A low-salt temperature-sensitive double gel for delivering Omega-3 and its preparation method and application

Abstract

The present invention discloses a low-salt, temperature-sensitive double gel for delivering Omega-3 and its preparation method and application. The preparation method includes: S1, extracting pea protein with temperature-sensitive properties from fresh pea seeds using ammonium sulfate precipitation method; S2, adding the extracted pea protein and oligosaccharide to water for mixing to obtain a mixed solution, adding or not adding inorganic salts thereto, the mass concentration of the inorganic salts in the mixed solution is 0-0.3%, and the pH of the regulating system is 3-3.4; then the mixed solution after pH adjustment is plasma-treated to obtain a hydrogel with temperature-sensitive properties; S3, heating and stirring fish oil and monoglyceride until fully dissolved, and obtaining an oil gel loaded with Omega-3 after cooling; S4, mixing the obtained hydrogel and the obtained oil gel, and obtaining after high-speed shearing. The obtained low-salt, temperature-sensitive double gel has excellent thermal reversible properties, can delay the oxidation of Omega-3, and can ensure the intake demand of Omega-3 for the elderly under low-salt conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of plant protein processing, and more specifically to a low-salt, temperature-sensitive double gel for delivering Omega-3, and a preparation method and application thereof. Background Art

[0002] Omega-3 fatty acids are primarily derived from eicosapentaenoic acid (EPA, containing five unsaturated bonds) and docosahexaenoic acid (DHA, containing six unsaturated bonds) found in algae, fish, and other substances. Omega-3 fatty acids can reduce the risk of heart disease and stroke. They are also important for the development and maintenance of brain and cognitive function, improving memory and thinking skills. Furthermore, omega-3 fatty acids have anti-inflammatory properties and can alleviate the symptoms of inflammatory diseases such as arthritis and inflammatory bowel disease. For the treatment of inflammatory skin diseases, they can improve drug penetration, alleviate symptoms such as redness, swelling, and itching, and promote skin repair and healing. Overall, omega-3 fatty acids have numerous benefits for human health. However, omega-3s are highly susceptible to oxidation, and their oxidation products can be harmful to the human body. Residual fish oil on the surface of some traditional delivery systems, such as nanoemulsions and oil gels, can also accelerate lipid oxidation.

[0003] Dual gels are an emerging bidirectional system typically composed of two gel phases, an oil phase and an aqueous phase. They can deliver lipophilic and hydrophilic ingredients individually or simultaneously, and offer advantages over emulsions, oleogels, and hydrogels in delivering lipophilic bioactives across the skin membrane. However, to date, dual gels have primarily been used in the pharmaceutical and cosmetic fields, with relatively limited application in the food industry.

[0004] In addition, children and the elderly have relatively high demands for Omega-3, but they have certain developmental or degenerative defects in their oral chewing function. Therefore, in order to allow such people with dysphagia or clinical patients with swallowing problems to better supplement nutrients or active ingredients, constructing a gel with temperature-sensitive properties is an effective solution.

[0005] A thermosensitive gel is a colloid that can reversibly transform the state of a sol-gel system in response to temperature changes. Thermosensitive gels form a relatively stable three-dimensional network structure formed by physical crosslinking between molecular chains through hydrogen bonds, intermolecular forces, and macromolecular entanglement. The resulting gel can be restored to a solution state by heating to a critical temperature. Currently, gelatin and gellan gum are commonly used as raw materials for preparing thermoreversible gels. These thermoreversible gels can melt in the mouth and are therefore widely used in the production of puddings, desserts, and other products.

[0006] Currently, most protein-based thermosensitive gels are made from animal protein, while reports on the use of plant protein to prepare thermosensitive gels are relatively rare. This is because plant protein is poorly water-soluble, resulting in poor gelation. However, plant protein offers better sustainability and appropriate nutritional value and functionality. Furthermore, for environmental and consumer health reasons, replacing animal protein with plant protein is a future development trend.

[0007] Pea protein has always attracted much attention due to its high nutritional value, low sensitivity and low toxicity. Globulin and albumin are the two major protein groups in pea protein, accounting for 70-80% and 10-20% respectively. Legume protein (11S), vicilin protein (7S) and conviction protein are the three main proteins of globulin. Legume protein is a hexameric protein (~360kDa) with six subunits connected by disulfide bonds. Vicilin protein and conviction protein are both trimeric proteins, ~150kDa and ~210kDa respectively, without disulfide bonds. Studies have found that pea protein extracted by salt is mainly vicilin protein and conviction protein.

[0008] Pea protein also possesses functional properties such as gelation, foaming, and emulsification. Because pea protein primarily consists of salt-soluble globulins, it has low solubility in aqueous solutions and is difficult to form gels without the addition of salt ions. Consequently, most salt-ion gels have a high salt content. However, the World Health Organization recommends that a daily salt intake of more than three grams and less than six grams is beneficial for the health of the elderly. Exceeding six grams can increase blood pressure and lead to various complications. Therefore, it is crucial for the elderly to reduce their overall salt intake in their daily lives.

