A method for preparing a swallowing-aiding gel

Abstract

The present invention discloses a method for preparing a gel for assisting swallowing, and belongs to the field of food. The purpose of the present invention is to address the problems that the types of food suitable for people with special dietary needs such as the elderly, people with swallowing disorders and people undergoing postoperative care are scarce, the nutritional components are single, and the safety and health of their diet cannot be guaranteed. A gel with the same components but different texture characteristics is successfully constructed through a mild enzymatic reaction, and the structure and interaction of the basic constituent units of the gel network are further regulated by texture control technology, so that a protein gel product with high or low gel properties with different textures can be successfully obtained to provide safe and nutritious swallowing-assisting protein gel products for different consumer groups / patients / pets with special dietary needs.

Description

Technical Field

[0001] The invention relates to the preparation of gel, and is used to easily manufacture food that is easy for people with difficulty in swallowing and chewing to take. The invention belongs to the field of food, and includes special medical formula food. Background Art

[0002] Due to the deterioration of physiological functions, the elderly population needs to pay special attention to the safety of oral processing in their dietary choices. Patients with degenerative diseases of the central nervous system or after cancer surgery often have abnormal oropharyngeal and laryngeal muscle movements and difficulty swallowing due to physiological or pathological reasons such as lesions. In mild cases, they may cough when drinking water and eat slowly; in severe cases, they may easily induce aspiration pneumonia, dehydration, malnutrition, etc.

[0003] Foods with different textures may present different safety hazards during oral processing (i.e. eating or ingesting). For example, when consuming fluid foods, choking may occur if the liquid is too thin, while liquids that are too thick may pose a risk of suffocation; when consuming solid foods, dry, hard, and fibrous foods should be avoided because these foods may be difficult to chew and swallow, too hard, and difficult to digest; while foods with a soft and moist texture require less chewing force and are easy to swallow, so they are more suitable for the elderly, especially those with chewing and swallowing disorders. Therefore, in response to the dietary safety issues of special groups such as the elderly, people with chewing and swallowing disorders, and people in illness or postoperative care, research on thickened liquids and texture-modified foods has become more and more in-depth, and is committed to optimizing the texture characteristics of food to obtain the corresponding chewing and swallowing adaptability to ensure dietary safety.

[0004] The existing technology is more about chopping or crushing ingredients for cooking in daily care. In addition to ordinary food, chopped food, extremely finely chopped food, mixed food, paste food, liquid food, etc. are provided. However, there are still many in-depth research and development difficulties that need to be explored in depth to make these chopped or crushed ingredients into food or products that can be circulated and sold in the market, such as the shelf life of such foods with high water activity, how to solve the colony growth and inhibition problems of this type of complex food system, and how to maintain the color of vegetables if it contains both vegetables and meat, etc. In short, the method of preparing food for swallowing assistance by such existing technology is only suitable for on-site processing of ingredients in homes, nursing homes, health care homes, hospitals and other places for consumption and eating. In the production of commercialized food for swallowing assistance, it is usually necessary to add thickeners to increase its viscosity during food preparation, reduce the movement speed of food boluses in the digestive tract, and avoid aspiration. By adding thickeners to food to improve the texture characteristics of food, a lot of convenience is provided for clinical and home care. However, thickeners also have some limitations in clinical or home care: (1) such as low yield stress, sticky feeling, poor taste, and lack of chewing pleasure; (2) poor smoothness, and when attached to the throat, it also increases the risk of inhalation into the trachea; (3) the need for additional nutrients, which brings inconvenience to the operator during preparation. The addition of thickeners is also not conducive to the promotion of assisted swallowing gels as ordinary foods. At this stage, the food industry is paying more and more attention to clean label food design. In addition, some researchers have also developed some semi-solid nutrients, such as CN104394844A, which records a semi-solid nutrient for gastric atrophy. Two gels of different strengths are mixed with agar and processed starch to prepare a semi-solid nutrient for tube feeding, so as to meet the purpose of high shape retention when squeezed out from a syringe, low adhesion to the tube, and low resistance when squeezed out of the tube. This type of technical solution is mainly aimed at tube-fed patients, helping to solve the problems of shape retention, adhesion and resistance during tube feeding, but is not suitable for direct swallowing by patients.

