Preparation method and application of freeze-dried meal replacement powder block with low glycemic index

Abstract

The invention discloses a preparation method and application of a freeze-dried meal replacement powder block with a low glycemic index. The preparation method comprises the following steps: selecting plantain large bananas in a specific growth period, carrying out heat-moisture treatment and vacuum low-temperature drying to prepare banana resistant starch with high resistant starch content, combining fine pretreatment (ultrasonic cleaning, steam blanching and low-temperature drying) of raw materials such as spinach, broccoli and Chinese yam, and compounding zero-calorie sugar, cooked soybean meal, gordon euryale seed powder and probiotic powder, so as to prepare the banana resistant starch with high resistant starch content. A multi-component nutrition synergistic system is formed. A porous uniform structure is constructed by adopting pre-homogenization, three-section ultrasonic 3D printing and integrated freeze-drying technologies, and the rehydration rate and the survival rate of probiotics are remarkably improved. Through the synergistic effect of the resistant starch and the gordon euryale seed polysaccharide, the low glycemic index is realized, and meanwhile, the proliferation of beneficial bacteria in intestinal tracts is promoted. The product has instant convenience, nutritional functionality and long shelf life, and is suitable for the field of healthy meal replacement food.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and in particular relates to a preparation method of a low-glycemic index freeze-dried meal replacement powder block and its application. Background Art

[0002] With the accelerated pace of life and the refinement of dietary structure in modern society, excessive energy intake and nutritional imbalance have become key factors in inducing metabolic syndromes such as obesity and type 2 diabetes. In this context, the development of healthy foods that are both nutritionally balanced and convenient to eat has become an important technical direction for improving public nutritional status. As an important branch of functional foods, meal replacement powder achieves a balance between low calorie intake and basic nutritional supply through standardized nutritional formulas. It has become an effective carrier for weight management and chronic disease intervention and is deeply favored by consumers. In recent years, the market size of meal replacement powder products has continued to grow. However, existing meal replacement powder products mostly rely on basic raw materials such as soy protein and maltodextrin. Although they can provide a sense of fullness, they generally lack functional components such as dietary fiber, resistant starch and probiotics, resulting in a single nutritional function of the product, making it difficult to achieve a synergistic effect of blood sugar homeostasis regulation and intestinal flora regulation.

[0003] To improve sensory properties, traditional meal replacement powder products often add synthetic sweeteners, thickeners and other substances to prevent caking and increase the smoothness of drinking. However, long-term intake may cause intestinal inflammation. In addition, during the processing process, the current high-temperature spray drying process easily leads to the inactivation of heat-sensitive functional ingredients, and the active polysaccharide structure in the plant raw materials is easily destroyed, significantly reducing its physiological function. Therefore, screening natural functional raw materials and exploring new compounding technologies and processing methods have become the core direction of meal replacement powder product development (WANG X, ZHANG M, Qiu LQ, et al. Improvement of the Flavor of Powder-Form Meal Replacement: a Review of Relevant Technologies[J]. Food and Bioprocess Technology, 2023, 16(3): 492-509.). Studies have shown that adding resistant starch to meal replacement powder can increase the consistency and smooth taste of meal replacement powder, avoiding the roughness of traditional high-fiber products. Resistant starch can delay glucose absorption and reduce postprandial blood sugar peaks, making it suitable for diabetic patients and people who control sugar. However, resistant starch has problems such as strong hygroscopicity and easy agglomeration, and quality control requires full-process moisture control and formula collaborative design throughout the process chain.

[0004] Spinach is rich in iron, folic acid and chlorophyll, which can improve anemia and enhance antioxidant capacity. Broccoli is rich in dietary fiber, which can promote intestinal motility. Chinese yam contains mucin and oligosaccharides, which can regulate blood sugar and promote the proliferation of intestinal probiotics. Poria cocos is mainly composed of β-glucan and polysaccharides, which can enhance immunity and assist in diuresis and swelling. Gorgon fruit is rich in amylase inhibitors and B vitamins, which helps to strengthen the spleen and stop diarrhea. Soybeans provide high-quality plant protein, soy isoflavones and dietary fiber, which synergistically lower cholesterol and prolong satiety. However, as the raw material source for freeze-dried meal replacement powder, the above raw materials need to pay attention to issues such as control of heat-sensitive material loss, powder uniformity regulation, and formula compatibility optimization during the processing process. Otherwise, it is difficult to ensure the nutritional function and stability of the product.

