CN112056508A - Grain carbohydrate matrix for special medical food and preparation method thereof - Google Patents

Abstract

The invention discloses a method for preparing a grain carbohydrate matrix, comprising: (1) pulverizing grains to grain flour raw materials; (2) adding 3-5% soybean protein isolate to the grain flour, with a concentration of 8000-10000U /mL of high temperature alpha amylase solution 50-60mL/kg, mix well. (3) subjecting the grain flour raw material to steam enzymatic demodulation and tempering treatment, (4) extruding and puffing the grain flour after steam enzymatic demodulation and tempering treatment, the extrusion temperature is 110-130°C, and the screw speed is 150-250r/ min; (4) drying and pulverizing the extrudate to obtain carbohydrate base powder. The method of the invention adopts grain crushing-soybean protein addition-steam enzymatic demodulation-extrusion and puffing treatment to obtain the grain carbohydrate base powder with low viscosity, good reconstituting property and strong food flavor, which is suitable for the preparation of special medical food.

Description

A kind of grain carbohydrate matrix for special medical food and preparation method thereof

technical field

The present invention relates to the preparation technology of special nutrition food for special population, in particular to a grain carbohydrate matrix for special medical food and a preparation method thereof.

Background technique

Special medical purpose formula food, hereinafter referred to as special medical food, is a formula food specially processed and prepared to meet the special needs of nutrients or diets for people with restricted eating, digestion and absorption disorders, and metabolic disorders. Such foods have significant effects in improving the nutritional status of patients and reducing the medical costs of hospitalized patients.

In recent years, the special medical food industry has shown a good development trend in the world. The global market size of special medical food is about 56 billion to 64 billion yuan per year, and it continues to increase at an average annual growth rate of 6%. Compared with developed countries such as Europe and the United States, the research and application of special medical food in my country is obviously lagging behind, but the demand has grown rapidly in recent years, and the average annual growth rate of the market size has reached 37%. However, at present, most of the special medical foods used clinically in my country are foreign brand products, and the three energy-supplying substances of carbohydrates, proteins and fats in the existing products are mainly composed of protein powder, dextrin or starch, edible oil or special oil and other various substances. Nutrient raw materials are compounded, in which carbohydrates are mainly provided by dextrin. Although this formula principle has obvious advantages in accurately controlling the composition and content of various nutrients, and ensuring that the product has good preparation characteristics, however, products generally lack food flavor, high osmotic pressure, and gastrointestinal tolerance. poor, etc. For people who have long relied on special medical food as the main or only source of nutrition, the above problems will directly affect consumers' compliance and are not conducive to the exertion of nutritional support. Therefore, the flavor and taste of special medical food are still the restrictive factors affecting its clinical use, and they are also issues that need special attention in the development of new products of special medical food.

Cereals are the main staple food in people's daily diet and an important source of dietary carbohydrates. The unique flavor brought by cereals as carbohydrate substrates is unmatched by monomer nutrients such as dextrin and starch. Using grains as a carbohydrate matrix, according to the nutritional needs of specific groups, fortified processing of special medical food with nutritional ingredients will help improve the flavor and taste of the product and improve the patient's compliance. However, due to the high starch content, the processing of FSMP with grains as carbohydrate matrix has problems such as high product viscosity, poor preparation and dispersibility, and poor fluidity in tube feeding. Tube feeding is a common dietary intake route for special medical food, and the tube feeding fluidity of the product is an important factor affecting the incidence of nutrient tube blockage. Therefore, indicators such as viscosity, reconstitution dispersion and tube feeding fluidity have become the main problems affecting the processing of FSMP with grains as carbohydrate substrates. How to improve the starch predigestibility of grain carbohydrate matrix and improve the reconstitution characteristics of powder is an important technical bottleneck in the development of special medical food with grain as carbohydrate matrix.

