CN102919691B - Low-protein nutrition crispy slices and making method thereof - Google Patents

Abstract

The invention discloses low-protein nutrition crisp slices and a making method thereof. The low-protein nutrition crisp slices comprise, by weight, 90-95 parts of edible starch, 0.5-10 parts of cane sugar, 0.5-3 parts of malt extract, 0.5-2 parts of salt, 0.2-0.8 part of monostearin and 0.2-0.8 part of double-effect baking powder. The low-protein nutrition crisp slices are made by using the edible starch as a major ingredient and using cane sugar, malt extract, salt, monostearin, double-effect baking powder and the like as auxiliary materials and are nutritious, crispy and tasty and easy to digest and absorb. The low-protein nutrition crisp slices can be used as staple food at breakfast, can also be used as daily snack food, can control protein intake of nephrotic patients and phenyketonuria (PKU) patients, provide sufficient heat for the patients, and help the patients to develop a habit of eating low-protein food. By limiting the intake of the protein, diseases are prevented, and the low-protein nutrition crisp slices are ideal breakfast and snack food for the PKU patients and the nephrotic patients.

Description

Low-protein nutrient crisp chips and preparation method thereof

Technical Field

The invention relates to the technical field of food processing, in particular to a low-protein nutritional crisp chip and a preparation method thereof.

Background

Chronic renal failure refers to a clinical syndrome consisting of a series of symptoms and metabolic disorders that lead to progressive and irreversible decline in kidney function, through to loss of function, from various renal diseases. The terminal stage of chronic renal failure is known as uremia. Uremia is not an independent disease, but is a clinical syndrome shared by various advanced renal diseases, and is a syndrome composed of a series of clinical manifestations appearing when chronic renal failure enters an end stage. Statistics of international association of renal diseases on some countries and regions show that incidence of chronic renal failure is continuously increasing worldwide, about 1 ten thousand patients who newly develop chronic renal failure and receive dialysis treatment are in China, and the total number of patients who maintain hemodialysis and peritoneal dialysis treatment is about 5 to 6 ten thousand.

PKU is the abbreviation of phenylketonuria, which is caused by the defect of congenital phenylalanine hydroxylase in vivo, causing that phenylalanine can not be converted into tyrosine and is abnormally accumulated in vivo, and meanwhile, tyrosine, dopamine, norepinephrine, epinephrine, melanin and other metabolic formation obstacles cause a series of nervous system damages, thus being the main pathogenic cause of dull people. After birth, PKU patients can grow normally and become a normal person only by eating low phenylalanine food or low protein food (such as milk powder, protein and starch) and medicines for a long time. Once a PKU infant patient eats ordinary food, phenylalanine in the infant patient can be accumulated, and the intelligence of the infant patient is damaged.

Therefore, patients with renal failure, uremia, etc. need to be on a low protein diet, and excessive protein intake can increase glomerular filtration rate and renal plasma flow rate of renal patients, causing renal function impairment. The total amount is generally limited to 20-40 g (including animal and vegetable protein) according to the disease condition, the daily protein supply is about 0.5 g per kilogram of body weight, and high-quality protein such as milk, egg, lean meat and the like is required to be properly selected within a limited range. However, excessive protein intake by PKU patients causes intellectual and language development disorders, which worsen with age, and, in addition, the children suffer from pale hair and skin color, and the smell of rats from urine and sweat. Therefore, patients with PKU cannot ingest too much phenylalanine nor too little phenylalanine, and since the natural proteins all contain 4-6% phenylalanine, the ingestion of natural proteins must be controlled, with no more than 0.5% protein in the daily diet.

At present, few foods developed aiming at renal failure, uremia patients and PKU patients are sold in the market, the foods are mainly staple foods such as low-protein rice, low-protein flour sheets and low-protein flour, and the types of the foods are quite single.

Disclosure of Invention

The invention aims to provide a low-protein nutritional crisp chip and a preparation method thereof, and the preparation method has simple process, and provides a food which is crisp in taste, easy to digest and absorb, convenient and quick for patients.

In order to achieve the above object, according to one aspect of the present invention, there is provided a low-protein nutritional crisp comprising the following raw materials in parts by weight: 90-95 parts of edible starch, 0.5-10 parts of cane sugar, 0.5-3 parts of malt extract, 0.5-2 parts of salt, 0.2-0.8 part of monoglyceride and 0.2-0.8 part of double-effect baking powder.