[0005] Banana is a tropical fruit with high nutritional value. Its rich resistant starch has significant effects in regulating blood sugar, improving intestinal flora and preventing metabolic syndrome. In particular, unripe green bananas and Plantain plantains are high-quality sources (Minenhle K, Eugenie K, Bhekisisa CD. Functional properties and in vitro starch digestibility of infrared-treated (micronized) green banana flour [J]. Journal of the Science of Food and Agriculture, 2023, 103 (9): 4329-4339.). Compared with other bananas, Plantain plantains have a dense starch granule structure and a high content of amylose. During the ripening process, starch degradation is slow, and it has higher digestibility and thermal stability, making it more suitable for industrial processing. However, existing banana processing products are mostly limited to snacks, and there are still technical bottlenecks in the field of meal replacement products. This is mainly due to its strong hygroscopicity and easy gelatinization at high temperatures, which makes product quality difficult to control. Summary of the Invention

[0006] To address the shortcomings and deficiencies of existing technologies, the present invention provides a method for preparing a low-glycemic index freeze-dried meal replacement powder and its application. This invention is not only suitable for people with intestinal health management, blood sugar control, and rapid nutritional supplementation needs, but also enriches meal replacement powder product formats, transcending the single function of traditional meal replacement powders and endowing the product with intestinal flora regulation properties.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for preparing a freeze-dried meal replacement powder comprises the following steps:

[0009] 1) Spinach powder, broccoli powder, yam powder, banana resistant starch, zero-calorie sugar, cooked soybean powder, gorgon fruit powder, and probiotic powder are mixed in proportion to obtain a composite powder;

[0010] 2) slurrying the composite powder and water in proportion, and pre-homogenizing to obtain a composite powder homogeneous slurry;

[0011] 3) homogenizing the composite powder into a slurry and subjecting it to a three-stage ultrasonic 3D printing process to obtain a 3D printing composite powder;

[0012] 4) The 3D printed composite powder is placed in a refrigerator for quick freezing, and then placed in a freeze dryer for freeze drying to obtain a freeze-dried meal replacement powder block.

[0013] Preferably, the preparation method of the spinach powder, broccoli powder, yam powder and gorgon fruit powder in step 1) is: selecting spinach, broccoli, yam and gorgon fruit raw materials, and ultrasonically cleaning, steam blanching, cutting and quick freezing, low-temperature drying, crushing and sieving the raw materials to obtain spinach powder, broccoli powder, yam powder and gorgon fruit powder with a particle size of 80-100 mesh, respectively. More preferably, the particle size is controlled to be 100 mesh.

[0014] Preferably, the preparation method of the banana resistant starch in step 1) is as follows: Plantain plantains with a growth period of 180-240 days are selected, and the plantains are washed, sliced, soaked, subjected to wet heat treatment, vacuum-dried at low temperature, ultrafinely crushed, and sieved to obtain banana resistant starch with a particle size of 80-100 mesh.

[0015] Preferably, the process parameters of the heat-moisture treatment of the banana resistant starch in step 1) are 105-120° C., 60-120 min, more preferably 110° C., 90 min.

[0016] Preferably, the process parameters for vacuum low-temperature drying of the banana resistant starch in step 1) are 45-55° C., 0.005-0.020 MPa, and 240-360 min, more preferably 45-50° C., 0.015 MPa, and 300 min.

[0017] Preferably, the process parameters of the ultrafine grinding of the banana resistant starch in step 1) are a particle size of 300-500 mesh after grinding, an ultrafine grinding temperature of ≤35°C, and a processing time of 10-15 minutes. More preferably, the particle size after grinding is 400 mesh, the ultrafine grinding temperature is 30°C, and the processing time is 12 minutes.

