Study On The Effect Of Unidirectional Sheeting On The Mechanical Properties Of Dough Sheet And The Quality Of Noodles

In the production of noodles,the sheeting process is a crucial operation.The sheeting operation is crucial to the formation of the gluten network in the noodle dough,which significantly affects the quality of the final noodle product.In this study,commercially available wheat flour was used as the raw material.The dough and noodles were prepared with different water addition,resting methods,and raw material conditions.By combining the microstructure of the dough sheet,the changes in the mechanical properties of the dough and the quality of the noodles during the unidirectional sheeting process were analyzed.The main research results are as follows:(1)Regarding the he mechanical properties of the dough sheet,the unidirectional sheeting process includes two processes: compound sheeting and continuous sheeting.In this experiment,the mechanical properties of the 3mm noodles obtained by the compound sheeting and the 1mm noodles obtained by the continuous sheeting were measured.By only changing the number of compound sheeting,we found that: In the plane tensile measurement of the dough sheet,with the increase of the number of sheeting,the maximum tensile force and the maximum elongation of the 3mm dough sheet and the 1mm dough sheet both increased first and then decreased;at the same time,the rupture stress of the two kinds of dough sheet and The rupture strain also showed a trend of first increasing and then decreasing,and it basically had the maximum value of the compound sheeting 4 times dough sheet.In the stress relaxation measurement of the dough sheet,with the increase of the number of compound sheeting,the equilibrium elastic coefficient E0 of the 3mm dough sheet and 1mm dough sheet first increased and then decreased,and the maximum value appeared at 4 times of compound sheeting;The relaxation time ? of the 3mm dough sheet and the 1mm dough sheet also increased first and then decreased,but it peaked at 6 times of sheeting.With the increase of the amount of water added,the rupture strain of the dough sheet increased significantly,the rupture stress decreased significantly,the equilibrium elasticity coefficient E0 decreased significantly,and the relaxation time ? decreased significantly.After changing the resting method of noodle making,it is found that the crumbly dough resting has the largest fracture stress and equilibrium elastic coefficient,the double resting has the largest breaking strain and elongation,and the un-resting noodles have the worst mechanical properties.Changing the raw materials of flour found that the high protein content in high-gluten flour significantly increased the cracking strain,cracking stress,relaxation time and equilibrium elasticity coefficient of the dough.The highgluten flour dough has the best mechanical properties,and the low-gluten flour noodles sheet has the worst mechanical properties.(2)Regarding microstructure of the dough sheet,Throughout the sheeting process,we observed the microstructure of the 3mm dough sheet and 1mm dough sheet obtained with different compound sheeting times.The gluten network of 3mm noodles has gone through undeveloped,fully developed and over-developed stages.The change trend of the microstructure of the gluten network of the 1 mm dough was the same as that of the 3 mm dough.Compound sheeting 6 times was conducive to the formation of gluten network and the extension of gluten protein,so that the starch was fully encapsulated in the gluten protein network structure to form a continuous whole;while excessive sheeting process(20 times)would destroy the gluten network structure and the network structure would become ineffective Evenly,part of the starch fell off from the network structure.The increase of moisture content was conducive to the formation of gluten network.38% moisture content dough sheet was the best,and the microstructure of 30% moisture content was the worst.The microstructure of the dough in the crumbly dough resting method was the most continuous and complete,and the clusters of starch and protein in the microstructure of the dough in the un-resting method were serious and the structure was the worst.The high protein content in high-gluten flour was conducive to the development of gluten.The poor protein quality in low-gluten flour leaded to discontinuous gluten network and the worst microstructure.(3)For the quality of noodles,the water absorption and cooking loss of noodles showed the evolution law of decreased first and then increased with the increased of the number of compound sheeting,and basically the noodles made by compound sheeting 6 times had the minimum value.The breaking force and breaking distance of noodles first increased and then decreased with the increase of the number of compound sheeting,and basically the noodles obtained by compound sheeting 4 times have the maximum value.As the amount of water increased,the water absorption and cooking loss of the noodles showed a decreasing trend.The breaking force of the noodles was significantly reduced.The breaking distance was significantly increased.For different resting methods,the cooking characteristics of the unresting noodles were the worst,and the other three resting methods had little effect on the cooking characteristics of the noodles.The breaking force of the noodles in the crumbly dough resting and un-resting methods was significantly greater than that of the double resting and the dough sheet resting with the noodles.The order of the noodles breaking distance: double resting > the dough sheet resting > the crumbly dough resting >un-resting.For different raw materials,high-gluten flour noodles had the best cooking characteristics,and low-gluten flour noodles had the worst cooking characteristics.With the increase of protein content in flour,the breaking force and breaking distance of noodles increased significantly.