[0005] Food gels have been widely used to prepare texture-modified foods due to their unique semi-solid properties. At the same time, gels are also a good model for studying structure-texture relationships. The network structure of the gel affects its texture properties, such as elasticity and fracture. Different network structures also lead to different chewing properties, 3D printing properties, and tissue engineering application properties. By changing the microstructure of the gel network, the texture properties of the food matrix can be affected, which in turn affects the performance of the food during oral processing and / or other processing. This also means that by regulating the structure of the network building units or the interaction between the units, it is expected to regulate the three-dimensional network structure and texture properties of the macro gel, so as to obtain the desired oral processing and / or other processing properties, help people with dysphagia to eat, improve the eating experience of people with special dietary needs, reduce the occurrence of choking, and prevent aspiration pneumonia. By adding other components to the gel matrix, different functional foods can be designed, such as traditional nutrient-enhanced foods. The gel can also serve the creation of 3D printed foods and future foods.

[0006] In response to the above problems, it is necessary to develop a gel food that is safe, has good taste, is chewy, and smooth, and can be adjusted according to the different needs of patients with different degrees of swallowing disorders. The gel food can be eaten directly as a gel, or it can be embedded with different nutrients to meet the nutritional needs of different groups of people. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a method for preparing a protein gel for assisting swallowing, and its multi-scenario application as a food with adjustable texture.

[0008] The method for preparing the protein gel for assisting swallowing described in the present invention uses milk protein powder as a raw material, and successfully constructs a gel with the same components and different texture characteristics based on a mild enzymatic reaction. The texture control technology is used to control the structure of the basic building blocks of the gel network and their interactions, and a gel with high or low gel properties is successfully obtained. The method can provide a gel food with suitable texture and comprehensive nutrition for the elderly, people with swallowing disorders, and people with diseases or postoperative care, and can also be used as an adjustable soft gel in more scenarios.

[0009] The method for preparing the swallowing-aiding protein gel of the present invention is to use milk protein powder to undergo a protein cross-linking reaction under the action of an enzyme to prepare a soft gel material; the enzyme is chymosin, which is an aspartic acid protease that can specifically cut the peptide bond between Phe105-Met106 of κ-casein in milk, destroy casein micelles and cause protein coagulation, and can be derived from animals, plants and microorganisms. In addition, it includes adjusting the concentration of protein, adjusting the concentration of chymosin added, adding different types and amounts of regulators (including Ca 2+ or Mg 2+The regulatory technologies including the regulation of the three-dimensional network structure formed by protein coagulation can be used to regulate the three-dimensional network structure formed by protein coagulation to obtain different texture characteristics. For example, regulating the protein concentration can regulate the concentration of the network constituent units (proteins) and thus affect the thickness of the chains constituting the network (protein segments constituting the network). Regulating the concentration of enzyme addition and the concentration of the regulator can regulate the interaction between the network constituent units and the thickness and strength of the chains constituting the network, which ultimately affects the chewing and swallowing performance of the gel, making it suitable for people with different chewing and swallowing disorders. The different texture characteristics include at least: ① IDDSI level 4, no chewing is required, usually eaten with a spoon (can also be eaten with a fork), but cannot be drunk from a cup because the texture is not easy to flow and cannot be sucked with a straw; suitable for people with chewing or swallowing pain, tooth loss, and ill-fitting dentures and lack of tongue thrust); ② IDDSI level 5, can be eaten with a fork or spoon, and in some cases can be eaten with chopsticks, can be scooped out and placed on a plate to form, and tongue force is required to help chew and swallow; suitable for people with pain or fatigue when chewing, tooth loss, and ill-fitting dentures; ③ IDDSI level 6, can be eaten with a fork, spoon or chopsticks, can be crushed or broken with a fork, spoon or chopsticks, no need to cut such food with a knife, but can be used to help load the fork or spoon, chewing and tongue thrust are required before swallowing to move the food; suitable for people with pain or fatigue when chewing, missing teeth, and ill-fitting dentures.

[0010] The method for preparing the protein gel for assisting swallowing of the present invention mainly comprises the following steps:

[0011] (1) Raw material processing: After the milk protein powder is fully hydrated, it is processed using a homogenizer to obtain a protein solution;

[0012] The biggest problem in the application of MPC or milk protein powder is that the solubility of the raw material itself will deteriorate during storage, and the product produced cannot obtain stable quality assurance. The protein solution obtained by fully hydrating the protein raw material and then processing it with a certain pressure and homogenization times can ensure the stability of the product.