[0018] Preferably, the preparation method of the cooked soybean powder in step 1) is: selecting soybeans, washing, microwave baking, peeling, crushing, and sieving to obtain cooked soybean powder with a particle size of 80-100 mesh, more preferably 100 mesh.

[0019] Preferably, the probiotic in step 1) is one of Bifidobacterium, Lactobacillus, and Lactococcus, more preferably Bifidobacterium.

[0020] Preferably, in parts by mass, the ratio of each material in step 1) is: 12-15 parts by mass of the spinach powder, 3-5 parts by mass of broccoli powder, 20-25 parts by mass of yam powder, 25-30 parts by mass of banana resistant starch, 5-8 parts by mass of zero-calorie sugar, 15-20 parts by mass of cooked soybean powder, 10-13 parts by mass of gorgon fruit powder, and 10-13 parts by mass of probiotics.

[0021] Preferably, in parts by mass, the ratio in step 2) is: 100-110 parts by mass of the composite powder and 300-350 parts by mass of water, more preferably 100-105 parts by mass of the composite powder and 300-310 parts by mass of water.

[0022] Preferably, the pre-homogenization temperature in step 2) is 40-60°C, more preferably 40-50°C.

[0023] Preferably, in step 3), the three-stage ultrasonic 3D printing is ultrasonic-assisted printing at the nozzle during the 3D printing process, and the entire printing process includes three printing processes at different temperatures (temperature zones) performed sequentially. The printing time of the three different temperature zones is equal, and the three temperature zones are respectively controlled at 45-55°C, 55-70°C and 35-40°C, the ultrasonic power is 100-300W, and the overall printing time is controlled at 15-20min. More preferably, the three temperature zones are respectively at 45-50°C, 60-65°C and 35-38°C, the ultrasonic power is 150-200W, and the overall printing time is 15min.

[0024] Preferably, the quick freezing temperature in step 4) is -40 to -50°C for 120 to 180 min, more preferably -40 to -45°C for 120 to 130 min.

[0025] The present invention also provides a freeze-dried meal replacement powder block prepared by the method.

[0026] The present invention also provides the use of the freeze-dried meal replacement powder in preparing food or medicine for regulating intestinal flora.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects.

[0028] (1) The present invention innovatively introduces a three-stage temperature-controlled ultrasonic 3D printing technology. In the process of preparing meal replacement powder blocks, by setting different temperature zones and nozzle ultrasonic power, the slurry is thermally induced layer by layer at low temperature to avoid the inactivation of heat-sensitive nutrients and probiotics due to high temperature. During the printing process, a micro-scale controllable porous three-dimensional network structure is formed, which is conducive to freezing nucleation and subsequent water migration control. Finally, after freeze-drying, a stable porous powder block structure with an average pore size of 20-60μm and a specific surface area increased by 28% is obtained. This structure has a good encapsulation and sustained release protection effect on probiotics. Testing under a simulated gastrointestinal digestion environment found that the survival rate of probiotics was as high as 82.5%, which is much higher than that of traditional powdered meal replacement products (less than 40%). The rehydration recovery rate after freeze-drying is good, and the palatability and solubility are significantly improved. This configuration achieves precise protection and directional release of functional factors while ensuring morphological integrity. The technical path has good versatility and scalability.

