Thermostable vitamin c microcapsule with immune enhancement and preparation method thereof

Abstract

This invention relates to the field of pet food additives, specifically disclosing a heat-resistant vitamin C microcapsule with immune-enhancing properties and its preparation method. The microcapsule is composed of vitamin C, β-1,3-D-glucan, galactooligosaccharides, antioxidants, excipients, and deionized water. The preparation method involves uniformly mixing galactooligosaccharides, β-1,3-D-glucan, vitamin C, optional antioxidants, optional excipients, and deionized water, followed by spray drying to granulate the mixture into a solid dispersion. This dispersion can be used in pet extruded food, compound feed, premixed feed, or pet nutritional supplements. It solves the problem of vitamin C's easy decomposition during high-temperature processing of pet food and also achieves the additional functions of immune enhancement and intestinal regulation.

Description

Technical Field

[0001] This invention belongs to the field of pet food additive technology, specifically relating to a heat-resistant vitamin C microcapsule with immune-enhancing function and its preparation method. Background Technology

[0002] Vitamin C (L-ascorbic acid) is an essential nutrient for pet growth and development, playing important roles in anti-oxidation, promoting collagen synthesis, enhancing immunity, and improving gut health. It is widely used in pet compound feed, premixed feed, and nutritional supplements. However, vitamin C is highly heat-sensitive and oxidizing. During high-temperature processing of pet food (such as extrusion, conditioning, and drying), it is easily oxidized and decomposed, leading to reduced activity and content loss. The loss rate can typically reach 40%-70%, making it impossible to guarantee that pets ingest sufficient effective vitamin C and affecting the nutritional quality of the feed.

[0003] To address the thermal stability issue of vitamin C, current technologies often employ spray drying to prepare solid dispersions or microcapsules. These microcapsules are then encapsulated by a carrier, forming a physical barrier to isolate vitamin C from external factors such as heat, oxygen, and humidity. Currently, commonly used carriers include maltodextrin, inulin, and regular whey protein. However, these carriers only provide basic protection for vitamin C, have limited functionality, and some are not fully compatible with the processing characteristics of pet food and the physiological needs of pets.

[0004] Galacto-oligosaccharides, as a natural prebiotic, primarily function to promote the proliferation of beneficial intestinal bacteria (such as Bifidobacteria and Lactobacillus), thereby improving gut health, enhancing immunity, and assisting in regulating nutrient absorption. They exhibit high stability under neutral pH conditions and do not decompose when heated at 100°C for 1 hour or 120°C for 30 minutes.

[0005] β-1,3-D-glucan has significant immune-enhancing effects, stimulating macrophage activity in pets and improving their resistance. It also possesses good heat resistance and film-forming properties, making it suitable as an encapsulation carrier. However, there are currently no reports on technologies using β-1,3-D-glucan combined with galactooligosaccharides as a carrier for encapsulating vitamin C and preparing pet-specific microcapsules with both immune-enhancing and heat-resistant functions, nor are there any related patent protections.

[0006] Therefore, in view of the shortcomings of existing vitamin C microcapsules, such as insufficient heat resistance and single function, which cannot meet the high-temperature processing requirements of pet food and the immune needs of pets, it is of great practical significance and application value to develop a vitamin C microcapsule with β-1,3-D-glucan and galactooligosaccharide as a composite carrier, which has both immune enhancement and heat resistance functions, as well as its preparation method. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a heat-resistant vitamin C microcapsule with both immune enhancement and its preparation method. This invention solves the problems of poor heat resistance, single function, inability to adapt to high-temperature processing of pet food, and inability to meet the immune needs of pets. It achieves the triple function of "vitamin C heat stability protection + prebiotic intestinal regulation + immune enhancement", which is suitable for the processing needs of various pet foods such as pet extruded food and compound feed.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A heat-resistant vitamin C microcapsule with immune-enhancing properties is made from the following raw materials in parts by weight: 5-20 parts vitamin C, 10-30 parts β-1,3-D-glucan, 20-40 parts galactooligosaccharide, 1-5 parts antioxidant, 5-65 parts excipients, and 300-500 parts deionized water.

[0009] Furthermore, the vitamin C is L-ascorbic acid with a purity of ≥99%, ensuring the activity and nutritional value of vitamin C.

[0010] Furthermore, the β-1,3-D-glucan is derived from Saccharomyces cerevisiae, with water-soluble β-1,3-D-glucan being the main component of the raw material. Its molecular weight is 20-50 kDa. β-1,3-D-glucan in this molecular weight range not only has excellent immune-enhancing activity but also better film-forming properties. When combined with galactooligosaccharides, it can form a more effective protective structure, improving the encapsulation effect and heat resistance.