[0013] The milk protein powder includes but is not limited to casein micellar powder, milk protein concentrate powder, skim milk powder or whole milk powder, etc., and its source includes but is not limited to cow's milk, buffalo milk, goat milk, sheep milk, dromedary camel milk, Bactrian camel milk, donkey milk and deer milk, etc., and can be milk protein powder;

[0014] The milk protein powder can also be replaced by liquid milk. When the production raw material is liquid milk, it does not need to be hydrated and homogenized, and can be directly produced continuously, but it needs to be diluted or concentrated and evaporated to a certain protein concentration before processing. Generally, after collecting milk, the dairy factory processes the standardized milk (that is, the raw milk is passed through a centrifuge to obtain skim milk with a fat content of 0.05% and cream with a fat content of 40%. After the raw milk is standardized, subsequent product processing can be carried out according to the protein and fat content of the product. Standardization of raw milk is a processing that must be performed after each dairy factory collects and purifies milk) to obtain a protein solution with a milk protein quality of less than 3%;

[0015] (2) Gel preparation: mixing the protein solution described in step (1) with chymosin to carry out an enzymatic reaction to prepare a gel, and after the gel is formed, performing an enzyme inactivation treatment;

[0016] The rennet can be rennet from various animals, plants and microorganisms, including but not limited to rennet from cow stomach, pig stomach and sheep stomach, ginger protease, papain, ficin, bromelain, albizin, artichoke protease, cheese mold and yeast, etc.

[0017] When the protein solution is mixed with chymosin in step (2), the protein concentration can be adjusted to adjust the concentration of the network building units, or the concentration of the added enzyme can be adjusted, or the type and amount of the regulator (mainly inorganic salt ions, including Ca 2+ and Mg 2+ etc.), in order to regulate the interaction between the network constituent units and adjust the thickness and strength of the chains constituting the network, thereby regulating the basic constituent units of the gel network and further affecting the formation of the gel in step (2).

[0018] In one embodiment of the present invention, the amount of chymosin added in step (2) is 0.1 to 100 U·g per gram of protein. -1 . Preferably 5-20 U·g per gram of protein -1 .

[0019] In one embodiment of the present invention, the regulator is not limited to Ca 2+ Mg 2+ Inorganic salts such as Ca 2+ The range is 0 to 0.688 g per gram of milk protein concentrate or casein micelles.

[0020] In one embodiment of the present invention, in step (1), the milk protein concentrate or casein micelles are fully hydrated and then homogenized, and then, in step (2), the protein solution and the inorganic salt ion regulator are mixed, stirred evenly, and then rennet is added, mixed, and reacted at 35 to 55° C. for 0.5 to 24 hours, and the enzyme is inactivated after the reaction is completed. Preferably, the reaction temperature is 50° C. and the time is 1 to 6 hours.

[0021] In one embodiment of the present invention, during hydration in step (1), the mass fraction of the milk protein concentrate or casein micelles relative to water is 0.1% to 15% w / w, preferably 3% to 12% w / w.

[0022] In one embodiment of the present invention, the pH during the reaction in step (2) is 4.0 to 8.0, preferably 6.0 to 8.0.

[0023] In one embodiment of the present invention, the homogenization pressure in step (1) is 5-150 MPa, and the homogenization is performed 1-8 times. Preferably, the homogenization pressure is 90-120 MPa, and the homogenization is performed 3 times.

[0024] In one embodiment of the present invention, the enzyme inactivation in step (2) is performed at high temperature for a short time. Optionally, the enzyme is inactivated in a constant temperature water bath at 60 to 80° C. for 10 to 20 minutes.

[0025] In one embodiment of the present invention, ginger protease is used as the enzyme:

[0026] (1) Casein micelles or concentrated milk protein solution are fully hydrated, with a concentration of 70-150 g / L -1 (7% to 15% w / w, below 7% w / w, pure protein gel cannot be formed), homogenized using a high-pressure homogenizer, with a homogenization pressure of 120 MPa, and homogenized 3 times;

[0027] (2) The amount of ginger enzyme added is 5-20 U·g per gram of milk protein concentrate or casein micelles -1 The pH value of the mixed solution of milk protein concentrate or casein micelles and ginger protease is 6.0-8.0. The mixed solution is placed in a constant temperature water bath at 50°C for reaction for 2 hours. After the reaction, the sample is taken out and placed in a constant temperature water bath at 80°C for 10 minutes to inactivate the enzyme. The gel food is then quickly cooled to room temperature.

