A composite modified starch, its preparation method and application in ice cream 3D printing

Abstract

The present invention discloses a composite modified starch, a preparation method thereof, and an application thereof in ice cream 3D printing, belonging to the technical field of food 3D printing. The components of the composite modified starch include hydroxypropyl distarch phosphate, wherein the molar substitution degree of hydroxypropyl is 0.06-0.14. The composite modified starch can play a thickening and emulsifying effect in ice cream, realizing the applicability of ice cream for 3D printing. The present invention adopts the method of "pulsed electric field + crosslinking + etherification" to improve the performance and modification efficiency of the modified starch. The physical action of the pulsed electric field decomposes the semi-crystalline flakes and crystalline regions of the starch, releasing more energy to promote the reaction of starch molecules with crosslinking agents and etherification reagents, which is beneficial to the formation of hydroxypropyl distarch phosphate. The present invention uses modified starch as a thickener for ice cream production for the first time, which can realize the personalized design of precise ice cream, realize the freedom of ice cream form, and has broad market prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of food 3D printing, and particularly relates to a composite modified starch, a preparation method thereof, and an application thereof in ice cream 3D printing. Background Art

[0002] 3D printing is a solid free-form additive manufacturing technology and belongs to one of the rapid prototyping technologies for realizing the layer-by-layer construction of complex solid geometries by using digital models. The advantages of 3D printing have been demonstrated in food processing, including the manufacture of complex food shapes, personalized foods, accuracy of nutritional ratios, simplified supply chains, reduced waste, and expanded ingredient ranges. In particular, the 3D printing of ice cream can achieve creative designs, can produce various delicate shapes, patterns, and decorations, realize customized designs, and meet consumers' demands for personalization and innovation. Consumers can choose their favorite flavors, colors, shapes, etc. to obtain a personalized ice cream experience.

[0003] Ice cream is a frozen drink with expanded volume made from raw materials such as water, milk or dairy products, eggs or egg products, sugar, emulsifiers, flavors, etc. through processes such as mixing, sterilization, homogenization, aging, freezing, and hardening. The thickening of the ice cream system is a key step in improving the applicability of ice cream 3D printing. Starch is a green and renewable thickening agent and is an important processing raw material and auxiliary material in the food industry, and is widely used in fields such as convenience foods, flavoring products, and frozen foods. However, due to some basic properties of native starch, such as cold water insolubility and the instability of the paste liquid under conditions such as acid, heat, and shear, the application range of starch is somewhat limited. Especially in ice cream products, compared with other hydrocolloids, the gelatinization viscosity of native starch is too high and the emulsifying property is poor, which will affect the taste of ice cream.

[0004] In recent years, modified starch has developed rapidly. On the basis of the inherent properties of starch, in order to improve the performance of starch and expand its application range, physical, chemical, or enzymatic methods are used to change the particle structure or molecular structure of starch, so that a series of changes occur in the properties of starch (such as gelatinization characteristics, dispersibility, viscosity, emulsifying property, gelation, etc.), increasing certain functions of starch or introducing new characteristics to make it more suitable for certain application requirements. Such products that have been processed twice and have changed properties are collectively referred to as modified starch. Compared with ordinary starch, modified starch has characteristics such as low gelatinization temperature, high transparency, high solubility, strong gelation, good freeze-thaw stability, low viscosity, low temperature resistance, and high temperature resistance. Therefore, it is expected to solve the problems of high gelatinization viscosity and poor emulsifying property of native starch in ice cream production by using modified starch.

[0005] In addition, to meet the requirements of ice cream 3D printing, modified starch also needs to meet the following requirements: (1) Improve the 3D printability of ice cream, and after being mixed with other ingredients of ice cream, it can utilize 3D printing equipment to achieve personalized design of ice cream; (2) Improve the emulsifying performance of starch, and enhance the 3D printing feasibility of the ice cream system by adding modified starch; (3) Improve the taste of starch-based ice cream and avoid poor taste of ice cream caused by excessive hardness of frozen starch.