Related researches have been carried out to improve the predigestibility and preparation dispersibility of grain powder. The study found that adding high-temperature α-amylase to the grain can partially hydrolyze the grain starch and reduce the viscosity of the powder by using the high temperature in the extruding cavity during the extrusion process. However, because the extrusion process time is only about 20s, the enzyme and the substrate cannot fully interact, the enzymatic hydrolysis effect is relatively limited, and the flavor quality of the powder needs to be further improved. In view of the above problems, the present invention creates a grain carbohydrate matrix preparation technology based on the addition of an appropriate amount of soybean protein, which is based on raw material pulverization-steam enzymatic deconditioning-extrusion expansion, so as to promote the gelatinization and degradation of grain starch, and at the same time, by controlling protein-reduction The degree of Maillard reaction between sugars further improves the flavor quality and reconstitution characteristics of the base powder.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide a method for preparing a grain carbohydrate matrix for special medical food, which can improve the predigestibility of grain starch and the preparation properties of powder, and at the same time improve the flavor quality of the matrix.

The second object of the present invention is to provide a cereal carbohydrate matrix prepared by the above preparation method, which has the characteristics of low viscosity, good tube feeding fluidity and good food flavor, and can replace other carbohydrate raw materials and be used as special Raw materials for the development of medical food.

The first object of the present invention is realized through the following technical solutions:

A method for preparing a cereal carbohydrate matrix for special medical food, the processing flow is as follows:

Grain crushing → soybean protein isolate addition → steam enzymatic deconditioning → extrusion puffing → drying → crushing

Specifically include the following steps:

(1) the grain is pulverized to obtain the grain flour raw material;

(2) Add the grain powder raw material into the raw material mixing tank, add soybean protein isolate with a weight percentage of 3-5%, and add a high-temperature α-amylase solution with a concentration of 8000-10000U/mL through a spray device, and the addition amount is 50 -60mL/kg, mix the enzyme liquid, grain powder and protein evenly through the stirring device;

(3) sending the mixed mixture into a conditioner for steam enzymatic demodulation treatment;

(4) The grain powder after steam enzymatic decomposing and tempering is sent to the extrusion puffing machine through the screw conveyor for extrusion puffing, the extrusion temperature is 110-130 ℃, and the screw speed is 150-250 r/min.

(5) The extrudate is dried and then pulverized to obtain the cereal carbohydrate base powder.

The present invention establishes a method for preparing a special medical food carbohydrate matrix of raw material pulverization-protein addition-steam enzymatic deconditioning-extrusion expansion, specifically:

In the present invention, a certain amount of soybean protein isolate is added to the cereal powder, and the reducing sugars such as dextrin generated in the process of steam enzymatic deconditioning and extrusion and puffing undergo a moderate Maillard reaction with the protein, which can improve the flavor and quality of the powder. , and further melting, shearing, etc. in the extrusion process can promote the degradation of protein and improve the predigestibility of protein. Through flavor evaluation and analysis, it was found that when the added amount of soybean protein isolate was 3-5% and the extrusion temperature was controlled at 110-130°C, the extrudate had obvious baking flavor, and the sensory score reached the highest level.

The preparation concentration and addition amount of the enzyme liquid in the present invention affect the dosage of the enzyme, and when the dosage of the enzyme is 400-600 U/g, the preparation and dispersibility of the obtained matrix is the best. On the premise that the amount of enzyme added is determined, the concentration of the enzyme solution is determined to control the amount of water added during the process of adding the enzyme solution. Since the steam enzymatic hydrolysis and tempering process will further increase the moisture content in the grain flour raw material, and the enzymatic hydrolysis will decompose the starch into dextrins and oligosaccharides, the result of the above comprehensive effect will lead to shearing of the material during the extrusion process. The reduction of the force significantly reduces the puffing effect of the grain and affects the gelatinization and degradation of the remaining starch. Therefore, in order to ensure that the moisture content in the grain flour raw material is controlled at a certain level during extrusion and puffing to achieve an ideal puffing effect, the above-mentioned settings are made for the concentration and addition amount of the enzyme liquid and the amount of steam.

