Two-phase gel loaded with natural antioxidant as well as preparation method and application of two-phase gel

Abstract

The invention discloses biphase gel loaded with natural antioxidants as well as a preparation method and application of the biphase gel. The biphase gel is obtained by mixing oil gel and hydrogel in a mass ratio of (20: 80)-(80: 20) through a physical effect, wherein the hydrogel is composed of a water-soluble natural antioxidant and a polysaccharide aqueous solution; the oleogel is composed of an oleogel agent, a fat-soluble natural antioxidant, a small molecule emulsifier and edible oil. According to the present invention, the water-soluble nutrients are loaded in the hydrogel, and the fat-soluble nutrients are loaded in the oil gel to prepare different types of the two-phase gel nutrient delivery systems simultaneously loading the hydrophilic and hydrophobic natural antioxidants so as to effectively improve the steady-state protection effect and the bioavailability of the nutrients.

Description

Technical Field

[0001] The invention belongs to the technical field of nutrient delivery, and in particular relates to a two-phase gel loaded with natural antioxidants, and a preparation method and application thereof. Background Art

[0002] Natural antioxidants have attracted extensive attention due to their antioxidant, anti-atherosclerotic, anti-inflammatory, anti-aging and anti-tumor physiological functions that are beneficial to human health. The most reported natural antioxidants include ascorbic acid, resveratrol, epigallocatechin gallate (EGCG), astaxanthin and curcumin. However, these natural antioxidants have poor stability and low gastrointestinal absorption rate. After ingestion, they will be rapidly metabolized and degraded in the body, resulting in low utilization rate, which greatly limits their application in the food industry. Therefore, research in recent years has been committed to developing efficient delivery systems for the embedding and delivery of natural antioxidants.

[0003] As a new type of biomaterial, biphasic gel has shown great potential in the field of nutrient delivery. This structure has unique biphasic properties and can regulate nutrient release according to environmental conditions, thereby improving its bioavailability and stability. Traditional nutrient delivery systems often have problems such as uncontrollable release rate and low bioavailability, which makes it difficult to meet the needs of modern people for healthy diet and nutritional supplements. The emergence of biphasic gel provides a new way to solve these problems. The two-phase gel structure of biphasic gel enables it to simultaneously deliver hydrophilic and lipophilic nutrients. Its excellent biocompatibility and safety can be well integrated into human tissues, reducing adverse reactions and side effects. Therefore, biphasic gel has broad application prospects in the fields of food, nutrition and medicine.

[0004] However, despite the many advantages of biphasic gels for nutrient delivery, they still face some challenges in practical applications. For example, how to optimize the formula and structure of biphasic gels to better control the release behavior of nutrients; how to evaluate the stability and safety of biphasic gels during digestion; and how to combine biphasic gels with other nutrients or drugs to achieve synergistic effects. These issues require us to conduct in-depth research and exploration. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] One of the purposes of the present invention is to provide a dual-phase gel loaded with natural antioxidants, by loading fat-soluble nutrients in oil gel and water-soluble nutrients in hydrogel to prepare different types of dual-phase gel nutrient delivery systems that simultaneously load hydrophilic and hydrophobic natural antioxidants, thereby effectively improving the steady-state protection effect and bioavailability of nutrients.

[0008] In order to solve the above technical problems, the present invention provides the following technical solution: a two-phase gel loaded with natural antioxidants, comprising:

[0009] It is obtained by mixing oil gel and hydrogel in a mass ratio of 20:80 to 80:20 through physical action;

[0010] Wherein, the hydrogel is composed of a water-soluble natural antioxidant and a polysaccharide aqueous solution;

[0011] The oil gel is composed of an oil gelling agent, a fat-soluble natural antioxidant and edible oil;

[0012] The water-in-oil type dual-phase gel loaded with natural antioxidants can delay the release of nutrients and free fatty acids.

[0013] As a preferred embodiment of the biphasic gel loaded with natural antioxidants of the present invention, the water-soluble natural antioxidants include one of ascorbic acid, anthocyanins, epigallocatechin gallate (EGCG), glutathione, and collagen peptide; the water-soluble natural antioxidants in the hydrogel are present in an amount of 0.01 to 0.2% by mass, and the polysaccharides are present in an amount of 1 to 5% by mass.

[0014] As a preferred embodiment of the dual-phase gel loaded with natural antioxidants of the present invention, the polysaccharide is one or more of gellan gum, hydroxypropyl methylcellulose, xanthan gum, carrageenan, guar gum, sodium alginate and locust bean gum.

[0015] As a preferred embodiment of the biphasic gel loaded with natural antioxidants of the present invention, the fat-soluble natural antioxidants include one of vitamin A, vitamin E, curcumin, astaxanthin, lycopene, resveratrol, β-carotene, quercetin, and coenzyme Q10; the fat-soluble natural antioxidants in the oil gel are present in an amount of 0.01-0.2% by mass, the small molecule emulsifier is present in an amount of 0.5-5% by mass, the edible oil is present in an amount of 90-97% by mass, and the oil gel is present in an amount of 3-10% by mass.

[0016] As a preferred embodiment of the dual-phase gel loaded with natural antioxidants of the present invention, the oil gel is one or more of glyceryl monostearate, beeswax, rice bran wax, candelilla wax, carnauba wax, sunflower seed wax, and corn wax;

[0017] The edible oil is one or more of soybean oil, rapeseed oil, peanut oil, sunflower seed oil, rice bran oil, corn oil, linseed oil, olive oil, wheat germ oil, cottonseed oil, almond oil, tea seed oil, sesame oil, algae oil, and palm oil.

