CN115746172B - Preparation method and fresh-keeping application of pH sensitive starch-based carrier - Google Patents
Preparation method and fresh-keeping application of pH sensitive starch-based carrier Download PDFInfo
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- 229920002472 Starch Polymers 0.000 title claims abstract description 173
- 239000008107 starch Substances 0.000 title claims abstract description 173
- 235000019698 starch Nutrition 0.000 title claims abstract description 173
- 238000002360 preparation method Methods 0.000 title abstract description 14
- VFLDPWHFBUODDF-FCXRPNKRSA-N curcumin Chemical compound C1=C(O)C(OC)=CC(\C=C\C(=O)CC(=O)\C=C\C=2C=C(OC)C(O)=CC=2)=C1 VFLDPWHFBUODDF-FCXRPNKRSA-N 0.000 claims abstract description 158
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 120
- 229940109262 curcumin Drugs 0.000 claims abstract description 109
- 239000004148 curcumin Substances 0.000 claims abstract description 103
- 235000012754 curcumin Nutrition 0.000 claims abstract description 79
- VFLDPWHFBUODDF-UHFFFAOYSA-N diferuloylmethane Natural products C1=C(O)C(OC)=CC(C=CC(=O)CC(=O)C=CC=2C=C(OC)C(O)=CC=2)=C1 VFLDPWHFBUODDF-UHFFFAOYSA-N 0.000 claims abstract description 79
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 74
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims abstract description 57
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 claims abstract description 50
- 125000002057 carboxymethyl group Chemical group [H]OC(=O)C([H])([H])[*] 0.000 claims abstract description 45
- 229920000858 Cyclodextrin Polymers 0.000 claims abstract description 34
- 239000001116 FEMA 4028 Substances 0.000 claims abstract description 31
- WHGYBXFWUBPSRW-FOUAGVGXSA-N beta-cyclodextrin Chemical compound OC[C@H]([C@H]([C@@H]([C@H]1O)O)O[C@H]2O[C@@H]([C@@H](O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O3)[C@H](O)[C@H]2O)CO)O[C@@H]1O[C@H]1[C@H](O)[C@@H](O)[C@@H]3O[C@@H]1CO WHGYBXFWUBPSRW-FOUAGVGXSA-N 0.000 claims abstract description 31
- 235000011175 beta-cyclodextrine Nutrition 0.000 claims abstract description 31
- 229960004853 betadex Drugs 0.000 claims abstract description 31
- 238000003756 stirring Methods 0.000 claims abstract description 29
- 238000006386 neutralization reaction Methods 0.000 claims abstract description 27
- 239000012153 distilled water Substances 0.000 claims abstract description 26
- 238000000034 method Methods 0.000 claims abstract description 17
- 239000003513 alkali Substances 0.000 claims abstract description 15
- 238000005303 weighing Methods 0.000 claims abstract description 14
- 230000004913 activation Effects 0.000 claims abstract description 13
- UGTZMIPZNRIWHX-UHFFFAOYSA-K sodium trimetaphosphate Chemical compound [Na+].[Na+].[Na+].[O-]P1(=O)OP([O-])(=O)OP([O-])(=O)O1 UGTZMIPZNRIWHX-UHFFFAOYSA-K 0.000 claims abstract description 12
- 239000002994 raw material Substances 0.000 claims abstract description 11
- 239000003431 cross linking reagent Substances 0.000 claims abstract description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 70
- 238000006243 chemical reaction Methods 0.000 claims description 39
- 239000000047 product Substances 0.000 claims description 23
- 239000008367 deionised water Substances 0.000 claims description 21
- 229910021641 deionized water Inorganic materials 0.000 claims description 21
- 238000001035 drying Methods 0.000 claims description 20
- 238000007873 sieving Methods 0.000 claims description 20
- 239000000725 suspension Substances 0.000 claims description 20
- 238000001816 cooling Methods 0.000 claims description 15
- 150000003254 radicals Chemical class 0.000 claims description 15
- 238000002390 rotary evaporation Methods 0.000 claims description 14
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 10
- 230000035484 reaction time Effects 0.000 claims description 10
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 9
- 238000009835 boiling Methods 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 9
- 239000001301 oxygen Substances 0.000 claims description 9
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- 239000000203 mixture Substances 0.000 claims description 7
- 238000006555 catalytic reaction Methods 0.000 claims description 6
- 238000004132 cross linking Methods 0.000 claims description 6
- 238000012869 ethanol precipitation Methods 0.000 claims description 6
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- 239000000178 monomer Substances 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 238000000967 suction filtration Methods 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- 238000005119 centrifugation Methods 0.000 claims description 4
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- 238000002156 mixing Methods 0.000 claims description 2
