Research And Application Of Laser Transmission Method For Measuring The Orientation Degree Of Dried Meat

Dried meat is a kind of favorite processed meat products in daily life.Taste and textural properties of processed meat products are key factors to decide its popularity.Fiber orientation of the meat products is an important measurement indicator for quality control.There are also some problems using traditional test methods,such as false ginseng,invisible natural flesh fibers,bad taste,and so on.Therefore,we developed a non-destructive photon propagation method to quantify fiber orientation of dried meat.We chose the extruded dried meat as samples,and then put sample into the laser device using a digital camera to collect laser transmission reflection images.The quantitative analysis for the obtained image was implemented by self-compiled computer program with the help of the MATLAB software.On the basis of this,the extrusion process parameters were optimized.Contents of the research are as follows:1.Using dried meat with oriented structure as raw material,there is a significant difference in performance between the orientation direction and the direction perpendicular to the orientation direction due to the anisotropy of the oriented dried meat and the propagation characteristics of laser in biological tissues.Therefore,when light shoot into the interior of the anisotropic medium,the light will be preferred along the fiber direction to propagate.The square of the ratio of the axis to the minor axis can be used to characterize the degree of fiber orientation of the anisotropic structure of the dried meat inside.Based on the theory above,a laser acquisition image test device was designed and built.with a wavelength of 633 nm and a power of 5 mw was used as the incident light source.After the laser through the neutral filter,when the aperture of the digital camera and the focal length are set as F/5.6 and 100 mm,respectively,it will show an angle between the incident direction of the light source and the sample,which is named as theta(?).The best experimental parameters were determined through preliminary experiments.The camera exposure time was 1/400 s,and the light source incident angle was 45°.2.Using self-made MATLAB program to perform the following main processes: Firstly,the image acquired by the laser device was input in the MATLAB and the Gaussian filtering was used to de-noise.Next,the edge of the image was enhanced,so that the fitting ellipse can detect the edge of the image more precisely.Thirdly,using the morphological edge enhancement and closed operation.Finally,the least squares method was used to obtain the best ellipse fitting from the outermost periphery to the equal intensity pixel,and the B value was eventually obtained.3.Process parameters of extruded pork was optimized.Based on the quantitative analysis of the degree of orientation of dried pulp fiber in laser transmission,the influence of zone III barrel temperature of extruder,moisture content of material,and screw speed on the fiber orientation of the extrudate was comprehensively investigated,and the optimum extrusion dry process parameters were obtained as following: the zone III barrel temperature was 155.88 °C,the material contained 42.44% water,and the screw speed was 179.86 r/min.Under this condition,the predicted degree of fiber orientation of the extrudate was 1.84619.The structure and orientation of dry muscle fibers of squeezed pork produced at this condition was more obvious,and the quality of the dried pork muscle fibers was better.And this type of dried pork shape.The common form of dry pork has a high market acceptance in the market.In summary,this paper constructed a laser transmission method for measuring the degree of orientation of extruded dried meat fibers and optimized the extrusion process parameters.Applied the laser technology,with non-destructive,accurate and rapid characteristic,to food inspection has laid a foundation for inspecting other foods with oriented structure.