[0018] As a preferred embodiment of the dual-phase gel loaded with natural antioxidants of the present invention, the oil gel also includes a small molecule emulsifier, and the small molecule emulsifier is one or more of polyglycerol polyricinoleate, monostearate glyceryl, sucrose fatty acid ester, lactic acid fatty acid glyceryl ester, citric acid fatty acid glyceryl ester, propylene glycol fatty acid ester, and diacetyl tartaric acid monoglyceride.

[0019] As a preferred embodiment of the dual-phase gel loaded with natural antioxidants of the present invention, the physical action is one or more of high-speed shearing, ice-water bath, and high-pressure homogenization.

[0020] As a preferred embodiment of the dual-phase gel loaded with natural antioxidants of the present invention, the edible oil is a mixed oil, and the mixed oil is one of palm oil and algae oil, palm oil and soybean oil, coconut oil and soybean oil, and palm stearin and soybean oil in a volume ratio of 1:1.

[0021] Another object of the present invention is to provide a method for preparing the biphasic gel loaded with natural antioxidants as described above, comprising:

[0022] The polysaccharide solution loaded with water-soluble natural antioxidants is gelled to obtain a hydrogel;

[0023] Using an oil gelling agent to induce gelation of an oil phase loaded with fat-soluble natural antioxidants and containing a small molecule emulsifier and edible oil to obtain an oil gel;

[0024] The oil gel and the hydrogel in a mass ratio of 20:80 to 80:20 are mixed, and a two-phase gel loaded with natural antioxidants is prepared by physical action.

[0025] Another object of the present invention is to provide the use of the above-mentioned dual-phase gel loaded with natural antioxidants in the preparation of antioxidant products, wherein the dual-phase gel is an oil-in-water type.

[0026] Another object of the present invention is to provide use of the above-mentioned dual-phase gel loaded with natural antioxidants in simultaneously delivering water-soluble and fat-soluble natural antioxidants, wherein the dual-phase gel is a water-in-oil type.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention can obtain three types of biphasic gels loaded with natural antioxidants, namely, O / W type, bicontinuous type and W / O type by adjusting the mass ratio of the oil-water phase; the crystal network structure of the oil gel in the biphasic gel inhibits the oxidation of oils in the system to a certain extent, and the W / O type biphasic gel with a higher oil gel content exhibits the strongest oxidation stability; compared with the biphasic gel loaded with only one antioxidant, the biphasic gel loaded with both water-soluble and fat-soluble antioxidants has a better antioxidant effect.

[0029] The dual-phase gel system of the present invention significantly improves the embedding rate, stability and bioavailability of natural antioxidants, and can effectively delay the release of nutrients and free fatty acids in the gastrointestinal tract. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0031] Figure 1 Optical microscope (upper) and polarizing microscope (lower) images of the two-phase gel system I prepared in Example 1;

[0032] Figure 2 The embedding rate diagram of the two-phase gel system I prepared in Examples 1 to 3 (left) and the embedding rate diagram of the two-phase gel system II prepared in Example 4 (right);

[0033] Figure 3 POV and TBARS values ​​of the two-phase gel system I prepared in Examples 1 to 3 and Comparative Examples 1 to 5 stored at 25°C for 35 days, including O / W type (a) (b); bicontinuous type (c) (d); W / O type (e) (f);

[0034] Figure 4 The graphs are the retention rates of antioxidant substances in the O / W (a), bicontinuous (b) and W / O (c) type biphasic gel systems I prepared in Comparative Examples 2 to 5 during storage for 35 days;

[0035] Figure 5 The graphs are the changes in the natural antioxidant content (left) and the relative reduction ratio (right) of the pure water gel prepared in Comparative Example 6, the pure oil gel prepared in Comparative Example 7 and the two-phase gel system II prepared in Example 4 during the 20-day storage process;

[0036] Figure 6 POV value and TBARS value diagram of the two-phase gel system II prepared in Examples 4 to 6 and Comparative Example 8 stored at 45° C. for 25 days;

[0037] Figure 7 The microstructure of the two-phase gel system I prepared in Example 1 during in vitro digestion;

[0038] Figure 8 This is a release curve of FFA of the two-phase gel system I prepared in Example 1 during in vitro intestinal digestion;

[0039] Fig. 9 The release curves of astaxanthin (a) and ascorbic acid (b) and the schematic diagram of the structural changes (c) of the two-phase gel system I prepared in Example 1 during in vitro digestion;

[0040] Fig.10 Bioavailability graphs of natural antioxidants during in vitro digestion of the two-phase gel system I prepared in Example 1 (left) and the two-phase gel system II prepared in Example 4 (right). DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0042] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0043] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0044] Unless otherwise specified, the raw materials used in the examples were purchased commercially.

[0045] The test method used in the embodiment of the present invention is:

[0046] (1) Determination method of oxidation lag time (T):

[0047] Differential scanning calorimetry (DSC) is used to determine the hysteresis time of oil oxidation. An appropriate amount of sample is weighed and placed in the sample dish of the DSC and sealed. The sealed sample dish is then placed in the test cell of the DSC instrument and the test parameters are set, including the test temperature range, heating rate, oxygen pressure, etc. Before the test, the sample is purged with nitrogen to remove the air in the sample dish, reduce the influence of oxygen, and ensure the accuracy of the test. The sample is then heated at the set heating rate until the predetermined test temperature is reached. After reaching the set temperature, the nitrogen purge is stopped and replaced with a certain pressure of oxygen, usually 3.5 MPa, to simulate the conditions of oil oxidation. The oxidation process of oil under heating and oxygen is monitored using DSC, and the heat flow changes of the sample are recorded. The DSC curve is observed to determine the oxidation hysteresis time (T), that is, the time from the start of oxygen to the occurrence of the oxidation reaction. This is usually manifested as a sharp exothermic peak on the DSC curve, and the oxidation hysteresis time (T) can be obtained based on the curve.