- 238000010025 steaming Methods 0.000 claims description 2
- 239000000243 solution Substances 0.000 claims 19
- 239000012670 alkaline solution Substances 0.000 claims 1
- 239000000969 carrier Substances 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract description 13
- 235000019426 modified starch Nutrition 0.000 abstract description 10
- 229920000881 Modified starch Polymers 0.000 abstract description 9
- 239000004368 Modified starch Substances 0.000 abstract description 9
- 239000005452 food preservative Substances 0.000 abstract description 5
- 235000019249 food preservative Nutrition 0.000 abstract description 5
- 230000004048 modification Effects 0.000 abstract description 4
- 238000012986 modification Methods 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 3
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- 229920002845 Poly(methacrylic acid) Polymers 0.000 description 16
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- 238000011068 loading method Methods 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 4
- 238000002329 infrared spectrum Methods 0.000 description 4
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 3
- 230000003993 interaction Effects 0.000 description 3
- HFHDHCJBZVLPGP-UHFFFAOYSA-N schardinger α-dextrin Chemical compound O1C(C(C2O)O)C(CO)OC2OC(C(C2O)O)C(CO)OC2OC(C(C2O)O)C(CO)OC2OC(C(O)C2O)C(CO)OC2OC(C(C2O)O)C(CO)OC2OC2C(O)C(O)C1OC2CO HFHDHCJBZVLPGP-UHFFFAOYSA-N 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 230000000977 initiatory effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000008961 swelling Effects 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- 206010061218 Inflammation Diseases 0.000 description 1
- 206010028980 Neoplasm Diseases 0.000 description 1
- WQZGKKKJIJFFOK-UHFFFAOYSA-N alpha-D-glucopyranose Natural products OCC1OC(O)C(O)C(O)C1O WQZGKKKJIJFFOK-UHFFFAOYSA-N 0.000 description 1
- WQZGKKKJIJFFOK-DVKNGEFBSA-N alpha-D-glucose Chemical compound OC[C@H]1O[C@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-DVKNGEFBSA-N 0.000 description 1
- 229920006320 anionic starch Polymers 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 201000011510 cancer Diseases 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 239000012876 carrier material Substances 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000013066 combination product Substances 0.000 description 1
- 229940127555 combination product Drugs 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000013270 controlled release Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000001727 in vivo Methods 0.000 description 1
- 230000004054 inflammatory process Effects 0.000 description 1
- 230000000968 intestinal effect Effects 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 230000004060 metabolic process Effects 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
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- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001766 physiological effect Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
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- 238000010526 radical polymerization reaction Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/90—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in food processing or handling, e.g. food conservation
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- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
The invention belongs to the technical field of modified starch. The preparation method of the pH sensitive starch-based carrier is characterized by comprising the following steps: step one, selecting carboxymethyl starch, potassium persulfate, methacrylic acid and sodium hydroxide; adding distilled water and carboxymethyl starch into a three-neck flask, and gelatinizing to obtain gelatinized carboxymethyl starch; adding potassium persulfate solution for activation; adding methacrylic acid neutralization solution to obtain grafted starch; and step two, weighing grafted starch and beta-cyclodextrin, putting the grafted starch and the beta-cyclodextrin into alkali liquor prepared from sodium hydroxide, slowly stirring at 40 ℃, and adding a cross-linking agent sodium trimetaphosphate to obtain the pH sensitive starch-based carrier. The method takes carboxymethyl starch as a raw material, has certain pH sensitivity and embedding function through double modification, realizes the functionalization of the carrier, has simple preparation flow and low cost, and is convenient for mass production; the invention uses the carrier to embed the food preservative curcumin, which solves the problems that curcumin is not easy to use and is sensitive to environment.