[0028] In one embodiment of the present invention, ginger protease is used as the enzyme, and Ca 2+ The structure and interaction of the basic building blocks of the gel network (casein micelles) are regulated, and the method comprises the following steps:

[0029] (1) Casein micelles or concentrated milk protein solution are fully hydrated, with a concentration of 30 to 150 g / L -1(3% to 15% w / w), homogenized using a high-pressure homogenizer at a homogenization pressure of 120 MPa, and homogenized 3 times;

[0030] (2) The amount of calcium chloride added was 0-0.688 g per gram of milk protein concentrate or casein micelle, and the amount of ginger protease added was 5-20 U·g per gram of milk protein concentrate or casein micelle. -1 The reaction pH of the mixed solution is 6.0-8.0, and then it is placed in a constant temperature water bath at 50°C for 2 hours. After the reaction, the sample is taken out, placed in a constant temperature water bath at 80°C for 10 minutes to inactivate the enzyme, and quickly cooled to room temperature to obtain gel foods with different textures.

[0031] The swallowing-aiding protein gel prepared by the method of the present invention can be used as a food or a food matrix. The use as a food matrix means that it can be used as a nutrient carrier. The food matrix can be used to meet the needs of people with special diets. The nutrients include water-soluble nutrient elements. The swallowing-aiding protein gel can be integrated with water-soluble nutrient elements to obtain a functionally enhanced food for marketing and consumption.

[0032] The protein gel for assisting swallowing prepared by the method of the present invention can also be used in more scenarios such as 3D printing and future food creation. For example, the gel foods prepared above are 3D printed separately to obtain ready-to-eat 3D printed foods with different hardness. Weigh about 30g of different gel samples and put them into the barrel of the 3D printer, and select a print nozzle with a diameter of 0.84mm. Make a 3D model, and set parameters such as software slicing. The printing speed is set to 30mm / s, the printing temperature is 25℃, the printing platform height is 1mm, the printing internal filling rate is set to 40%, and the retraction speed is 50mm / s. Ready-to-eat 3D printed foods with different hardness can be obtained.

[0033] Beneficial effects of the present invention:

[0034] Compared with the addition of thickeners in the prior art, the present invention can produce food that meets the requirements of clean labels; the present invention prepares a gel food matrix modified by enzyme method and texture control technology based on green chemical modification technology. The innovation of the gel is that only milk protein can be used to create gels of different strengths (that is, corresponding to the needs of consumers with different swallowing and chewing difficulties). The preparation method is simple, easy to operate, and feasible. There is no need to constantly change the appropriate food additives to obtain a specific texture, and there is no need to additionally change the type of thickener or add other food additives that may cause phase separation or microphase separation of complex food component systems, or change the manufacturing method (which may cause additional expenses for fixed assets such as production machines), etc., which will not lead to a sudden increase in fixed costs. Simply put, if a group of people need products with the same nutritional formula, then the method of the present invention can produce gels with exactly the same nutritional formula but different textures, which can be provided to people with different swallowing and chewing difficulties. It does not involve time-consuming and labor-intensive complex changes in the formula. Changes in the formula are risky and may lead to product defects such as undesirable flavor / texture. In addition, some food additives can also cause physical and mental health problems for specific groups of people. Sometimes, changes in recipes can even directly affect the classification of food. For example, in many countries, milk chocolate and dark chocolate with added sugar substitutes cannot be labeled as "milk chocolate" or "dark chocolate" because sugar substitutes are not allowed in standardized chocolate and such products do not meet the requirements of the "Standard of Identity".