[0011] Furthermore, the antioxidant is one or more of citric acid, sodium L-ascorbate, and vitamin E. Preferably, citric acid and sodium L-ascorbate are compounded in a weight ratio of 1:1 to 2, which can synergistically inhibit the oxidative decomposition of vitamin C and further improve the stability of the microcapsules.

[0012] Furthermore, the excipient is one or more of corn starch and sorbitol, preferably a mixture of sorbitol and corn starch in a weight ratio of 1:1 to 2.

[0013] The method for preparing the above-mentioned heat-resistant vitamin C microcapsules with immune-enhancing properties is characterized by comprising the following steps: (1) Raw material pretreatment: β-1,3-D-glucan, galactooligosaccharide, antioxidant and excipients are pulverized and passed through an 80-100 mesh sieve for later use; (2) Preparation of the material solution: Add vitamin C, pretreated antioxidant and excipients to deionized water, stir until uniform, adjust the pH to 6.0-7.0, then add β-1,3-D-glucan and galactooligosaccharide, stir for 20-30 min at 40-60℃ and 200-300 r / min to obtain the encapsulation material solution; (3) Spray drying: The encapsulation liquid prepared in step (2) is passed through an 80-100 mesh sieve and then sent into a spray dryer. The inlet air temperature is adjusted to 160-180℃, the outlet air temperature to 70-90℃, the feed rate to 10-20mL / min, and the atomization pressure to 0.2-0.4MPa. Spray drying is carried out to obtain a solid dispersion, namely the heat-resistant vitamin C microcapsules with immune enhancement. (4) Post-processing: Cool the microcapsules obtained by spray drying to room temperature (25±2℃), pass them through a 60-80 mesh sieve to remove agglomerated particles, then seal them in packaging and store them in a dry and cool place.

[0014] Furthermore, in step (2), the pH of the embedding solution is adjusted to 6.5.

[0015] Furthermore, in step (3), the inlet air temperature of the spray dryer is 170℃, the outlet air temperature is 80℃, the feed rate is 15mL / min, and the atomization pressure is 0.3MPa.

[0016] The prepared microcapsules retained ≥85% of vitamin C after being incubated at 130℃ for 30 min; and the vitamin C loss rate was ≤10% after being stored at 25±2℃ and 60±5% relative humidity for 12 months.

[0017] Compared with the prior art, the present invention has the following advantages: 1. Significantly Improved Heat Resistance: This invention uses a composite carrier of β-1,3-D-glucan and galactooligosaccharides. β-1,3-D-glucan has excellent heat resistance and film-forming properties, and works synergistically with galactooligosaccharides to form a more effective protective structure. It is prepared into a solid dispersion by spray drying, which can effectively isolate high temperature, oxygen and moisture, and significantly reduce the decomposition rate of vitamin C in the high-temperature processing (expansion and conditioning) of pet food. Tests show that at an expansion temperature of 130℃, the vitamin C retention rate can reach more than 85%, which is far higher than the encapsulation effect of existing ordinary carriers.

[0018] 2. Multifunctional: The composite carrier of this invention has three functions: galactooligosaccharides, as a prebiotic, can regulate the balance of intestinal flora in pets and improve intestinal health; β-1,3-D-glucan can enhance the immune function of pets, stimulate macrophage activity, and improve the resistance of pets; vitamin C has antioxidant and growth-promoting effects. The three work synergistically, which is more in line with the physiological needs of pets than existing single-function vitamin C microcapsules, and improves the nutritional value and functionality of pet food.

[0019] 3. Adaptable to pet food requirements: The raw materials used in this invention (β-1,3-D-glucan, galactooligosaccharides, vitamin C, antioxidants, and excipients) all meet the requirements of the "Feed Raw Material Catalog" and the "Feed Additive Variety Catalog," contain no harmful ingredients, and can be directly applied to various pet foods such as extruded pet food, compound feed, premixed feed, and nutritional supplements. Furthermore, the prepared microcapsule powder has good flowability, is easy to mix and add, and is suitable for the industrial production process of pet food.

[0020] 4. Simple preparation process and controllable cost: This invention adopts conventional spray drying technology, which is mature and easy to operate. It does not require complex equipment and process parameter adjustments. The raw materials are readily available and the cost is moderate, making it suitable for large-scale industrial production. It has high economic benefits and application prospects.

