Study On The Effect Of Gluten Protein On The Water Absorption Of Dough

Wheat flour consists of starch,protein,cellulose,minerals,fat,water and other ingredients.Wheat flour absorbs and holds water to form a viscoelastic dough,which is used to make a variety of foods.The water absorption rate of different flour is different.At present,the mechanism of the difference in water absorption of flour and its influencing factors are not clear.In this paper,a prediction model of water absorption of dough was established.The effect of gluten content and composition on water absorption of dough was also discussed.The aim of this study is to explore the rheological properties of dough and the inherent mechanism of dough quality formation,which is of great theoretical significance for flour food processing.The main results of this paper are as follows:（1）The relationship between the physicochemical properties of wheat flour,such as particle size distribution,ash content,protein content and quality,damaged starch content and water absorption of dough was analyzed.The results showed that the water absorption process of flour was so complicated that each physicochemical index of flour had both direct and indirect effects on the water absorption of dough.Among these indexes,LPP/LMP、D_[4,3]、wet gluten content and damaged starch content had a direct positive effect on the water absorption of the dough,while D₁₀ and ash content had a direct negative effect on the water absorption of the dough.The optimal regression model of water absorption of dough was established by stepwise regression analysis:Y_{Water Absorption}=34.076+0.705*X_{Wet gluten content}+1.477*X_{Damaged starch content}-49.887*X_{Ash content}-0.101*X_D50（R²=89.1%）.The results can provide reference for controlling and predicting water absorption in the processing of flour production.（2）The effect of different proportion of gluten and starch on water absorption of dough was studied.The results showed that the content of gluten had an important effect on the water absorption of dough.The increase of gluten content can increase the water absorption of flour,prolong the formation time and stability time of the dough.Flour with moderate protein content has a relatively stable moisture state in the process of dough mixing.Flour with high gluten content has a more stable protein secondary structure during the mixing process.（3）The effects of glutenin subunits（2+12,3+12,4+12,5+10）at Glu-D1 site on water absorption and water binding during dough formation in Xiaoyan 22 were analyzed.The results showed that the subunits of gluten had an important effect on the water absorption of dough.Under the background of Xiaoyan 22,only HMW-GS was different,the water absorption characteristics of flour were different.In the background of Xiaoyan 22,the order of water absorption is 4+12>5+10>2+12>3+12.The order of water binding state was:2+12>4+12>5+10>3+12.In conclusion,the water absorption properties of wheat flour dough can be improved by regulating gluten,damaged starch,ash content,particle size and gluten subunit composition.The ideal water-absorbing property of wheat flour requires that the protein content of wheat flour is moderate and the wheat flour has high-quality subunits.In addition,the ratio of protein/starch,HMW-GS/LMW-GS,x-HMW-GS/y-HMW-GS should also be appropriate.