Optimally, the present invention also transports the enzymatically conditioned and tempered materials to a high temperature resistant storage bin through a screw conveyor, and then extrudes and puffs after being stored for 10-20 minutes. Adding α-amylase during puffing treatment can reduce the agglomeration rate and viscosity of grain puffed powder to a certain extent, and improve its water solubility. However, due to the short duration of action, amylase can only play a very limited role. Through steam enzymatic deconditioning, the amylase and the substrate are reacted at high temperature, and then the conditioned material is transferred to the storage silo to make the enzyme continue to function for 10-20min by taking advantage of the fact that the conditioned material is at a higher temperature. The enzymatic hydrolysis reaction time makes the grain starch fully enzymatically hydrolyzed. When the standing reaction time in the storage silo is less than 10min, the degree of pre-enzymolysis of starch is not enough, and the viscosity of the obtained cereal base powder is high, but when the reaction time is too long (>20min), due to excessive enzymolysis of starch, the subsequent The puffing of the extruded extrudate was too low, and the gelatinization degree of the residual starch decreased.

Optimally, in step (3) of the present invention, the parameters of the steam enzymatic demodulation and tempering are controlled as follows: the steam conditioning time is 1.5-2.5min, the saturated steam pressure is 0.2-0.3MPa, and the total steam volume is controlled at 7-7% of the weight of the conditioning material. 9%.

Optimally, the grain size of the grain flour in step (1) of the present invention is between 10-20 meshes. Comparing the reconciliation properties of extrudates obtained from grain flours of different particle sizes under the same processing conditions, it was found that either too large or too small a particle size would have a negative impact on the reconciliation properties of the extrudates. When the grain granules are small, the enzyme and starch granules have a sufficient effect, and the enzymatic hydrolysis effect is good. However, in the process of steam conditioning, when the grain size is too small, the viscosity of the grain flour increases under the action of steam and enzymes, and the powder fluidity is serious. Reduced, the effect of steam is insufficient, and the conveying efficiency of raw materials in the conditioner is affected at the same time, and the small grain particles increase the moisture content of the raw materials due to excessive water absorption, resulting in a decrease in the shear force during the extrusion process.

Preferably, the drying treatment in step (5) adopts hot air or heat pump drying, so that the moisture content of the extrudate reaches below 7%.

Optimally, the granularity of the carbohydrate base powder obtained by pulverizing in step (5) is between 60-100 meshes.

A cereal carbohydrate matrix for special medical food is prepared by the above preparation method.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention can further improve the flavor of the extrudate by adding a certain proportion of soybean protein isolate to the pulverized grain raw material, and controlling the degree of Maillard reaction during moist heat treatment such as steam conditioning and extrusion puffing. The extrudate has a distinct roasted aroma. At the same time, under the action of high heat and mechanical shearing in the above-mentioned treatment process, the intermolecular hydrogen bonds and disulfide bonds of the protein are broken, resulting in the degradation of the protein and the increase of the soluble protein content, which is beneficial to the digestion and utilization of the protein.

(2) The present invention utilizes α-amylase to degrade starch to generate dextrin and oligosaccharide at high temperature, thereby reducing the characteristics of starch viscosity, and the steam is continuously introduced into the steam conditioner to ensure that the material is maintained at a higher temperature, and then the steam The treated grain powder is transferred to a high temperature resistant storage silo for heat preservation for a certain period of time to achieve full enzymatic hydrolysis of grain starch. In the subsequent extrusion process, under the action of further enzymatic hydrolysis of amylase and mechanical shear generated by the extruder, the starch in the grain is further degraded and destroyed, and a large amount of small molecular carbohydrates are generated. Moreover, by increasing the number of storage bins, the time difference between the steam pre-enzymatic demodulation and the extrusion process can be eliminated, and continuous production can be realized.