[0035] The gel with both viscosity and elasticity prepared by the present invention can be used as a food matrix material. The gel is formed by a small amount of solid components absorbing a large amount of liquid components as a continuous phase and expanding to a certain limit of volume. Rather than being a liquid, it is better to say that it exhibits the characteristics of an elastic solid. The solid component is called a gelling agent. The three-dimensional mesh structure formed by the gelling agent contains the liquid therein, so it is easy to obtain a gel that encapsulates different nutrients. By adjusting the constituent units of the gel, the cross-linking density, etc., a gel food that can be swallowed directly can be prepared without adding a thickener, and specific active nutrients can also be embedded and delivered. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Changes in storage modulus of 5% and 7% casein micelle-based protein gels

[0037] Figure 2 Changes in loss modulus of 5% and 7% casein micelle-based protein gels

[0038] Figure 3 Changes in water holding capacity of 5% and 7% casein micelle-based protein gels

[0039] Figure 4Changes in textural properties of 5% and 7% casein micelle-based protein gels

[0040] Figure 5 Macroscopic gel images and SEM structures of 5% and 7% casein micelle-based protein gels

[0041] Figure 6 ISSDI Testing of 5% and 7% Casein Micellar-Based Protein Gels

[0042] Figure 7 Casein micellar base Ca 2+ Regulating the storage modulus of protein gels

[0043] Figure 8 Casein micellar base Ca 2+ Regulating the loss modulus of protein gels

[0044] Fig. 9 Casein micellar base Ca 2+ Modulating the water holding capacity of protein gels

[0045] Fig.10 Casein micellar base Ca 2+ Regulating the gel strength of protein gels

[0046] Fig.11 Casein micellar base Ca 2+ Modulating the elasticity of protein gels

[0047] Fig.12 Casein micellar base Ca 2+ Regulating the cohesion of protein gels

[0048] Fig.13 Casein micellar base Ca 2+ Modulating the chewiness of protein gels

[0049] Fig.14 Casein micellar base Ca 2+ Macroscopic images and SEM images of regulated protein gels

[0050] Fig.15 Casein micellar base Ca 2+ IDDSI test experiment of regulating protein gel DETAILED DESCRIPTION

[0051] Methods for determining indicators:

[0052] 1. Rheological analysis of gel:

[0053] The formation of casein micellar gel and the changes in storage modulus and loss modulus during the curdling process were monitored using a Discovery HR-3 rheometer equipped with a cone-plate fixture (40 mm diameter, 2° angle, and 58 μm cutoff). 2+ After adding ginger protease, the sample was loaded on the rheometer platform. After loading, a small amount of silicone oil was added to the part of the sample that was in contact with the air to prevent water loss and isolate the air. During the experiment, the sample was oscillated at a constant frequency of 0.1 Hz, with a strain of 1%. The operating conditions were 50°C for 60 minutes. The storage modulus and loss modulus of the sample were recorded every 10 seconds to monitor the process of the solution forming a gel.

[0054] 2. Scanning electron microscope (SEM) observation and analysis of gel:

[0055] After the curd was formed, the sample was cut into 1 cm 3 The cubes were sampled, frozen in liquid nitrogen and then freeze-dried. The samples were freeze-dried at -50°C for 48 hours. The network structure of the dried samples was observed under a scanning electron microscope. The samples were adhered to the short section with double-sided tape and coated with a 15nm gold-palladium layer using a cathode coating instrument. The morphology of the fractured section was then observed using a scanning electron microscope (TM3030, Hitachi, Japan) at a high voltage of 15.0kV and a magnification of 200× to 3000×.

[0056] 3. Analysis of water holding capacity (WHC) of gel:

[0057] Transfer the casein micelle solution or gel food to a centrifuge tube to form a gel. Weigh the centrifuge tube before and after adding the sample to obtain the mass of the sample in the centrifuge tube. Control the mass of the sample to be around 10±0.2g, which is recorded as W1. After the curd is formed, centrifuge at 3000g for 15min at 20℃. After the centrifugation is completed, remove the supernatant from the centrifuge and weigh the centrifuge tube, which is recorded as W2. Calculate according to formula (1).

[0058] WHC (water holding capacity) = (W1-W2) / W2(1)

[0059] 4. Total texture analysis (TPA) of gel:

[0060] Casein micellar gel was prepared in a cylindrical glass container with an inner diameter of 30 mm and a height of 70 mm. Each sample was measured twice using a P 0.5R probe under the following test conditions: a pre-test speed of 1 mm / s (speed before sample contact), a test speed of 2 mm / s, a deformation of 50%, and a trigger force of 5 g. The hardness, elasticity, cohesiveness, and chewiness of each sample were measured.

