| Pitaya is a new type fruit developed in recent years.It is abudant in vitamin,water-solubility dietary fiber,vegetable protein and beta lain.Pitaya has been drawn much attention worldwide not only for its unique and exotic appearance and striking co lor,but also for their high nutritional value and health properties.Pitaya’s squame easily turns yellow and wilting while its fruit pulp is prone to softing at room temperature resulting in loss of commodity value.Pitaya fruits are sensitive to low temperature and develop chilling injury symptoms during refrigerated storage.Therefore,it is necessary to explore appropriate storing temperature for pitaya.In this study,Dayeshuijing pitaya was used as materials to study its quality changes in term of rot rate,hardness,TSS,values of L,a and b,T-AOC,SOD,POD,PPO,betalain,total phenols and flavone,starch,main components of organic acid and sugar during storage process in in 0 ℃,3 ℃,7 ℃,15 ℃ and 20 ℃.The main results were as follows: 1.Temperature below 7 ℃could significantly reduce the decay rate,reduce the resoling of its main component of organic acid and sugar,vitamin C,starch and other nutrition.But temperature below 3 ℃ caused chilling injury which broke the structure of the cell,make the solidity reduce quickly and the surface pit,and arise rotten spot symptom,making the pitaya fruit lose commercial value and storing in low temperature in a long time resulted in decreasing of solidity.2.During the storage process,the rot rate of pitaya increased with the increase of storage temperature and storage days.The trend of solidity reduced as the days of storing increases.In color difference quota,although the general changing trend of Light is not fluctuating,Light constantly decreases when stored in the temperature beyond 15 ℃;a value firstly increase and then decrease as the days of storing increases;b value to rise.The content of TSS trends to reduce.The content of betaine generally to go up when stored below 7 ℃ while it tends to reduce when stored beyond 15 ℃.3.Changes of phenolics,antioxidant enzymes,polyphenol oxidase and T-AOC during storage: The activity of T-AOC at first was drop and then the rise,the final decline trend.The activity of PPO trends to increase firstly and then decrease as the content of POD constantly ascends.The activity of SOD when stored below 7 ℃ trends to decrease firstly and then raise up while it constantly reduces when stored beyond 15 ℃.The activity of C AT shows to trend to continuously reduce while it tends to firstly decrease and then increase when stored beyond 15 ℃.The total phenols trends to reduce while total flavone change little.4.Although the main content of organic acid and reducing sugar trends to reduce,citric acid trends to rise firstly and then decrease,the content of starch trends to reduce. |
