Research On The Effect And Mechanism Of Heat-treated Egg White Powder On Improving The Quality Of Steamed Bread

Egg white powder is a substitute for fresh egg white,which contains the same type of protein as fresh egg white,and is rich in many amino acids needed by the human body.In contrast,heat-treated egg white powder has better functional properties and is often added to food to improve the texture and flavor of food.As a traditional food,steamed buns have always been loved by the Chinese people,but there are problems with low protein and lysine content in grain products,which cannot meet people’s pursuit of high nutrition and high quality staple food.Therefore,in this paper,heat-treated egg white powder was applied to steamed bread,and its effect on the characteristics of mixed dough and the quality of steamed bread and its mechanism were further studied.First,the effect of heat-treated egg white powder on the mixing characteristics was studied,and the results were found: With the increased of the addition amount of heat-treated egg white powder,the water absorption rate of the mixed dough gradually decreased,and the forming time increased significantly;When the addition amount is 4 %,the stability time of the mixed dough is the longest,and the weakening degree is the lowest;With the increasing amount of heat-treated egg white powder,the peak viscosity,minimum viscosity and final viscosity increased obviously,the recovery value of the mixed powder paste became smaller,and the gelatinization temperature decreased.Secondly,the influence of heat treated egg white powder on mixed dough characteristics was studied.The results showed that: With the increase of the amount of heat-treated egg white powder,the dough tensile strength increased first and then decreased,and when the amount of heat-treated egg white powder was 4 %,the dough had the best tensile strength,the largest tensile distance,and the elastic modulus and viscous modulus were closest to the control group.Under electron microscope,it was found that the mixed dough with heat-treated egg white powder formed continuous and dense gluten network structure,which enhanced the ability of gluten protein to wrap starch particles.Through the study of the influence of heat-treated egg white powder on steamed bread quality,it is found that: The addition of heat-treated egg white powder improved the sensory quality of the steamed bread,increased the toughness and elasticity of the steamed bread,and added a unique taste,but excessive addition will cause the steamed bread to have an unacceptable odor,and it will have a negative impact on the taste,and the surface of the steamed bread will appear Unsmooth phenomenon;The inner pores of the steamed buns are round and the inner structure is dense,and the pores are evenly distributed;And when the addition amount is 4 %,the specific volume is the largest;And when the addition amount is4 %,the specific volume is the largest;The addition of heat-treated egg white powder improved the hardness,stickiness and chewiness of the steamed bread,but when the addition amount is greater than 4 %,the elasticity and recovery are significantly reduced,so the addition of heat-treated egg white powder should not exceed 4 %;Compared with the blank steamed bread,the steamed bread added with heat-treated egg white powder showed a significant upward trend in L*,a* and b* values;It can be seen from the microstructure that the addition of an appropriate amount of heat-treated egg white powder maked the gluten structure more compact;Compared with the control group,the steamed bread added with heat-treated egg white powder had less strongly bound water and more weakly bound water;Combined with the analysis of the sensory quality of steamed bread and the results of specific volume and texture,when the addition amount is 4 %,the sensory quality is the best,the specific volume is the largest,and the elasticity and hardness of the steamed bread are within the acceptable range.The effect of heat-treated egg white powder on the flavor of wheat steamed bread was studied.The results showed that: PCA analysis showed that the three groups of samples contained significant differences in flavor substances,including wheat steamed bread,egg white powder steamed bread and heat-treated egg white powder steamed bread;A total of38 volatile flavor compounds were detected by GC-MS analysis of the three types of steamed bread.The relative contents of alcohols,esters,acids and hydrocarbons in wheat steamed buns were the highest,while the relative contents of aldehydes were higher in egg white flour steamed buns and heat-treated egg white flour steamed buns.Next,further research was conducted on the influence mechanism of heat-treated egg white powder on the properties of mixed dough and steamed bread.The results found: With the increased of the addition amount of heat-treated egg white powder,the content of free sulfhydryl groups in the dough decreased,and the content of disulfide bonds showed an upward trend;The ionic bond first increased and then decreased,the hydrogen bond decreased first and then increased,and the hydrophobic interaction decreased significantly;The α-helix and β-sheet showed an upward trend first and then a downward trend,theβ-turn and random coil showed a downward trend as a whole,and the network structure of gluten tended to be more stable;With the increased of the addition amount of heat-treated egg white powder,the content of sulfhydryl groups in steamed bread decreased,and the content of disulfide bonds increased;The ionic bond first increased and then decreased,the hydrogen bond decreased first and then increased,and the hydrophobic interaction decreased significantly;The α-helix and β-sheet rise first and then fall,while β-turn and random coil first fall and then rise.The addition of too much egg white powder will lead to an increase in the disorder of gluten protein.The addition of an appropriate amount of heat-treated egg white powder has a significant impact on dough characteristics and has a positive effect on the improvement of steamed bread quality.Therefore,this study provides theoretical guidance for improving the quality of steamed bread and has very important significance for the improvement and research and development of steamed bread.