[0048] (2) In vitro simulated digestion test method:

[0049] Oral stage: Prepare 7.5 mL of simulated oral fluid, which contains 0.298 mg / mL NaCl, 0.896 mg / mL KCl and 0.6 mg / mL α-amylase. Mix the prepared simulated oral fluid with an equal amount of the biphasic gel sample, adjust the pH of the reaction system to 6.8, maintain the temperature at 37°C, and digest at 100 r / min for 10 min.

[0050] Gastric stage: prepare 15 mL of simulated gastric fluid containing 2 mg / mL NaCl and 3.2 mg / mL pepsin, mix the prepared simulated gastric fluid with the orally digested sample, adjust the pH of the reaction system to 2.0, maintain the temperature at 37 °C, and digest at 100 r / min for 120 min.

[0051] Small intestine stage: The simulated small intestinal fluid is composed of three parts, among which the small intestinal reserve solution is a mixed solution of CaCl2 (36.7 mg / mL) and NaCl (218.7 mg / mL); the bile salt solution is prepared by dissolving porcine bile salt (54 mg / mL) in a phosphate buffer at pH 7.0; and the mixed enzyme solution is prepared by dissolving lipase (48 mg / mL) and trypsin (24 mg / mL) in a phosphate buffer at pH 7.0. The mixture after gastric digestion was adjusted to pH 7.0 with 0.1 mol / L NaOH solution, and then 7.5 mL of simulated small intestinal fluid was added, containing 3.5 mL of bile salt solution, 2.5 mL of mixed enzyme solution and 1.5 mL of small intestinal reserve solution, and the temperature was maintained at 37°C, and digestion was carried out at 100 r / min for 120 minutes.

[0052] All digestion processes are performed under strict control of pH changes.

[0053] (3) Determination of free fatty acid (FFA) release rate during in vitro digestion

[0054] The hydrolysis of oil occurs during intestinal digestion, and the free fatty acid content in the system is determined by the pH steady-state titration method. Titrate with 0.1 mol / L NaOH solution for 2 hours, and the pH of the digestive fluid is always maintained at 7.0. Record the volume of NaOH solution consumed and calculate the FFA release rate. The calculation formula is as follows:

[0055]

[0056] Among them, M NaOH is the concentration of NaOH solution (0.1 mol / L), V NaOH is the volume used in the titration process (L), M 油 is the molecular weight of the oil (880 g / mol), W 油 is the total mass of oil in the digestive system (g).

[0057] (4) Determination of the release rate of natural antioxidants during in vitro digestion

[0058] During the simulated gastrointestinal stage, 1 mL of chyme was taken from the digestive fluid every 30 minutes, centrifuged at 12000g for 10 minutes at 4°C, and the non-micelle portion was collected. After the collected non-micelle portion was extracted and diluted to an appropriate multiple, the absorbance value at 260nm was measured by ultraviolet spectrophotometry to determine the release rate curve of ascorbic acid. The collected digestive fluid was extracted with acetone and centrifuged at 8000g for 10 minutes at 4°C to extract astaxanthin. The organic phase was then collected, and the release of astaxanthin was measured at 472nm using acetone as a control. The release rate of ascorbic acid and astaxanthin was calculated as follows:

[0059]

[0060] Among them, C 释放 is the amount of ascorbic acid or astaxanthin released during digestion, C 总 is the amount of ascorbic acid or astaxanthin entrapped in the biphasic gel.

[0061] (5) Determination of the bioavailability of natural antioxidants in in vitro digestion

[0062] After in vitro digestion of the biphasic gel loaded with hydrophilic and hydrophobic natural antioxidants, the micelle fraction was obtained by centrifugation at 12,000 g for 30 min at 4°C. The micelle fraction was diluted and the contents of water-soluble and fat-soluble natural antioxidants in the micelles were determined. Finally, the bioavailability of natural antioxidants was calculated according to the following formula:

[0063]

[0064] Among them, C 胶束 is the content of water-soluble or fat-soluble natural antioxidants in micelles, C 总 It is the content of water-soluble or fat-soluble natural antioxidants in the biphasic gel before digestion.

[0065] Example 1

[0066] (1) Preparation of hydrogel

[0067] 1.2% (w / w) gellan gum powder was slowly added to deionized water, and stirred at 200 r / min for 30 min at room temperature to obtain a gellan gum aqueous solution. Then, 0.05% (w / w) ascorbic acid was added to the gellan gum hydrogel and stirred evenly to form an ascorbic acid-loaded hydrogel solution.

[0068] (2) Preparation of oil gel

[0069] 0.05% astaxanthin was added to the mixed oil phase (palm oil: algae oil = 1:1), and stirred at 500r / min in a dark state until the nutrient was completely dissolved in the oil. Then 4% (w / w) GMS was mixed with 96% (w / w) mixed oil phase, heated to 85°C, and stirred at 500r / min for 30 minutes to form a uniform astaxanthin-loaded oil gel solution.

[0070] (3) Preparation of biphasic gel system I

[0071] The prepared hydrogel and oil gel were mixed at 85°C with an oil-water mass ratio of 40:60, 65:35, and 80:20, and then homogenized and emulsified at 8000 r / min for 2 min using a high-speed disperser. The obtained emulsion gel was then stirred and cooled in an ice water bath to obtain different types (W / O type, bicontinuous type, and O / W type) of biphasic gels loaded with ascorbic acid and astaxanthin.

