Development Of Extruded Gluten-free Potato Whole Flour Noodles

Since potatoes are rich in resources and do not contain gluten protein,they can be used as raw materials for gluten-free noodles.However,it is precisely because of the gluten-free nature that during the noodle production process,there are often production and quality problems such as poor cooking characteristics,easy breakage,and difficulty in processing and molding.The potato whole powder was mixed with specific exogenous starch and exogenous protein to develop extruded gluten-free potato noodles by twin screw extruder,and explore the effects of exogenous addition on extruded noodles from the aspects of quality properties,microstructure based on the response surface test,in order to optimize the process parameters of the twin screw extruder.The effect of freeze-thaw on noodles and the changes of tensile and texture characteristics of noodles during storage were carried out.The conclusions were as followings:(1)Under the addition of different kinds of starch,protein and salt,the infrared spectrum of potato noodles did not change significantly,and no new characteristic peaks appeared,indicating that the types of starch and protein and the changes of added amount had no substantial effect on the characteristic groups of the molecular structure of potato noodles.Univariate experiments showed that under the premise of fixed protein addition and fixed extrusion parameters,the texture characteristics,cooking characteristics and water absorption of noodles were better than those of potato starch addition and other addition of tapioca starch under the premise of fixed protein addition and fixed extrusion parameters,and the micromorphology of the cross-section of extruded noodles with tapioca starch added was more delicate,firm and smooth.The type of protein had a great influence on the texture characteristics of potato whole flour noodles,and when the amount of rice hydrolyzed protein was 6%,the hardness,cohesion and elasticity of the noodles were the best.The scanning electron microscopy shows the best cross-sectional smoothness and fine and compact structure;When the salt addition amount was 1%,the elasticity and water absorption of the noodles were the largest,and the micromorphology of the noodle section was relatively smooth and delicate.In summary,the optimal ratio of compound flour noodles was that the amount of tapioca starch added was 10%,the amount of hydrolyzed protein added to rice was 6%,and the amount of salt added is 1%,which all based on potato whole flour mass of 100 g.This recipe makes compound flour noodles more conducive to obtaining extruded potato noodles with good cooking characteristics.(2)After optimizing the process parameters of the screw extruder on the response surface,it is obtained that the feeding speed is 20 Hz,the speed is 21 Hz,and the temperature is 75℃.This is converted to feeding speed 10r/min,screw speed 150r/min,temperature 75℃.Under these conditions,the sensory evaluation score of potato noodles was(82 ± 1),which was basically consistent with the theoretical value,indicating that the model fit well.The color determination of L*a*b* showed that compared with potato whole flour noodles,gluten-free potato extruded noodles made with 10% tapioca starch,6% rice hydrolyzed protein and1% salt addition and optimized extrusion parameters increased brightness,decreased red and green values,and increased yellow and blue values,and the color was close to that of commercially available wheat flour noodles.(3)The number of freeze-thaw times had a significant effect on the texture characteristics,water absorption rate and breaking rate of noodles,with the increase of freeze-thaw times,the hardness and elasticity of compound flour noodles decreased,the breaking distance decreased,the tensile work first increased and then decreased,the maximum tensile force gradually increased,the water absorption rate of noodles decreased and the breaking rate increased,and the breaking rate of compound flour noodles was close to that of wheat flour noodles.The number of freeze-thaw times has a greater impact on the quality of noodles,and it is recommended that the number of freeze-thaws should not exceed two times.(4)The ductility and plasticity of floured noodles deteriorated with the increase of storage time during the storage period,but the strength and toughness of compound flour extruded noodles were higher than those of wheat flour and raw potato whole flour during the same period.The hardness of compound flour noodles decreased in the early stage of storage,but its hardness increased with the extension of storage time,and the elasticity remained better than wheat flour noodles and potato whole flour noodles,and the chewiness was greater than that of wheat flour noodles,suitable for children and teenagers.