[0009] Therefore, developing a method for preparing a low-salt thermosensitive gel using pea protein as raw material to encapsulate the active ingredient Omega-3 is very important for the elderly who need to supplement Omega-3. Summary of the Invention

[0010] To address the aforementioned issues, the first objective of the present invention is to provide a method for preparing a low-salt, temperature-sensitive dual-gel for omega-3 delivery. This method utilizes temperature-sensitive pea protein, oligosaccharides, and inorganic salts to create a temperature-sensitive hydrogel. This hydrogel is then mixed with an omega-3-loaded oleogel to produce a food-grade, low-salt, temperature-sensitive dual-gel suitable for elderly consumption.

[0011] A second object of the present invention is to provide an oral delivery system for omega-3, prepared using the above-described method. This oral delivery system, with strict salt control, exhibits excellent mechanical properties and thermal stability, and can both delay omega-3 oxidation and ensure digestion and release in the intestine.

[0012] The third object of the present invention is to provide an oral delivery system using the Omega-3 described above for use in the food field.

[0013] In order to achieve the above first object, the present invention adopts the following technical solutions:

[0014] The present invention discloses a method for preparing a low-salt temperature-sensitive double gel for delivering Omega-3, comprising the following steps:

[0015] S1. Pea protein with temperature-sensitive properties was extracted from fresh pea seeds using ammonium sulfate precipitation method;

[0016] S2. Adding the extracted pea protein and oligosaccharide to water and mixing to obtain a mixed solution, adding or not adding an inorganic salt, wherein the mass concentration of the inorganic salt in the mixed solution is 0-0.3%, and adjusting the pH of the system to 3-3.4; then subjecting the pH-adjusted mixed solution to plasma treatment to obtain a hydrogel having temperature-sensitive properties;

[0017] S3, heating and stirring the fish oil and monoglyceride until fully dissolved, and cooling to obtain an omega-3 loaded oil gel;

[0018] S4, mixing the hydrogel obtained in step S2 and the oil gel obtained in step S3, and performing high-speed shearing to obtain the product.

[0019] The low-salt, temperature-sensitive double gel provided by the present invention is an oil-in-water, low-salt Omega-3 delivery system with a pea protein-oligosaccharide-based hydrogel as the aqueous phase and a fish oil-oil gel as the oil phase. It has a unique three-dimensional network structure, obvious thermal reversibility, excellent Omega-3 oxidation stability, and good sensory and texture properties. It can maintain a gel state at room temperature. In this state, the active ingredient Omega-3 encapsulated in the double gel can be stably present, reducing the chance of Omega-3 oxidation, while maintaining good molding and the stability of the double gel system. When the ambient temperature stably rises to above 80°C, it turns into a sol state. In this state, it is used to simulate the process of the low-salt, temperature-sensitive double gel entering the human body after consumption. It was found that Omega-3 is gradually exposed and stably released in the gastrointestinal environment, with a good release effect.

[0020] In terms of pea protein extraction, the present invention uses ammonium sulfate precipitation to extract pea protein from fresh pea seeds, giving the obtained pea protein a temperature-sensitive property, which is superior to the conventional alkali dissolution and acid precipitation extraction method. At the same time, in order to improve the problem of poor water solubility of pea protein, oligosaccharides are used to undergo glycosylation with pea protein to promote pea protein gelation and form a gel network. In addition, oligosaccharides can also form hydrogen bonds with water molecules to increase the hydration capacity of the gel, improve the stability of the gel, and replace the role of salt ions in the gelation process to a certain extent. Although it can present a thermally reversible effect and significantly reduce the degree of oxidation of Omega-3, the double gel is still low in terms of hardness, chewiness and intestinal release of Omega-3. In order to obtain better double gel performance, based on the concept of salt control, the appropriate introduction of a small amount of inorganic salt can significantly enhance the performance of the double gel in hardness, chewiness and intestinal release of Omega-3. Therefore, under the synergistic effect of oligosaccharides and inorganic salts, a double gel with low salt temperature-sensitive properties that can stably release Omega-3 in the intestine is finally successfully prepared.

[0021] Furthermore, the inorganic salt is selected from NaCl, and the mass concentration of the inorganic salt in the mixed solution is 0.1-0.3%. For example, it can be 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, etc.

[0022] Oligosaccharides are prepared from polysaccharides through degradation pathways. Compared to polysaccharides, they are more easily absorbed by the human body and have higher biological activity. The marine oligosaccharides, as one type of oligosaccharide, are small molecule polymers obtained by degrading marine polysaccharides through different methods. They are salt-soluble, and the degraded marine oligosaccharides show stronger biological activity than polysaccharides, and have antioxidant activity, anti-tumor activity, immunomodulatory activity, anti-inflammatory activity, regulation of intestinal microorganisms and many other biological activities. In one embodiment, the gel properties of pea protein can be improved by inducing low temperature in a plasma field to modify marine oligosaccharides, so that pea protein can form a more stable gel without adding or adding a small amount of salt. In the present invention, the oligosaccharides include marine oligosaccharides, selected from one or more of chitosan oligosaccharides, carrageenan oligosaccharides, brown algae oligosaccharides, and agar oligosaccharides.

[0023] Furthermore, the mass ratio of the pea protein to the oligosaccharide is 20-30:1. For example, it can be 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, 30:1, etc.

