Effect Of Ultra-high Pressure Treatment On 3D Printing Characteristics Of Blueberry Gel System

3D printing technology of food is a kind of processing technology that produces 3D three-dimensional food through layered printing of materials and layer-by-layer superposition.It can optimize the diet nutrition according to the dietary needs of different people,and conveniently produce healthy and nutritious food with personalized shape and texture.3D printing of food mainly focuses on extrusion molding.The development of appropriate food materials is the key to promote the development of 3D printing technology.The extrusion performance,gel strength,formability and ductility of printing materials can be improved by adjusting to obtain products with good printing effect.In this paper,the blueberry gel system was used as the 3D printing material,and pectin,konjac gum and sucrose were added to the system to improve the printing characteristics of the material and obtain the appropriate printing material.On this basis,the effects of different ultra-high pressure processing conditions on the printing effect and stability of blueberry gel system were studied.The response surface optimization experiment was designed to further study the influence of three variables: pectin,konjac gum additive amount and ultra-high pressure treatment pressure on the printing effect of the gel system.Finally,the mechanism of ultra-high pressure to improve the printing performance is analyzed.This paper provides a technical reference for using 3D printing technology to develop food,and provides solutions for digital food design and nutrition control.The main work of this paper is as follows:By studying the physical properties of gels related to 3D printing,the formula of blueberry gels system suitable for 3D printing of extruded food was determined.To investigate the effects of blueberry pectin,konjac gum and sucrose on 3D printing.The results show that adding a certain amount of pectin,konjac gum and sucrose can improve the suitability of gel printing and improve the molding effect of printed samples.Konjac gum increases toughness and hardness,sucrose can flavor and lock up short distance of water.When the amount of addition exceeds 6:4:2g respectively,the printability of the gel material will be reduced,and problems such as extrusion wire breakage and sample deformation will occur.When the mass of blueberry pulp: pectin: konjac gum: sucrose was 22.5:4:2:1g,the water mass fraction of the gel system was 68.45±0.70%,and the obtained gel system had a good 3D printing effect.On the basis of the formula obtained above,the ultra-high pressure treatment was carried out to explore the effect of ultra-high pressure treatment on the printing effect of the blueberry gel system and the sample structure stability.The research results showed that the gel system after ultra-high pressure treatment was squeezed evenly and the lines between the filaments were clear.The treatment pressure less than 400 MPa has little effect on the gel properties,and the appropriate pressure treatment time(10 min)can improve the sample resolution,and the model reduction degree can reach more than 90%.Compared with the treatment time,the treatment pressure has a significant effect on the sample formability.The response surface optimization experiment was designed to further study the influence of three variables: pectin,konjac gum additive amount and ultra-high pressure treatment pressure on the printing effect of the gel system.The results show that the amount of konjac gum added has a great impact on the printing deviation.After optimization and adjustment,the sample printing effect is the best,the lines between the printing wires are clear,the connection is tight,and the printing size deviation is the smallest.Finally,the mechanism of ultra-high pressure to improve the printing performance is analyzed.The gel system is an amorphous structure.After ultra-high pressure treatment,the gel material structure is more stable,the molecular space is smaller,more compact,the gel strength is increased,the print sample has good support.The main intermolecular forces in the gel system are hydrogen bonds and there is a small amount of hydrophobic interaction.The gel system has high crystallinity before and after the ultra-high pressure treatment,and the gel with high crystallinity is accompanied by faster recovery performance,which indicates that the gel after the ultra-high pressure treatment is conducive to the sample molding.The experimental results show that the ultra-high pressure technology can be used to pre-process 3D printing materials to improve the accuracy of the printed samples and produce personalized food.