Regulation Of AsA-GSH Cycle On The Respiration Off-flavor Of Broccoli Under High O₂/CO₂ Controlled Atmospheres

Off-flavor is a serious problem of fruits and vegetables under controlled atmospheres,which mainly occurs in respiratory metabolism pathway and closely relates to the sensitive high CO₂ characteristics of fruits and vegetables.Studies have shown that AsA-GSH cycle can provide NAD+,alleviate oxidative stress,maintain the membrane stability and cell microstructure,it is necessary to study whether the cycle can inhibit anaerobic respiration and reduce the off-flavor by the way of providing energy.This project using broccoli as experimental material,using high O₂/CO₂ controlled atmospheres as treatment means,arounding the ascorbate-glutathione cycle?AsA-GSH?,with the energy metabolism as a link,and with the off-flavor metabolism of respiratory metabolism as the center,combining with the analysis of nutrients?respiratory metabolism?resistant high CO₂ respiratory metabolism pattern and respiratory metabolism of off-flavor metabolism inquiry system of broccoli,provide the theories and methods of regulating off-flavor metabolism of respiratory during storage of fruits and vegetables.The results are as follows:In the experiment of controlled atmosphere,we design three treatments,i.e.40% O₂ + 40% CO₂ + 20% N₂,50% O₂ + 40% CO₂ + 10% N₂,60% O₂ + 40% CO₂?natural atmosphere for the control?,storage temperature is 15?,the relative humidity was controlled at 80%-90%.Respiratory rate,the activity of respiratory enzyme and storage quality were determined regularly during storage of broccoli.The results showed that the chlorophyll and vitamin C content of 40% O₂ + 40% CO₂ + 20% N₂ is the highest and decreased slowly during storage,respiration rate and etiolating rate is the lowest,and this teratment is conducive to maintaining the storage quality of broccoli;the alcohol dehydrogenase?pyruvate decarboxylase and alcohol acyltransferase activity of 60% O₂ + 40% CO₂ is the lowest,and the content of acetaldehyde,ethanol and ethyl acetate are decreased,this treatment can effectively avoid the accumulation of off-flavor,and alleviate the phenomenon caused by high CO₂ during storage.In the experiment of spraying AsA and GSH,we spray AsA of 0.05%,0.1%,0.2% and 0.4%,spray GSH of 0.4%,0.8%,0.2% and 1.6%,to study the preservation effect of ASA and GSH on broccoli to select the appropriate GSH content,The results showed that AsA had little effect on broccoli during storage,so this topic has not carried on the further research to AsA.0.8% GSH is conducive to the storage quality of broccoli,the weight and chlorophyll lose rate and etiolating rate of this treatment are the lowest,and it is conducive to keep green.0.4% GSH can reduce the respiratory off-flavor accumulation of broccoli mainly in the lowest PDC?ADH?AAT activities and the highest CCO?SDH activities,which can reduce the occurrence of anaerobic respiration.In the combination of exogenous GSH and controlled atmosphere,we design three treatments,i.e.40% O₂ + 40% CO₂ + 20% N₂,50% O₂ + 40% CO₂ + 10% N₂,60% O₂ + 40% CO₂?natural atmosphere for the control?,all the treatments are spraied 0.4% GSH,storage temperature is 15?,and the relative humidity was controlled at 80%-90%,measuring quality,respiration off-flavor,respiratory pathway enzymes activities and the level of energy metabolism of broccoli to study the reduction mechanism of AsA-GSH cycle controlled atmospheres on off-flavor of fruits and vegetables.The results showed that the GSH treatment showed good results in the preservation of broccoli and the relief of off-flavor.AsA-GSH cycle could reduce the probability of anaerobic respiration,and then reduce the accumulation of respiratory metabolism.