[0072] Example 2

[0073] The only difference from Example 1 is that in step (2), astaxanthin in the oil gel formula is replaced by resveratrol, and the rest is the same as Example 1, to obtain different types of biphasic gels loaded with ascorbic acid and resveratrol.

[0074] Example 3

[0075] The only difference from Example 1 is that in step (3), astaxanthin in the oil gel formula is replaced by curcumin, and the rest is consistent with Example 1, thereby obtaining different types of biphasic gels loaded with ascorbic acid and curcumin.

[0076] Comparative Example 1

[0077] (1) Preparation of hydrogel

[0078] 1.2% (w / w) gellan gum powder was slowly added to deionized water and stirred at 200 r / min for 30 min at room temperature to form a transparent hydrogel solution.

[0079] (2) Preparation of oil gel

[0080] 4% (w / w) GMS was mixed with 96% (w / w) mixed oil phase (palm oil: algae oil = 1:1), heated to 85°C, and stirred at 500 r / min for 30 min to form a uniform oil gel solution.

[0081] (3) Preparation of biphasic gel system I

[0082] The prepared hydrogel and oil gel were mixed at 85°C in the ratio of oil to water phase mass ratio of 40:60, 65:35, and 80:20, and then homogenized and emulsified at 8000 r / min for 2 min using a high-speed disperser. The obtained emulsion gel was then stirred and cooled in an ice water bath to obtain different types of biphasic gels without adding natural antioxidants.

[0083] Comparative Example 2

[0084] The only difference from Example 1 is that in step (2), no astaxanthin is added to the oil gel, and the rest is the same as in Example 1, thereby obtaining different types of biphasic gels loaded with only ascorbic acid.

[0085] Comparative Example 3

[0086] The only difference from Example 1 is that in step (1), no ascorbic acid is added to the hydrogel, and the rest is the same as in Example 1, thereby obtaining different types of biphasic gels loaded only with astaxanthin.

[0087] Comparative Example 4

[0088] The only difference from Example 1 is that in step (1), ascorbic acid is not added to the hydrogel, and in step (2), astaxanthin is replaced by curcumin. The other steps are the same as in Example 1, and different types of biphasic gels loaded with only curcumin are obtained.

[0089] Comparative Example 5

[0090] The only difference from Example 1 is that in step (1), ascorbic acid is not added to the hydrogel, and in step (2), astaxanthin is replaced by resveratrol. The rest is the same as in Example 1, and different types of biphasic gels loaded only with resveratrol are obtained.

[0091] Example 4

[0092] (1) Preparation of hydrogel

[0093] 3% (w / w) HPMC powder was slowly added to deionized water heated to 70°C, slowly cooled to room temperature and stirred at 200 rpm to form a transparent hydrogel solution. 0.1% (w / w) EGCG powder was then added to the hydrogel solution and stirred until EGCG was completely dissolved to obtain an EGCG-loaded hydrogel solution.

[0094] (2) Preparation of oil gel

[0095] 0.1% (w / w) resveratrol powder was added to soybean oil, and stirred at 500 rpm for 30 minutes in a dark state until resveratrol was completely dissolved in soybean oil. Then 10% (w / w) beeswax and 1% (w / w) PGPR were added to soybean oil, quickly heated to 85°C, and quickly stirred until the beeswax was completely melted to form a uniform oil gel solution loaded with resveratrol.

[0096] (3) Preparation of biphasic gel system II

[0097] The prepared oil gel and hydrogel were mixed at 85°C with an oil-water mass ratio of 80:20, 55:45, and 20:80, and homogenized and emulsified at 6000 rpm for 2 min using a high-speed disperser. The obtained emulsion gel was then quickly transferred to a 4°C refrigerator for overnight refrigeration, and three different types of composite two-phase gels (W / O type, bicontinuous type, and O / W type) were obtained.

[0098] Comparative Example 6

[0099] Steps (2) and (3) of Example 4 were omitted, and the rest of the steps were kept the same as in Example 4 to obtain a pure hydrogel solution loaded with EGCG.

[0100] Comparative Example 7

[0101] Steps (1) and (3) of Example 4 were omitted, and the rest of the steps were the same as those of Example 4, thereby obtaining a pure oil gel solution loaded with resveratrol.

[0102] Comparative Example 8

[0103] (1) Preparation of hydrogel

[0104] 3% (w / w) HPMC powder was slowly added to deionized water heated to 70° C., slowly cooled to room temperature and stirred at 200 rpm to form a transparent hydrogel solution.

[0105] (2) Preparation of oil gel

[0106] 10% (w / w) beeswax and 1% (w / w) PGPR were added to soybean oil, quickly heated to 85° C., and quickly stirred until the beeswax was completely melted to form a uniform oil gel solution.

[0107] (3) Preparation of biphasic gel system II

[0108] The prepared oil gel and hydrogel were mixed at 85°C with an oil-water mass ratio of 80:20, 55:45, and 20:80, and homogenized and emulsified at 6000 rpm for 2 min using a high-speed disperser. The obtained emulsion gel was then quickly transferred to a 4°C refrigerator for overnight refrigeration to obtain a blank biphasic gel without adding natural antioxidants.

[0109] Example 5

[0110] The only difference from Example 4 is that in step (1), ECGC is not added to the hydrogel, and the rest is the same as Example 4, thereby obtaining different types of biphasic gels loaded with only resveratrol.