[0024] Furthermore, the mass concentration of pea protein in the mixed solution in step S2 is 10-15%, preferably 12-14%.

[0025] Furthermore, the plasma treatment in step S2 specifically involves using a low-temperature plasma treatment apparatus to draw the pH-adjusted mixed solution and place it in a reactor for plasma treatment. The plasma treatment is performed at a power of 80-100 W and for a treatment time of 3-10 minutes. Experimental findings indicate that plasma treatment facilitates gel formation, increases the formation of disulfide and hydrogen bonds, improves the gelation properties of pea protein, and enhances the mechanical properties of the gel. Furthermore, plasma treatment has been found to improve the gelation properties of pea protein while enhancing the temperature-sensitive properties of the hydrogel.

[0026] Furthermore, the mass ratio of the hydrogel to the oleogel is 2-5:1.

[0027] Furthermore, the high-speed shearing is performed at 15,000-25,000 rpm for 3-5 minutes.

[0028] Furthermore, the content of Omega-3 in the fish oil is 20.0-31.0 wt %, and Omega-3 includes two components, namely, eicosapentaenoic acid and docosahexaenoic acid.

[0029] Furthermore, when preparing the oil gel, the ratio of the added amount of fish oil and monoglyceride is 8-10:1 (v / v).

[0030] Furthermore, in step S2, the specific extraction process of the pea protein is as follows:

[0031] NaCl solution was added to fresh pea seeds at a solid-solubility ratio of 1:8-12, the pH was adjusted to 8-8.5 with NaOH solution, stirred evenly, centrifuged, and a primary supernatant was obtained; anhydrous (NH4)2SO4 was added to the primary supernatant, stirred, the pH was adjusted to 7.5-7.9 with HCl solution, centrifuged, and a secondary supernatant was obtained; anhydrous (NH4)2SO4 was added to the secondary supernatant, stirred, centrifuged, and a precipitate was obtained; the precipitate was dialyzed using a 3500-5000Da dialysis bag for 48-72 hours, freeze-dried, ground, and sieved to obtain pea protein.

[0032] Furthermore, during the pea protein extraction process, the concentration of the NaCl solution is 0.2-0.5 mol / L, preferably 0.5 mol / L; the concentration of the NaOH solution is 0.5-2 mol / L, preferably 2 mol / L; and the concentration of the HCl solution is 0.5-2 mol / L, preferably 2 mol / L.

[0033] Furthermore, anhydrous (NH4)2SO4 is added to the primary supernatant in an amount of 55-70% of its saturation level, and anhydrous (NH4)2SO4 is added to the secondary supernatant in an amount of 85-95% of its saturation level. The saturation level data of (NH4)2SO4 can be obtained by querying the ammonium sulfate saturation level table.

[0034] Furthermore, the centrifugal speed is 8000-10000 rpm, and the centrifugal time is 10-30 min.

[0035] In order to achieve the above second purpose, the present invention adopts the following technical solutions:

[0036] The present invention discloses an oral delivery system of Omega-3 prepared by the above-mentioned preparation method.

[0037] In order to achieve the third object, the present invention adopts the following technical solutions:

[0038] The present invention discloses an application of the oral delivery system of Omega-3 described above in the food field.

[0039] The beneficial effects of the present invention are as follows:

[0040] 1. The present invention designs a low-salt, temperature-sensitive dual gel capable of delivering Omega-3. The low-salt, temperature-sensitive dual gel comprises a hydrogel system composed of pea protein-oligosaccharides and an oleogel system composed of fish oil-monoglyceride. This is an oil-in-water dual gel. The active ingredient Omega-3 in the fish oil is encapsulated in the oleogel system, which can delay its oxidation. The dual gel provided by the present invention is a low-salt, thermoreversible active ingredient delivery system that can ensure the stability of the active ingredient during storage and ensure sufficient release after consumption, thus meeting the Omega-3 intake needs of the elderly under low-salt conditions.

[0041] 2. The pea protein extracted from fresh pea seeds by the ammonium sulfate precipitation method in the present invention has a thermosensitive property, which is an important prerequisite for preparing a thermosensitive double gel and has obvious advantages over the traditional alkali dissolution and acid precipitation extraction method; the extracted pea protein is subjected to a glycosylation reaction with oligosaccharides or the gelling property of the pea protein is improved under the synergistic effect of oligosaccharides and inorganic salts. In addition, the experiment also found that plasma treatment is more conducive to the formation of a hydrogel with thermosensitive properties.

[0042] 3. This invention utilizes pea protein and oligosaccharides as raw materials to prepare a thermosensitive hydrogel, and fish oil and monoglycerides as raw materials to prepare an omega-3-loaded oleogel. The thermosensitive hydrogel and omega-3-loaded oleogel are then thoroughly mixed through high-speed shearing to produce a low-salt, thermosensitive dual gel capable of delivering omega-3. This innovative approach demonstrates that the dual gel's unique three-dimensional network structure enhances the oxidative stability of fish oil, strengthens the oxidative barrier, and improves sensory and textural properties.

[0043] 4. The low-salt, temperature-sensitive dual gel designed in the present invention has unique rheological properties, and can better supplement Omega-3 for children, the elderly and other people with dysphagia or swallowing problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] Figure 1 The thermoreversible performance test diagram of different hydrogel samples in Experimental Example 1 is shown.

