Research On The Formation Mechanism And Quality Control Technology Of Yuba

Yuba is one of the traditional soybean products in China,which is favored by more consumers because of its rich nutrients.However,the current low degree of standardization and automation in the production of Yuba in China have caused large fluctuations in product quality.Therefore,it is particularly important to improve the quality and stability of Yuba.This paper studies the soybean varieties,soy milk components,high-pressure homogenization technology,and the structure of soy milk in the filming process that affect the quality of Yuba.The aim is to provide references and references for the in-depth research and technical improvement of Yuba,and to standardize and standardize the production of Yuba.Provide theoretical basis and guidance.The main research contents and results are as follows:(1)Determine the soybean varieties that are most suitable for the production of Yuba.First,the 27 soybean varieties were divided into four categories by cluster analysis,and the correlation between soybean grain composition and Yuba quality was analyzed.The results showed that the main components of Yuba(protein,fat)content and soybean grain quality indicators All have a strong correlation;the texture characteristics of Yuba are mainly related to soy protein and protein components.Secondly,the basic physical and chemical indexes of soybeans and the quality indexes of Yuba were further analyzed by principal components.The analysis results showed that 12 indexes of soybean and Yuba quality can be expressed by 3 principal components,and the selected varieties are calculated according to the expressions of the 3 principal components.According to the comprehensive score,the soybean of Heinong 85 variety is most suitable for making Yuba.(2)Study the effects of soy milk components on the quality of Yuba.On the basis of the basic components of soy milk,the ratio of soy milk components is adjusted.Through a single factor test,the tensile strength and sensory score of the Yuba are used as the response values.The response surface method is used to investigate the protein/fat,11S/7S and transglutaminase addition on the quality of Yuba.It was finally determined that the soy milk with the highest quality of Yuba was:protein/fat 2.80,11S/7S 2.7,transglutaminase addition amount 1.60 U/g,at this time the Yuba tensile strength was 7.24 kg/cm2 and the sensory score was 90.08 points.The quality evaluation results of Yuba show that compared with the Yuba made from the soy milk before the regulation,the tensile strength,elasticity,chewiness,sensory quality and yield of the Yuba made from the soy milk after the regulation are greatly improved.(3)Study the effects of homogenization pressure and homogenization times on the characteristics of soy milk and the basic nutrients and quality characteristics of Yuba.The results show that the solubility of soy milk is greatly affected by high-pressure homogenization.When the homogenization pressure is 40 MPa,the solubility can reach 83.76%;the surface sulfhydryl content of soy milk increases with the increase of homogenization pressure and homogenization times.Increase first and then decrease,and reach the maximum value of 4.15?mol/g when the homogenization pressure is 50 MPa for the second time.The surface hydrophobicity results show that the surface hydrophobicity of soy milk has an upward trend during the homogenization process,and the highest is 998.446;The results of soy milk particle size measurement showed that excessive high-pressure homogenization would make the particles in the system form aggregates again and make the particle size larger.The results of the research on the effect of high-pressure homogenization on the quality of Yuba showed that the basic nutrient content and mechanical properties of Yuba showed a trend of first increasing and then decreasing with the increase of homogenization pressure and homogenization times.Secondly,the correlation analysis between soy milk characteristic indexes and Yuba quality indexes showed that the basic nutrient content of Yuba was significantly correlated with the solubility of soy milk protein,and the mechanical properties were significantly correlated with surface sulfhydryl content and surface hydrophobicity.Based on the above research,it is believed that the soy milk is most beneficial to improve the quality of Yuba after the 40 MPa homogenization twice.(4)The basic composition,aggregation degree,micro morphology of Yuba,protein subunits and structural changes of soy milk were studied.The results showed that during the continuous filming process,the relative solid content of protein in soy milk decreased significantly,the relative solid content of total sugar increased significantly,the relative solid content of fat remained basically unchanged,the protein content of Yuba was significantly reduced,and the content of fat and The total sugar content rose slightly.The particle size distribution results show that the particle size of the soy milk gradually increases during the filming process,indicating that large aggregates are continuously formed in the soy milk,and these aggregates cannot participate in the film formation.During the filming process,the sulfhydryl content and surface hydrophobicity changes of soy milk showed an overall upward trend,indicating that the protein was fully heated and the spatial structure was organized in an orderly manner.The internal sulfhydryl and hydrophobic groups were exposed on the surface,and the molecules were hydrophobic and connected together,so that Yuba continue to form.The results of Fourier infrared spectroscopy showed that the content of ?-sheets gradually decreased,and the irregular curls first increased and then decreased,indicating that the ordered soymilk protein structure gradually changed to the irregular curled structure,which increased the chance of intermolecular interactions.Promote film formation on the surface of soy milk.Scanning electron microscopy results can be observed,as the filming progresses,the fat particles wrapped on the surface of the Yuba gradually become larger,making the film structure loose,so that the film cannot be formed in the later stage.