[0111] Example 6

[0112] The only difference from Example 4 is that in step (2), resveratrol is not added to the oil gel, and the rest is the same as Example 4, to obtain different types of biphasic gels loaded with only EGCG.

[0113] Example 7

[0114] This example is a test of the microstructure of the two-phase gel system I prepared in Example 1, and the microstructure of the sample is measured by optical microscopy and polarizing microscopy.

[0115] Figure 1 Optical microscope (upper) and polarizing microscope (lower) images of the above two-phase gel system. Figure 1 It can be seen that when the oil phase ratio is 40%, the biphasic gel is O / W type, and the oil phase droplets are completely and evenly dispersed in the hydrogel. The gellan gum-based hydrogel structure hinders the movement of oil droplets and improves the static stability of the biphasic gel. Through polarized light microscopy, it can be seen that there is a crystal shell on the surface of the oil phase droplet, and a crystal network can be observed inside the droplet. The droplet is stabilized by the interface crystallization and the crystal network. As the oil phase content increases to 65%, it presents the typical characteristics of a bicontinuous biphasic gel, and the oil and water phases simultaneously form a complex bicontinuous network. When the oil phase content in the biphasic gel reaches 80%, the biphasic gel is W / O type. The dense fat crystal network of the external phase can effectively make the oil phase present a solidified state, while fixing the position of the hydrogel droplets, thereby improving the stability of the biphasic gel. The change in the oil gel-hydrogel ratio leads to the emergence of phase transition phenomenon, making the biphasic gel present O / W type, bicontinuous type and W / O type.

[0116] Example 8

[0117] This example is a test of the embedding efficiency of water-soluble and fat-soluble natural antioxidants by different types of two-phase gels prepared in Examples 1 to 3 and Example 4. The embedding efficiency of the two-phase gel system I is calculated according to the following formula:

[0118]

[0119] Among them, C, C 初 are the concentration of natural antioxidants in the two-phase gel and the concentration of natural antioxidants initially added, respectively.

[0120] Depend on Figure 2 (Left) It can be seen that the average initial embedding rate of all antioxidants is higher than 90% and less than 98%. The initial embedding rate of fat-soluble antioxidants in O / W type biphasic gel is slightly higher than that in bicontinuous type and W / O type biphasic gel, while the initial embedding rate of ascorbic acid in the three types of biphasic gels shows the opposite trend. Figure 2 (Right) shows the embedding rate of natural antioxidants by the biphasic gel system II prepared in Example 4. As can be seen from the figure, the embedding rate of resveratrol is slightly lower than that of EGCG. The initial embedding rates of EGCG and resveratrol both decrease with the decrease of the oil gel content. The lowest initial embedding rate appears in the O / W biphasic gel with an oil gel content of 20%. The W / O biphasic gel has a good embedding effect. Compared with the biphasic gel system II prepared in Example 4, the biphasic gel system I prepared in Example 2 has a better embedding effect on resveratrol.

[0121] Example 9

[0122] This example is a determination of the oxidation stability of the two-phase gel system I prepared in Comparative Examples 1 to 5 and Examples 1 to 3. A 40g two-phase gel sample is placed in a 50mL sample bottle and the bottle cap is covered, and stored in a constant temperature box at 25°C for 60 days. 0.5g of sample is taken out on the 1st, 7th, 14th, 21st, 28th and 35th days of storage for the determination of oxidation stability. (1) Determination of primary oxidation products: According to the method of GB5009.227-2016, the peroxide value (POV) of the two-phase gel is determined as the primary oxidation product value. (2) Determination of secondary oxidation products: According to the method of GB5009.181-2016 Determination of malondialdehyde in food, the reactant (TBARS) value generated by the reaction of malondialdehyde and thiobarbituric acid is determined as the secondary oxidation product value.

[0123] like Figure 3As shown, all types of biphasic gels are most susceptible to oxidation when no antioxidants are added. In the O / W biphasic gel, the antioxidant effects of single antioxidants are ranked from best to worst as astaxanthin, ascorbic acid, resveratrol, and curcumin. Compared with Comparative Examples 3 to 5, the amount of oxidation products formed in Examples 1 to 3 is lower than the amount of oxidation products formed when only one fat-soluble antioxidant is loaded, indicating that the biphasic gel loaded with ascorbic acid and fat-soluble antioxidants at the same time has a better antioxidant effect.

[0124] Example 10

[0125] This example is a determination of the retention rate of natural antioxidants in the biphasic gel system I prepared in Comparative Examples 2 to 5. The biphasic gels loaded with resveratrol, astaxanthin, curcumin and ascorbic acid were stored in a 25°C constant temperature box for 35 days, and the concentration of natural antioxidants in the biphasic gel was regularly determined. The retention rate (%) of natural antioxidants in the biphasic gel during storage was calculated according to the following formula:

[0126]

[0127] Among them C 前 , C 后 These are the concentrations of natural antioxidants in biphasic gel I before and after storage, respectively.

[0128] like Figure 4 As shown in the figure, in the three types of biphasic gels, the retention rate of fat-soluble antioxidants was higher than that of water-soluble antioxidants, indicating that the stability of the three fat-soluble antioxidants was better than that of ascorbic acid. In the O / W biphasic gel, the degradation rate of ascorbic acid was the fastest, with a retention rate of 9.7% at 14 days. In the W / O biphasic gel, the retention rate of ascorbic acid was about 20% after a storage time of 28 days, indicating that the W / O structure is conducive to the protection of ascorbic acid. In addition, the higher the oil phase content of the biphasic gel, the lower the relative reduction ratio of antioxidants during storage. This is because the fat crystal network in the oil phase provides a good barrier for antioxidants, which can protect the active substances and reduce their degradation.