Description
Technical Field
The invention belongs to the technical field of modified starch, and particularly relates to a preparation method of a pH sensitive starch-based carrier and application thereof in the technical field of preservation.
Background
The starch has the advantages of wide source range, low cost, degradability, reproducibility, high safety and biocompatibility, has great development potential in the application field of carrier materials, but the natural starch has poor hydrophobicity and low resistance, and is difficult to meet the condition of serving as a carrier of the fat-soluble functional factors. The alpha-D-glucopyranose is a basic unit for forming starch, and has higher-activity hydroxyl groups at 2, 3 and 6 positions, so that the molecular structure of the starch is easy to modify and regulate. By modifying the starch, the starch has the potential of being used as a carrier, improves the application performance of the starch and improves the embedding effect of the functional factors. Carboxymethyl starch is a cold water-soluble anionic starch derivative and has the advantages of wide source, low production cost, simple process and the like. At present, carboxymethyl starch is used as a raw material, and a grafting product is produced through a free radical grafting copolymerization reaction and acrylic acid, acrylamide, styrene and the like. The grafting starch copolymerization principle can be divided into three types of free radical initiation, ionic interaction and condensation addition, and the grafting modified starch is obtained by modifying carboxymethyl starch through the free radical initiation in a first mode. Beta-cyclodextrin is an oligomer composed of seven glucopyranoses, has a hollow structure with hydrophilic outside and hydrophobic inside, can form inclusion compounds with some hydrophobic organic molecules through host-guest interaction, and has certain adsorption characteristics. Cyclodextrin molecules have a large number of hydroxyl groups that can be combined with other materials by cross-linking agents or other chemical interactions to give cross-linked cyclodextrin polymers. The invention combines the grafted starch with beta-cyclodextrin through the cross-linking agent to obtain the composite modified starch.
Curcumin is a green natural food preservative, is nontoxic and harmless, has certain physiological effects of resisting oxidation, cancer, inflammation and the like, but has poor water solubility, low bioavailability, poor self stability and sensitivity to external factors such as ultraviolet rays, oxygen and temperature, and severely restricts the application field of curcumin. There are many documents reporting that different types of carrier lines are applied to improve the bioavailability of curcumin, but there are still problems to be solved, such as difficult control of the release rate of curcumin in vivo, easy metabolism in intestinal environment, and sensitivity to environment, thereby affecting the application of curcumin.
Based on the current situation of low curcumin bioavailability, carboxymethyl starch is subjected to graft crosslinking dual modification, the molecular structure of the starch is regulated, pH sensitive modified starch is prepared, and a starch-curcumin compound is constructed. The starch-based carrier has corresponding pH sensitivity through process optimization, simultaneously, the modified starch is subjected to infrared characterization to ensure synthesis, and finally, the embedded curcumin solves the problems of poor water solubility, poor stability and low bioavailability of the curcumin.
Disclosure of Invention
The first object of the invention is to provide a preparation method of pH sensitive starch-based carrier, which takes carboxymethyl starch as raw material, and has certain pH sensitivity and embedding function by double modification, thus realizing the functionalization of the carrier, having simple preparation flow, low cost and being convenient for mass production; the invention also aims to embed the food preservative curcumin by using the carrier, so as to solve the problems of difficult utilization and environmental sensitivity of the curcumin.