[0006] Therefore, developing a composite modified starch and its preparation process for ice cream 3D printing is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of the present invention is to provide a composite modified starch suitable for ice cream 3D printing, improve the printability of the material, and enhance the stability and taste of the ice cream system under the conditions of meeting 3D printing.

[0008] To achieve the above purpose, the present invention adopts the following technical solutions:

[0009] The present invention provides a composite modified starch for ice cream 3D printing, and the components of the composite modified starch include hydroxypropyl distarch phosphate, wherein the molar substitution degree of hydroxypropyl is 0.06 - 0.14.

[0010] Research of the present invention shows that compared with other modified starches such as acid hydrolyzed starch, oxidized starch, carboxymethyl starch, α-starch, hydroxypropyl starch, cold water soluble starch, etc., the composite modified starch of hydroxypropyl distarch phosphate can be prepared into 3D printing ink after being mixed with other ingredients of ice cream as a thickener and emulsifier, and has high printing accuracy. With the increase of hydroxypropyl substitution degree, the printing accuracy is improved, and it has the applicability for ice cream 3D printing processing.

[0011] The present invention also provides a method for preparing the above-mentioned composite modified starch, and the preparation method includes the following steps:

[0012] (1) Add starch into an aqueous solution containing a crosslinking agent, adjust the pH value to alkaline, carry out a crosslinking reaction under the action of pulsed electric field, adjust the pH to neutral after the reaction ends, and wash with water to obtain a crosslinked modified starch milk;

[0013] (2) Add sodium sulfate and propylene oxide into the crosslinked modified starch milk under the action of pulsed electric field for etherification reaction, and then filter, wash with water, and dry to obtain the composite modified starch.

[0014] Furthermore, the starch is at least one of tapioca starch, corn starch, potato starch, rice starch, sweet potato starch, and wheat starch.

[0015] The present invention treats starch with a crosslinking agent and an etherifying agent under the action of a pulsed electric field, and uses the physical action of the pulsed electric field to decompose the semi-crystalline flakes and crystalline regions of starch, making the hydroxyl groups on glucose more accessible to the crosslinking agent and the etherifying agent, which is beneficial to the formation of hydroxypropyl distarch phosphate.

[0016] Further, in steps (1) and (2), the pulsed electric field treatment conditions are: electric field strength 10 - 50 kV / cm, pulse width 0 - 100 μs, and pulse frequency 1 - 2000 Hz.

[0017] Preferably, the pulsed electric field treatment conditions are: electric field strength 15 kV / cm, pulse width 40 μs, and pulse frequency 1000 Hz.

[0018] Further, in step (1), the pH value of the starch slurry is adjusted to 10 - 12 with sodium hydroxide to improve the dispersibility of starch.

[0019] The crosslinking agent can be, but is not limited to, sodium trimetaphosphate, sodium hexametaphosphate, and phosphorus oxychloride.

[0020] The molar ratio of the starch to the crosslinking agent is 1:1 - 1:3.

[0021] Further, the crosslinking reaction conditions are 30 - 60 °C for 60 - 90 min.

[0022] Preferably, the crosslinking reaction conditions are 50 °C for 80 min. The heating condition helps to increase the reaction rate. After the reaction, filtration and washing with water are carried out to remove impurities, and crosslinked modified starch milk is prepared.

[0023] In step (2), in the etherification reaction system, sodium sulfate inhibits the swelling of starch, and propylene oxide is used as an etherifying agent to introduce hydroxypropyl groups into the modified starch.

[0024] Further, in the etherification reaction system, the mass - volume percentage concentration of sodium sulfate is 5 - 15%, and the mass - volume percentage concentration of propylene oxide is 2 - 5%; the etherification reaction conditions are: reacting at 15 - 60 °C for 4 - 24 h, and adjusting the pH to 5.5 - 7.5 after the reaction.

[0025] Preferably, in the etherification reaction system, the mass percentage concentration of sodium sulfate is 8%, and the mass percentage concentration of propylene oxide is 2%; the etherification reaction conditions are: reacting at 50 °C for 20 h.