[0061] 5. IDDSI analysis of gel:

[0062] All gel samples were subjected to Category 4 IDDSI testing, which includes the spoon tilt test and the fork drop test. In this study, the spoon tilt test was used to analyze the "puree" consistency of pasty foods that do not require chewing. It is done with a small sample of the food scooped out with a spoon, and the sample should (a) retain its shape on the spoon; and (b) fall off the spoon easily when tilted or turned sideways. After tilting, there should be little to no residue on the spoon. Foods can be determined to belong to Class 3 or Class 4 or Class 5 by the fork drop test, depending on how easily a scooped sample can accumulate on the fork.

[0063] 6. 3D printing of gel:

[0064] Weigh about 30g of different gel samples and put them into the barrel of the 3D printer, select a print head with a diameter of 0.84mm, make a 3D model, and set parameters such as software slicing, set the printing speed to 30mm / s, the printing temperature to 25℃, the printing platform height to 1mm, the printing internal filling rate to 40%, and the retraction speed to 50mm / s, and you can get ready-to-eat 3D printed food with different hardness.

[0065] Example 1 Preparation of pure protein gel based on casein micelles

[0066] In this embodiment, ginger protease is used as the enzyme to induce casein micelles to form an edible gel. Ginger protease cuts κ-CN on the surface of casein micelles, reduces the repulsive force between casein micelles, and induces casein micelles to aggregate to form a gel. The method includes the following steps:

[0067] (1) Casein micelles are fully hydrated, with a concentration of 50 g·L -1 or 70g·L -1 (i.e. 5% w / w or 7% w / w), homogenize using a high-pressure homogenizer at a homogenization pressure of 120 MPa, homogenize 3 times, and place the resulting solution in a 4°C refrigerator for later use.

[0068] (2) The amount of ginger enzyme added was 10 U·g per gram of casein micelles -1 The pH of the mixed solution of casein micelles and ginger protease is 7.0. The mixed solution is placed in a 50°C constant temperature water bath for reaction for 2 hours. After the reaction is completed, the sample is taken out and placed in an 80°C constant temperature water bath for enzyme inactivation for 10 minutes, and then quickly cooled to room temperature to obtain a gel food.

[0069] Characterization and analysis of the obtained gel:

[0070] According to rheological experiments ( Figure 1 , 2 ) and macro results ( Figure 5 ) It can be seen that 5% casein micelles cannot form gel, and 7% is the critical concentration of casein micelle gel. The gel formed by 7% casein micelles contains larger broken structures ( Figure 5 ), water holding capacity and texture properties are not perfect ( Figure 3 , 4 ). According to the IDDSI guidelines, the gel formed by 7% casein micelles can slide down the tilted spoon as a whole and maintain its shape, and can form a small tail in the gap of the fork, but does not drip continuously, so it is classified as the fourth level ( Figure 6 ), only a small amount of tongue thrust is required to swallow, which is suitable for the general elderly population and patients with chewing and swallowing disorders.

[0071] Example 2 Preparation of Ca based on casein micelles 2+ Regulated protein gel

[0072] In this example, ginger protease was used as the enzyme, and Ca 2+ Regulate the structure and interaction of the basic building blocks of the gel network (casein micelles). 2+ The carboxyl groups of glutamic acid and aspartic acid attached to casein micelles form calcium bridges to connect adjacent micelles, leading to micelle aggregation; the formation of calcium bridges and micelle aggregation reduce the sites for ginger protease to cut κ-CN, thereby regulating the formation and structure of curd. 2+ The addition of Ca will also affect the activity of ginger protease. 2+ The addition affects the casein micelles and enzyme reaction, thereby affecting the network structure and texture properties of the latex gel. The method comprises the following steps:

[0073] (1) Casein micelles or concentrated milk protein solution are fully hydrated to a concentration of 50 g / L -1 (5% w / w), homogenized using a high-pressure homogenizer at a homogenization pressure of 120 MPa, and homogenized 3 times.

