Relationship Between Water Absorption Speed And Wheat Flour Composition And Its Effect On Dough Quality

The processing of staple foods such as steamed bread and noodles involves the process of wheat flour absorbing water to form dough.Studies have shown that the different water absorption speeds of wheat flour affect the rheological properties of the dough and the quality of the flour products.To explore the factors affecting the water absorption speed in the components of wheat flour,and to clarify the effect of water absorption speed on the quality of dough and flour products,the water absorption speeds were determined by a farinometer,and the relationship between the change of component content and the water absorption speed was explored with the flour of different water absorption speeds as research objects.On this basis,the main components affecting the water absorption speed were determined,and the effects of changes in the physical and chemical properties of the components on the water absorption speed of wheat flour were studied,providing theoretical support for the milling and staple food processing industries.The main research results are as follows:Protein,wet gluten and starch have great influence on the water absorption speed of wheat flour.When the crude protein content decreased from 13.25% to 6.98%,wet gluten content decreased from 38.81% to 19.19%,and starch content increased from 60.59% to68.41%,the water absorption speed of wheat flour increased from 0.17 g/s to 3.87 g/s.The gluten index had no effect on the water absorption speed of wheat flour.When the water absorption speed of wheat flour increased,the settlement value of wheat flour decreased from69.50 mL to 32.50 mL,and the grain swelling index decreased from 5.24% to 3.33%,which had significant changes(P<0.05).The basic moisture content of wheat flour has an effect on the amount of water added and the time of dough formation.When the moisture content of wheat flour is high,the amount of water needed to form dough decreases,while when the moisture content is low,the amount of water needed to form dough increases.However,the water content of wheat flour had no significant effect on the water absorption speed of wheat flour.Correlation analysis of wheat flour component content and water absorption speed showed that protein and water absorption speed(P<0.01,r=-0.907),starch and water absorption speed(P<0.01,r=0.628).It can be seen that protein and starch are the most influential factors on water absorption speed.The chemical composition of protein and starch was studied.It was found that the content of albumin and globulin,water-soluble proteins,did not change significantly with the water absorption rate.It had no significant effect on the water absorption rate of wheat flour.When the content of water-insoluble protein(glutenin)decreased from 4.02% to 1.53%and the content of glutenin from 5.28% to 2.77%,the water absorption rate of wheat flour decreased(P<0.05).When the glutamic acid content decreased from 4.54% to 2.48%,the proline content decreased from 1.40% to 0.83%,and the cysteine content decreased from 0.14%to 0.04%,the water absorption rate of wheat flour also showed a downward trend.With the decrease of amino acid content,the interaction between protein molecules decreased.The interaction between gluten content and linking protein was influenced by amino acid content,and then the water absorption rate of wheat flour was affected.The disulfide bond content decreased from 13.31 umol/g to 9.05 umol/g,and the water absorption rate of wheat flour decreased(P<0.05).Amylopectin,as the most abundant component in starch,affects the water absorption of starch particles,and its content increases from 47.44% to 53.07%,and the water absorption rate of wheat flour increases(P<0.05).The variation of water absorption speed will affect the rheological properties of dough.The starch content of wheat flour with high water absorption speed is relatively high,which will weaken the toughness of the gluten network,and the loosening of the gluten network will lead to the decline of dough strength.Therefore,with the increase of water absorption speed,the silty quality and extensograph properties of wheat flour showed a decreasing trend.As can be seen from the laser scanning confocal image,the starch particles of wheat flour with low water absorption speed are closely bound to protein,and the swelling degree of starch particles is slightly smaller,while the starch particles of wheat flour with high water absorption speed have a larger degree of water absorption and swelling.At the same time,with the increase of wheat flour water absorption speed,the hardness of steamed bread decreased from 3114 g to 1416 g,the adhesion decreased from 2529 to 1188,and the masticability decreased from 2408 to 1111,showing significant changes(p<0.05).This indicates that the steamed bread produced by the wheat flour with a higher water absorption speed is softer,while the steamed bread produced by the wheat flour with a lower water absorption speed is more chewy.