[0029] (2) The present invention uses banana resistant starch prepared by wet heat treatment, vacuum low-temperature drying and ultrafine grinding as the main structural matrix, with a particle size controlled at about 400 meshes, a stable crystal structure and strong resistance to enzyme digestion. By synergistically compounding with low-GI ingredients such as yam powder, gorgon powder and soybean powder, the overall glycemic potential of the system is further reduced. More importantly, the three-stage temperature-controlled ultrasonic 3D printing method adopted by the present invention realizes a dense composite structure of heat-induced directional cross-linking and layer-by-layer stacking during the printing process, forming a microstructure barrier with strong spatial closure and continuous pore walls, which significantly blocks the direct contact between starch and digestive enzymes. Simulated enzymatic hydrolysis experiments show that the printed structure can reduce the overall enzymatic hydrolysis rate of the system by about 46%, delay the sugar release peak by about 30 minutes, and the overall pGI value is lower than 45, which is better than similar unprinted samples (pGI 64). The structural shielding effect is the key to the synergistic mechanism of "physical enzyme control + nutritional sugar control", which enables meal replacement products to have both sustained-release properties and digestion-resistant structure, providing a new strategy for the development of healthy sugar-controlled staple food replacement products.

[0030] (3) By synergistically combining plant-based raw materials such as spinach, broccoli, soybeans, yam, and gorgon fruit with probiotic powder (such as bifidobacteria and lactic acid bacteria), the product is given a new function of regulating intestinal microecology while maintaining metabolic nutritional balance. In vitro simulated intestinal fermentation experiments showed that the powder block can significantly increase the abundance of probiotics, with bifidobacteria and lactobacilli increasing by 241% and 214% respectively, and the F / B value decreasing by 32%. More significantly, within a 48-hour fermentation cycle, the total short-chain fatty acid content (acetic acid + propionic acid + butyric acid) induced by the powder block reached 78.6 mmol / L, which is about 2.3 times higher than that of conventional meal replacement powder, and butyric acid accounts for more than 21%, playing a key role in intestinal epithelial repair and anti-inflammation. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below with reference to examples and comparative examples, but the embodiments of the present invention are not limited thereto.

[0032] The term "1 part by mass" as used in the specific embodiments of the present invention refers to 1 g. In actual production processes, the amount of each raw material or substance used can be scaled up according to the mass formula. In the examples of the present invention, if no specific conditions are specified, the conditions are conventional or recommended by the manufacturer. All raw materials, reagents, etc. used without specifying the manufacturer are commercially available.

[0033] The raw materials used in the present invention are described below:

[0034] Spinach powder, broccoli powder, yam powder, and gorgon fruit powder can be purchased commercially, and the powder particle size must be 80-100 mesh. Spinach powder, broccoli powder, yam powder, and gorgon fruit powder can also be prepared by the following method: spinach, broccoli, yam, and gorgon fruit are selected, and are ultrasonically cleaned, steam blanched, cut into pieces and quick-frozen, low-temperature dried, crushed, and sieved to obtain spinach powder, broccoli powder, yam powder, and gorgon fruit powder with a particle size of 80-100 mesh.

[0035] The cooked soybean powder is prepared by the following method: soybeans are selected, washed, microwave-baked, peeled, crushed, and sieved to obtain cooked soybean powder with a particle size of 80-100 meshes.

[0036] Banana resistant starch is prepared using the following method: Plantain bananas grown for 180-240 days are cleaned, sliced, soaked, subjected to wet heat treatment, vacuum-dried at low temperatures, ultrafinely ground, and sieved to obtain banana resistant starch with a particle size of 80-100 mesh. The wet heat treatment temperature is controlled at 105-120°C for 60-120 minutes, more preferably at 110°C for 90 minutes. The vacuum-drying process parameters are: temperature 45-55°C, pressure 0.005-0.020 MPa, and treatment time 240-360 minutes, more preferably: temperature 45-50°C, pressure 0.015 MPa, and treatment time 300 minutes. The ultrafine grinding process parameters are: target particle size 300-500 mesh, treatment temperature ≤35°C, and treatment time 10-15 minutes, more preferably: target particle size 400 mesh, treatment temperature 30°C, and treatment time 12 minutes.