In order to achieve the above purpose, the invention adopts the following scheme: the preparation method of the pH sensitive starch-based carrier is characterized by comprising the following steps:
step one, (1) selecting raw materials: the mass ratio of potassium persulfate to methacrylic acid is 2-10 percent, and the weight ratio of the potassium persulfate to the methacrylic acid is as follows: methacrylic acid mass is 1: 2-1: 6, selecting carboxymethyl starch, potassium persulfate, methacrylic acid and sodium hydroxide for later use according to the mass ratio (neutralization degree) of sodium hydroxide to methacrylic acid of 10% -30%;
(2) methacrylic acid neutralization solution: weighing sodium hydroxide, dissolving in 10mL of distilled water to prepare sodium hydroxide solution, and mixing with methacrylic acid to obtain a neutralization solution for later use;
(3) potassium persulfate solution: preparing a potassium persulfate solution with 20mL of distilled water for later use;
(4) according to carboxymethyl starch: the mass ratio of distilled water is 1:10 to 1:50, adding distilled water and carboxymethyl starch (namely sodium carboxymethyl starch and CMS) into a three-neck flask, and uniformly dispersing the carboxymethyl starch by magnetic stirring; placing the mixture into a water bath kettle to be gelatinized for 0.5 to 1 hour at 50 to 90 ℃, and cooling the mixture to a reaction temperature (the reaction temperature is 50 to 80 ℃) after the gelatinization to obtain gelatinized carboxymethyl starch;
(5) adding potassium persulfate solution (initiator) into gelatinized carboxymethyl starch to activate starch hydroxyl groups to generate free radicals, wherein the activation time is 0.5-1 h, and the reaction temperature is 50-80 ℃;
(6) slowly adding methacrylic acid neutralization solution (PMAA) after activation, and carrying out free radical graft copolymerization under the catalysis of potassium persulfate solution (initiator), wherein nitrogen is introduced into the whole reaction system to remove oxygen interference, the reaction temperature is 50-80 ℃, and the reaction time is 1-3 h; sequentially carrying out deionized water and ethanol precipitation on the product after the reaction, removing monomers and homopolymers by suction filtration, drying and sieving the product to obtain grafted starch (CMS-PMAA);
step two, crosslinking the grafted starch (CMS-PMAA) obtained in the step one with beta-cyclodextrin (beta-CD): the mass ratio of the beta-cyclodextrin to the grafted starch is 1:10 to 1:2, grafting starch: alkali liquor=0.1 to 0.2g:1mL (namely, the ratio of grafted starch to alkali liquor is 0.1-0.2 g/mL), and the mass ratio of sodium trimetaphosphate to grafted starch is 1: 10-3: 10; weighing grafted starch and beta-cyclodextrin, putting the grafted starch and beta-cyclodextrin into alkali liquor prepared from sodium hydroxide, slowly stirring at 40 ℃, slowly adding a cross-linking agent sodium trimetaphosphate, reacting for 1-2 hours to obtain massive gel, crushing the massive gel, sequentially washing and drying the massive gel with deionized water, ethanol and acetone, and sieving to obtain a pH sensitive starch-based carrier { or }: grafted cross-linked starch (CMS-PMAA-beta-CD).
Further, the concentration of the sodium hydroxide solution in the first step is 0.1-0.3 g/mL.
Further, the concentration of the potassium persulfate solution in the first step is 0.004-0.048 g/mL.
Further, the degree of substitution of carboxymethyl starch selected in step one is 0.2.
Further, the gelatinization temperature in the first step was 90 ℃.
Further, in the first step, the product is dried and sieved: the drying temperature is 40 ℃, and the sieving is 200 meshes.
Further, in the second step, the concentration of sodium hydroxide in the alkali liquor is 0.01-0.02 g/mL (distilled water is used as a solvent).
Further, in the second step, the dried materials are screened: the drying temperature is 40 ℃, and the sieving is 200 meshes.
