Study On The Experiment And Heat And Mass Transfer In Controlled Atmosphere Storage Of Red Raspberry

Raspberries are known as "golden fruit pulp" and "king of fruits",including vitamins,pectin and a large amount of amino acids.Due to raspberry skin is thin,content abundant water,susceptible to mechanical damage,difficulties in storage and transportation,goods lose their original value.So the raspberries fresh-keeping technology study has real economic significance.Through the investigation of a large number of previous literatures,the best storage conditions were determined from experiment,in order to achieve the best storage effect.Firstly,on the basis of summarizing the development status of domestic and foreign CA storage,this paper expounds various storage methods and research status.Mainly introduces the principle of CA technology and composition;the parameters affecting the storage effect including:temperature,relative humidity,ratio of gas volume.Through experiment study the effects of various parameters on the raspberry fresh,determined the best storage conditions.Through theoretical analysis,the paper expounds the causes of water loss and temperature change of red raspberry in the preservation process.The mathematical and physical models of surface and internal temperature,water evaporation in precooling process are establishe,explain the rule of change in the process.Introduced the finite element analysis in briefly,through numerical analysis and finite element analysis,simulation of temperature change during precooling.Compare the two methods to determine the correctness of the simulation.Compared with the experimental results,the precooling scheme was determined.Determination of experimental methods,compare the storage effect of red raspberry and other ways to store red raspberries.The optimal storage method and storage conditions were obtained by analyzing the data.By setting several groups of different temperature and gas volume ratio to experimental comparison,through the analysis of raspberries weightlessness rate,decay rate,titratable acid content and other factors,determine the best storage environment as:temperature is 1±0.5?,ratio of gas volume is 5%O2+20%CO2+75%N2,relative humidity above 90%.