Study Of Inspection For Frozen And Refrigerated Fruits And Vegetables Based On Digital Image Processing

For the past few years,with the rapid development of food refrigeration technology and the continuous improvement of cold chain technology,people’s demand for food has reached a new height,that is,while satisfying the quantity of food,its quality has also been improved.However,during the freezing and freezing process of food,whether it is the growth of ice crystals or the sensitivity of cold-sensitive fruits and vegetables to low temperature stress,it will seriously affect the quality of food.Therefore,the effective detection of food quality problems has gradually become a research hotspot.At present,the common detection method is to measure the physical and chemical indicators of food,texture parameters,etc.by off-line detection methods,but these detection methods are often accompanied by damage to the samples.In this paper,low temperature microscopic imaging detection technology,digital image correlation detection technology and hyperspectral imaging detection technology will be applied to detect the quality of frozen and frozen fruits and vegetables.The apple was subjected to low temperature environment simulation treatment using a constant temperature and humidity chamber.The low temperature microscopic imaging detection system was used to observe the apple cells with different temperature and different rewarming rate,and the texture analyzer,the sugar acid meter and the color space measuring instrument were used.Apple’s physical properties,acidity,sugar content,color and other parameters were comprehensively analyzed for the quality of frozen damage in apples.The results showed that the acidity,sugar content and pulp hardness of the peel after freezing at 24h and 48h decreased,which was caused by the ice crystal growth caused by the freezing process,and the apple was dehydrated after melting;It is apparent that the color of the frozen damaged sample is darker than the unfrozen sample.The experiment of different cooling rate of uniaxially stretched carrot specimens was carried out by tension low-temperature cold table.The high-resolution,low-offset CCD camera combined with telecentric lens was used to image the samples with pre-formed speckles to obtain stress-Strain curves were applied to study the mechanical properties of carrots under low temperature conditions using digital image correlation methods.The measurement results show that with the increase of tensile deformation,the stress-strain curve of carrot shows a strengthening trend and the elastic modulus decreases significantly.When the cooling rates are 3℃/min and 6℃/min,respectively,and the temperature is maintained at-12 ℃.the elastic modulus changes gradually become smaller;compared,the cooling rates are 12 ℃/min and 6℃/min,respectively.When the temperature is maintained at-18℃,the elastic modulus is also reduced,and there is a minimum when the strain is in the range of 0.02-0.03.However,the elastic modulus tends to become larger and is still lower than before the fracture.The modulus of elasticity of the stage.This means that a larger rate of cooling and a lower holding temperature keep the carrots in a better elastic state.This is also consistent with the law of food storage,thus verifying the effectiveness of digital image correlation technology in measuring the elastic modulus of frozen carrots.The chilling environmental conditions of the sacred fruit were simulated by a constant temperature and humidity chamber,and classified according to the degree of chilling damage.Using ENVI5.1 and SPSS data analysis software to correct the hyperspectral image data of cherry tomatoes and perform a series of analysis on cropping,noise reduction,average spectral extraction,preprocessing and feature wavelength extraction of the image region of interest,and judge by Fisher.Methods A model for judging the different chilling injury indexes of virgin fruit was established.The analysis results show that the correlation coefficients of the model correction set established by MSC,SG-MSC,SNV and SG-SNV pretreatment are more than 85.7%,and the four groups are good when judging the mild chilling damage.The performance rate was as high as 97.7%,and the correct rate of the SG-SNV training group for the severely chilled fruit was as high as 91.3%.