The application { embedded curcumin (Cur) } of the pH-sensitive starch-based carrier obtained by the preparation method is characterized by comprising the following steps: step 1), preparing curcumin/ethanol solution; step 2), adding a pH sensitive starch-based carrier { or: preparing a carrier solution of grafted crosslinked starch (CMS-PMAA-beta-CD) by deionized water, stirring and gelatinizing in a boiling water bath for 30-60 min; cooling to 40-50 ℃ after gelatinization, and adjusting the pH value of the solution to 7-9 to obtain carrier suspension; the mass ratio of curcumin to pH sensitive starch-based carrier is 1: 50-1: and 10, dropwise adding curcumin/ethanol solution into carrier suspension under water bath heating, stirring for 2-5h, removing ethanol by rotary evaporation after the whole process is finished, centrifuging to remove unencapsulated curcumin, and freeze-drying supernatant to obtain the starch-curcumin compound (St-Cur).
Further, the concentration of curcumin/ethanol solution in the step 1) is 2.5mg/mL.
Further, the carrier suspension concentration in step 2) is 10 to 20mg/mL.
Further, in the step 2), the spin-steaming time is 0.5h, the temperature is 40 ℃, the centrifugal speed is 1000r/min, and the centrifugal time is 10min.
The invention has the following beneficial effects:
1. the carboxymethyl starch is used for grafting methacrylic acid to achieve the purpose of pH sensitivity, and the corresponding pH sensitive interval is achieved by changing experimental conditions, so that the subsequent application of the sensitive interval of the carrier to different carrier fields is facilitated.
2. The embedding rate of the starch carrier is increased by crosslinking beta-cyclodextrin with sodium trimetaphosphate, the beta-cyclodextrin has a cavity structure, and the carrier is functionalized by combining the pH sensitivity of the carrier, and meanwhile, the carrier is utilized to embed curcumin serving as a food preservative, so that the curcumin has different release characteristics at different pH values.
3. The invention adopts methacrylic acid to improve the pH sensitivity of the starch carrier, and increases the embedding rate and the controlled release effect of the product by crosslinking beta-cyclodextrin, thereby solving the problems of poor water solubility, low utilization rate, instability and easy decomposition of the natural food preservative curcumin. The invention provides theoretical guidance for improving the bioavailability of the curcumin lipid-soluble functional factor and has good application prospect in the food field.
4. The loss rate of the embedded starch-curcumin compound is obviously reduced.
Drawings
FIG. 1 is a graph showing the effect of different experimental conditions (A: CMS to PMAA ratio, B: neutralization degree of methacrylic acid neutralization solution, C: initiator concentration, D: reaction temperature, E: reaction time) on swelling degree of starch at different pH values.
FIG. 2 is a Fourier infrared spectrum of the raw materials and modified starch of the present invention.
FIG. 3 is a graph showing the effect of different experimental conditions (A: ratio, B: pH, C: time) of the invention on the embedding rate and loading amount of the starch embedded curcumin.