[0046] Figure 2 The thermoreversible performance test diagram of different double gel samples in Experimental Example 4 is shown.

[0047] Figure 3 The release of Omega-3 from different double gel samples in Experimental Example 7 in simulated saliva, simulated gastric juice, and simulated intestinal juice is shown. DETAILED DESCRIPTION

[0048] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the following detailed description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0049] Description of experimental materials and experimental instruments

[0050] The model of the low-temperature plasma treatment instrument used in the present invention is CTP-2000K, and the matching reactor model is DBD-50.

[0051] The fish oil used in the present invention is commercially available experimental fish oil, which contains 30 wt% of Omega-3.

[0052] Example 1

[0053] This embodiment provides a method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, which specifically includes the following steps:

[0054] S1. Extract pea protein using ammonium sulfate precipitation: At room temperature, add 0.5 mol / L NaCl solution to fresh pea seeds at a solid-solubility ratio of 1:10, adjust the pH to 8.2 with 2 mol / L NaOH solution, stir for 60 minutes, and centrifuge at 8000 rpm for 15 minutes to obtain a primary supernatant; add anhydrous (NH4)2SO4 to the primary supernatant to 65% saturation, stir for 30 minutes, adjust the pH to 7.7 with 2 mol / L HCl solution, centrifuge at 8000 rpm for 15 minutes, and obtain a secondary supernatant; add anhydrous (NH4)2SO4 to the secondary supernatant to 95% saturation, stir for 30 minutes, and centrifuge at 8000 rpm for 15 minutes to obtain a precipitate; dialyze the obtained precipitate with a 3500Da dialysis bag for 48 hours, freeze-dry, grind, and sieve in sequence to obtain pea protein with temperature-sensitive properties.

[0055] S2. Preparation of hydrogel: At room temperature, 1.3 g of pea protein (PPI) and 52 mg of chitosan oligosaccharide (COS) were weighed and dissolved in water. The mixture was stirred for 30 min by a magnetic stirrer to uniformly disperse the pea protein and chitosan oligosaccharide in the water to obtain a mixed solution. The mass concentration of pea protein in the mixed solution was 13%. NaCl was added to the mixed solution, and the mass concentration of NaCl in the mixed solution was 0.1%. The pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. The mixed solution after pH adjustment was drawn into a low-temperature plasma treatment apparatus and placed in a reactor for plasma treatment (CP). The treatment power was 100 W and the treatment time was 5 min. Cool to room temperature and store at 4 ° C for 24 h to obtain a hydrogel with temperature-sensitive properties, which was recorded as CP-PPI / COS.

[0056] S3. Preparation of oil gel: At room temperature, weigh 9 ml of fish oil and 1 ml of monoglyceride, incubate in an 80°C water bath for 10 min, cool to room temperature, and store at 4°C for 24 h to obtain an Omega-3 loaded oil gel.

[0057] S4. Preparation of a double gel: The prepared hydrogel and oil gel were mixed at a mass ratio of 4:1 at 80°C, high-speed sheared at 20,000 rpm for 3 minutes, and then cooled to room temperature to obtain a low-salt, temperature-sensitive double gel for Omega-3 delivery without oil leakage.

[0058] Example 2

[0059] This embodiment provides a method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, which specifically includes the following steps:

[0060] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0061] S2. Preparation of hydrogel: At room temperature, 1.3 g of pea protein and 52 mg of carrageenan oligosaccharide (CAS) were weighed and dissolved in water. The mixture was stirred for 30 min by a magnetic stirrer to uniformly disperse the pea protein and chitosan oligosaccharide in the water to obtain a mixed solution. The mass concentration of pea protein in the mixed solution was 13%. NaCl was added to the mixed solution, and the mass concentration of NaCl in the mixed solution was 0.1%. The pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. A low-temperature plasma treatment apparatus was used to absorb the mixed solution after adjusting the pH and place it in a reactor for plasma treatment. The treatment power was 100 W and the treatment time was 5 min. Cool to room temperature and store at 4 ° C for 24 h to obtain a hydrogel with temperature-sensitive properties, which was recorded as CP-PPI / CAS.

[0062] S3. Preparation of oil gel: the preparation method is the same as that in Example 1.

[0063] S4. Preparation of double gel: The preparation method is the same as that of Example 1. The obtained double gel has no oil leakage.

[0064] Example 3

[0065] This embodiment provides a method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, which specifically includes the following steps:

[0066] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0067] S2. Preparation of hydrogel: At room temperature, 1.3 g of pea protein and 52 mg of agar oligosaccharide (AGS) were weighed and dissolved in water. The pea protein and chitosan oligosaccharide were evenly dispersed in water by stirring with a magnetic stirrer for 30 min to obtain a mixed solution. The mass concentration of pea protein in the mixed solution was 13%. NaCl was added to the mixed solution, and the mass concentration of NaCl in the mixed solution was 0.1%; the pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. A low-temperature plasma treatment instrument was used to absorb the mixed solution after adjusting the pH and place it in a reactor for plasma treatment. The treatment power was 100 W and the treatment time was 5 min. Cool to room temperature and store at 4 ° C for 24 h to obtain a hydrogel with temperature-sensitive properties, which was recorded as CP-PPI / AGS.