(3) The cereal carbohydrate base powder developed by the present invention has good preparation properties and nasogastric tube fluidity, and can meet the basic needs of special medical food preparation. More importantly, the present invention selects the cereals with flavor and mouthfeel that are more suitable for Chinese people. As a raw material, the prepared carbohydrate matrix powder food has a richer flavor, and compared with dextrin and other nutrients as a matrix, it can provide the product with a significant grain baking flavor, thereby improving the flavor quality of the product and helping to ensure the compliance of long-term consumers.

Detailed ways

The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention.

Example 1

A method for preparing a cereal carbohydrate matrix for special medical food, comprising the following steps:

(1) By adjusting the crushing time, sieve diameter and hammer sieve gap of the grain pulverizer, pulverize to obtain the grain powder raw material with a particle size between 10-20 mesh.

(2) 5% soybean protein isolate was added to the pulverized grain flour.

(3) Prepare the high temperature alpha amylase solution with distilled water, so that the enzyme concentration is 10000U/mL, and the added amount of the high temperature alpha amylase solution is controlled to be 50 mL/kg, and the mixture is uniform.

(4) Transfer the grain raw material powder after the enzyme addition and mixing into a conditioner for steam enzymatic demodulation and tempering treatment. Set the steam conditioning time to 2min, the saturated steam pressure to 0.25MPa, and the total steam volume to be controlled within the conditioning period. 8% of material weight.

(5) The grain powder after the steam enzymatic deconditioning and tempering treatment is transported by the screw conveyor and transferred to the storage bin for stacking and standing for 20 minutes, and then sent to the extrusion puffing machine through the screw conveyor for puffing. The screw speed is 150r/min.

(6) The extrudate is dried by hot air or heat pump, so that the moisture content of the extrudate is less than 7%. The dried extrudate is pulverized into powder with a particle size of 60-100 mesh to obtain carbohydrate base powder.

Example 2

A method for preparing a cereal carbohydrate matrix for special medical food, comprising the following steps:

(1) By adjusting the crushing time, sieve diameter and hammer sieve gap of the grain pulverizer, pulverize to obtain the grain powder raw material with a particle size between 10-20 mesh.

(2) 3% soybean protein isolate was added to the pulverized grain flour.

(3) The high-temperature α-amylase solution is prepared with distilled water, so that the enzyme concentration is 10,000 U/mL, and the addition rate of the high-temperature α-amylase solution is controlled to be 60 mL/kg.

(4) Transfer the grain raw material powder after the enzyme addition and mixing into the conditioner for steam enzymatic demodulation and tempering treatment, set the steam conditioning time to 2.5min, the saturated steam pressure to 0.3MPa, and the total steam volume to be controlled at the adjusted temperature. 9% of the mass of the material.

(5) The grain powder after the steam enzymatic deconditioning and tempering treatment is transported by the screw conveyor and transferred to the storage bin for stacking and standing for 10 minutes, and then sent to the extrusion puffing machine through the screw conveyor for puffing. The screw speed is 250r/min.

(6) The extrudate is dried by hot air or heat pump, so that the moisture content of the extrudate is less than 7%. The dried extrudate is pulverized into powder with a particle size of 60-100 mesh to obtain carbohydrate base powder.

Example 3

A method for preparing a cereal carbohydrate matrix for special medical food, comprising the following steps:

(1) By adjusting the crushing time, sieve diameter and hammer sieve gap of the grain pulverizer, pulverize to obtain the grain powder raw material with a particle size between 10-20 mesh.

(2) 4% soybean protein isolate was added to the pulverized grain flour.

(3) The high-temperature alpha-amylase solution was prepared with distilled water, so that the enzyme concentration was 8000 U/mL, and the addition amount of the high-temperature alpha-amylase solution was controlled to be 50 mL/kg.

(4) Transfer the grain raw material powder after the enzyme addition and mixing into the conditioner for steam enzymatic demodulation and tempering treatment. Set the steam conditioning time to 1.5min, the saturated steam pressure to 0.2MPa, and the total steam volume to be controlled at the adjusted temperature. 7% of the mass of the material.