[0026] Another object of the present invention is to provide the application of the composite modified starch in ice cream 3D printing. The application includes: using the composite modified starch as a thickening agent and an emulsifier to be mixed with other raw materials of ice cream to prepare 3D printing ink. By mass percentage, the ice cream 3D printing raw materials contain 6 - 12% of the composite modified starch.

[0027] The present invention also provides a method for 3D printing ice cream, comprising the following steps:

[0028] 1) Mix the raw materials for preparing ice cream, perform pasteurization, and after cooling, perform homogenization to obtain a pretreated material; the raw materials, by mass percentage, include: 6-12% of composite modified starch, 15-30% of whole milk powder, 5-12% of vegetable oil, 6-20% of granulated sugar, 0-2% of emulsifier, and the balance is water;

[0029] 2) Load the pretreated material into the material cylinder of a 3D printer, perform low-temperature aging of the gel, and then perform 3D printing; the conditions for the 3D printing are: the printing speed is 15-30 mm / s, the printing filling rate is 60-100%, the diameter of the printing nozzle is 0.6-1.5 mm, and the printing temperature is 4-25 °C;

[0030] 3) After the 3D printing is completed, freeze the finished product.

[0031] Further, by mass percentage, the composition of the raw materials is: 6% of composite modified starch, 22% of whole milk powder, 10% of vegetable oil, 6% of granulated sugar, 1% of monoglyceride, and the balance is water.

[0032] Further, in step 1), the temperature of the pasteurization is 65-100 °C, and the time is 5-30 min.

[0033] Further, the homogenization is performed by high-pressure microfluidization treatment, and the treatment pressure is 5-100 Pa. The use of high-pressure microfluidization to treat the ice cream material improves the taste of the ice cream.

[0034] Further, in step 2), the low-temperature aging temperature is 0-10 °C, and the time is 4-24 h.

[0035] The 3D printing parameter settings affect the 3D printing accuracy of the ice cream. The ice cream products printed under the above 3D printing conditions show relatively high accuracy. Preferably, the printing speed is 30 mm / s, the printing filling rate is 80%, and the diameter of the printing nozzle is 0.84 mm.

[0036] Further, in step 3), after the ice cream is printed, it is immediately transferred to be stored at -10 to -30 °C.

[0037] The beneficial effects of the present invention are as follows:

[0038] (1) The composite modified starch provided by the present invention can play a thickening and emulsifying effect in ice cream, realizing the applicability of 3D printing of ice cream. Compared with other thickeners, the composite modified starch provided by the present invention does not increase the viscosity of the ice cream system and retains the original taste of the ice cream. Compared with other modified starches, the composite modified starch provided by the present invention has higher emulsifying performance, can balance the oil phase and water phase of the ice cream to prepare ice cream 3D printing ink, and improve the stability of the ice cream system. In addition, compared with other modified starches, the composite modified starch provided by the present invention does not increase the hardness of the ice cream system and improves the taste of the starch-based ice cream.

[0039] (2) The present invention uses the method of "pulsed electric field + crosslinking + etherification" to improve the performance and modification efficiency of modified starch. The physical action of the pulsed electric field decomposes the semi-crystalline flakes and crystalline regions of the starch, promotes the reaction of starch molecules with crosslinking agents and etherification reagents, and is conducive to the formation of hydroxypropyl distarch phosphate.

[0040] (3) The present invention first uses modified starch as a thickener in ice cream production to improve the plasticity of ice cream. Hydroxypropyl distarch phosphate is used to mix with other ingredients of ice cream to prepare ice cream 3D printing ink, and corresponding parameters such as printing speed and filling rate are set to achieve precise personalized design of ice cream, realizing the freedom of ice cream form, and having broad market prospects. Description of the Drawings

[0041] Figure 1 It is the standard curve of propylene glycol.

[0042] Figure 2 It is the physical picture of 3D printed ice cream prepared from the raw materials under the conditions of Example 1. a, b, c, and d are cube, Qiushi Eagle, cartoon dragon, and turtle patterns respectively.

[0043] Figure 3 It is the molecular structure (a) and hydroxypropyl substitution degree (b) of starch modified by pulsed electric field with different electric field intensities.

