. |
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