Study On Hydrostatic Damage Characterization Of Korla Fragrant Pear

Korla fragrant pear is one of the pillar fruit industries in Southern Xinjiang.It is famous at home and abroad for its sweet taste,thin skin and thin flesh.Korla fragrant pear needs to undergo tedious processing before being sold on the market,which causes mechanical damage of different degrees.There are many types of mechanical damage,mainly in the form of static pressure,impact,vibration and various composite loads.Among them,static pressure damage is the main component type of mechanical damage.At present,the damage detection technology of Korla fragrant pear before storage is not perfect,resulting in the mixing phenomenon of lossless and lossless Korla fragrant pear and shortening the shelf life of Korla fragrant pear.Therefore,it is urgent to identify damaged Korla sweet pear and clarify the impact of static pressure damage on the shelf life of Korla sweet pear,providing guidance for the reduction and increment of korla sweet pear industry and promoting the high-quality development of Korla sweet pear industry.Around the Korla fragrant pear is an urgent need to solve in the process of postharvest circulation grading time-consuming,grading not jing,damage identification and other important problems are studied,discussed the electrical properties change along with the change of korla fragrant pear fruit weight,using electronic characteristics build korla fragrant pear fruit weight quantitative model,through the laboratory to simulate the static damage,expounds that the law of damage to the electrical characteristics of fragrant pear,The static pressure damage identification model of Korla fragrant pear with electrical characteristics was established.At the same time,the influence of different picking time and static pressure conditions on electrical parameters of normal fragrant pears and the influence of storage time on electrical parameters of damaged fragrant pears were studied,so as to clarify the influence rule of different picking time,different static pressure conditions and storage time on the damage of fragrant pears,providing reference for the characterization of static pressure damage of Korla fragrant pears.The electrical characteristic technology was used to detect the electrical characteristics of Korla fragrant pear in the process of post-harvest circulation,and a model was established to detect the degree of static pressure damage of Korla fragrant pear using electrical characteristics,which was helpful to improve the characterization and detection of static pressure damage of Korla fragrant pear in the process of circulation.The research contents of this paper are as follows:(1)Carry out the static pressure damage storage test of Korla fragrant pear.The storage time of pear with decay rate of 10%under different deformation was analyzed.The storage time of Korla fragrant pear under different static pressure conditions was investigated by the compression of the visible surface damage of Korla fragrant pear as the critical point.Different static pressure conditions changed the internal structure of Korla fragrant pear,resulting in the destruction of cell wall and cell membrane,shortened storage time and reduced sales of Korla fragrant pear.Through the experiment,it can be found that the higher the static pressure deformation,the greater the storage time of Korla fragrant pear,shorten the shelf life.(2)Calibration of Korla fragrant pear weight by electrical characteristics.In order to provide a new method for the classification of Korla fragrant pear,the electrical parameter change data of Korla fragrant pear with different quality were collected.The relationship model between mass and electrical characteristics is y=a+bx+cx~2,and the optimal detection model is the equivalent parallel capacitance y=-21.7210+0.3655x-7.9441x~2at 1MHz frequency.(3)Using electrical characteristics to detect the static pressure damage of Korla fragrant pear,analyze the influence of different static pressure conditions on electrical characteristics,build the static pressure damage identification model,and determine the static pressure damage characterization method.Different static pressure conditions have different effects on the storage time of Korla fragrant pear.When the static pressure deformation is less than 3mm,the deformation has little effect on the storage time,but after 3mm,the deformation has a great effect on the storage time.With the increase of the deformation,the storage time decreases and the shelf life shortenes.In the range of testing frequency,the electrical parameters change regularly with the increase of deformation.With the increase of deformation,the parallel equivalent capacitance(Cp)increases,the complex impedance(Z)increases,the quality factor(Q)increases,and the parallel equivalent resistance(Rp)decreases.Cp decreases continuously under the same test condition,Rp,Z and Q increase continuously under the same test condition.During the same storage period,Cp,Rp and Z decreased with increasing test frequency.Q increases positively with test frequency.When static pressure damage was detected at different picking time,the mathematical model of deformation and parallel equivalent capacitance was optimal at 100k Hz frequency.The mathematical model of deformation and parallel equivalent resistance is optimal at 100k Hz frequency.The mathematical model of deformation and complex impedance is optimal at 1MHz frequency.The mathematical model of deformation and quality factor is optimal at 10k Hz frequency.Under the specific test frequency,the mathematical model between static pressure damage deformation and electrical parameters was established,and the fitting effect was good,indicating that the mathematical model of electrical characteristics could identify and characterize the degree of static pressure damage of Korla fragrant pear.The optimal Z and deformation model was established at 1MHz frequency,and the fitting coefficients of different picking time were all greater than0.9690.(4)The storage period was based on the hydrostatic damage characterization method of Korla fragrant pear.In a specific frequency,the Cp value increases and the Q,Z and Rp values decrease with the extension of storage time.The mathematical model of deformation and parallel equivalent capacitance is optimal under different storage time at 1MHz frequency.The mathematical model of deformation and parallel equivalent resistance is optimal at 1MHz frequency.The mathematical model of deformation and complex impedance is optimal at 1k Hz frequency.The mathematical model of deformation and quality factor is optimal at 100k Hz frequency.The fitting of quadratic function model at each test frequency is better,which can be used to identify the static pressure damage of Korla fragrant pear during storage period.In the model establishment of different storage time,Cp and deformation model were best established at 1MHz frequency,and the fitting coefficients were both greater than 0.9738.