(5) The grain powder after the steam enzymatic deconditioning and tempering treatment is transported by the screw conveyor and transferred to the storage bin for stacking and standing for 15 minutes, and then sent to the extrusion puffing machine through the screw conveyor for puffing. The screw speed is 200r/min.

(5) The extrudate is dried by hot air or heat pump, so that the moisture content of the extrudate is less than 7%. The dried extrudate is pulverized into powder with a particle size of 60-100 mesh to obtain carbohydrate base powder.

The comparative analysis results of the matrix obtained by the present invention are as follows:

(1) Analysis of carbohydrate matrix powder prepared by different treatment processes

Using rice as raw material, the performance test of grain carbohydrate base powder includes base powder preparation characteristics, flavor quality and nutritional content. The experimental group used the carbohydrate base powder prepared in Example 1 to conduct relevant performance analysis. Take extrusion puffing and enzyme extrusion puffing as control. The processing conditions of extrusion and puffing are the same as in Example 1: the rice is pulverized to 10-20 mesh, the soybean protein isolate powder with a weight ratio of 5% is added, and water is added to adjust the moisture content of the raw material to about 20%, and the extrusion temperature is 125 ° C. The screw speed is 150r/min. Enzyme-added extrusion expansion is to adjust the moisture content of rice flour to about 20% by adding 400U/g high-temperature α-amylase solution, and the other is the same as direct extrusion expansion. The specific test results are shown in Table 1 and Table 2.

Table 1: Effects of different treatment processes on the brewing properties and flavor scores of base powder

Note: When the letters next to the values in the same column are different, it means that the difference reaches a significant level, p<0.05

The water solubility index is used to measure the degradation degree of starch in powder, which is related to the amount of starch degraded to form soluble small molecules. Due to the action of high temperature α-amylase, the starch structure in the powder is destroyed, a large amount of soluble sugars are released, its water solubility index increases, and the fluidity of the powder is enhanced, so the agglomeration rate and dispersion time during the preparation process are increased. are significantly reduced. Although the base powder processed by direct extrusion and extrusion with enzyme extrusion also has a certain baking aroma, it can be seen from the sensory score analysis that the baking aroma of the base powder prepared by the technical treatment of the present invention is more obvious than the former two, which can significantly improve the powder. sensory qualities of the body.

Table 2: Effects of different treatment processes on the nutritional components of base powder

Note: When the letters next to the values in the same column are different, it means that the difference reaches a significant level, p<0.05

As can be seen from Table 2, the reducing sugar and soluble protein content of the rice flour treated by the method of the present invention are all significantly higher than the direct enzymatic extrusion and puffing, and the starch content is significantly reduced, which is also the method that can significantly improve the powder. An important reason for the flushing characteristics.

(2) Performance test of complete nutrition formula powder for special medical food prepared from grain carbohydrate matrix obtained by different processing techniques

The principle of preparing FSMP complete nutrition formula powder is to use rice as raw material, and use grain carbohydrate base powder prepared by different processing techniques to replace dextrin and starch carbohydrates in FSMP complete nutrition formula powder. The amount of protein and fat added in the formula powder was fine-tuned by other ingredients such as protein and fat contained in the formula powder, and the complete nutrition formula powder of special medical food with different processed rice as the carbohydrate matrix was prepared. The specific formula is shown in Table 3.

Table 3 Composition of main nutrient components of special medical food with different carbohydrate sources (/100g)

Formula description: The non-substitution formula in the table above represents the basic formula composition of the FSMP full-nutrition formula powder commonly used in the market. The powder oil contains about 50% vegetable oil, and its packaging materials are mainly carbohydrates and A small amount of protein. 3 alternative recipes Using rice flour prepared by different processing techniques as carbohydrate matrix to replace maltodextrin in non-replacement recipes, the rice raw material contains about 8% protein, and a further 5% soy protein isolate was added in the preparation of the base powder , so the amount of casein added in the formula is reduced by 5g accordingly.