[0068] S3. Preparation of oil gel: the preparation method is the same as that in Example 1.

[0069] S4. Preparation of double gel: The preparation method is the same as that of Example 1. The obtained double gel has no oil leakage.

[0070] Example 4

[0071] This embodiment provides a method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, which specifically comprises the following steps:

[0072] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0073] S2. Preparation of hydrogel: At room temperature, 1.3 g of pea protein and 52 mg of brown algal oligosaccharide (AOS) were weighed and dissolved in water. The pea protein and chitosan oligosaccharide were evenly dispersed in water by stirring with a magnetic stirrer for 30 min to obtain a mixed solution. The mass concentration of pea protein in the mixed solution was 13%. NaCl was added to the mixed solution, and the mass concentration of NaCl in the mixed solution was 0.1%; the pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. A low-temperature plasma treatment instrument was used to absorb the mixed solution after adjusting the pH and place it in a reactor for plasma treatment. The treatment power was 100 W and the treatment time was 5 min. Cool to room temperature and store at 4 ° C for 24 h to obtain a hydrogel with temperature-sensitive properties, which was recorded as CP-PPI / AOS.

[0074] S3. Preparation of oil gel: the preparation method is the same as that in Example 1.

[0075] S4. Preparation of double gel: The preparation method is the same as that of Example 1. The obtained double gel has no oil leakage.

[0076] Comparative Example 1

[0077] This comparative example provides a method for preparing a hydrogel. The preparation method is the same as that of Example 1, except that the mixed solution is not subjected to plasma treatment using a low-temperature plasma treatment apparatus. The prepared hydrogel is recorded as PPI / COS.

[0078] Comparative Example 2

[0079] This comparative example provides a method for preparing a hydrogel. The preparation method is the same as that of Example 2, except that the mixed solution is not subjected to plasma treatment using a low-temperature plasma treatment apparatus. The prepared hydrogel is recorded as PPI / CAS.

[0080] Comparative Example 3

[0081] This comparative example provides a method for preparing a hydrogel. The preparation method is the same as that of Example 3, except that the mixed solution is not subjected to plasma treatment using a low-temperature plasma treatment apparatus. The prepared hydrogel is recorded as PPI / AGS.

[0082] Comparative Example 4

[0083] This comparative example provides a method for preparing a hydrogel. The preparation method is the same as that of Example 4, except that the mixed solution is not subjected to plasma treatment using a low-temperature plasma treatment apparatus. The prepared hydrogel is recorded as PPI / AOS.

[0084] Comparative Example 5

[0085] This comparative example provides a method for preparing a hydrogel, which specifically comprises the following steps:

[0086] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0087] S2. Preparation of hydrogel: The preparation method is the same as that of Example 1, except that chitosan oligosaccharide is not added and plasma treatment is not performed. The obtained hydrogel is recorded as PPI.

[0088] Comparative Example 6

[0089] This comparative example provides a method for preparing a hydrogel, which specifically comprises the following steps:

[0090] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0091] S2. Preparation of hydrogel: The preparation method is the same as that of Example 1, except that chitosan oligosaccharide is not added. The obtained hydrogel is recorded as CP-PPI.

[0092] Test Example 1

[0093] The thermoreversible properties of the hydrogel samples prepared in Examples 1-4 and Comparative Examples 1-6 were tested as follows: the sample was placed in a vial, with the loading amount being about 1 / 3 of the vial volume. The vial was turned upside down at room temperature to observe whether the hydrogel at the bottom of the vial would flow. The inverted vial was then heated at 80°C for 5 minutes, and the hydrogel at the bottom of the vial was observed to flow. The vial was then cooled to room temperature and the hydrogel at the bottom of the vial was observed to flow. The results are shown in FIG. Figure 1 , cp means plasma treatment, and un-cp means no plasma treatment.

[0094] pass Figure 1 It can be seen that the samples of Examples 1-4 and Comparative Example 6 treated with plasma all have obvious thermal reversible properties, while Comparative Examples 1-5 that have not been treated with plasma show varying degrees of decreased thermal reversibility. Comparative Example 5 completely loses its thermal reversible properties, and Comparative Example 1 has a relatively favorable effect.

[0095] Test Example 2

[0096] The hardness, viscosity, elasticity, chewiness and cohesion of the hydrogel samples prepared in Examples 1-4 and Comparative Examples 1-6 were tested using a texture analyzer (model TA.TOUCH). The test method is as follows: adjust the probe to 1-2 cm from the bottom of the cup, set the default trigger force value to 5.00, set the rebound distance to 5 mm higher than the test sample height, and perform height calibration. The experimental type is a full texture test, the test type is downward pressure, and the target mode is deformation. Set the target value, the pre-test speed is 2 mm / s, the test speed is 1 mm / s, and the post-test speed is 1 mm / s. See Table 1 for the results. It can be seen from Table 1 that the hardness and chewiness values of CP-PPI / COS are relatively low, making it more suitable for children, the elderly and people with dysphagia.

