The Effction Of Konjac Glucomannan Fragment For Dough Properties And Bread Quality

The object of this thesis is konjac glucomannan.First of all,it used response surface methodology to optimize the acid degradation process.Then the four konjac glucomannan fragment with different molecular weights had been screening of.Followed,The average molecular weight,of these konjac glucomannan fragment,the rheological properties,and thermodynamic properties had been determined.Afer this,Adding the fragment into the dough.Testing the rheological properties characteristic,fermentation characteristics.Final is the baking test and the final proceeds of flour products and sensory evaluation.Eventually we had get the following conclusions:1 The degradation of konjac glucomannan and the physical and chemical characteristics testWith the degradation of konjac glucomannan,The molecular weight had been decreased.With the degradation,it easier to be dissolved,which is likely to be used.Though the deteminnation of the rheological properties and thermodynamic properties,we could find to reduce the molecular weight of konjac glucomannan as the certain extent,the change of physical and chemical properties will be no significant.2 Adding konjac glucomannan fragment into the flour:(1)From the silty features,with adding the four different molecular weights konjac glucomannan clips,the absorbent volume of the dough has been gradually increased.And the first increases and then decreases with increasing molecular weight.The most obvious increased trend is the KGM2.The d ugh stability time was also rising.Except the KGM1,adding the remaining three konjac glucomannan fragment will degree the dough formation time as vary reduction(2)From the tensile properties,With adding the four different molecular weights konjac glucomannan fragment into the mix the dough,it can increasing the dough extensibility.It a so made the maximum tensile strength and maximum draw ratio highly and powder forces decreased.It showed that Mixed dough with four different molecular weight konjac glucomannan fragments could add toughness enhancement,which made it become extension changed for the better performance.And increased toughness and extensibility balance performance,dough shaping ability,gluten strength.(3)from the fermentation performance,Overall,adding the four different molecular weights konjac glucomannan fragment increased the total gas production in the fermentation,however,to show the poor endurance.Especially for the late in the fermentation.The main reason is adding four different molecular weights konjac glucomannan fragment to obstacle to the formation of gluten network.And reducing the dough to hold gas performance,decreaseing volume during the fermentation process.By the physical properties measured,adding four different molecular weights konjac glucomannan fragment would reduce the initial hardness of the dough.But with fermented dough,the hardness weak of degree gradually flatten.And to add four different molecular weight of konjac glucomannan fragment decreases dough viscosity,the effectiong of which is not improved during the fermentation.(4)from the baking properties,Adding four different molecular weights konjac glucomannan fragment,the volume of bread,the epidermal color,the shape,the internal organization and the tast.have varying degrees of change.When add the fragment of konjac glucomannan,the bread specific volume first increased and then decreased.The color,with the konjac glucomannan fragment adding,had significantly improved.At the physical properties of the bread,adding the konjac glucomannan fragment could increases the crispness of fresh bread epidermis,but reduce the hardness and chewiness of the bread core at the same time.Flexibility would be increased.Adding konjac glucomannan fragment eimpated on the aging status of the aging of bread during the bread during storage.Mainly to the increase in hardness and weak in elastic.But for the relatively blank and control products,adding konjac glucomannan fragment will made the attenuation to be much smaller.And always better than the value.That is,adding the konjac glucomannan fragment can play to a certain extent which could slow down the aging of the bread.In which the adding fragment of KGM2 effect is most obvious.