Research And Application Of Pretreatment To Improve The Dough Characteristicsof Corn Flour

Corn has the reputation of "longevity food" and contains nutrients such as vitamins,carotene,lecithin,calcium,iron,phosphorus,glutathione and riboflavin.With the change of dietary structure,the nutritional and health care value of corn is gradually recognized,so it is of great significance to apply corn to the preparation of traditional staple food.In this experiment,dent corn was used as raw material,and the corn was pretreated by extrusion,cooking and drying,and ultra-fine grinding.The corn flour obtained after treatment was used in the development of dumpling flour,and the shelf life of corn dumpling flour was determined..The specific research results are as follows:The characteristics of three types of corn flour,including extrusion,cooking drying and ultra-fine grinding,were analyzed.The results showed that the hardness,elasticity and cohesion of the corn flour dough increased after extrusion and puffing.After cooking and drying,the hardness,elasticity and recovery of corn flour dough increased slightly,the water absorption rate and weakening degree increased,the dough forming time increased by 6.10 min,and the dough stabilization time increased by 2.15 min.The peak value of cooking and drying corn flour increased.The viscosity and valley viscosity increased by 309.30 cp and 371.35 cp,respectively.After ultrafine pulverization,the hardness of corn flour dough decreased,the water absorption rate increased,the degree of weakening decreased,the dough formation time increased by 1.49 min,and the dough stabilization time increased by 1.80 min.The viscosity increased by 208.70 cp and 490.00 cp,respectively.Extruded corn flour combined with ordinary corn flour can make pure corn flour steamed dumplings.The optimal process parameters for making steamed dumpling skins are determined by single factor and orthogonal experiments as follows: the ratio of extruded and expanded corn flour to corn flour is 6: 4.The water temperature of kneading noodles is 50 ℃,and the waking time is 60 minutes.The corn dumpling skin under this process condition is complete,without cracking phenomenon,golden color and unique corn flavor.Through single factor and orthogonal experiments,the optimal process parameters of cooking and drying corn flour for making dumpling skins are determined as follows:the ratio of cooking and drying corn flour to wheat flour is 7:3,the water temperature for kneading is 50 ℃,and the resting time is 60 min.The surface of the corn dumpling skin produced under the technological conditions is smooth,moderate in hardness and softness,and has less damage.Through single factor and orthogonal experiments,the optimal process parameters of ultra-finely ground corn flour for making dumpling skins were determined as follows:the ratio of ultra-finely ground corn flour to wheat flour is 7:3,the mixing water temperature is 50 ℃,and the resting time is 40 min.,The corn dumpling skin produced under this process condition has fine taste and uniform color.Determination of the shelf life of dumpling flour: The first-order kinetic model combined with the Arrhenius equation was used to obtain the prediction formula for the storage period of the fatty acid value of different pretreated corn dumpling flour.The storage period prediction model established by fatty acid value has high accuracy,and the shelf life of corn dumpling powder is determined by combining the changes of water activity and chromaticity.The results showed that the shelf life of the corn dumpling powder extruded and puffed,the corn dumpling powder cooked by cooking and drying,and the corn dumpling powder treated by ultrafine grinding were 119 d,127 d and 107 d,respectively.