[0044] Figure 4 It is the influence of pulsed electric field-assisted modification of starch with different electric field intensities on the accuracy of 3D printing of ice cream.

[0045] Figure 5 It is the influence of different modified starches on the accuracy of 3D printing of ice cream.

[0046] Figure 6 It is the influence of 3D printing filling rate on the accuracy of 3D printing of ice cream.

[0047] Figure 7 It is the influence of 3D printing speed on the accuracy of 3D printing of ice cream.

[0048] Figure 8 The influence of nozzle size for 3D printing on the accuracy of 3D printed ice cream.

[0049] Note: There are significant differences between groups marked with different letters in the above figure, that is, P < 0.05. Specific implementation manners

[0050] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the scope of protection of the present invention.

[0051] Unless otherwise specified, the test methods used in the following embodiments are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, are reagents and materials that can be obtained from commercial channels.

[0052] Cassava starch (CAS: 9005-25-8), ethanol (CAS: 64-17-5), sodium hydroxide (CAS: 1310-73-2), sodium trimetaphosphate (CAS: 7785-84-4), sodium sulfate (CAS: 7757-82-6), propylene oxide (CAS: 75-56-9), hydrochloric acid (CAS: 7647-01-0), whole milk powder (purchased from Bright Dairy Co., Ltd., raw material: raw cow milk), vegetable oil (CAS: 8002-75-3), granulated sugar (CAS: 57-50-1), monoglyceride (CAS: 111-03-5), hydroxypropyl distarch phosphate (CAS: 53124-00-8), acid-modified starch (CAS: 65996-64-7), sodium starch octenyl succinate (CAS: 66829-29-6), acetate starch (CAS: 9045-28-7), oxidized starch (CAS: 65996-62-5), acetylated distarch adipate (CAS: 63798-35-6), acetylated distarch phosphate (CAS: 68130-14-3), carboxymethyl starch (CAS: 9063-38-1), α-starch (CAS: 9057-07-2), hydroxypropyl starch (CAS: 68584-86-1).

[0053] The cold water soluble starch is prepared by the following method: weighing 50.0g of cassava starch into a beaker, adding 300mL of 80% (V / V) ethanol solution to dissolve; adding 200mL of 3.0mol / L sodium hydroxide solution, maintaining heating in a water bath at 30°C, reacting for 30min, neutralizing with 3mol / L hydrochloric acid ethanol solution to pH=7.0, then washing with 40% (V / V) ethanol solution, then washing with 95% (V / V) ethanol solution, and finally washing with anhydrous ethanol; drying / freeze-drying the wet solid at 50°C; grinding the blocky solid again and sieving.

[0054] Pulsed electric field (LABOX-650F), high-pressure microfluidizer (Nanogenizer-110P), and 3D printer (Foodbot-S2).

[0055] The general method involved in the following embodiments:

[0056] 1. Starch properties

[0057] 1.1 Hydroxypropyl substitution degree

[0058] 1) Propylene glycol standard curve

[0059] Select 1,2-propylene glycol to draw a standard curve. First, use a pipette to successively transfer 1.00, 2.00, 3.00, 4.00 and 5.00 mL of 1.00 mg / mL 1,2-propylene glycol standard solution into a 100 mL volumetric flask. After making up to volume with distilled water, the concentrations of the 1,2-propylene glycol standard solution are 10, 20, 30, 40 and 50 μg / mL, respectively.

[0060] Prepare a 25mL stoppered glass test tube in advance, immerse the glass test tube in an ice water bath, add 1.00mL of 10.00, 20.00, 30.00, 40.00 and 50.00μg / mL propylene glycol standard solutions in turn, and add 8mL of concentrated sulfuric acid. Then place the glass test tube in a boiling water bath and heat for 3 minutes, and then quench the glass test tube in an ice water bath. When the solution is close to room temperature, slowly add 0.6mL of 3% ninhydrin indicator along the wall of the test tube, shake upside down, and place it in a 25℃ water bath and let the solution stand for 100 minutes. Then add concentrated sulfuric acid to the test tube to adjust the solution volume to 25mL, and shake upside down. After standing for 5 minutes, use a reagent blank for comparison, and use a UV-1800 ultraviolet spectrophotometer to measure the absorbance at 595nm. The absorbance measurement time for all solutions is controlled within 15 minutes. Draw an absorbance-concentration standard curve, such as Figure 1 shown.