[0097] Table 1

[0098] sample hardness Adhesion elasticity chewability Cohesion PPI 32.90±3.51a 7.20±0.94a 0.35±0.01a 5.24±0.53bc 0.51±0.04a PPI / COS 29.31±27.3ab 5.04±1.9a 0.32±0.01ab 5.17±0.88bc 0.51±0.02a PPI / CAS 27.30±0.68bc 9.12±1.53bc 0.36±0.01a 5.45±0.9bc 0.56±0.03a PPI / AGS 32.12±2.52a 6.75±1.44a 0.36±0.01a 6.25±0.15ab 0.55±0.03a PPI / AOS 32.47±0.14a 13.42±1.25de 0.40±0.02a 7.92±1.58a 0.61±0.05a CP-PPI 26.19±0.45cd 6.59±0.45a 0.34±0.03ab 5.20±0.78bc 0.59±0.06a CP-PPI / COS 24.33±0.46de 6.16±0.82a 0.32±0.04ab 4.77±0.20bc 0.62±0.02a CP-PPI / CAS 27.53±0.36bc 7.84±1.15ab 0.36±0.04a 5.59±0.06bc 0.58±0.01a CP-PPI / AGS 26.09±0.31cd 6.78±0.96a 0.36±0.01a 5.77±0.56bc 0.61±0.03a

[0099] Note: Different lowercase letters in the same column indicate the significance of the difference, that is, when the test data of different samples contain the same letters under the same test item, it means there is no significant difference. If the letters contained in the test data of different samples are completely different, it means there is a significant difference (p < 0.05).

[0100] Test Example 3

[0101] To ensure that the dual gel did not leak oil, this experimental example followed the preparation method of Example 1 and completed steps S1-S3 to prepare a hydrogel and an oleogel, respectively. The effects of high-speed shear conditions on the dual gel's oil leakage were then investigated. Treatments were performed at 10,000 rpm, 20,000 rpm, and 30,000 rpm for 1, 3, and 5 minutes, respectively. The results are shown in Table 2. Based on the results in Table 2, 20,000 rpm for 3 minutes was ultimately determined as the high-speed shear condition for subsequent experiments.

[0102] Table 2

[0103] 1min 3min 5min 10000rpm NG NG OK 20000rpm NG OK OK 30000rpm OK OK OK

[0104] Note: NG means oil leakage, OK means no oil leakage.

[0105] Example 5

[0106] This embodiment provides a method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, which specifically comprises the following steps:

[0107] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0108] S2. Preparation of hydrogel: At room temperature, 1.3 g of pea protein and 52 mg of chitosan oligosaccharide were weighed and dissolved in water. The mixture was stirred with a magnetic stirrer for 30 minutes to uniformly disperse the pea protein and chitosan oligosaccharide in the water to obtain a mixed solution having a pea protein concentration of 13%. No NaCl was added. The pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. The pH-adjusted mixed solution was then placed in a reactor using a low-temperature plasma treatment apparatus and subjected to low-temperature plasma treatment at a power of 100 W for 5 minutes. The solution was cooled to room temperature and stored at 4°C for 24 hours to obtain a hydrogel with thermosensitive properties.

[0109] S3. Preparation of oil gel: the preparation method is the same as that in Example 1.

[0110] S4. Preparation of double gel: The preparation method is the same as that of Example 1. The obtained double gel has no oil leakage.

[0111] Example 6

[0112] This embodiment provides a method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, which specifically includes the following steps:

[0113] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0114] S2. Preparation of hydrogel: At room temperature, 1.3 g of pea protein and 52 mg of chitosan oligosaccharide were weighed and dissolved in water. The mixture was stirred with a magnetic stirrer for 30 minutes to uniformly disperse the pea protein and chitosan oligosaccharide in the water to obtain a mixed solution having a pea protein mass concentration of 13%. NaCl was added to the mixed solution to a NaCl mass concentration of 0.2%. The pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. The pH-adjusted mixed solution was then placed in a reactor using a low-temperature plasma treatment apparatus and subjected to low-temperature plasma treatment at a power of 100 W for 5 minutes. The solution was cooled to room temperature and stored at 4°C for 24 hours to obtain a hydrogel with thermosensitive properties.

[0115] S3. Preparation of oil gel: the preparation method is the same as that in Example 1.

[0116] S4. Preparation of double gel: The preparation method is the same as that of Example 1. The obtained double gel has no oil leakage.

[0117] Example 7

[0118] This embodiment provides a method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, which specifically includes the following steps:

[0119] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0120] S2. Preparation of a hydrogel: At room temperature, 1.3 g of pea protein and 52 mg of chitosan oligosaccharide were weighed and dissolved in water. The mixture was stirred with a magnetic stirrer for 30 minutes to uniformly disperse the pea protein and chitosan oligosaccharide in the water to obtain a mixed solution having a pea protein mass concentration of 13%. NaCl was added to the mixed solution to a NaCl mass concentration of 0.3%. The pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. The pH-adjusted mixed solution was then placed in a reactor using a low-temperature plasma treatment apparatus and subjected to low-temperature plasma treatment at a power of 100 W for 5 minutes. The solution was cooled to room temperature and stored at 4°C for 24 hours to obtain a hydrogel with thermosensitive properties.