Furthermore, the raw material also comprises alpha-amylase, and the dosage of the alpha-amylase is 0.5-5 IU of the alpha-amylase added into each gram of edible starch.

Further, the raw materials also comprise 0.4-0.8 part of composite vitamins and trace elements in parts by weight; wherein the compound vitamin is selected from one or more of vitamin B1, vitamin B2, vitamin B6, vitamin B12, nicotinic acid, folic acid, pantothenic acid, vitamin A, vitamin C and vitamin E; the microelement is selected from one or more of calcium, iron and zinc.

Further, the raw materials further comprise 0.1-15 parts by weight of a taste additive, and the taste additive comprises any one of chocolate, barbecue seasoning powder and sweet milk.

Further, the raw materials comprise, by weight, 92.5 parts of edible starch, 5 parts of sucrose, 1 part of malt extract, 0.5 part of salt, 0.5 part of monoglyceride, 0.3 part of double-effect baking powder, 0.4 part of vitamin complex, 0.2 part of trace elements and 2.75IU of alpha-amylase added according to per gram of edible starch.

Further, the edible starch is one or a combination of more of corn starch, potato starch, wheat starch and rice starch; wherein the edible starch has a protein content of less than 0.5% by weight.

According to another aspect of the present invention, there is provided a process for preparing a low protein nutritional crisp comprising the steps of metering and sieving any of the above raw materials, mixing and stirring, press cooking, drying, tabletting, baking, flavoring and cooling.

Further, the extrusion curing step comprises: (1) conveying the mixture obtained by mixing and stirring into an extruder, and carrying out heat treatment in a heating section of the extruder, wherein the heat treatment comprises the following steps: 1, heating the mixture to 65-90 ℃, and adding 15-20 parts by weight of water into the mixture for tempering to obtain slurry; 2, continuously heating and curing the slurry to the temperature of 125-135 ℃ to obtain a cured product; (2) and cooling the cured product in a cooling section of an extruder, and extruding after cooling to obtain a cured semi-finished product.

Further, the step 1> further comprises the step of adding alpha-amylase into the mixture in an amount of 0.5-5 IU per gram of edible starch in the process of adding water for tempering.

Further, the extruder is a double-screw extruder, and the rotating speed of screws of the double-screw extruder is 160-250 r/min; the temperature of the cutting die head of the double-screw extruder is 75-90 ℃, and the cutting speed is 1300-1400 r/min.

Further, the drying step comprises: and drying the cured semi-finished product obtained in the extrusion curing step at 55-75 ℃ until the moisture content in the cured semi-finished product is 15-20% by weight.

Further, the baking step comprises: and baking the semi-finished product of the tablet obtained by the tabletting step at 140-220 ℃ until the water content of the semi-finished product of the tablet is 4-7% by weight.

By applying the technical scheme of the invention, the low-protein nutritional crisp chips prepared by adopting edible starch as a main raw material and adopting cane sugar, malt extract, salt, monoglyceride, double-effect baking powder and the like as auxiliary materials are rich in nutrition, crisp and tasty and easy to digest and absorb. The low-protein nutritional crisp can be used as staple food for breakfast and daily snack food, can control protein intake of renal failure, uremia and other nephropathies and PKU patients, can provide sufficient calorie for the nephropathies and the PKU patients, and helps the patients develop low-protein diet habit. Can prevent the occurrence and the deterioration of diseases by limiting the intake of protein, and the low-protein nutrient crisp chips are ideal breakfast foods and snack foods for patients with PKU, renal failure, uremia and the like.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

figure 1 shows a process flow diagram for making a low protein nutritional crisp according to an exemplary embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

According to a typical embodiment of the invention, the low-protein nutritional crisp comprises the following raw materials in parts by weight: 90-95 parts of edible starch, 0.5-10 parts of cane sugar, 0.5-3 parts of malt extract, 0.5-2 parts of salt, 0.2-0.8 part of monoglyceride and 0.2-0.8 part of double-effect baking powder.

The low-protein nutritional crisp chips prepared by adopting edible starch as a main raw material and adopting cane sugar, malt extract, salt, monoglyceride, double-effect baking powder and the like as auxiliary materials are rich in nutrition, crisp, tasty and easy to digest and absorb. The low-protein nutritional crisp can be used as staple food for breakfast and daily snack food, can control protein intake of renal failure, uremia and other nephropathies and PKU patients, can provide sufficient calorie for the nephropathies and the PKU patients, and helps the patients develop low-protein diet habit. Can prevent the occurrence and the deterioration of diseases by limiting the intake of protein, and the low-protein nutrient crisp chips are ideal breakfast foods and snack foods for patients with PKU, renal failure, uremia and the like.