[0021] 5. High stability and long shelf life: Through the synergistic effect of composite carrier encapsulation and antioxidants, this invention not only improves the thermal stability of vitamin C, but also enhances its storage stability. Under normal temperature and sealed storage conditions, the shelf life can reach more than 12 months, and the vitamin C loss rate is ≤10%, which solves the problem of activity loss during the storage of existing vitamin C microcapsules. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments, but it should be understood that the scope of the present invention is not limited to the scope of these embodiments. Example 1

[0023] A heat-resistant vitamin C microcapsule with immune-enhancing properties is made from the following raw materials in parts by weight: 5 parts vitamin C (99% purity), 10 parts β-1,3-D-glucan (molecular weight 20-50kDa), 20 parts galactooligosaccharide, 1 part citric acid, 2 parts sodium L-ascorbate, 22 parts sorbitol, 40 parts corn starch, and 330 parts deionized water.

[0024] Preparation method: (1) Raw material pretreatment: β-1,3-D-glucan, galactooligosaccharide, citric acid, sodium L-ascorbate, sorbitol and corn starch are pulverized and passed through an 80-mesh sieve for later use; (2) Preparation of the material solution: Add vitamin C, pretreated citric acid, sodium L-ascorbate, sorbitol and corn starch to deionized water, stir until uniform, adjust the pH to 6.2, then add pretreated β-1,3-D-glucan and galactooligosaccharide, stir for 20 min at 45℃ and 220 r / min to obtain the encapsulation material solution; (3) Spray drying: The encapsulating liquid is passed through an 80-mesh sieve and then fed into a spray dryer. The inlet air temperature is adjusted to 165℃, the outlet air temperature to 75℃, the feed rate to 18mL / min, and the atomization pressure to 0.25MPa. Spray drying is carried out to obtain a solid dispersion. (4) Post-processing: Cool the solid dispersion to 25°C, pass it through a 60-mesh sieve, seal and package it to obtain the target product.

[0025] The prepared microcapsules retained ≥85% of vitamin C after being incubated at 130℃ for 30 min; and the vitamin C loss rate was ≤10% after being stored at 25±2℃ and 60±5% relative humidity for 12 months. Example 2

[0026] A heat-resistant vitamin C microcapsule with immune-enhancing properties is made from the following raw materials in parts by weight: 12 parts vitamin C (99% purity), 20 parts β-1,3-D-glucan (molecular weight 20-50kDa), 30 parts galactooligosaccharide, 1 part citric acid, 1 part sodium L-ascorbate, 12 parts sorbitol, 24 parts corn starch, and 410 parts deionized water.

[0027] Preparation method: (1) Raw material pretreatment: β-1,3-D-glucan, galactooligosaccharide, citric acid, sodium L-ascorbate, sorbitol and corn starch were pulverized and passed through a 90-mesh sieve for later use; (2) Preparation of the material solution: Add vitamin C, pretreated citric acid, sodium L-ascorbate, sorbitol and corn starch to deionized water, stir until uniform, adjust the pH to 6.5, then add pretreated β-1,3-D-glucan and galactooligosaccharide, stir for 25 min at 50℃ and 250 r / min to obtain the encapsulation material solution; (3) Spray drying: The encapsulating liquid is fed into a spray dryer, and the inlet air temperature is adjusted to 170℃, the outlet air temperature to 80℃, the feed rate to 15mL / min, and the atomization pressure to 0.3MPa. Spray drying is carried out to obtain a solid dispersion. (4) Post-processing: Cool the solid dispersion to 25°C, pass it through a 70-mesh sieve, seal and package it to obtain the target product. Example 3

[0028] A heat-resistant vitamin C microcapsule with immune-enhancing properties is made from the following raw materials in parts by weight: 20 parts vitamin C (99% purity), 30 parts β-1,3-D-glucan (molecular weight 20-50kDa), 40 parts galactooligosaccharides, 1 part citric acid, 1 part sodium L-ascorbate, 4 parts sorbitol, 4 parts corn starch, and 460 parts deionized water.