[0074] (2) In this embodiment, Ca 2+ If added in the form of calcium chloride, Ca 2+ The amount of addition is calculated based on the mass of calcium chloride per gram of casein micelles, i.e.: Ca 2+ The addition amounts were 0.0267 g calcium chloride (sample S1), 0.0688 g calcium chloride (sample S2), 0.133 g calcium chloride (sample S3), 0.267 g calcium chloride (sample S4), and 0.688 g calcium chloride (sample S5) per gram of casein micelles. 2+ Add in the form of calcium chloride. Then, add ginger enzyme, the amount of ginger enzyme added is 10U·g per gram of casein micelles -1The reaction pH of the mixed solution was 7.0. The protein solution was first added with CaCl2 and then with ginger protease, and then placed in a 50°C constant temperature water bath for reaction for 2 hours. After the reaction, the sample was taken out and placed in an 80°C constant temperature water bath for enzyme inactivation for 10 minutes, and then quickly cooled to room temperature to obtain gel foods with different textures.

[0075] Characterization and analysis of the obtained gel:

[0076] According to rheology ( Figure 7 , 8 )、Macro and SEM( Fig.14 ) The results showed that when the calcium ion concentration was low (less than 0.0267gCaCl2 / g casein micelle), casein micelles could not form gels. As the calcium ion concentration increased, the network structure gradually changed from thin chains to thick chains, the network structure became more orderly, and the number of holes decreased.

[0077] According to water holding capacity ( Fig. 9 ) The results show that the water holding capacity of the gel is not high, basically below 25%. However, the water holding capacity of different gels is still different. In addition to the differences in hydrogen bonds and electrostatic interactions that constitute cluster chains and networks, the three-dimensional network structure of the gel also leads to differences in water holding capacity. The more breaks and holes in the gel, the lower the water holding capacity.

[0078] According to TPA analysis of the gel ( Figures 10 to 13 ) The results showed that the thin chain-like network structure led to weaker mechanical properties. As the cluster chain structure constructing the gel network became thicker and the network became more ordered, the hardness, elasticity and chewiness all showed an increasing trend.

[0079] Through IDDSI test result analysis ( Fig.15 ), through the spoon tilt test and fork dripping test, it was found that these gels can be classified into the fourth level (S4, S5, S8) and the fifth level (S6, S7). That is, they can be eaten with a spoon, smooth and not sticky; they can also be eaten with a fork, because they will not drip continuously from the fork gap, and the fourth-level samples will leave a small tail under the fork. Both types of food are suitable for people who have pain when chewing and swallowing or people who lack teeth in the IDDSI classification.

[0080] Example 3Ca 2+ Regulating the preparation of gel 3D printed food

[0081] Weigh about 30g of the gel prepared in Example 2 and put it into the barrel of a 3D printer, and select a print head with a diameter of 0.84mm. Make a 3D model, and set parameters such as software slicing, set the printing speed to 30mm / s, the printing temperature to 25°C, the printing platform height to 1mm, the printing internal filling rate to 40%, and the retraction speed to 50mm / s, and 3D printed reduced-salt instant foods with different hardness can be obtained.

Claims

1. A method for preparing a protein gel for assisting swallowing, characterized in that: Taking casein micelle powder as raw material, adding ginger protease into casein micelle solution, using ginger protease to catalyze protein cross-linking reaction, and preparing soft gel material, the amount of ginger protease added is 5-20U per gram of casein micelle, and the concentration of the casein micelle solution is 70-150g / L; Alternatively, casein micelle powder is used as a raw material, a regulator and ginger protease are sequentially added to a casein micelle solution, and a protein cross-linking reaction is catalyzed by ginger protease to prepare a soft gel material, wherein the regulator is calcium chloride, the amount of calcium chloride added is 0.0267-0.688 g per gram of casein micelle, the amount of ginger protease added is 5-20 U per gram of casein micelle, and the concentration of the casein micelle solution is 30-150 g / L.

2. The method for preparing a protein gel for assisting swallowing according to claim 1, characterized in that: The sources of the casein micelle powder include but are not limited to cow's milk, goat's milk, sheep's milk, dromedary camel milk, Bactrian camel milk, donkey milk and deer milk.

3. The method for preparing a protein gel for assisting swallowing according to claim 1 or 2, characterized in that: The main steps include: (1) Raw material processing: After the casein micelle powder is hydrated, it is processed using a homogenizer to obtain a casein micelle solution; (2) Gel preparation: The casein micelle solution described in step (1) is mixed with ginger protease to perform an enzymatic reaction to prepare a gel, and after the gel is formed, the enzyme is inactivated.

4. A protein gel for assisting swallowing prepared by the method of claim 1.

5. Use of the swallowing-assisting protein gel according to claim 4 as food.

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