In the invention, the raw material of the low-protein nutritional crisp chips mainly comprises edible starch and other auxiliary materials. Preferably, the edible starch is one or more of corn starch, potato starch, wheat starch and rice starch; wherein the protein content of the corn starch is less than 0.5%. Although the edible starch selected by the invention has very low protein content, in order to further control the intake of protein and phenylalanine, the edible starch with the protein content of less than 0.5 percent can obtain more nutritional and healthy breakfast cereals and snack foods, the invention is preferably, but not limited to, corn starch, and also can be potato starch, wheat starch or rice starch and one or more of the mixture of the potato starch, the wheat starch or the rice starch. Corn starch is preferred because it is abundant and inexpensive in source and has a protein content of less than 0.5% by weight, a moisture content of less than 14% by weight, and an ash and fat content of less than 0.15% by weight, respectively.

According to a preferred embodiment of the present invention, the raw material further comprises alpha-amylase, and the amount of the alpha-amylase is 0.5 to 5IU per gram of the edible starch. The added alpha-amylase can resist high temperature, and can cut off molecular chains of the starch under the high-temperature condition, so that the starch is hydrolyzed to a certain degree, and the digestibility and the crispness of the product are improved. According to the invention, the dosage of the added alpha-amylase is controlled to be 0.5-5 IU of alpha-amylase added into each gram of edible starch, under the condition, the degree of starch hydrolysis is proper, and the molecular weight of starch hydrolysate is favorable for improving the digestibility and crispness of the product. If the added amount is more, the starch is excessively hydrolyzed, the molecular weight of the starch hydrolysate is too small, the crispness of the product is not improved, and the enzyme preparation is excessively consumed; on the contrary, if the amount of α -amylase added is small, the degree of starch hydrolysis is too low, and the molecular weight of the starch hydrolysate is too high, the digestibility and crispness of the product cannot be improved. The dosage of the added alpha-amylase is controlled to be 0.5-5 IU per gram of edible starch, so that the aims of improving the digestibility and the crispness of the product can be fulfilled, the waste of the alpha-amylase is avoided, and the cost is reduced.

Preferably, the raw materials further comprise 0.4-0.8 part of compound vitamin and trace elements in parts by weight; wherein the vitamin complex is selected from vitamin B₁Vitamin C and vitamin CBiotin B₂Vitamin B₆Vitamin B₁₂One or more of nicotinic acid, folic acid, pantothenic acid, vitamin A, vitamin C and vitamin E; the microelement is selected from one or more of calcium, iron and zinc. The compound vitamins and trace elements are added into the raw materials to improve the nutritional value of the low-protein nutritional crisp chips.

Wherein, the compound vitamin and the trace element are added in an amount acceptable for food, and the general addition amount is as follows based on 1kg of raw material mixture: vitamin B₁4.6-9.2 mg of vitamin B₂4.6-9.2 mg/kg, vitamin B₆5.84-11.68 mg of vitamin B₁₂0.54-0.75 mg, 39.32-78.64 mg of nicotinic acid, 6.16-12.32 mg of folic acid, 17.4-34.8 mg of pantothenic acid, 13.2-26.4 mg of vitamin A, 50-100 mg of vitamin E, 211.2-422.4 mg/kg of vitamin C, 2132.10-4624.21 mg of calcium, 64-128 mg of iron and 51.2-102.4 mg of zinc. Mixing the above compound vitamins and microelements with other raw materials, and adding into extruder.

Preferably, the raw materials further comprise 0.1-15 parts by weight of taste additives, and the taste additives comprise one or more of chocolate, barbecue seasoning powder and sweet milk. The invention improves the nutritive value of the product by adding the compound vitamin and the trace element in the ingredients of the product.

According to a preferred embodiment of the present invention, the raw materials comprise, by weight, 92.5 parts of edible starch, 5 parts of sucrose, 1 part of malt extract, 0.5 part of salt, 0.5 part of monoglyceride, 0.3 part of double effect baking powder, 0.4 part of vitamin complex, 0.2 part of trace elements, and 2.75IU of alpha-amylase added per gram of edible starch. The raw materials in the weight portion ratio can be used for preparing the low-protein nutritional crisp chips with protein content lower than 0.5%, balanced nutrition, good digestibility and crisp mouthfeel.