[0061] 2) Determination of Hydroxypropyl Content

[0062] Accurately weigh 0.04 - 0.06 g of starch sample, transfer it to a 100 mL volumetric flask, pipette 25 mL of 0.5 mol / L sulfuric acid solution, add it to the volumetric flask, heat in a boiling water bath to fully gelatinize the starch. After heating for 30 min, cool the starch paste solution in the volumetric flask to room temperature.

[0063] Prepare 25 mL stoppered glass test tubes in advance and soak them in an ice - water bath. Take 1 mL of the above - mentioned starch paste solution and add it to the stoppered glass test tube. Then carefully and slowly add 8 mL of concentrated sulfuric acid, and invert the glass test tube up and down to mix evenly. Heat and decompose the glass test tube in a boiling water bath for 30 min. Immediately after the reaction ends, put the glass test tube into the ice - water bath. After the sample cools to room temperature, slowly add 0.6 mL of 3% ninhydrin indicator solution, invert it up and down to shake well, let it stand in a 25 °C water bath for 100 min, then add concentrated sulfuric acid to make the liquid volume in the test tube reach 25 mL, and invert it up and down to shake well. Using distilled water as a comparison, transfer it to a cuvette and let it stand for 5 min, measure the absorbance at 595 nm using an ultraviolet spectrophotometer, and calculate the molar substitution degree of hydroxypropyl in the sample according to the converted propylene glycol content.

[0064] The molar substitution degree (MS) of hydroxypropyl starch is calculated according to Formula 1 - 1 and Formula 1 - 2.

[0065]

[0066]

[0067] In Formulas (1 - 1) and (1 - 2):

[0068] H ---- Percentage content of hydroxypropyl, %;

[0069] F ---- Dilution factor of the sample or blank;

[0070] M1 ---- Mass of propylene glycol in the sample obtained from the standard working curve, g;

[0071] M0 ---- Mass of propylene glycol in the original starch blank sample obtained from the standard working curve, g;

[0072] W1 ---- Mass of the sample, g;

[0073] W0 ---- Mass of the original starch, g;

[0074] 0.7763 ---- Conversion coefficient for converting propylene glycol content to hydroxypropyl content;

[0075] 2.79 ---- Conversion coefficient for converting percentage content of hydroxypropyl to substitution degree.

[0076] 1.2 RVA analysis

[0077] Dissolve the prepared starch (2.0 g) in 25 mL of distilled water, and use a Rapid Visco-Analyzer to detect the change trend of the viscosity of the sample during the heating and cooling processes. Heating mode: The sample solution is maintained at 50 °C for 1 min, heated to 95 °C at a heating rate of 12 °C / min, kept at a constant temperature of 95 °C for 2.5 min, cooled to 50 °C at the same temperature change rate, and finally maintained at 50 °C for 2 min. Stirring rate: 960 rpm for the first 10 s, and then 160 rpm. Record the viscosity parameters.

[0078] 2. Ice cream performance

[0079] 2.1 Printing accuracy

[0080] The 3D printing model is a cuboid with dimensions of 30 (length) × 30 (width) × 15 (height) mm. After measuring the length, width, and height of the printed product with a vernier caliper, calculate the total error percentage to clarify the printing accuracy of the printed product. The specific calculation formula is as follows:

[0081]

[0082] 2.2 Texture detection

[0083] Place the frozen ice cream sample in a single layer on the sample stage of the texture analyzer, select a 35 mm cylindrical probe, and set the test program to two compression tests (TPA). The test parameters are set as follows: pre-test speed 1.50 mm / s; post-test speed 1.50 mm / s; compression distance 1.5 mm; time 10.00 s; trigger point force 0.4 g. According to the obtained force-time curve, use TexturePro CT software to output the texture performance parameters of the ice cream.