FIG. 4 is a graph showing the release behavior of the starch-curcumin complex (A) and the beta-cyclodextrin-curcumin complex (B) at different pH values.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
A method for preparing a pH-sensitive starch-based carrier, comprising the steps of:
step one, (1) selecting raw materials: the mass ratio of potassium persulfate to methacrylic acid is 2 percent, and the weight ratio of the potassium persulfate to the methacrylic acid is as follows: methacrylic acid mass is 1:2, selecting 2g of carboxymethyl starch, 0.08g of potassium persulfate, 4g of methacrylic acid and 1.2g of sodium hydroxide for later use according to the mass ratio (neutralization degree) of sodium hydroxide to methacrylic acid of 30%;
(2) methacrylic acid neutralization solution: 1.2g of sodium hydroxide is weighed and dissolved in 10mL of distilled water to prepare sodium hydroxide solution, and the sodium hydroxide solution is mixed with 4g of methacrylic acid to obtain a neutralization solution for standby;
(3) potassium persulfate solution: weighing 0.08g of potassium persulfate, and preparing a potassium persulfate solution by using 20mL of distilled water for later use;
(4) adding 100mL of distilled water and 2g of carboxymethyl starch (the mass ratio of the carboxymethyl starch to the distilled water is 1:50) into a three-neck flask, magnetically stirring to uniformly disperse the starch, placing the starch into a water bath kettle, gelatinizing for 0.5h at 70 ℃, and cooling to the reaction temperature of 50 ℃ after gelatinization to obtain gelatinized carboxymethyl starch;
(5) adding potassium persulfate solution (initiator) into gelatinized carboxymethyl starch to activate starch hydroxyl groups to generate free radicals, wherein the activation time is 0.5h, and the reaction temperature is 50 ℃;
(6) slowly adding methacrylic acid neutralization solution (PMAA) after activation, and carrying out free radical graft copolymerization under the catalysis of potassium persulfate solution (initiator), wherein nitrogen is introduced into the whole reaction system to remove oxygen interference, the reaction temperature is 50 ℃, and the reaction time is 1h; sequentially carrying out deionized water and ethanol precipitation on the product after the reaction, removing monomers and homopolymers by suction filtration, drying and sieving the product to obtain grafted starch (CMS-PMAA);
step two, weighing 10g of grafted starch and 1g of beta-cyclodextrin (according to the mass ratio of the beta-cyclodextrin to the grafted starch being 1:10), putting into 100mL of alkali liquor, slowly stirring at 40 ℃ (the concentration of the grafted starch is 0.1g/mL; the concentration of sodium hydroxide in the alkali liquor is 0.01 g/mL), slowly adding 2g of sodium trimetaphosphate as a crosslinking agent, reacting for 1h to obtain massive gel, crushing the massive gel, sequentially washing and drying with deionized water, ethanol and acetone, sieving (the drying temperature is 40 ℃, sieving with 200 meshes), and obtaining the pH sensitive starch-based carrier { or }: grafted cross-linked starch (CMS-PMAA-beta-CD).
The application { embedded curcumin (Cur) } of the pH-sensitive starch-based carrier obtained by the preparation method comprises the following steps: step 1), preparing a curcumin/ethanol solution with the concentration of 2.5 mg/mL; step 2), preparing a carrier solution with the concentration of 10mg/mL by using deionized water for the pH sensitive starch-based carrier, and stirring and gelatinizing in a boiling water bath for 30min; cooling to 40 ℃ after gelatinization, and adjusting the pH value of the solution to 8 to obtain carrier suspension; the mass ratio of curcumin to pH sensitive starch-based carrier is 1:50, dropwise adding curcumin/ethanol solution into carrier suspension under water bath heating, stirring for 2h, keeping away from light in the whole process, removing ethanol by rotary evaporation (rotary evaporation time is 0.5h, temperature is 40 ℃, centrifugal speed is 1000r/min, centrifugal time is 10 min), centrifuging to remove unencapsulated curcumin, and lyophilizing supernatant to obtain starch-curcumin compound (St-Cur).
