Effects And Mechanism Of Hypobaric Treatment On Freshing-Keep Of Blueberry And Broccoli

Hypobaric treatment can effectively restrain the physiological activity of fruits and vegetable and reduce the loss of nutrients and eliminate harmful gases. It is an innovative technology in fruits and vegetables freshness field. Compared with the existing technology, it has obvious advantage. In this paper, blueberry and broccoli were chosen as experimental materials from the fields of fruits and vegetables. The study on the effect of hypobaric storage of them can provide theoretical basis for its application in the market of fruits and vegetable.Northeast brilliant blueberry as experimental materials, atmospheric pressure cold (4±0.5℃) as control group (CK). And there are three experimental groups: the first group, hypobaric treatment (1500Pa±50Pa, 4±0.5℃); the second group, hypobaric preprocessing (1500Pa±50Pa,4±0.5℃) for 12h, then placed brilliant in the refrigerator (4℃); the third group, placed brilliant in the refrigerator (4℃) and used luL/L 1-MCP treatment. To investigate the sensory and physiological metabolism of blueberry during storage and compare the quality and freshness of blueberry fruits in different ways.The results of the study are as followed:①Compared with the control group,3 kinds of treatments can reduce the decay rate and the weight loss rate of blueberry by different degree. The decay rate and the weight loss rate is the lowest in the second group. And the fruit was kept well.②Compared with the control group,3 kinds of different processing ways can significantly inhibit the respiration rate of blueberry in the prophase of storage (P< 0.05). The inhibition of 1-MCP treatment was weakened in the late period of storage. In the whole storage period, the inhibitory effect was the best in the pre-treatment for 12h, which can maintain a high level of soluble of solids (TSS) content.③ The relative contents of total phenolics and flavonoids in the CK group were significantly lower than others in the later period of storage, which were not significantly different in the other 3 treatments and maintained at a higher levels; The anthocyanin contents of all groups is gradually increased in the early storage. The second group was most significant (P＜0.01). After 14 days storage, the anthocyanin content began to decline. During the whole storage period, the anthocyanin content of the second group was significantly higher than that in other groups (P< 0.01).④ Compared with fresh fruit, control group and other 3 test groups can increase the protective enzyme activity of fruit, superoxide dismutase (SOD) and catalase (CAT), which can delayed ripening and senescence of fruit as the storage time increased. During the whole storage, the protective enzyme activity of the second group was significantly higher than that of the other groups (P<0.05).The fresh-cut broccoli as experimental material, with normal refrigerated (0±1℃) as control group (CK), there are 3 kind of test groups, hypobaric treatment pre-processing (1000±50Pa, O±1℃) for 4h,12h,24h. Then place them into the refrigerator. Investigate the sensory and physiological index of broccoli in the whole storage. And compare fresh cut broccoli storage quality changes and preservation effect after different treatment.The results of the study are as followed:①CK group appeared soft water loss, part of curd yellow loose and fragrance tasteless on the 4th day of storage. Hypobaric 4H group remains green, curd organization is compact, accompanied by a strong flavor, and the incision mild dehydration until storage the 16 day; Hypobaric 12h and 24h group curd yellow flowering, edge incision browning a small amount of mildew and mild odor phenomenon in storage at 12th day; Each treatment group appeared slight dehydration phenomenon in the prophase of storage. The weight loss rate of CK group always the lowest in storage within 12 days, and hypobaric 4h group of weight loss rate was significantly higher than that of the other groups (P<0.05), hypobaric 24h water loss serious in late period of storage. ②Titration acid (TA) content of all groups showed a downward trend in the early stage. The TA content of the three groups rose rapidly in the 12 days storage, followed by a rapid decrease. At the end of storage, each had no significant difference. Compared with CK group, 4h group and 12h group can effectively retard the degradation of chlorophyll, maintain the broccoli green better. Compared with the CK group, 4h group can delay the degradation of broccoli TSS content in the early stage. And the TSS content of 12h group increased later gradually, the 24h group had a greater volatility due to serious water loss. Compared with the control group, the hypobaric pretreatment method can delay the accumulation of malondialdehyde (MDA), and the 12h group is significantly lower than the other groups (P＜0.01).③Compared with the CK group,3 different treatments can significantly inhibit the respiration rate of the fresh-cut broccoli (P<0.05) and delay the arrival of respiration peak, can improve the activity of SOD and inhibit the activity of POD. The effect of 4h group and 12h group is good.Conclusion:① Compared with atmosphere cold storage, hypobaric preprocessing (1500Pa±50Pa，4±0.5℃) for 12h could effectively inhibit the respiration intensity of postharvest blueberry, maintain higher levels of TSS content, high anthocyanin content, enhance the activity of protective enzyme, delay the ripening and senescence process of blueberry. ② Compared with atmosphere cold storage, hypobaric treatment pre-processing (1000±50Pa, O±1℃) for 4h can effectively delay the degradation of chlorophyll, inhibited the respiratory intensity, delay the accumulation of malondialdehyde (MDA) content, reduced membrane damage, maintain a good sensory quality. But it will bring some loss of water.