[0037] Examples 1-8

[0038] Step 1: Select Plantain plantains at an appropriate growth stage according to the operating conditions in Table 1. Moist heat treatment, vacuum drying, and ultrafine grinding are performed to obtain banana resistant starch. This is then mixed with spinach powder, broccoli powder, Chinese yam powder, Euryale gorgonii powder, cooked soybean powder, zero-calorie sugar, and probiotic powder of appropriate particle sizes to obtain a composite powder. The composite powder comprises, by weight, 12 parts spinach powder, 3 parts broccoli powder, 20 parts Chinese yam powder, 12 parts Euryale gorgonii powder, 15 parts cooked soybean powder, 5 parts zero-calorie sugar, 10 parts probiotic powder, and 25 parts banana resistant starch.

[0039] Step 2: Mix the composite powder and water in the proportions shown in Table 2 to prepare a slurry, and pre-homogenize to obtain a composite powder homogeneous slurry;

[0040] Step 3: The composite powder is homogenized into a slurry and subjected to a three-stage ultrasonic 3D printing process according to the temperature, ultrasonic frequency, and time shown in Table 2 to obtain a 3D printing composite powder;

[0041] Step 4: Place the 3D printed composite powder in a refrigerator for quick freezing according to the temperature and time shown in Table 2, and then place it in a freeze dryer for freeze drying to obtain a freeze-dried meal replacement powder block.

[0042] The probiotic survival rate, digestibility, in vitro glycemic index (pGI) and regulatory effect on intestinal flora of the obtained freeze-dried meal replacement powder are shown in Tables 5 and 6.

[0043] Table 1 Composite powder formula and process parameters in Examples 1-8

[0044]

[0045] Table 2 Slurry mixing ratio and process parameters of freeze-dried meal replacement powder blocks in Examples 1-8

[0046]

[0047] Comparative Examples 1-5:

[0048] According to the conditions and amounts shown in Tables 3 and 4, and with reference to the steps of Examples 1-8, freeze-dried meal replacement powder blocks were obtained.

[0049] The probiotic survival rate, digestibility, in vitro glycemic index (pGI) and regulatory effect on intestinal flora of the obtained freeze-dried meal replacement powder are shown in Tables 5 and 6.

[0050] Table 3 Composite powder formula and process parameters in Comparative Examples 1-5

[0051]

[0052] Table 4 Slurry mixing ratio and process parameters of freeze-dried meal replacement powder blocks in comparative examples 1-5

[0053]

[0054] The test method involved in the present invention is:

[0055] (1) The digestibility test method is as follows: weigh 1g (dry basis) sample into a conical flask, add 20ml sodium acetate buffer solution, and vortex mix. Separately, use 20ml sodium acetate buffer solution as a blank sample. Add 7 glass beads to simulate the gastrointestinal peristalsis environment, and place in a 37℃ constant temperature water bath shaker for a certain period of time. Then add 5ml of enzymatic hydrolysate to the conical flask, react at an amplitude of 160stoke / min for 20min, measure 0.5ml of the reaction solution and place it in a centrifuge tube containing 70% ethanol, take three portions, and centrifuge at 4000r / min for 5min. Then take 0.1ml of the supernatant and place it in a centrifuge tube containing 3ml of GOPOD reagent, and place it in a 45℃ water bath for 20min. Finally, the color-developed solution is tested for absorbance at 510nm. Take another 0.1ml of 1mg / ml glucose standard solution and perform the same treatment. At the same time, take 0.1ml of deionized water as a blank sample. After 120 min of reaction, another sample was taken, and its treatment and testing method was the same as that of the 20 min reaction solution.

[0056] The digestibility of the samples was characterized by the contents of rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS).

[0057]

[0058] Where: A t represents the absorbance value of the test sample, V represents the total volume of the test sample (ml), C represents the concentration of the standard glucose solution (mg glucose / ml), A s Represents the absorbance value of standard glucose solution, W t represents the mass of the sample, and D represents the dilution factor.

[0059] Substituting the results into the following formula, the digestibility of the sample can be calculated.

[0060] RDS=(G 20 -FG)×0.9

[0061] SDS=(G 120 -G 20 )×0.9

[0062] RS=TS-(RDS+SDS)

[0063] Where: G 20 represents the glucose content after 20 min of enzymatic hydrolysis, G 120 represents the glucose content after 120 min, FG represents the glucose content of the sample before enzymatic hydrolysis, and TS represents the total starch content.