[0084] Example 1: Performance of composite modified starch and 3D printing accuracy of ice cream

[0085] 1. Preparation method

[0086] Preparation of composite modified starch: 900 g of cassava starch (containing 10% water) was dispersed in 1625 mL of water (containing 6.5 g of sodium trimetaphosphate), and the pH was adjusted to 10.2 with sodium hydroxide to obtain a starch slurry. The pulsed electric field parameters were set as: frequency 1000 Hz, electric field strength 15 kV / cm, and pulse width 40 μs. The starch slurry was pumped into the treatment chamber at a constant flow rate of 60 mL / min, heated to 50 °C, reacted for 80 min, cooled, neutralized to pH 6.7, filtered, and washed with water to obtain a sodium trimetaphosphate cross-linked starch milk. 8% sodium sulfate (w / v) and 2% propylene oxide (w / v) were added to the above starch milk and reacted at 50 °C for 20 h, then the pH value was adjusted to 6.0 with 8-10% hydrochloric acid, and then filtered, washed and purified, dried at 30 °C, and pulverized and sieved to obtain composite modified starch. The above cross-linking and etherification reactions were carried out under the action of pulsed electric field.

[0087] Preparation of ice cream: By mass percentage, 6% of composite modified starch, 22% of whole milk powder, 10% of vegetable oil, 6% of granulated sugar, and 1% of monoglyceride were fully mixed and then 55% of water was added. It was pasteurized at 70 °C for 15 min, taken out and cooled, and then subjected to high-pressure microfluidization treatment in a high-pressure microfluidizer. The treatment pressure was 100 Pa. Subsequently, it was loaded into the feed cylinder of a 3D printer and aged at 4 °C in a refrigerator for 6 h. Then it was taken out for 3D printing. The nozzle diameter of the printer was 0.84 mm, the moving speed was 30 mm / s, the filling speed was 40 mm / s, and the filling rate was 80%.

[0088] 2. Performance testing

[0089] After testing, the degree of hydroxypropyl substitution in the composite modified starch after pulsed electric field treatment was 0.116, which was 54.67% higher than that without pulsed electric field, significantly improving the binding ability of starch and hydroxypropyl groups. The main component of the composite modified starch prepared in this example was hydroxypropyl distarch phosphate, and the shape, size and characteristics of starch granules could be directly identified by microscopic observation. Under the polarized light of the microscope, a typical polarized light cross could be observed. 1 g of modified starch was added to 20 mL of water to form a suspension, and a few drops of iodine solution were added. The color range should be from dark blue to brownish red.

[0090] After testing, the printing accuracy of the cuboid printed by 3D printing under the above conditions was 95.25%.

[0091] 3. Application

[0092] Replace the 3D printing model, use the raw materials prepared under the above conditions, load them into the 3D printer for 3D printing. As Figure 2As shown in the figure, the ice cream ink prepared from the novel composite modified starch provided in this embodiment can perfectly print the preset model, and accurately complete the printing of patterns such as a cuboid of 30×30×15 mm, the logo of Qiushi Academy, a cartoon dragon, and a tortoise.

[0093] Example 2: Structure, degree of substitution, and gelatinization properties of novel hydroxypropyl distarch phosphate

[0094] According to the starch preparation process in Example 1, when applying pulsed electric field strength, intensity gradients of 0, 5, 10, 15, 20, and 25 kV / cm were set, and the differences in the degree of substitution and gelatinization properties of hydroxypropyl distarch phosphate after pulsed electric field-assisted modification at different electric field strengths were tested.

[0095] The results are as Figure 3 shown. The physical action of the pulsed electric field decomposed the semi-crystalline lamellae and crystalline regions of the starch, releasing more energy to react with starch molecules, cross-linking agents, and etherifying reagents to increase the degree of substitution of the modified starch. Hydroxypropyl distarch phosphate has a high hydrophilicity due to hydroxypropyl. The original starch treated with hydroxypropylation can weaken the hydrogen bond strength inside the original starch granules, making the modified starch more easily absorb water and swell, thus facilitating the improvement of the water retention capacity and low-temperature stability of the starch.