[0129] Embodiment 11

[0130] This example is the calculation of the interaction index of natural antioxidants in different types of two-phase gel systems I prepared in Examples 1 to 3. The interaction index (Q) of two antioxidants is calculated based on the oxidation lag time (T) of hydroperoxide formation, and the interaction between astaxanthin, curcumin, resveratrol and ascorbic acid is evaluated. The interaction index of two natural antioxidants is calculated according to the following formula:

[0131]

[0132] Among them, A is astaxanthin, curcumin or resveratrol; B is ascorbic acid; A+B is a compound antioxidant; and blank means no antioxidant is added.

[0133] Table 1 Interaction index (Q) of antioxidants in the two-phase gels prepared in Examples 1 to 3

[0134] Antioxidants O / W type Double continuous type W / O Type Astaxanthin + Ascorbic Acid 1.31 1.24 1.07 Curcumin + Ascorbic Acid 0.92 0.80 0.87 Resveratrol + ascorbic acid 0.69 0.74 0.75

[0135] As shown in Table 1, the interaction indexes of astaxanthin and ascorbic acid in O / W, bicontinuous and W / O type biphasic gels are 1.31, 1.24, and 1.07, respectively, all greater than 1, which indicates that astaxanthin and ascorbic acid are synergistic in the biphasic gel, and the antioxidant capacity is significantly enhanced. The Q values ​​of curcumin and ascorbic acid compounded in the system are all less than 1, indicating that curcumin and ascorbic acid are antagonistic in the biphasic gel. Similarly, resveratrol and ascorbic acid are antagonistic. Compared with Example 2 and Example 3, the Q value of the biphasic gel prepared in Example 1 is the largest and the antioxidant effect is the strongest, so the best antioxidant combination in the biphasic gel system is astaxanthin and ascorbic acid.

[0136] Example 12

[0137] This example is the determination of the retention rate of natural antioxidants in the pure hydrogel prepared in Comparative Example 6, the pure oil gel prepared in Comparative Example 7, and the dual-phase gel system II prepared in Example 4. After the pure oil gel loaded with resveratrol, the pure hydrogel loaded with EGCG, and the dual-phase gel loaded with EGCG and resveratrol were stored in a 20°C constant temperature box for 20 days, the concentrations of resveratrol and EGCG were determined. The retention rate (%) of natural antioxidants in the pure oil gel, pure hydrogel, and dual-phase gel during storage was calculated according to the following formula:

[0138]

[0139] Among them C 前 , C 后 These are the concentrations of natural antioxidants before and after storage.

[0140] like Figure 5 As shown, the higher the oil gel content of the dual-phase gel, the lower the relative reduction ratio of natural antioxidants after 20 days of storage. This is because the dense crystalline network formed by the oil gel component in the dual-phase gel provides a good barrier for natural antioxidants, which can protect them from damage by the external environment and reduce degradation. Therefore, the W / O type dual-phase gel prepared in Example 4 has a relatively good protective effect on natural antioxidants.

[0141] Embodiment 13

[0142] This example is the determination of the oxidative stability of the two-phase gel system II prepared in Examples 4 to 6 and Comparative Example 8. 80 g of the two-phase gel sample was placed in a 100 mL sample bottle and covered with a bottle cap, and stored in a 45°C oven at a constant temperature for 30 days. All samples were kept sealed during storage. 3 g of sample was taken out on the 1st, 3rd, 6th, 10th, 15th, 20th and 25th days of storage for the determination of oxidative stability. (1) Determination of primary oxidation products: According to the method of GB5009.227-2016, the peroxide value (POV) of the two-phase gel was determined as the primary oxidation product value. (2) Determination of secondary oxidation products: According to the method of GB5009.181-2016 Determination of malondialdehyde in food, the reactant (TBARS) value generated by the reaction of malondialdehyde and thiobarbituric acid was determined as the secondary oxidation product value.

[0143] like Figure 6 As shown, compared with Comparative Example 8, the POV values ​​of the biphasic gels prepared in Examples 4 to 6 are smaller, which indicates that loading antioxidants can effectively improve the antioxidant capacity of the biphasic gel. Among them, the POV value and TBARS value of the biphasic gel loaded with resveratrol and EGCG are relatively small, indicating that the compound antioxidant can significantly improve the antioxidant capacity of the biphasic gel.

[0144] Embodiment 14

[0145] This example is an in vitro simulated digestion test of the two-phase gel loaded with natural antioxidants prepared in Example 1 and Example 4 as a nutrient delivery system, specifically including the simulation of the oral stage, gastric digestion stage and small intestinal digestion stage, and measuring the release rate of free fatty acids (FFA), the release rate and bioavailability of natural antioxidants during the in vitro simulated digestion process, and observing the microstructural changes of different types of two-phase gels during the in vitro digestion process under a microscope.

[0146] Figure 7 It is the microstructure of the two-phase gel system prepared in Example 1 during in vitro digestion. The microstructural changes of O / W, bicontinuous, and W / O biphase gels before digestion, after gastric digestion, and after intestinal digestion during the simulated digestion process were observed by laser confocal microscopy (CLSM). In the figure, red represents the oil phase and green represents the hydrogel. It can be seen from the figure that the diameter of the emulsion droplets of the O / W biphase gel did not change significantly at the end of gastric digestion, and the structure collapsed after 2 hours of intestinal digestion to form smaller oil droplets; the structure of the bicontinuous biphase gel changed significantly during the gastric digestion stage, and it changed from a bicontinuous form to a W / O type after gastric digestion; the oil phase structure of the W / O biphase gel did not change significantly after gastric digestion, and the structure collapsed after intestinal digestion to form some larger oil droplets.