[0029] Preparation method: (1) Raw material pretreatment: β-1,3-D-glucan, galactooligosaccharide, citric acid, sodium L-ascorbate, sorbitol and corn starch were pulverized and passed through a 100-mesh sieve for later use; (2) Preparation of the material solution: Add vitamin C, pretreated citric acid, sodium L-ascorbate, sorbitol and corn starch to deionized water, stir until uniform, adjust the pH to 6.8, then add pretreated β-1,3-D-glucan and galactooligosaccharides, stir for 28 min at 55℃ and 280 r / min to obtain the encapsulation material solution; (3) Spray drying: The encapsulating liquid is fed into a spray dryer, and the inlet air temperature is adjusted to 175℃, the outlet air temperature to 85℃, the feed rate to 12mL / min, and the atomization pressure to 0.35MPa. Spray drying is carried out to obtain a solid dispersion. (4) Post-processing: Cool the solid dispersion to 25°C, pass it through an 80-mesh sieve, seal and package it to obtain the target product.

[0030] Comparative Example 1 (Single galactooligosaccharide carrier) A vitamin C microcapsule is made from the following raw materials in parts by weight: 12 parts vitamin C, 30 parts galactooligosaccharides, 1 part citric acid, 1 part sodium L-ascorbate, 20 parts sorbitol, 36 parts corn starch, and 410 parts deionized water.

[0031] Preparation method: Except for the absence of β-1,3-D-glucan, the other steps are completely the same as in Example 2.

[0032] Comparative Example 2 (Single β-1,3-D-glucan carrier) A vitamin C microcapsule is made from the following raw materials in parts by weight: 12 parts vitamin C, 20 parts β-1,3-D-glucan, 1 part citric acid, 1 part sodium L-ascorbate, 22 parts sorbitol, 44 parts corn starch, and 410 parts deionized water.

[0033] Preparation method: Except for the absence of galactooligosaccharides, the other steps are completely the same as in Example 2.

[0034] Comparative Example 3 (maltodextrin + galactooligosaccharide carrier) A vitamin C microcapsule is made from the following raw materials in parts by weight: 12 parts vitamin C, 20 parts maltodextrin, 30 parts galacto-oligosaccharides, 1 part citric acid, 1 part sodium L-ascorbate, 12 parts sorbitol, 24 parts corn starch, and 410 parts deionized water.

[0035] Preparation method: Except for replacing β-1,3-D-glucan with maltodextrin, the other steps are completely the same as in Example 2.

[0036] Test data: To verify the heat resistance, storage stability, and immune-enhancing effect of the microcapsules of the present invention, relevant performance tests were conducted on the products of Examples 1-3 and Comparative Examples 1-3. The test methods and results are as follows: (1) Heat resistance test (simulating pet puffing processing conditions).

[0037] Test method: The microcapsules of each embodiment and comparative example were placed in a constant temperature oven at 130℃ (the conventional processing temperature of pet extruded food) for 30 minutes. After cooling to room temperature, the residual amount of vitamin C in the microcapsules was detected and the retention rate was calculated. Each group was tested 3 times and the average value was taken.

[0038] The test results are shown in Table 1 below: Table 1: Vitamin C Retention Rate

[0039] Conclusion: The microcapsules of Examples 1-3 all achieved a vitamin C retention rate of over 85% at 130℃, which is significantly higher than that of Comparative Examples 1-3 (retention rate of only 60.0%-65.8%). This indicates that the present invention uses a composite carrier of β-1,3-D-glucan and galactooligosaccharide, which can significantly improve the heat resistance of vitamin C and meet the high-temperature processing requirements of pet extruded food.

[0040] (2) Storage stability test.

[0041] Test method: The microcapsule aluminum foil bags of each embodiment and comparative example were vacuum sealed and stored in an environment of 25±2℃ and 60±5% relative humidity for 12 months. The vitamin C content was measured at 0 months, 6 months and 12 months and the loss rate was calculated. Each group was tested 3 times and the average value was taken.

[0042] The test results are shown in Table 2 below: Table 2: Storage Stability Test Data

[0043] Conclusion: The microcapsules of Examples 1-3 showed a vitamin C loss rate of ≤9.1% during a 12-month storage period, which was significantly lower than that of Comparative Examples 1-3 (loss rate of 17.3%-21.6%). This indicates that the microcapsules of the present invention have excellent storage stability, can be stored for a long time, and can effectively preserve the activity of vitamin C.

[0044] (3) Immune enhancement effect test (live pet test) Test method: Twenty healthy kittens (weighing 2-2.5 kg) were randomly divided into four groups of five kittens each: Example 2 group and Comparative Examples 1-3 groups. All kittens in each group were fed the same basic cat food, with microcapsules of the corresponding group added to the basic cat food (at a concentration of 0.5%) for 30 consecutive days. After the feeding period, peripheral blood was collected from the kittens to detect the level of immunoglobulin IgG in the serum (the higher the IgG level, the stronger the immune function). Each group was tested three times, and the average value was taken.