[0096] In addition, as shown in Table 1, the peak viscosity of the modified starch decreased significantly, which is beneficial for not overly increasing the viscosity of the ice cream system during the ice cream preparation process and affecting the taste. The decrease in the gelatinization temperature indicates that the hydrophilicity of the modified starch is improved and it is more easily hydrated and swollen after heating.

[0097] Table 1. Gelatinization properties of starch after pulsed electric field-assisted modification at different electric field strengths

[0098]

[0099]

[0100] Note: Values with different letters in the same column are significantly different (P<0.05).

[0101] Example 3: Influence of different pulsed electric field powers on the accuracy of ice cream 3D printing

[0102] According to the different pulsed electric field strengths in Example 2 and the ice cream preparation method in Example 1. The composite modified starches prepared with different pulsed electric field strengths were respectively used to prepare ice cream 3D printing inks. The ice cream 3D printing accuracy was tested.

[0103] The results are as Figure 4As shown, with the increase of pulsed electric field strength, the 3D printing accuracy of ice cream gradually improves. The ice cream prepared with the composite modified starch obtained at the intensity of 15 kV / cm has the highest 3D printing accuracy. With the continuous increase of pulsed electric field strength, the printing accuracy decreases, but it is still higher than that of the ice cream without applying electric field.

[0104] Example 4: Influence of different types of modified starch on the 3D printing accuracy of ice cream

[0105] Replace the new composite modified starch added in the ice cream preparation process in Example 1 with acid hydrolyzed starch, sodium octenyl succinate starch, acetate starch, oxidized starch, acetylated distarch adipate, acetylated distarch phosphate, carboxymethyl starch, α-starch, hydroxypropyl starch, and cold water soluble starch to prepare ice cream, with other conditions remaining unchanged. Test the 3D printing accuracy and texture properties of the ice cream.

[0106] The results are as Figure 5 shown. Among the replaced modified starches, only carboxymethyl starch, α-starch, hydroxypropyl starch, and cold water soluble starch can be used to prepare ice cream, and the rest of the starches cannot be used to prepare printing ink. Among the modified starches that can be used to prepare 3D printing ice cream ink, the printing accuracy is ranked in the following order: composite modified starch > cold water soluble starch > carboxymethyl starch > hydroxypropyl starch > α-starch. This shows that the modified composite modified starch of the present invention has better emulsifying properties, can balance the oil phase and water phase of ice cream, and improve the stability of the ice cream system.

[0107] The texture analysis of the ice cream is shown in Table 2. There are obvious differences in the texture properties of the 3D printing ice cream prepared with different modified starches. Among them, the 3D printing ice cream prepared with the composite modified starch has the lowest hardness and viscosity, and the highest elasticity. This shows that the modified composite modified starch of the present invention does not have the problem of freezing hardening of the original starch, and effectively improves the taste of the starch-based ice cream.

[0108] The above results show that the composite modified starch prepared by the present invention has the highest applicability in the 3D printing processing of ice cream.

[0109] Table 2. Texture properties of 3D printing ice cream prepared with different modified starches

[0110]

[0111] Note: Values with different letters in the same column are significantly different (P < 0.05).

[0112] Example 5: Influence of printing parameters on the accuracy of ice cream and the morphology of the best 3D printing ice cream product

[0113] According to the 3D printing process of ice cream in Example 1, the influence of printing parameters on the 3D printing accuracy of ice cream was verified by changing the filling rate, printing speed, and nozzle size. Among them, the sample with the best printing accuracy was selected for the preparation of the 3D printing ink for ice cream.

[0114] As Figure 6 shown, with the increase of the filling rate, the 3D printing accuracy of ice cream is significantly improved. A lower filling rate will reduce the self-supporting performance of the ice cream itself.

[0115] As Figure 7 shown, with the increase of the printing speed, the time required to complete the product gradually decreases, but the printing accuracy also decreases accordingly. A faster printing speed will cause incomplete extrusion lines during the printing process. Therefore, the ice cream has the highest accuracy and the fastest completion efficiency at a printing speed of 30 mm / s.