[0147] Figure 8The release of FFA during in vitro digestion of the two-phase gel prepared in Example 1 is reflected. The release of fatty acids in the two-phase gels of the three structures during digestion presents completely different rate characteristics. The O / W type two-phase gel releases FFA rapidly in the first 30 minutes of digestion, and the release rate is slow after 60 minutes; the bicontinuous type two-phase gel releases slowly during the entire digestion process; the W / O type two-phase gel releases slowly in the first 60 minutes of digestion, and the FFA release rate accelerates in the second half of digestion. Comparing the final release rates of FFA of the three types of two-phase gels after simulated gastrointestinal digestion, the O / W type two-phase gel has the highest FFA release rate, and the W / O type two-phase gel has the lowest FFA release rate, indicating that the W / O type two-phase gel is conducive to delaying the release of FFA.

[0148] like Fig. 9 As shown in the figure, the release rate of astaxanthin in the three types of biphasic gels during the gastric digestion stage is kept at a low level of no more than 5%, and astaxanthin is released rapidly during intestinal digestion. The main absorption site of astaxanthin is the small intestine, not the stomach. The release characteristics of the biphasic gel help the free astaxanthin to be efficiently utilized by the human body. Compared with astaxanthin, the biphasic gel has insufficient protective effect on ascorbic acid. Ascorbic acid in the external phase or bicontinuous phase is released rapidly during the gastric digestion stage with a high loss rate, but is released slowly during the intestinal digestion stage. Comparing the delivery effects of the three types of biphasic gels on nutrients, it is found that the W / O biphasic gel can effectively delay the release of nutrients, which is conducive to the absorption and utilization of nutrients by the human body. According to the structural schematic diagrams of different types of biphasic gels, it is speculated that in the O / W biphasic gel, due to the dilution effect and concentration diffusion effect of the digestive juice, the loose hydrogel is not enough to intercept ascorbic acid, resulting in a large amount of ascorbic acid being released prematurely. However, due to the protective effect of the oil phase, the W / O biphasic gel can retain more ascorbic acid, thereby delaying its release in the intestine.

[0149] Fig.10 This reflects the bioavailability of natural antioxidants after simulated in vitro digestion in the biphasic gel system. Fig.10 As shown in (left), the bioavailability of astaxanthin in the O / W type two-phase gel prepared in Example 1 is higher than that of the bicontinuous type and W / O type. This is because the O / W type two-phase gel can maintain a complete oil phase droplet structure during the gastric digestion stage. The good crystal barrier protects the nutrients in the oil phase, reducing the damage caused by gastric acid. More astaxanthin is released after entering the intestine, making it easy for the small intestine to digest and absorb. As for the delivery effect of ascorbic acid, the W / O type two-phase gel presents the highest bioavailability. This is attributed to the fact that the higher content of oil gel crystal network in the W / O type two-phase gel provides a good barrier, which reduces the damage to nutrients by the extremely acidic environment of the stomach and can retain more active substances to enter the small intestine for digestion and absorption. Fig.10As shown in (right), the bioavailability of the two natural antioxidants in the W / O type dual-phase gel prepared in Example 4 is significantly higher than that of the O / W type and the dual-continuous type. The dual-phase gel systems prepared in Examples 1 and 4 can significantly improve the bioavailability of nutrients.

[0150] Embodiment 15

[0151] On the basis of Example 1, the polysaccharide of the hydrogel is replaced by gellan gum, hydroxypropyl methylcellulose, xanthan gum, carrageenan, guar gum, sodium alginate, and locust bean gum, respectively, and other conditions remain unchanged to obtain a biphasic gel loaded with natural antioxidants. The prepared biphasic gel is used as an in vitro simulated digestion test of a nutrient delivery system, and the experimental results show that the W / O type biphasic gel can effectively delay the release of nutrients, which is conducive to the absorption and utilization of nutrients by the human body.

[0152] Example 16

[0153] On the basis of Example 1, the oil gel was replaced by beeswax, rice bran wax, candelilla wax, carnauba wax, sunflower seed wax, and corn wax respectively, and other conditions remained unchanged to obtain a biphasic gel loaded with natural antioxidants. The prepared biphasic gel was used as an in vitro simulated digestion test of a nutrient delivery system, and the experimental results showed that the W / O type biphasic gel can effectively delay the release of nutrients, which is conducive to the absorption and utilization of nutrients by the human body.

[0154] Embodiment 17

[0155] On the basis of Example 1, the edible oil was replaced by palm oil and algae oil in a volume ratio of 1:1 with palm oil and soybean oil in a volume ratio of 1:1, coconut oil and soybean oil in a volume ratio of 1:1, and palm stearin and soybean oil in a volume ratio of 1:1, respectively, and other conditions remained unchanged to obtain a biphasic gel loaded with natural antioxidants. The prepared biphasic gel was used as an in vitro simulated digestion test of the nutrient delivery system. The experimental results showed that the W / O type biphasic gel can effectively delay the release of nutrients, which is conducive to the absorption and utilization of nutrients by the human body.

[0156] Embodiment 18

[0157] On the basis of Example 1, the water-soluble natural antioxidants were replaced by anthocyanidins, epigallocatechin gallate, glutathione, and collagen peptides respectively from ascorbic acid, and other conditions remained unchanged to obtain a biphasic gel loaded with natural antioxidants. The prepared biphasic gel was used as an in vitro simulated digestion test of a nutrient delivery system, and the experimental results showed that the W / O biphasic gel can effectively delay the release of nutrients, which is conducive to the absorption and utilization of nutrients by the human body.