The experimental group used the carbohydrate base powder prepared in Example 1 to prepare the complete nutritional formula powder of special medical food. The control group adopts the carbohydrate base powder prepared by other treatment processes, including extrusion and extrusion, and enzyme extrusion, and the treatment parameters of the other groups are the same as those in Example 1.

The performance test of the above-mentioned FSMP complete nutrition formula powder includes preparation characteristics and sensory evaluation:

(a) Measurement of viscosity

Weigh 5.00g of sample in the special aluminum cylinder of the RVA measuring instrument, add 20mL of distilled water, put it into the rotating blade, snap the aluminum cylinder into the measuring tank, start the measurement program, and measure the viscosity. The measurement procedure is as follows: 38°C for 13 min, the rotation speed for the first 10 s is 960 r/min, and then the rotation speed is maintained at 160 r/min throughout the whole measurement process.

(b) Determination of residual rate of nasogastric tube

Weigh 40.00g of the sample into a 500mL beaker, add 65°C water to make 200mL of nutrient solution, stir evenly and transfer it into an infusion bottle, after cooling to room temperature, use a disposable infusion set to simulate the gravity drip method of clinical enteral nutrition support Carry out instillation, and the flow rate is controlled at 100-150mL/h. After all the instillation of the nutrient solution is completed, the weight of the adherents on the inner wall of the nasogastric feeding tube is weighed to calculate the residual rate of the nutrient solution.

(c) Sensory evaluation

25 healthy volunteers were recruited to conduct sensory evaluation on the powder and the prepared nutrient solution. Place the sample in a clean white porcelain dish, and visually observe the color of the powder in a well-lit, soft environment. In addition, pour 20.00g of the sample into a transparent container, add 80mL of water at 65°C to prepare a nutrient solution, stir well, smell its smell, observe its reconstitution, and taste its taste. The samples are randomly coded and evaluated at room temperature. After each evaluation of a sample, it is necessary to rinse the mouth with pure water, and then proceed to the evaluation of the next sample. The sensory evaluation table is formulated with reference to the QB 4221-2011 standard, as shown in Table 4. The total evaluation score is calculated as the sum of the four cumulative items.

Table 4 Sensory evaluation standard of FSMP complete nutrition formula powder

(3) Test results and analysis

The specific performance test results of the FSMP complete nutrition formula powder prepared by different treatment processes are shown in Table 5 and Table 6:

Table 5: Evaluation of Ease of Use of Complete Nutrition Formula Powders for Different Special Medical Foods

Table 6: Sensory evaluation results of complete nutritional formula powders for different FSMPs

According to the different types of diseases and pathophysiological states of patients, the ways of taking FSMP powder can be divided into two ways: direct oral feeding, feeding through nasogastric tube or gastroenterostomy tube. On the premise of ensuring sufficient and balanced nutrition of the product, the taste and flavor of the product and the convenience of preparation and use are important factors affecting its clinical application. Therefore, the present invention screened the representative indexes that affect the convenience of formula powder preparation: water solubility index, viscosity and residual rate of nasogastric tube. , the results are shown in Table 5.

As can be seen from Table 5, the complete nutritional formula powder for special medical food prepared by replacing maltodextrin with the carbohydrate matrix prepared in Example 1, its water solubility index, viscosity, and the residual amount in the nutrient tube during the simulated nasogastric feeding process Both are equivalent to the conventional FSMP formula powder with maltodextrin as the carbohydrate matrix. Compared with the formula powder prepared by direct extrusion and extrusion extrusion or enzyme extrusion expansion as the carbohydrate matrix instead of dextrin, the water-soluble The sex index is significantly improved, and the viscosity of the product and the residual rate of the nasogastric tube are significantly reduced, indicating that the convenience of use of the complete nutritional formula powder for special medical food prepared with the carbohydrate matrix prepared by the present invention is comparable to that of the conventional formula using maltodextrin as carbohydrate. The effect of the product is equivalent, which is obviously better than that of direct extrusion and extrusion extrusion technology.

