Effects Of Controlled Atmosphere And Reactive Oxygen Species On Chlorophyll Degradation And Its Regulation

In order to study the effect of chlorophyll degradation and reactive oxygen species on the stability of broccoli in the atmosphere,three experiments were carried out in this paper.First,the ratio of 30%,40% and 50% of CO2 was set at 50% of the fixed O2,and the chlorophyll correlation index and reactive oxygen species metabolism of broccoli under 15? storage conditions.was carried out on a regular basis.Also,compare the natural atmosphere;second,set 5.33,10.71,21.43 and 42.85 n M O₂^-.for exogenous spraying?water spray as control?,the chlorophyll content,vitamin C content,superoxide anion content,hydrogen peroxide content,SOD and CAT activities were measured during the storage of broccoli at 15?;finally,conduct the air conditioning experiment after the optimum concentration of exogenous O₂^-.was sprayed,the gasification experiment was carried out to verify the intrinsic relationship between chlorophyll degradation and reactive oxygen species during storage of broccoli.The results are as follows:1,The storage of broccoli is strongly influenced by the CO2 content,and the high CO2 content is easy to produce anaerobic respiration to produce ethanol,acetaldehyde;the low CO2 content is easy to increase the chlorophyllase and pheophytin activity of broccoli,rapid degradation of chlorophyll,yellowing of broccoli and loss of ascorbic acid.Under the experimental conditions,50%O2+50%CO2 treatment could effectively retard chlorophyll degradation of broccoli and achieve good preservation effect.With the increase of CO2 content,the degradation rate of Vc and chlorophyll content of broccoli decreased obviously.Among them,the gas mass fraction of 50%O2+50%CO2 treatment can significantly reduce the damage to broccoli,the whole storage period can better keep the fresh broccoli Vc,chlorophyll content,reduce the rate of yellowing,slowing the fresh broccoli deterioration speed.The results showed that the treatment with 50%O2+50%CO2 was the best,then 50%O2+40%CO2 and 50%O2+30%CO2,and the natural condition of CK was the worst.2,Low content such as 5.33 nM O₂^-.or 10.71 nM O₂^-.treatment can inhibit the chlorophyll degradation rate,maintain the vitamin C content and decrease the accumulation of hydrogen peroxide?H₂O₂?in the body partly.High CAT and SOD activity retarded the accumulation of endogenous superoxide anions and prolonged the storage time of broccoli.High content of exogenous active oxygen treatment that is 21.43 nM O₂^-.and 42.85 nM O₂^-.treatment,so that the broccoli superoxide anion and hydrogen peroxide content increased significantly,promoted the broccoli chlorophyll degradation and Vc loss,but not conducive to broccoli storage and preservation.3,Exogenous O₂^-.combined with the air conditioning experiment,select the optimum concentration of exogenous O₂^-.spray and carry out air conditioning treatment.Relative to the air conditioning experiment,50%O2+50%CO2 treatment can reduce H₂O₂ and 50%O2+50%CO2 treatment,and the optimum concentration of exogenous O₂^-.superoxide anion accumulation in the body to maintain the activity of POD,CAT and SOD,slow down the accumulation rate of MDA and Vc loss,reduce the rate of yellowing,inhibit the activity of chlorophyllase and pheophytin in broccoli,and effectively promote the effect of broccoli green,reduce the damage to the broccoli,conducive to its storage.