[0158] Embodiment 19

[0159] On the basis of Example 1, the fat-soluble natural antioxidants were replaced by vitamin A, vitamin E, curcumin, lycopene, resveratrol, β-carotene, quercetin, and coenzyme Q10 respectively from astaxanthin, and other conditions remained unchanged to obtain a biphasic gel loaded with natural antioxidants. The prepared biphasic gel was used as an in vitro simulated digestion test of the nutrient delivery system, and the experimental results showed that the W / O type biphasic gel can effectively delay the release of nutrients, which is conducive to the absorption and utilization of nutrients by the human body.

[0160] Embodiment 20

[0161] On the basis of Example 4, the small molecule emulsifier of the oil gel is replaced by monostearate glyceryl, sucrose fatty acid ester, lactic acid fatty acid glyceryl, citric acid fatty acid glyceryl, propylene glycol fatty acid ester, diacetyl tartaric acid monoglyceride, and other conditions remain unchanged to obtain a biphasic gel loaded with natural antioxidants. The prepared biphasic gel is used as an in vitro simulated digestion test of the nutrient delivery system. The experimental results show that the bioavailability of the two natural antioxidants in the prepared W / O type biphasic gel is significantly higher than that of the O / W type and the bicontinuous type. The prepared biphasic gel system can significantly improve the bioavailability of nutrients.

[0162] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A two-phase gel loaded with natural antioxidants, characterized in that: It is obtained by mixing oil gel and hydrogel in a mass ratio of 20:80 to 80:20 through physical action; Wherein, the hydrogel is composed of a water-soluble natural antioxidant and a polysaccharide aqueous solution; The oil gel consists of an oil gelling agent, a fat-soluble natural antioxidant and edible oil.

2. The dual-phase gel loaded with natural antioxidants as claimed in claim 1, characterized in that: The water-soluble natural antioxidant comprises one of ascorbic acid, anthocyanin, epigallocatechin gallate, glutathione and collagen peptide; the water-soluble natural antioxidant in the hydrogel is present in an amount of 0.01-0.2% by mass, and the polysaccharide is present in an amount of 1-5% by mass.

3. The two-phase gel loaded with natural antioxidants as claimed in claim 1 or 2, characterized in that: The polysaccharide is one or more of gellan gum, hydroxypropyl methylcellulose, xanthan gum, carrageenan, guar gum, sodium alginate and locust bean gum.

4. The dual-phase gel loaded with natural antioxidants as claimed in claim 3, characterized in that: The fat-soluble natural antioxidant comprises one of vitamin A, vitamin E, curcumin, astaxanthin, lycopene, resveratrol, beta-carotene, quercetin and coenzyme Q10; the fat-soluble natural antioxidant in the oil gel is present in an amount of 0.01-0.2% by mass, the small molecule emulsifier is present in an amount of 0.5-5% by mass, the edible oil is present in an amount of 90-97% by mass, and the oil gel is present in an amount of 3-10% by mass.

5. The two-phase gel loaded with natural antioxidants according to any one of claims 1, 2 and 4, characterized in that: The oil gel is one or more of glyceryl monostearate, beeswax, rice bran wax, candelilla wax, carnauba wax, sunflower seed wax, and corn wax; The edible oil is one or more of soybean oil, rapeseed oil, peanut oil, sunflower seed oil, rice bran oil, corn oil, linseed oil, olive oil, wheat germ oil, cottonseed oil, almond oil, tea seed oil, sesame oil, algae oil, and palm oil.

6. The dual-phase gel loaded with natural antioxidants as claimed in claim 5, characterized in that: The oil gel also includes a small molecule emulsifier, which is one or more of polyglycerol polyricinoleate, monostearate glyceryl, sucrose fatty acid ester, lactic acid fatty acid glyceryl ester, citric acid fatty acid glyceryl ester, propylene glycol fatty acid ester, and diacetyl tartaric acid monoglyceride.

7. The two-phase gel loaded with natural antioxidants according to any one of claims 1, 2, 4 and 6, characterized in that: The edible oil is a mixed oil, and the mixed oil is one of palm oil and algae oil, palm oil and soybean oil, coconut oil and soybean oil, and palm stearin and soybean oil in a volume ratio of 1:1; The physical action is one or more of high-speed shearing, ice-water bath, and high-pressure homogenization.

8. The method for preparing the dual-phase gel loaded with natural antioxidants as claimed in claim 1, characterized in that: include, The polysaccharide solution loaded with water-soluble natural antioxidants is gelled to obtain a hydrogel; Using an oil gelling agent to induce gelation of an oil phase loaded with fat-soluble natural antioxidants and containing a small molecule emulsifier and edible oil to obtain an oil gel; The oil gel and the hydrogel in a mass ratio of 20:80 to 80:20 are mixed, and a two-phase gel loaded with natural antioxidants is prepared by physical action.

9. Use of the biphasic gel loaded with natural antioxidants according to any one of claims 1 to 7 in the preparation of antioxidant products, characterized in that: The dual-phase gel is an oil-in-water type.

10. Use of the biphasic gel loaded with natural antioxidants according to any one of claims 1 to 7 for simultaneously delivering water-soluble and fat-soluble natural antioxidants, characterized in that: The dual-phase gel is of the water-in-oil type, and the water-in-oil dual-phase gel loaded with natural antioxidants can delay the release of nutrients and free fatty acids.

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