Example 2
A method for preparing a pH-sensitive starch-based carrier, comprising the steps of:
step one, (1) selecting raw materials: the mass ratio of potassium persulfate to methacrylic acid is 4 percent, and the weight ratio of the potassium persulfate to the methacrylic acid is as follows: methacrylic acid mass is 1:4, selecting 2g of carboxymethyl starch, 0.32g of potassium persulfate, 8g of methacrylic acid and 1.6g of sodium hydroxide for later use according to the mass ratio (neutralization degree) of sodium hydroxide to methacrylic acid being 20%;
(2) methacrylic acid neutralization solution: 1.6g of sodium hydroxide is weighed and dissolved in 10mL of distilled water to prepare sodium hydroxide solution, and the sodium hydroxide solution is mixed with 8g of methacrylic acid to obtain a neutralization solution for standby;
(3) potassium persulfate solution: weighing 0.32g of potassium persulfate, and preparing a potassium persulfate solution by using 20mL of distilled water for later use;
(4) adding 100mL of distilled water and 2g of carboxymethyl starch into a three-neck flask, magnetically stirring to uniformly disperse the starch, gelatinizing the starch in a water bath kettle at 80 ℃ for 1h, and cooling to a reaction temperature of 60 ℃ after gelatinization to obtain gelatinized carboxymethyl starch;
(5) adding potassium persulfate solution (initiator) into gelatinized carboxymethyl starch to activate starch hydroxyl groups to generate free radicals, wherein the activation time is 1h, and the reaction temperature is 60 ℃;
(6) slowly adding methacrylic acid neutralization solution (PMAA) after activation, and carrying out free radical graft copolymerization under the catalysis of potassium persulfate solution (initiator), wherein nitrogen is introduced into the whole reaction system to remove oxygen interference, the reaction temperature is 60 ℃, and the reaction time is 2 hours; sequentially carrying out deionized water and ethanol precipitation on the product after the reaction, removing monomers and homopolymers by suction filtration, drying and sieving the product to obtain grafted starch (CMS-PMAA);
step two, weighing 10g of grafted starch and 2g of beta-cyclodextrin (according to the mass ratio of the beta-cyclodextrin to the grafted starch being 1:5), putting the mixture into 50mL of alkali liquor, slowly stirring the mixture at 40 ℃ (the concentration of the grafted starch is 0.2g/mL; the concentration of sodium hydroxide in the alkali liquor is 0.015 g/mL), slowly adding 2g of sodium trimetaphosphate as a crosslinking agent, reacting for 1h to obtain massive gel, crushing the massive gel, sequentially washing and drying the massive gel with deionized water, ethanol and acetone, sieving the washed massive gel (the drying temperature is 40 ℃, and sieving the massive gel by 200 meshes) to obtain the pH sensitive starch-based carrier { or (called): grafted cross-linked starch (CMS-PMAA-beta-CD).
The application { embedded curcumin (Cur) } of the pH-sensitive starch-based carrier obtained by the preparation method comprises the following steps: step 1), preparing a curcumin/ethanol solution with the concentration of 2.5 mg/mL; step 2), preparing a carrier solution with the concentration of 10mg/mL by using deionized water for the pH sensitive starch-based carrier, and stirring and gelatinizing in a boiling water bath for 30min; cooling to 40 ℃ after gelatinization, and adjusting the pH value of the solution to 9 to obtain carrier suspension; the mass ratio of curcumin to pH sensitive starch-based carrier is 1:40, dropwise adding curcumin/ethanol solution into carrier suspension under water bath heating, stirring for 3h, avoiding light in the whole process, removing ethanol by rotary evaporation (rotary evaporation time is 0.5h, temperature is 40 ℃, centrifugal speed is 1000r/min, centrifugal time is 10 min), centrifuging to remove unencapsulated curcumin, and lyophilizing supernatant to obtain starch-curcumin compound (St-Cur).