[0064] (2) In vitro glycemic index (pGI) test method: Weigh 1g (dry basis) sample into a conical flask, add glass beads and 20mL distilled water, and make a blank control. Adjust the solution pH to 1.2, add 1mL of 2% pepsin solution, and incubate at 37℃ for about 10min. Take 0.5mL of digestion solution to measure glucose equivalent, which is recorded as the glucose equivalent at 0min. At the same time, adjust the incubation solution pH to 5.2, add 5mL of mixed enzyme, and continue incubation at 37℃. Take 0.5mL of digestion solution to measure glucose equivalent at 20, 60, 120, and 180min, respectively. Calculate the starch hydrolysis rate of the sample during the digestion process based on the measured glucose equivalent.

[0065]

[0066] The starch hydrolysis curve of the sample was plotted with starch hydrolysis rate as the ordinate and time as the abscissa. This curve follows the first-order reaction equation. The area under the curve (AUC) was calculated, and the hydrolysis index (HI) and predicted glycemic index (PGI) of the sample were calculated according to the following formula.

[0067]

[0068] PGI = 39.71 + (0.549 × HI)

[0069] Where: tf represents the end time of digestion (i.e. 180 min), t0 represents the start time of digestion (i.e. 0 min).

[0070] (3) Study on the influence of intestinal flora: Accurately weigh 1g (dry basis) of freeze-dried meal replacement powder sample into a 150mL conical flask, place 7 glass beads in each flask and add 20mL of sodium acetate buffer, vortex mix. Adjust the pH of the sample to 1.2 with 5% hydrochloric acid solution, and record the amount of hydrochloric acid used. Add 1mL of 2% pepsin solution and incubate in a 37℃ water bath shaker for 30min, and prepare a blank group at the same time. Then, adjust the pH of the sample to 5.2 with 1M and 0.1M sodium hydroxide solutions, add 5mL of mixed enzyme, vibrate and hydrolyze at 37℃ and 160rpm for 120min, and inactivate the enzyme in a boiling water bath for 10min. After the sample cools to room temperature, centrifuge at 6000r / min for 15min, add 20mL of distilled water again and centrifuge under the same conditions, dry the precipitate in a vacuum drying oven at 35℃, crush and sieve for use.

[0071] The conical-bottom centrifuge tubes of the above samples were accurately weighed in advance and sterilized under UV light for 30 minutes. Then 8 mL of culture medium and 1 mL of fecal bacteria solution were added and fermentation experiments were carried out in an incubator under anaerobic conditions at 37 ° C. Five time points were set at 0, 6, 12, 24 and 48 h, and 3 parallels were set for each time point. The centrifuge tubes were removed at each time point and centrifuged at 10,000 r / min and 4 ° C for 10 minutes. The supernatant and precipitate were stored in a -80 ° C refrigerator.

[0072] Method for determining bacterial abundance:

[0073] DNA was extracted from in vitro fermentation pellet samples frozen at -80°C to obtain total bacterial DNA. The V3-V4 region of the bacterial 16S rRNA gene was amplified using the following primers: 338F 5'-ACCTACGGGAGGCAGCA-3' and 806R 5'-GACTACHVGGGTWTCT AAT-3'. The amplified amplified amplification sequence was sequenced on the GENEDENOVA platform. Data analysis revealed the F / B ratio and probiotic abundance.

