The Effects Of Wheat Germ Power On The Characteristics Of Dough And The Quality Of Steamed Bread

This paper mainly focuses on the wheat germ flour mixing system,and the change of gelatinization properties of mixed powder by DSC and RVA.The microstructure of different dough was observed by SEM.The migration of dough during storage was investigated by low field NMR.The main flavoring substances of the dough were analyzed by GC-MS.The main results were as follows:1.The contents of protein and fat in wheat flour were 10.60%and 0.76%.The contents of protein and fat in germ were 34.80%and 10.82%.The starch content of germ was 40.86%,lower than that of wheat flour.After sieved,the germ?100 mesh?was added to flour according to the proportion of 0%,2%,4%,6%,8%and 10%,and the basic physicochemical properties of the mixed powder were determined.Differential scanning calorimetry?DSC?analysis and rapid viscosity?RVA?shows that T₀?gelatinization temperature?and T_P?peak temperature?increased with the increasing addition of wheat germ;gelatinization enthalpy and temperature range was increased first and then decreased with the increasing addition of wheat germ.And the peak viscosity and breakdown value and the amount of germ inversely,The gelatinized starch process was blocked.The proportion of germ adding was small,and the change of RVA parameter was small.With the increase of the proportion of wheat germ,the changes of RVA parameters also become larger.2.The elastic modulus?G??and viscosity modulus?G???of the dough increased with the addition of germ,and G?was higher than G??.The tangent of loss angle?tan??first increased and then decreased with the increase of germ.Tan?at 4%and 6%was approximately the same.3.As the proportion of germ increased,the color and brightness of steamed bread also changed.The brightness first increased and then decreased,and reached the peak at 4%.Because of the addition of high fat content,the lipid was oxidized during high temperature,and the color of steamed bread deepened,and the b value continued to rise.The hardness,adhesiveness and chewiness of steamed bread showed a trend of first decline and then increased,and the lowest value appeared at 2%,while the elasticity and cohesiveness of steamed bread increased first and then decreased,and the highest value appeared at 2%.4.The change of water migration of the steamed bread with different proportions of germ addition were measured by LF-NMR.The water change trend of steamed bread with different proportions was explored,and the best proportion of germ addition was obtained,so that the steamed bread was suitable for storage.5.When the grem was added with 2%,the microstructure inside the dough didn't change.The air chamber pores and gluten protein films could be clearly seen.The expanded starch granules were embedded in the gluten structure,forming a stable structure.However,after the addition of the large proportion of the germ,the gluten film was broken,the starch granules were exposed and deformed,and the structure of the gluten was deteriorated6.The results of GC-MS analysis showed that the wheat germ could bring the fragrance of the fragrant fruit and vegetable to the steamed bread,but the volatile components and species were different of steamed bread with different proportions of germ addition.The content of aldehydes,ketones and furans is less,but it is an effective component of the aroma of steamed bread.The higher the proportion of wheat germ added,the higher the relative content of volatile components.When the ratio of additton was 10%,the most volatile substances were detected with the content of 68.923%,second only to 66.017%of the addition ratio of 6%.