Experimental Study On The Effect Of Vacuum Ultra-ice Temperature On Tomato And The Analysis Of The Law

As one of the main members of the big country of fruit and vegetable production,our country attaches great importance to the methods and application of fruit and vegetable storage.Up to now,in order to solve the problem of how to store fruits and vegetables in limited time and reduce internal consumption,a series of warehouses have been set up in China.In recent years the low-carbon environmental protection policies are being carried out at home and abroad,and the researchers have gradually turned from the cold storage technology to the research and development of other low-energy preservation technology.In this paper,8 kinds of local varieties of tomatoes in Harbin were used as experimental materials,and the suitability,the best storage temperature and the vacuum degree of different varieties of tomatoes under ice temperature were determined through the measurement experiments.The ice temperature values of 8 local varieties of tomatoes in Harbin were measured at 0.1 MPa atmospheric pressure and 0.08 MPa,0.06 MPa and 0.04 MPa under three different vacuum conditions,the ice temperature values of different varieties of tomatoes are not completely the same,and the same varieties of tomatoes under different pressures are not completely the same.The effects of multiple factors on vacuum super-ice temperature of 8 different varieties of tomato were studied,the effects of freezing point regulator type（A）,freezing point regulator concentration（B）,soaking time（C）and vacuum degree（D）on sugar content,water loss rate and over ice temperature were analyzed.The total number of groups is 44 × 8=2048,which can not be carried out in the limited time.After selecting the L16（45）form in the orthogonal experiment,the number of experimental groups was reduced to 16 × 8=128,which could be completed in limited time.Through the analysis of range and variance of orthogonal experiment,the optimum scheme of each tomato was obtained.The cooling process of tomato was simplified,and the model of numerical simulation of tomato was assumed After the foundation is established,the heat transfer mathematical and physical model of two-dimensional finite element for tomato is established,then the grid is divided,and the temperature cloud maps at different time points in the cooling process of experiment are measured.Finally,according to the simulation results of tomato temperature and the actual measurement results of the change trend,comparative analysis of the causes of error.The effects of sugar content and water loss rate on the temperature of vacuum over-ice of tomato were studied.The experimental data were substituted into the formula to verify the accuracy of the formula,and two different kinds of tomatoes were used to verify the accuracy of the optimal conditions.Convenient market according to sugar content,water loss rate more convenient calculation of tomato storage temperature,reduce the rate of fruit and vegetable rot.