[0121] S3. Preparation of oil gel: the preparation method is the same as that in Example 1.

[0122] S4. Preparation of double gel: The preparation method is the same as that of Example 1. The obtained double gel has no oil leakage.

[0123] Comparative Example 7

[0124] This embodiment provides a method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, which specifically includes the following steps:

[0125] S1. Extracting pea protein by ammonium sulfate precipitation: the preparation method is the same as that in Example 1.

[0126] S2. Preparation of a hydrogel: At room temperature, 1.3 g of pea protein and 52 mg of chitosan oligosaccharide were weighed and dissolved in water. The mixture was stirred with a magnetic stirrer for 30 minutes to uniformly disperse the pea protein and chitosan oligosaccharide in the water to obtain a mixed solution having a pea protein mass concentration of 13%. NaCl was added to the mixed solution to a NaCl mass concentration of 0.4%. The pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. The pH-adjusted mixed solution was then placed in a reactor using a low-temperature plasma treatment apparatus and subjected to low-temperature plasma treatment at a power of 100 W for 5 minutes. The solution was cooled to room temperature and stored at 4°C for 24 hours to obtain a hydrogel having thermosensitive properties.

[0127] S3. Preparation of oil gel: the preparation method is the same as that in Example 1.

[0128] S4. Preparation of double gel: The preparation method is the same as that of Example 1. The obtained double gel has no oil leakage.

[0129] Comparative Example 8

[0130] This comparative example uses commercially available pea protein as a raw material to prepare a double gel, specifically comprising the following steps:

[0131] At room temperature, 1.3 g of pea protein and 52 mg of chitosan oligosaccharide were weighed and dissolved in water. The mixture was stirred with a magnetic stirrer for 30 minutes to uniformly disperse the pea protein and chitosan oligosaccharide in the water, resulting in a mixed solution with a pea protein concentration of 13%. NaCl was added to the mixed solution to a NaCl concentration of 0.1%. The pH of the mixed solution was adjusted to 3 using a 1 mol / L HCl solution. The pH-adjusted mixed solution was then placed in a reactor using a low-temperature plasma treatment apparatus and treated with a low-temperature plasma at a power of 100 W for 5 minutes. The solution was then cooled to room temperature and stored at 4°C for 24 hours to obtain a hydrogel.

[0132] The preparation method of the oil gel and the double gel was the same as that of Example 1, and the double gel obtained had no thermal reversible property.

[0133] Test Example 4

[0134] The thermoreversible properties of the double gel samples prepared in Example 1, Examples 5-7, and Comparative Example 7 were tested as follows: the sample was placed in a vial, with the loading amount being about 1 / 3 of the vial volume. The vial was turned upside down at room temperature to observe whether the double gel at the bottom of the vial would flow. The inverted vial was then heated at 80°C for 5 minutes, and the double gel at the bottom of the vial was observed to flow. The vial was then cooled to room temperature and the double gel at the bottom of the vial was observed to flow. The results are shown in FIG. Figure 2 .

[0135] pass Figure 2 It can be seen that when the NaCl mass concentration is 0%-0.2%, the double gel sample has obvious thermal reversible properties. When the mass concentration is 0.3%, the thermal reversible effect of the double gel sample begins to deteriorate, but still retains some thermal reversible effects. After continuing to increase the amount of NaCl added, the double gel sample loses its thermal reversible properties.

[0136] Test Example 5

[0137] The hardness, viscosity, elasticity, chewiness, and cohesion of the hydrogel samples prepared in Example 1, Examples 5-7, and Comparative Example 7 were tested using a texture analyzer using the same testing methods as in Experimental Example 2. The results are shown in Table 3. Table 3 shows that the hardness and chewiness of the hydrogels increase with increasing NaCl addition.

[0138] Table 3

[0139] NaCl mass concentration hardness Adhesion elasticity chewability Cohesion 0％ 20.783±1.160a 13.327±0.892d 0.323±0.025c 3.060±0.609d 0.450±0.035cd 0.1％ 23.557±1.364b 20.335±0.106b 0.385±0.048b 5.093±0.636c 0.520±0.022bc 0.2％ 28.197±0.670b 16.480±0.071c 0.318±0.046c 9.120±0.636ab 0.557±0.045ab 0.3％ 29.950±1.228c 22.043±0.329a 0.556±0.011a 10.630±1.206a 0.677±0.068a 0.4％ 34.713±2.397d 16.685±0.771c 0.537±0.047a 12.115±1.138a 0.607±0.021a

[0140] Note: Different lowercase letters in the same column indicate the significance of the difference, that is, when the test data of different samples contain the same letters under the same test item, it means there is no significant difference. If the letters contained in the test data of different samples are completely different, it means there is a significant difference (p < 0.05).

[0141] Test Example 6

[0142] This test example examined the antioxidant properties of the dual-gel samples prepared in Example 1, Examples 5-7, and Comparative Example 7. The testing method was as follows: the dual-gel samples were irradiated with UVC light to simulate a rapid oxidation process. Commercially available fish oil (the same raw material used in the examples) was used as a control. The degree of oxidation was determined using the thiobarbituric acid (TBRAS) method. The results are shown in Table 4. As shown in Table 4, the dual-gel samples exhibited a slowing effect on the oxidation of omega-3 fatty acids at addition levels of 0% to 0.4% NaCl.