According to another aspect of the present invention, there is provided a process for preparing a low protein nutritional crisp, as shown in figure 1, comprising the steps of metering and sieving any of the above raw materials, mixing and stirring, press cooking, drying, tabletting, baking, flavoring and cooling.

The invention firstly measures and sieves the main material edible starch and the added auxiliary materials, and the fineness of the common edible starch is required to pass through a 80-mesh sieve. Mixing and stirring the sieved raw materials, extruding and puffing, drying, tabletting, baking and flavoring to obtain the low-protein nutritional crisp rich in vitamins and minerals with low protein content and high calorie. The preparation method has the advantages of simple process, high automation degree, high production efficiency, low energy consumption, high utilization rate of raw materials, no pollution, low nutrition loss, easy digestion and absorption, good taste, convenient eating, and suitability for large-scale production.

Preferably, the extrusion curing step comprises: (1) conveying the mixture obtained by mixing and stirring into an extruder, and carrying out heat treatment in a heating section of the extruder, wherein the heat treatment comprises the following steps: 1, heating the mixture to 65-75 ℃, and adding 15-20 parts by weight of water into the mixture for tempering to obtain slurry; 2, continuously heating and curing the slurry to the temperature of 125-135 ℃ to obtain a cured product; (2) and cooling the cured product in a cooling section of an extruder, and extruding after cooling to obtain a cured semi-finished product.

The mixed and stirred raw materials are powdery mixture, the powdery mixture is conveyed to a mixer to be fully and uniformly mixed, and then the mixture is conveyed to an extruder through a screw conveyor. Preferably, the extruder is a double-screw extruder, wherein the screw rotating speed of the double-screw extruder is 160-250 r/min. Under the pushing action of the screw, the material moves forwards. When the material passes through the cylinder of the extruder, the material absorbs water to swell, gelatinizes, cracks, plasticizes, recombines and homogenizes under the combined action of moisture, temperature, pressure and mechanical shearing force. And the mixture is sprayed out of the die holes to form a cured product with a certain shape and a small amount of porous structures.

The double-screw extruder comprises the following different temperature zones, wherein the temperature of the zone II is 65-90 ℃, the temperature of the zone III is 125-135 ℃, the temperature of the zone IV is 115-125 ℃, the temperature of the zone V is 80-100 ℃, and the temperature of the zone VI is 75-90 ℃. Wherein the temperature of the cutting die head of the double-screw extruder is 75-90 ℃, and the cutting speed is 1300-1400 r/min.

According to the invention, preferably, 15-20 parts by weight of water is added into the mixture for tempering when the temperature of the zone II is 65-90 ℃, so that the mixture absorbs water, swells and gelatinizes, and the mixture is beneficial to curing. The tempering by adding water to the mixture at a temperature in the range of 65 ℃ to 90 ℃ is selected in consideration of the fact that the water absorption rate is high in this temperature range, and if the temperature is too high, the feeding of the extruder is difficult. The operation of the quenching and tempering extruder is stable at the temperature, and the obtained product has excellent quality. Preferably, the step 1> further comprises adding alpha-amylase into the mixture in an amount of 0.5-5 IU per gram of edible starch in the process of adding water for tempering. Wherein the high temperature resistant alpha-amylase can be directly added into the mixture, or the high temperature resistant alpha-amylase can be prepared into 0.1 percent solution and added into a double-screw extruder together with water. The digestibility and the crispness of the product can be improved by adding the high-temperature resistant alpha-amylase, and the high-temperature resistant alpha-amylase is added within the temperature range of 65-90 ℃ to gelatinize the starch and carry out enzymatic hydrolysis.

The twin-screw extruder of the present invention is preferably a circular hole-shaped die, but is not limited thereto, and the die shape may be configured according to the desired product. The temperature of the circular hole-shaped die head adopted by the invention is 75-90 ℃, the cutting speed is 1300-1400 r/min, and the cured product is cut into spherical particles under the micro-expansion condition to obtain a cured semi-finished product. And conveying the cured semi-finished spherical particles to a fluidized bed for drying by adopting an air flow conveying mode. Preferably, the drying step comprises: drying the cured semi-finished product at 55-75 ℃ until the moisture content in the cured semi-finished product is 15-20% by weight. The moisture content is controlled within 15-20% by weight, so that the particles entering the tablet press are prevented from being adhered to each other and are prevented from adhering to the press roll.

