Studies On Sensitivity To High CO₂Injury And Storage Safety Of ’fuji’ Apple

’Fuji’apples were taken as experiment material to study the variation of sensitivity to high CO2injury under different storage temperatures(O℃,4.4℃,10℃and20℃), CO2concentrations(2%,5%,10%,20%and50%), processing time(24h,55h,10d and14d), and physiological states(postharvest or cold storage for60days), the quality and safety changes of storage period was identified, the bioaccessibility of polyphenols during shelf-life in response to treatment with high CO2was assessed, the relationship between soluble protein and CO2stress was also discussed. Provided a theoretical basis for preservation, avoiding CO2injury in atmosphere controlled storage of’Fuji’apples and high CO2treatment of mildewproof during shelf-life.The sensitivity and safy to high CO2injury influenced by storage temperatures, duration and physiological states. The performances under50%CO2for55hours, then stored in0℃and20℃, through the regular observation, injury symptoms on skin and flesh investigated were all for CO2injury. Symptoms of CO2injury at0℃was detected later than20℃, but the injured degree was not reduced. The apples refrigerated at0℃for2months, treated with50%CO2for55hours, then kept at4.4℃and20℃for49days, no significant CO2injury was detected.’Fuji’apples without refrigerate were more sensitive and less safety to high CO2concentration. Treated with10%CO2for14days, fruit were sensitive to10%CO2at4.4℃,10%CO2can inhibit the ripening of apples at20℃. The shelf life test demonstrated that delayed treatment reduced the sensitivity to CO2.Short time high CO2treatment significantly inhibited the physiological senescence of fruit, delayed the emergence of the peak of ethylene.’Fuji’apples kept in10%CO2for10days, then stored at10℃for150days, no CO2injury was detected. Product of peroxidated membrance lipoid (MDA) accumulated little, the occurrence of ethylene peak was postponed for30days compared with the control, total phenolic contents were maintained at high levels, kept the well quality.High CO2treatment markly maintained the bioavailability of fruit. The apples refrigerated at0℃for2months, then kept at4.4℃and20℃with10%CO2for14days, no CO2injury was detected. The bioaccessibility of polyphenols was assessed using an in vitro digestion system that simulated the physiochemical changes occuring in the upper gastrointestinal tract, the bioaccessibility was20%-25%. Treated with50%CO2, data shows that22%-29%of the antioxidant in polyphenol was extractable by digestive fluid, and the bioaccessibility was best maintained. Though the flavor become bad, effective nutrient loss was not significant.High CO2damage mechanism found that the soluble proteins changed when’Fuji’ apples subjected to CO2stress injury. SDS-PAGE analysis of soluble proteins in browning flesh of damaged apples indicated that8protein bands(60.9、47.3、40.7、34.3、28.7、22.2、19.6and18.6kD)were related to high CO2stress. It is speculated that changes of protein influenced by different CO2concentrations, stress durations, temperatures, and different physiological states, further tests and studies should be made.