[0074] Table 5 Probiotic survival rate and digestibility of freeze-dried meal replacement powder blocks in Examples 1-8 and Comparative Examples 1-5

[0075]

[0076] Table 6 Nutritional properties of freeze-dried meal replacement powder blocks in Examples 1-8 and Comparative Examples 1-5

[0077]

[0078] The data in the table show that the Plantain banana's growth period, processing technology, and three-stage temperature-controlled ultrasonic 3D printing temperature control strategy all significantly impact the quality and nutritional benefits of the freeze-dried meal replacement powder. Plantain bananas with a 240-day (approximately 8-month) growth cycle were selected because they produce 27.9±0.3% high-resistant starch, which has a significant positive effect on regulating pGI values (41.3±0.3) and increasing the abundance of intestinal probiotics (Bifidobacteria 26.9±0.3%). When moist heat treatment (110°C, 90 min), vacuum low-temperature drying (50°C, 0.015 MPa, 300 min) and three-stage ultrasonic 3D printing (45°C / 60°C / 30°C, 170W, 15 min) work synergistically, and the composite powder-water ratio is optimized to 100:300 and the ultrafine grinding particle size is controlled to 400 mesh, the processing characteristics and nutritional function regulation effect of the freeze-dried meal replacement powder are best, and the following are simultaneously achieved: probiotic survival rate >96.1±0.4%, resistant starch content >27.8±0.3%, pGI value <42, and bifidobacterium colonization rate >26.8±0.4%.

[0079] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for preparing a low glycemic index freeze-dried meal replacement powder, characterized in that: The steps include: 1) Spinach powder, broccoli powder, yam powder, banana resistant starch, zero-calorie sugar, cooked soybean powder, gorgon fruit powder, and probiotic powder are mixed in proportion to obtain a composite powder; 2) slurrying the composite powder and water in proportion, and pre-homogenizing to obtain a composite powder homogeneous slurry; 3) homogenizing the composite powder into a slurry and subjecting it to a three-stage ultrasonic 3D printing process to obtain a 3D printing composite powder; 4) The 3D printed composite powder is placed in a refrigerator for quick freezing, and then placed in a freeze dryer for freeze drying to obtain a freeze-dried meal replacement powder block.

2. The preparation method according to claim 1, characterized in that Step 1) The preparation method of the spinach powder, broccoli powder, yam powder and gorgon fruit powder is as follows: spinach, broccoli, yam and gorgon fruit are selected, and respectively subjected to ultrasonic cleaning, steam blanching, cutting and quick freezing, low-temperature drying, crushing and sieving to obtain spinach powder, broccoli powder, yam powder and gorgon fruit powder with a particle size of 80-100 mesh.

3. The preparation method according to claim 1, characterized in that Step 1) The banana resistant starch is prepared by washing, slicing, soaking, heat-treating, vacuum-drying, ultrafine grinding, and sieving to obtain banana resistant starch with a particle size of 80-100 mesh. The cooked soybean powder is prepared by washing, microwave-baking, peeling, grinding, and sieving to obtain cooked soybean powder with a particle size of 80-100 mesh.

4. The preparation method according to claim 1, characterized in that The probiotic in step 1) is one of bifidobacterium, lactobacillus and lactococcus.

5. The preparation method according to claim 1, characterized in that In parts by mass, the spinach powder in step 1) is 12-15 parts by mass, the broccoli powder is 3-5 parts by mass, the yam powder is 20-25 parts by mass, the banana resistant starch is 25-30 parts by mass, the zero-calorie sugar is 5-8 parts by mass, the cooked soybean powder is 15-20 parts by mass, the gorgon fruit powder is 10-13 parts by mass, and the probiotic powder is 10-13 parts by mass.

6. The preparation method according to claim 1, characterized in that In parts by mass, the composite powder in step 2) is 100-110 parts by mass, and water is 300-350 parts by mass; the pre-homogenization temperature in step 2) is 40-60°C.

7. The preparation method according to claim 1, characterized in that Step 3) The three temperature zones of the three-stage ultrasonic 3D printing are respectively controlled at 45-50°C, 55-70°C and 35-40°C, the ultrasonic power is 100-300W, and the overall printing time is controlled at 15-20min; The printing speed is 60 mm / s and the nozzle diameter is 0.6 mm.

8. The preparation method according to claim 1, characterized in that Step 3) The quick freezing temperature is -40 to -50°C and the time is 2 to 3 hours.

9. The freeze-dried meal replacement powder obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the freeze-dried meal replacement powder according to claim 9 in preparing food or medicine for regulating intestinal flora.

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