And conveying the dried cured semi-finished spherical particles to a tablet press by using a belt conveyor for tabletting, adjusting the gap between compression rollers to press the material into thin slices with the thickness of 0.4-0.6 mm, and baking in a spouted bed type oven. Preferably, the baking step comprises: and baking the semi-finished product of the tablet obtained by the tabletting treatment at the temperature of 140-220 ℃ until the water content of the semi-finished product of the tablet is 4-7% by weight. After baking, the product is flaky, is off-white in color, has tiny bubbles on the surface, is not smooth and has special fragrance.

And (3) discharging the baked semi-finished product out of the furnace, putting the semi-finished product into air for natural cooling, endowing the semi-finished product with flavor when the temperature of the semi-finished product is close to room temperature, and generally adopting a roller type spraying machine to spray the low-protein nutritional tablets with the flavoring to endow the semi-finished product with special flavor. And naturally cooling the product, and quickly packaging and hermetically storing the product when the temperature of the product is close to room temperature so as to prevent the product from absorbing moisture in the air again and getting damp. The flavored product is quickly packaged and sealed for storage, so that the product is prevented from absorbing moisture in the air again and getting damp.

The invention adopts an enzymatic extrusion puffing technology to improve the crispness of the product and make the product easier to digest and absorb. The obtained low-protein nutritional crisp chips are crisp and delicious, have rich nutrition and are easy to digest and absorb, can be used as staple food during breakfast, can also be used as daily snack food, can control the protein intake of renal failure patients, uremia patients and other nephrotic patients and PKU patients, can provide enough heat for the patients, help the patients to develop habits of low-protein diet, avoid the occurrence and the deterioration of diseases by limiting the protein intake, and are ideal breakfast food and snack food for the patients with PKU, renal failure, uremia and the like.

In addition, the product can be directly used and can be instantly eaten after being soaked in cold and hot drinks, so that the problem that the market supply and demand contradiction of developing leisure functional foods for special crowds such as nephropathy patients and PKU patients in China is well solved, the research and development directions of low-protein foods in the international market are met, and the foods are more targeted, more nutritional, more scientific and more convenient.

The following examples are provided to further illustrate the beneficial effects of the present invention.

Example 1

The raw material formula is as follows: corn starch: 90 parts by weight, sucrose: 10 parts by weight, malt extract: 0.5 part by weight, salt: 0.5 part by weight, monoglyceride: 0.2 part by weight, double-effect baking powder: 0.5 part by weight.

The raw materials in parts by weight are uniformly mixed by a mixer and then are conveyed to an extruder by a screw conveyor, and simultaneously 15 parts by weight of water and 0.5IU of alpha-amylase are added into a zone II of the extruder. The temperature of each temperature zone of the extruder is respectively adjusted to 65 ℃ of the temperature of a zone II, 125 ℃ of the temperature of a zone III, 115 ℃ of the temperature of a zone IV, 80 ℃ of the temperature of a zone V, 75 ℃ of the temperature of a zone VI, the rotation speed of a screw is 220r/min, the temperature of a die head is adjusted to 80 ℃, the cutting rotation speed is 1300r/min, the extruded semi-finished product is cut, the spherical semi-finished product is conveyed to a fluidized bed at 60 ℃ after cutting, the semi-finished product is dried until the moisture of the semi-finished product is 15-20%, then the semi-finished product is pressed into 0.3mm thin slices in a tablet machine, and finally the thin slices are baked in an oven. In order to obtain the low-protein nutritional tablets with various tastes, after cooling, spraying barbecue seasoning powder on the surfaces of the corn flakes in a coating pan, and drying to obtain the barbecue-flavored low-protein nutritional tablets.

Examples 2 to 6

The preparation steps are the same as those in example 1, except for the mixture ratio of the raw materials.

Table 1 raw material ratio

TABLE 2 sensory indices of the products

TABLE 3 nutrient table of low-protein nutritious chips (content per 100 g)

As can be seen from the sensory index and table of the low-protein nutritional crisp in table 2 and the nutritional ingredient table, the low-protein nutritional crisp prepared in the embodiment of the present invention has good sensory evaluation and balanced nutrition. In particular, the low-protein nutritional crisp chips prepared in example 4 have proper sweetness, proper salty taste, wheat flavor, crisp taste, uniform texture, bright surface and no bubbles; the low-protein crisp chips have balanced nutrient components, are easy to digest, have low protein (less than 1.0 percent) and lower production components, and are a better processing method for the low-protein crisp chips.

