Research On The Modeling Effect And Shape Retention Of The Extrusion-based 3D-printed Typical Prepared Vegetarian Food

Three-dimensional(3D)printing is an emerging technology that can fabricate a 3D object via layer-by-layer deposition.This technology applies an extrusion method for gel or slurry materials via a nozzle controlled by a computer connected to a computer aided design(CAD)model.3D food printing will have a great impact in developing new types of food,individualizing food needs and alleviating food supply shortage.The properties of the raw materials used for printing,the shape accuracy of the printed products and the printing efficiency of the machine are vital for the development of 3D printing technology,and also the bottleneck restricting the wide application of 3D printing technology in the food field.3D printable food materials need to have a certain degree of fluidity,formability,and have qualified physical and chemical properties.In this dissertation,the gel system based on vegetarian food was established by concentrating certain ingredients as raw materials and viscosity modifiers.The mechanical and rheological properties of the material were modified by using different types and amount of ingredients,and the appropriate formula was determined for the 3D printing process.Based on the material properties,the 3D printing process parameters of the material were configured to optimize printing accuracy,which is necessary to meet the geometric fidelity to the target object.This study lays a theoretical foundation and practical application on understanding the application in 3D food printing technology to achieve precise control.Firstly,the effect of different extrusion ways of fused deposition modeling on the quality of 3D printed samples was studied to make bedding for subsequent research.Results showed that the screw-based extrusion way of 3D printing was beneficial to continuously feed the material,whereas the syringe-based extrusion way of 3D printing was available to a wider range of extruded materials.Secondly,the effect of samples with different composition which has special physical properties on 3D printing,and an optimized formula of samples which is technically applied to 3D food printing were investigated.Results showed that the best shape of 3D printing baking dough which was retained with proper gel formation characteristics and physical properties was obtained with a recipe containing water(29 g),sucrose(6.6 g),butter(6.0 g),flour(48 g)and egg(10.4 g)per 100 g of formulation and jelly candy made with water(46.27g),sucrose(47.01 g)and gelatin(6.72 g)per 100 g of formulation were the optimized conditions to print samples matching with targeted geometry.These materials should be homogenous and have appropriate flow properties for extrusion as well as can support its structure during and after printing process.Thirdly,different processing parameters were applied to improve the quality of 3D printed products.The results showed that,Results showed that the printed-baking-dough whose shape best matched the target geometry could be obtained with the following processing parameters: the filament diameter of 2.30 mm,the nozzle movement speed of 25mm/s,the nozzle diameter of 2.0 mm,the nozzle height of 2.40 mm and the extruding temperature of 30? in the 3D printing.Then,pre-treatment and post-treatment of 3D printing were adopted to improve the quality of 3D printed products.Especially for extruded dough which still needed to be baked prior to being eaten,maintaining the shape of the printed products after baking was also very important.Results showed that microwave vacuum drying 4 min mango gel obtained the best shape matching the target model and fast-cooling at –65? baking-dough for more than 10 min after printing and before baking had the best shape retention.Therefore,the optimization of pre-treatment and post-treatment of 3D printing was solved and the total quality of baked-dough printed products improved.Finally,the preliminary analysis of the printing accuracy of a 2-nozzle-extrusion3D-printed cold dish was developed.In this study,the shape of the inner part of the structure and ratios of the ingredients,the material properties(rheological properties,water holding capacity,water status distribution,texture properties and sensory properties)of the cold dish,and the final qualities of 3D constructs were investigated.The rheological properties and texture properties of the material consisting of 500 g/kg mango juice gel and 500 g/kg mashed potatoes were suitable for 2-nozzle 3D printing of the designed objects for Method A.Results showed that both the mango juice gel and the mashed potatoes were suitable for Method B,and the flavor of the printed samples with the tetrahedron model with different layers for Method B can be distinguished using an e-nose.