[0143] Table 4

[0144]

[0145] Note: Different lowercase letters in the same row indicate the significance of the difference, that is, when the test data of different samples contain the same letters under the same test item, it means there is no significant difference. If the letters contained in the test data of different samples are completely different, it means there is a significant difference (p < 0.05); the values in Table 4 are TBRAS values, in μg / L, and the lower the value, the higher the antioxidant capacity.

[0146] Test Example 7

[0147] This test example is used to investigate the digestion of the double gel samples prepared in Example 1 and Examples 5-7 in a simulated in vivo manner. The standardized INFOGEST in vitro digestion model is used to simulate the digestion stages of saliva (SSF), gastric juice (SGF) and intestinal juice (SIF). Liquid nitrogen is used to rapidly cool each digestion stage to terminate the digestion, and the release of Omega-3 in each digestion stage is determined according to the method of GB5009.227-2023. The specific test method is as follows: 1) 5 clean centrifuge tubes are taken, 5 mL of saliva and 0.1000 g of double gel sample are added thereto respectively, the mixture is thoroughly mixed and placed in a shaker at 37°C. After incubation for 2 minutes, one centrifuge tube is taken out and cooled with liquid nitrogen to terminate the reaction, and the release of Omega-3 in each digestion stage is measured respectively. The release of EPA and DHA in the saliva stage was measured; 2) the remaining 4 centrifuge tubes were taken out at the same time at the 2nd minute, and 5mL of gastric juice was added to each tube. After thorough mixing, they were placed in a 37℃ shaker. One sample was taken out at the 1st hour and 3rd hour respectively, and the reaction was terminated by cooling with liquid nitrogen. The release of EPA and DHA in the gastric juice stage was measured respectively; 3) the remaining 2 groups of samples were taken out at the same time at the 3rd hour, and 10mL of intestinal juice was added to each tube. After thorough mixing, they were placed in a 37℃ shaker. One sample was taken out at the 5th hour and 8th hour respectively, and the reaction was terminated by cooling with liquid nitrogen. The release of EPA and DHA in the intestinal juice stage was measured respectively. The determination method refers to GB5009.227-2023, and the release rate of Omega-3 was calculated based on this. The results are shown in Table 1. Figure 3 .Depend on Figure 3 It can be seen that from the final simulated intestinal fluid digestion stage, the Omega-3 release rates of Examples 1, 6 and 7 are relatively high. Examples 1 and 7 are basically completely released, and Example 6 releases more than 80%. However, the release is relatively small in the simulated saliva digestion stage and the simulated gastric fluid digestion stage, indicating that the dual gel provided by the present invention can ultimately complete sufficient release in the intestinal fluid environment and has met the conditions for human application.

[0148] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing a low-salt, temperature-sensitive double gel for delivering Omega-3, characterized in that: The steps include: S1. Pea protein with temperature-sensitive properties was extracted from fresh pea seeds using ammonium sulfate precipitation method; S2. Adding the extracted pea protein and oligosaccharide to water and mixing to obtain a mixed solution, adding or not adding an inorganic salt, wherein the mass concentration of the inorganic salt in the mixed solution is 0-0.2%, and adjusting the pH of the system to 3-3.4; then subjecting the pH-adjusted mixed solution to plasma treatment to obtain a hydrogel having temperature-sensitive properties; S3, heating and stirring the fish oil and monoglyceride until fully dissolved, and cooling to obtain an omega-3 loaded oil gel; S4, mixing the hydrogel obtained in step S2 and the oleogel obtained in step S3, and subjecting the mixture to high-speed shearing to obtain the obtained product; In step S1, the specific extraction process of the pea protein is as follows: Add NaCl solution to fresh pea seeds at a solid-solubility ratio of 1:8-12, adjust the pH to 8-8.5 with NaOH solution, stir evenly, centrifuge, and take a primary supernatant; add anhydrous (NH4)2SO4 to the primary supernatant, stir, adjust the pH to 7.5-7.9 with HCl solution, centrifuge, and take a secondary supernatant; add anhydrous (NH4)2SO4 to the secondary supernatant, stir, centrifuge, and take a precipitate; dialyze the precipitate using a 3500-5000 Da dialysis bag for 48-72 hours, freeze-dry, grind, and sieve to obtain pea protein; The inorganic salt in step S2 is selected from NaCl; The oligosaccharide is selected from chitosan oligosaccharide; The plasma treatment in step S2 is specifically to use a low-temperature plasma treatment instrument to absorb the pH-adjusted mixed solution and place it in a reactor for plasma treatment, with a power of 80-100W and a treatment time of 3-10 minutes; The high-speed shearing is performed at 15,000-25,000 rpm for 3-5 minutes.

2. The preparation method according to claim 1, characterized in that The mass ratio of the pea protein to the oligosaccharide is 20-30:

1.

3. The preparation method according to claim 1, characterized in that The mass ratio of the hydrogel to the oleogel is 2-5:

1.

4. An oral delivery system for Omega-3, characterized in that The preparation method is described in any one of claims 1 to 3.

5. Use of the oral delivery system according to claim 4 in preparing food.

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