The low-protein nutritional crisp chips prepared by the method have the following advantages:

1. the product selects edible starch, particularly corn starch as a raw material, the fortified nutrient has high nutritive value, is easy to digest, has low protein content and high heat content, is low in price, and has wide application market.

2. Compared with the traditional process, the advanced enzymatic extrusion puffing technology is adopted, so that the processing technology of the food is improved, the tissue state, the taste and the digestibility of the product are greatly improved, and the product quality is improved. Meanwhile, the process flow is shortened, and the color and variety of the food are enriched; the production cost is reduced, and the labor intensity is reduced.

3. The types of products are increased, the types of the current low-protein food products mainly comprise low-protein dough sheets, low-protein meal powder, low-protein vermicelli, low-protein rice and the like, most of the low-protein meal products are staple food, leisure food is not available, the low-protein meal powder is inconvenient to eat, and the habit of low-protein diet can not be thoroughly developed by patients with renal failure, uremia and PKU (passive keyless entry) patients.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (11)

1. A preparation method of low-protein nutritional crisp chips is characterized by comprising the steps of metering and sieving raw materials of the low-protein nutritional crisp chips, mixing and stirring, extruding and curing, drying, tabletting, baking, flavoring and cooling;

the low-protein nutritional crisp chips comprise the following raw materials in parts by weight:

2. the method for preparing the low-protein nutritional crisp chips according to claim 1, wherein the raw material further comprises alpha-amylase, and the dosage of the alpha-amylase is 0.5-5 IU of the alpha-amylase added to each gram of edible starch.

3. The method for preparing the low-protein nutritional crisp chips according to claim 1, wherein the raw materials further comprise 0.4-0.8 parts of compound vitamins and trace elements by weight; wherein,

said vitamin complex is selected from vitamin B₁Vitamin B₂Vitamin B₆Vitamin B₁₂One or more of nicotinic acid, folic acid, pantothenic acid, vitamin A, vitamin C and vitamin E;

the trace elements are selected from one or a combination of more of calcium, iron and zinc.

4. The method for preparing the low-protein nutritional crisp chips according to claim 1, wherein the raw materials further comprise 0.1-15 parts by weight of taste additives, and the taste additives comprise any one of chocolate, barbecue seasoning powder and sweet milk.

5. The method of making a low protein nutritional crisp according to claim 3 wherein said raw materials comprise, by weight, 92.5 parts of edible starch, 5 parts of sucrose, 1 part of malt extract, 0.5 parts of salt, 0.5 parts of monoglyceride, 0.3 parts of double effect baking powder, 0.4 parts of multivitamins, 0.2 parts of trace elements, and 2.75IU of alpha-amylase added per gram of edible starch.

6. The method of making low protein nutritional crisp according to any of claims 1 to 5 wherein said edible starch is one or a combination of corn starch, potato starch, wheat starch and rice starch; wherein the protein content of the edible starch is less than 0.5%.

7. The method of making low protein nutritional crisp of claim 1 wherein said step of extrusion cooking comprises:

(1) conveying the mixture obtained by mixing and stirring into an extruder, and carrying out heat treatment in a heating section of the extruder, wherein the heat treatment comprises the following steps:

1, heating the mixture to 65-90 ℃, and adding 15-20 parts by weight of water into the mixture for tempering to obtain slurry;

2, continuously heating and curing the slurry to the temperature of 125-135 ℃ to obtain a cured product;

(2) and cooling the cured product in a cooling section of the extruder, and extruding the cooled cured product to obtain a cured semi-finished product.

8. The method of making low-protein nutritional crisp according to claim 7, wherein the step 1> further comprises adding alpha-amylase to the mixture in an amount of 0.5-5 IU per gram of edible starch during the addition of water for tempering.

9. The method for preparing the low-protein nutritional crisp chips according to claim 7, wherein the extruder is a twin-screw extruder, and the screw rotating speed of the twin-screw extruder is 160-250 r/min; the temperature of the cutting die head of the double-screw extruder is 75-90 ℃, and the cutting speed is 1300-1400 r/min.

10. The method of making a low protein nutritional crisp according to claim 1 wherein said drying step comprises: and drying the cured semi-finished product obtained in the extruding and curing step at 55-75 ℃ until the moisture content in the cured semi-finished product is 15-20% by weight.

11. The method of making a low protein nutritional crisp according to claim 1 wherein said baking step comprises: and baking the semi-finished tabletting product obtained in the tabletting step at 140-220 ℃ until the water content in the semi-finished tabletting product is 4-7% by weight.

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