Respiration Model And Quality Of Carambola Under Modified Atmosphere Packaging During Storage

Due to the inefficient preservation method, the spoilage of fruits and vegetables in Chinahas caused great economic losses thought the the production of fruits and vegetables hasraised. So postharvest technology is very important and modifiled atmosphere packagingtechnology （MAP） is one of the efficient methods to extend shelf life of fruits andvegetables. This paper took carambola as case study, the main contents and results of theresearch were below.1Respiration rate of carambola was measured by the closed system method at differenttemperatures under different gas compositions in this work. Results indicated thattemperature has greatest impact on Carambola initial respiration rate. Reducing the O₂orincreasing CO₂concentration can decrease the initial respiration rates, and thisphenomenon was more significantly at the higher temperatures. Michaelis-Menten andArrhenius-type relationship were adopted to create initial respiration rate prediction modelfor carambola, which took temperature, O₂initial concentration and CO₂initialconcentration into account. And verification result showed that the predictionperformance of this model was good. Besides, the sensitivities of initial respiration rate ofcarambola for these3factors in a sescending order follow as: temperature>CO₂concentration>O₂concentration. Another model was created to predict the respirationrate of carambola during storage at this initial atmosphere condition （5%O₂+5%CO₂）, andthis model performed well. Moreover, the influence of storage environment has beentested, the results showed that Carambola can reached anaerobic respiration state via theincrease of temperature or CO₂concentration.2The impact of5different treatments at12℃on Carambola’s color, texture and mainnutrition content had been studied. Results indicated that MAP treatment has good resultson maintain Carambola’s color, texture and main nutrition content. Treatment5%O₂+5%CO₂performed best, and its shelf life of control was35～40d （non-MAPwas20～25d）.3The influences of5different treatments at12℃on Carambola’s Vc, total phenol,flavonoid contents and peroxidase activity had been studied. Results indicated that MAPcan effectively delay the peak time of Vc, total phenol, flavonoid contents and peroxidaseactivity. Also MAP can maintain the Vc, total phenol and flavonoid contents effectively.Besides MAP can inhibit peroxidase activity 4The preservative effects of3treatments including non-modified atmospherepackagings （non-MAP） at12and25℃and MAP at12℃were explored. During storage,the activity of acid invertase and neutral invertase was higher than sucrose synthase andsucrose phosphate synthase activity. And invertases （especially acid invertase） were thekey enzymes of glycometabolism of Carambola postharvest stage. Both low temperatureand MAP can delay the peak time of invertase activity and inhibit the invertase activity atthe same time. These can delay the speed of sugar degradation effectively.