Study On The Effect Of Sodium,Potassium,Calcium And Magnesium Ions On Noodle Quality

In the production of noodles,salt modifiers such as Na Cl,Na₂CO₃ and K₂CO₃ are often added.These salts are soluble in water and exist in an ionic state,their influence on dough noodles is also in the form of ions.This topic mainly studies the influence of metal ions Na⁺,K⁺,Ca²⁺,Mg²⁺on the quality of noodles.Starting from the two major components of flour,the effects of Na⁺,K⁺,Ca²⁺,and Mg²⁺on gluten protein components and starch components were studied separately.It mainly includes the flour characteristics of flour,the stretching characteristics of dough,the texture characteristics of noodles,and the influence of Na⁺,K⁺,Ca²⁺,Mg²⁺on gluten protein components and starch components.The effects of Na⁺,K⁺,Ca²⁺,and Mg²⁺on the quality of noodles were systematically explored to provide a theoretical basis for finding other metal ion salts that may replace sodium ions.The main findings are as follows:1.The effect of metal ions on flour properties,gelatinization properties,tensile properties,wet gluten content,etc.was studied.The results show that Na⁺,K⁺,Ca²⁺,Mg²⁺can influence the water absorption of flour,the wet gluten content of the dough and the gluten strength,increase the gelatinization viscosity,gelatinization temperature and attenuation value of flour.With the increase of Na⁺and K⁺content,the gluten network structure is gradually strengthened,and the dough forming time,stabilizing time and maximum tensile resistance increase.Due to the high ionic strength of Ca²⁺and Mg²⁺,the interaction between gluten,starch,and water molecules is destroyed,resulting in a decrease in the maximum tensile resistance of the dough and an increase in elongation.2.The effects of metal ions on the color,moisture distribution,microstructure,cooking and texture characteristics of noodles were studied.The results show that Na⁺,K⁺,Ca²⁺,and Mg²⁺increase the weakly bound water content of the noodles,and the optimal cooking time of the noodles is significantly shortened,and the water absorption is reduced.The texture characteristics show that Na⁺and K⁺improve the hardness and elasticity index of noodles,increase the stretching distance and breaking force of noodles;Ca²⁺and Mg²⁺decrease the hardness and elasticity index of noodles and reduce the breaking force of noodles.It is found through the noodle microstructure that Na⁺and K⁺make the noodle microstructure more compact,the surface is smooth and delicate,the reflection of light is enhanced,the brightness of the noodle is improved,and the texture characteristics of the noodle are improved;Ca²⁺and Mg²⁺weaken the gluten protein network structure,expose the starch granules inside the noodles,reduce the tightness between the protein and starch,loosen the noodle structure,increase the absorption of light,darken the noodle color,and increase the cooking loss.3.The effects of metal ions on starch transparency,swelling degree,water release rate,gelatinization characteristics,degree of order,and granular shape of starch suspension were studied.The results show that Na⁺,K⁺,Ca²⁺,and Mg²⁺increase the solubility of starch and decrease the transparency of starch paste.The addition of Na⁺and K⁺reduces the peak-valley viscosity of starch,and increases the attenuation value and regeneration value.peak viscosity and final viscosity show the rule of increasing first and then decreasing with the increase of Na⁺and K⁺content,gelatinization temperature and peak time are not affected.Ca²⁺significantly increases the peak viscosity,final viscosity,attenuation value and regeneration value,with the increase of Ca²⁺content,the peak viscosity and the final viscosity show first increase and then decrease,both reach the maximum when the Ca²⁺content is 0.2 mmol/g,Peak and valley viscosity,peak time and pasting temperature are not affected by Ca²⁺.Mg²⁺significantly increased the peak viscosity,attenuation value,final viscosity and regenerative value,among them,the attenuation value changes the most,increasing by at most 40%.According to the particle morphology,all four metal ions have the effect of inhibiting the water swelling of starch particles.among them,the effect of Mg²⁺is the most significant,however,it has no significant effect on the crystalline area and order degree of starch.4.The effects of metal ions on water retention,water distribution,secondary structure,disulfide bonds,protein molecular weight,and gluten protein structure characteristics of gluten proteins were studied.The results show that Na⁺,K⁺,Ca²⁺,and Mg²⁺improve the water holding capacity of gluten protein.Nuclear magnetic resonance analysis found that metal ions increased the free water content of gluten protein,Na⁺,K⁺and Ca²⁺also reduced the content of deep-bound water.the deep-bound water moved to weakly-bound water,however,Mg²⁺had no effect on the content of bound water.Through the measurement of disulfide bonds,it was found that Na⁺,K⁺,Ca²⁺increased the content of disulfide bonds in gluten protein,and Mg²⁺had no significant effect on the change of disulfide bond content.Gel electrophoresis analysis found that these four metal ions did not affect the molecular weight of gluten protein,and did not change the gluten protein subunit,it just changed the content of gluten protein secondary structure.Through infrared analysis,it was found that with the addition of Na⁺and K⁺,the?-turn content of gluten protein increased significantly,?-fold and?-helix tend to increase first and then decrease;K⁺increased the content of?-fold and decreased the content of?-turn;Ca²⁺and Mg²⁺had the same effect on the secondary structure of gluten protein.The content of?-fold and random curl decreased,and the content of?-helix and?-turn increased.According to the structural properties of gluten protein,it was found that Na^+,K⁺,Ca^2+,and Mg²⁺greatly improved the tensile properties of gluten protein,the fracture strength and ductility increased,and the hardness and viscosity decreased.Among them,Ca²⁺has the most significant effect on gluten protein hardness,and K⁺and Mg²⁺have the most significant effect on gluten protein viscosity.