[0116] As Figure 8 shown, the nozzle size determines the shearing effect and extrusion pressure on the ice cream ink. With the increase of the nozzle size, the 3D printing accuracy of ice cream first increases and then decreases. A smaller nozzle will cause the ink not to be extruded or the extrusion lines to be discontinuous, and a larger nozzle will cause the printing resolution to decrease and the surface to be rough. Therefore, the ice cream printed with a nozzle with a pore diameter of 0.84 mm has the highest accuracy.

[0117] The above optimal printer parameters and 3D printing ice cream ink are used to print personalized patterns. All 3D printed products show high accuracy, with no obvious collapse of the samples, no swelling at the edges of the samples, not rough, and distinct edges.

Claims

1. Application of a composite modified starch in 3D printing of ice cream, characterized in that, The composition of the composite modified starch includes hydroxypropyl distarch phosphate, wherein the molar substitution degree of hydroxypropyl is 0.06 - 0.14; calculated by mass percentage, the ice cream 3D printing raw material contains 6 - 12% of the composite modified starch.

2. The application according to claim 1, characterized in that, The preparation method of the composite modified starch includes the following steps: (1) Add starch into an aqueous solution containing a cross-linking agent, adjust the pH value to alkaline, carry out a cross-linking reaction under the action of a pulsed electric field, after the reaction ends, adjust the pH to neutral, wash with water, and obtain a cross-linked modified starch milk; (2) Add sodium sulfate and propylene oxide into the cross-linked modified starch milk under the action of a pulsed electric field to carry out an etherification reaction, then filter, wash with water, and dry to obtain the composite modified starch.

3. The application according to claim 2, wherein The starch is at least one of tapioca starch, corn starch, potato starch, rice starch, sweet potato starch, and wheat starch.

4. The application according to claim 2, characterized in that In steps (1) and (2), the pulsed electric field treatment conditions are: electric field strength 10 - 50 kV / cm, pulse width 0 - 100 μs, pulse frequency 1 - 2000 Hz.

5. The application according to claim 2, characterized in that, In step (1), adjust the pH to 10 - 12, the cross-linking reaction conditions are 30 - 60 °C, and the reaction time is 60 - 90 min.

6. The application according to claim 2, wherein In step (2), in the etherification reaction system, the mass-volume percentage concentration of sodium sulfate is 5 - 15%, and the mass-volume percentage concentration of propylene oxide is 2 - 5%; the etherification reaction conditions are: react at 15 - 60 °C for 4 - 24 h, and after the reaction ends, adjust the pH to 5.5 - 7.

5.

7. A method for 3D printing ice cream, characterized in that, Include the following steps: 1) Mix the raw materials for preparing ice cream, carry out pasteurization, and after cooling, carry out homogenization to obtain a pretreated material; the raw materials calculated by mass percentage include: 6 - 12% of composite modified starch, 15 - 30% of whole milk powder, 5 - 12% of vegetable oil, 6 - 20% of granulated sugar, 0 - 2% of emulsifier, and the balance is water; the composition of the composite modified starch includes hydroxypropyl distarch phosphate, wherein the molar substitution degree of hydroxypropyl is 0.06 - 0.14; 2) Load the pretreated material into the 3D printer material cylinder, after low-temperature aging of the gel, carry out 3D printing; the conditions for 3D printing are: printing speed is 15 - 30 mm / s, printing filling rate is 60 - 100%, printing nozzle diameter is 0.6 - 1.5 mm, and printing temperature is 4 - 25 °C; 3) After 3D printing is completed, freeze the finished product.

8. The method for 3D printing ice cream according to claim 7, characterized in that, In step 1), the temperature of pasteurization is 65 - 100 °C, and the time is 5 - 30 min; homogenization is carried out by high-pressure microfluidization treatment, and the treatment pressure is 5 - 100 Pa.

9. The method for 3D printing ice cream according to claim 7, characterized in that, In step 2), the low-temperature aging temperature is 0 - 10 °C, and the time is 4 - 24 h.

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