[0045] The test results are shown in Table 3 below: Table 3: Results of serum IgG content detection

[0046] Conclusion: The serum IgG levels of kittens in Example 2 group all reached above 4.6 g / L, which was significantly higher than that in Comparative Examples 1-3 (3.5-4.1 g / L). This indicates that the synergistic effect of β-1,3-D-glucan and galactooligosaccharides in the microcapsules of the present invention can effectively enhance the immune function of pets and achieve the dual effect of "nutritional protection + immune enhancement", which is superior to existing microcapsule products.

[0047] 1. The core innovation of this invention lies in the use of β-1,3-D-glucan and galactooligosaccharide as a composite carrier, combined with spray drying technology to prepare vitamin C microcapsules. This not only solves the problem of vitamin C being easily decomposed during high-temperature processing of pet food, but also achieves the additional functions of immune enhancement and intestinal regulation. Moreover, all raw materials comply with the "Feed Raw Material Catalog" or "Feed Additive Variety Catalog", and are suitable for the industrial production of pet food and the physiological needs of pets.

[0048] 2. The embodiments of the present invention are merely preferred solutions. The raw material ratio and process parameters can be adjusted within the scope of protection of the claims according to actual production needs, and all such adjustments fall within the scope of protection of the present invention.

[0049] 3. Conventional process steps not mentioned in this invention (such as raw material crushing, mixing, packaging, etc.) can be implemented using conventional technical means in the field and will not affect the implementation effect of this invention.

Claims

1. A heat-resistant vitamin C microcapsule having an immune-enhancing effect, characterized by comprising: a vitamin C core; a first layer of a water-soluble polymer; a second layer of a water-soluble polymer; and a third layer of a water-soluble polymer. It is composed of the following raw materials in parts by weight: 5-20 parts vitamin C, 10-30 parts β-1,3-D-glucan, 20-40 parts galactooligosaccharide, 1-5 parts antioxidant, 5-65 parts excipients, and 300-500 parts deionized water.

2. The microcapsule according to claim 1, characterized in that, The vitamin C mentioned is L-ascorbic acid with a purity of ≥99%.

3. The microcapsule according to claim 1, characterized in that, The β-1,3-D-glucan is derived from Saccharomyces cerevisiae and has a molecular weight of 20-50 kDa.

4. The microcapsule according to claim 1, characterized in that, The antioxidant is one or more of citric acid, sodium L-ascorbate, and vitamin E.

5. The microcapsule according to claim 4, characterized in that, The antioxidant is a compound of citric acid and sodium L-ascorbate in a weight ratio of 1:1 to 2.

6. The microcapsule according to claim 1, characterized in that, The excipients are one or more of corn starch and sorbitol.

7. The microcapsule according to claim 1, characterized in that, The weight parts of each raw material are as follows: Vitamin C 12 parts, β-1,3-D-glucan 20 parts, galactooligosaccharide 30 parts, antioxidant 2 parts, excipients 36 parts, and deionized water 390 parts.

8. A method for preparing heat-resistant vitamin C microcapsules with immune-enhancing properties as described in any one of claims 1-7, characterized in that, Includes the following steps: (1) Raw material pretreatment: β-1,3-D-glucan, galactooligosaccharide, antioxidant and excipients are pulverized and passed through an 80-100 mesh sieve for later use; (2) Preparation of the material solution: Add vitamin C, pretreated antioxidant and excipients to deionized water, stir until uniform, adjust the pH to 6.0-7.0, then add β-1,3-D-glucan and galactooligosaccharide, stir for 20-30 min at 40-60℃ and 200-300 r / min to obtain the encapsulation material solution; (3) Spray drying: The encapsulating liquid is passed through an 80-100 mesh sieve and then fed into a spray dryer. The inlet air temperature is adjusted to 160-180℃, the outlet air temperature to 70-90℃, the feed rate to 10-20mL / min, and the atomization pressure to 0.2-0.4MPa. Spray drying is carried out to obtain a solid dispersion. (4) Post-processing: Cool the solid dispersion to room temperature, pass it through a 60-80 mesh sieve, seal and package it to obtain the product.

9. The preparation method according to claim 8, characterized in that, In step (2), the pH of the embedding solution is adjusted to 6.

5.

10. The preparation method according to claim 8, characterized in that, In step (3), the inlet air temperature of the spray dryer is 170℃, the outlet air temperature is 80℃, the feed rate is 15mL / min, and the atomization pressure is 0.3MPa.

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