As mentioned above, in addition to the sensory qualities such as the dispersive flavor quality of the preparation, it is also an important factor affecting the clinical use of FSMP. Therefore, the sensory evaluation criteria listed in Table 4 are used to evaluate the characteristics of FSMP prepared with different carbohydrate bases. The total nutritional formula powder of medical food was comprehensively evaluated from four aspects: structure, odor, taste, and reconstitution. The results are shown in Table 6. Although the whole nutrition formula powder for special medical food prepared with rice flour prepared by extrusion extrusion and enzyme extrusion extrusion as the carbohydrate matrix is better than the conventional formula without substitution in terms of smell and taste, its reconstitution score is far away. Lower than the latter, resulting in a significantly lower score of the comprehensive evaluation result than the conventional formula without substitution. The odor, taste and mouthfeel of the special medical food complete nutrition formula powder prepared with the carbohydrate matrix prepared by the present invention are further improved compared with the direct extrusion and extrusion extrusion and the enzyme-added extrusion extrusion. Comparable levels, therefore, the composite evaluation score was significantly higher than the conventional formula without replacement and the formula with carbohydrate matrix replacement prepared by the other two techniques.

Similar effects were observed for wheat flour, corn flour and millet flour, or mixtures thereof, measured with rice in the above experiments.

The above examples describe in detail the different implementation processes of the present invention. Similar test data results can also be obtained from the substrates prepared in other examples, which are not listed one by one; Personnel can realize the purpose of the present invention according to the content disclosed in the present invention. Any improvement and deformation made on the basis of the concept of the present invention all fall within the protection scope of the present invention, and the specific protection scope is recorded in the claims. prevail.

Claims (7)

1. a preparation method for the cereal carbohydrate substrate of special medical food, is characterized in that, comprises the following steps: (1) the grain is pulverized to obtain the grain flour raw material; (2) adding the soybean protein isolate that is 3-5% by weight to the grain flour, and adding the high-temperature α-amylase solution 50-60 mL/kg with a concentration of 8000-10000 U/mL, and stirring uniformly; (3) sending the uniformly mixed grain flour raw material into a conditioner for steam enzymatic demodulation treatment; (4) extruding and puffing the grain powder after the steam conditioning treatment, the extrusion temperature is 110-130 ° C, and the screw speed is 150-250 r/min; (5) The extrudate is dried and then pulverized to obtain carbohydrate base powder. 2. The preparation method of the cereal carbohydrate matrix for special medical food according to claim 1, characterized in that, in step (1), the grain size of the cereal powder raw material is between 10-20 meshes. 3. the preparation method of the cereal carbohydrate substrate for special medical food according to claim 1, is characterized in that, in step (3), the parameter control of steam enzyme demodulation and tempering treatment is as follows: steam conditioning time is 1.5-2.5 min, the saturated steam pressure is 0.2-0.3MPa, and the total steam volume is controlled at 7-9% of the weight of the conditioning material. 4. the preparation method of the grain carbohydrate matrix for special medical food according to claim 1, is characterized in that, in step (4), the material after the steam enzymatic demodulation treatment is transported to high temperature resistant storage by screw conveyor. In the silo, after 10-20 minutes of accumulation and storage, extrusion and puffing are carried out. 5. the preparation method of the cereal carbohydrate matrix for special medical food according to claim 1, is characterized in that, in step (5), drying process adopts hot air or heat pump drying, makes the moisture content of extrudate reach below 7% . 6. The preparation method of the cereal carbohydrate matrix for special medical food according to claim 1, wherein the granularity of the carbohydrate matrix powder obtained by pulverizing in step (5) is between 60-100 mesh. 7. A cereal carbohydrate matrix for special medical food, characterized in that, it is obtained by the preparation method according to any one of claims 1-6.