Example 3
A method for preparing a pH-sensitive starch-based carrier, comprising the steps of:
step one, (1) selecting raw materials: the mass ratio of potassium persulfate to methacrylic acid is 8 percent, and the weight ratio of the potassium persulfate to the methacrylic acid is as follows: methacrylic acid mass is 1:6, selecting 2g of carboxymethyl starch, 0.96g of potassium persulfate, 12g of methacrylic acid and 2.4g of sodium hydroxide for later use according to the mass ratio (neutralization degree) of sodium hydroxide to methacrylic acid of 20%;
(2) methacrylic acid neutralization solution: 2.4g of sodium hydroxide is weighed and dissolved in 10mL of distilled water to prepare sodium hydroxide solution, and the sodium hydroxide solution is mixed with 12g of methacrylic acid to obtain a neutralization solution for standby;
(3) potassium persulfate solution: weighing 0.96g of potassium persulfate, and preparing a potassium persulfate solution by using 20mL of distilled water for later use;
(4) adding 100mL of distilled water and 2g of carboxymethyl starch into a three-neck flask, magnetically stirring to uniformly disperse the starch, gelatinizing the starch in a water bath kettle at 60 ℃ for 1h, and cooling to the reaction temperature of 80 ℃ after gelatinization to obtain gelatinized carboxymethyl starch;
(5) adding potassium persulfate solution (initiator) into gelatinized carboxymethyl starch to activate starch hydroxyl groups to generate free radicals, wherein the activation time is 1h, and the reaction temperature is 80 ℃;
(6) slowly adding methacrylic acid neutralization solution (PMAA) after activation, and carrying out free radical graft copolymerization under the catalysis of potassium persulfate solution (initiator), wherein nitrogen is introduced into the whole reaction system to remove oxygen interference, the reaction temperature is 70 ℃, and the reaction time is 3 hours; sequentially carrying out deionized water and ethanol precipitation on the product after the reaction, removing monomers and homopolymers by suction filtration, drying and sieving the product to obtain grafted starch (CMS-PMAA);
step two, weighing 10g of grafted starch and 3g of beta-cyclodextrin (according to the mass ratio of the beta-cyclodextrin to the grafted starch being 3:10), putting into 100mL of alkali liquor, slowly stirring at 40 ℃ (the concentration of the grafted starch is 0.1g/mL; the concentration of sodium hydroxide in the alkali liquor is 0.02 g/mL), slowly adding 3g of sodium trimetaphosphate as a crosslinking agent, reacting for 2 hours to obtain massive gel, crushing the massive gel, sequentially washing and drying with deionized water, ethanol and acetone, sieving (the drying temperature is 40 ℃, sieving with 200 meshes), and obtaining the pH sensitive starch-based carrier { or }: grafted cross-linked starch (CMS-PMAA-beta-CD).
The application { embedded curcumin (Cur) } of the pH-sensitive starch-based carrier obtained by the preparation method comprises the following steps: step 1), preparing a curcumin/ethanol solution with the concentration of 2.5 mg/mL; step 2), preparing a carrier solution with the concentration of 10mg/mL by using deionized water for the pH sensitive starch-based carrier, and stirring and gelatinizing in a boiling water bath for 30min; cooling to 40 ℃ after gelatinization, and adjusting the pH value of the solution to 7 to obtain carrier suspension; the mass ratio of curcumin to pH sensitive starch-based carrier is 1: and 20, dropwise adding curcumin/ethanol solution into a carrier suspension under water bath heating, reacting and stirring for 4 hours, wherein light shielding is needed in the whole process, ethanol is removed by rotary evaporation after the reaction is finished (rotary evaporation time is 0.5h, temperature is 40 ℃, centrifugal speed is 1000r/min, centrifugal time is 10 min), unencapsulated curcumin is removed by centrifugation, and supernatant is freeze-dried to obtain the starch-curcumin compound (St-Cur).
Example 4
A method for preparing a pH-sensitive starch-based carrier, comprising the steps of:
step one, (1) selecting raw materials: the mass ratio of potassium persulfate to methacrylic acid is 8 percent, and the weight ratio of the potassium persulfate to the methacrylic acid is as follows: methacrylic acid mass is 1:5, selecting 2g of carboxymethyl starch, 0.8g of potassium persulfate, 10g of methacrylic acid and 1g of sodium hydroxide for later use according to the mass ratio (neutralization degree) of sodium hydroxide to methacrylic acid of 10%;
(2) methacrylic acid neutralization solution: 1g of sodium hydroxide is weighed and dissolved in 10mL of distilled water to prepare sodium hydroxide solution, and the sodium hydroxide solution is mixed with 10g of methacrylic acid to obtain a neutralization solution for standby;
(3) potassium persulfate solution: weighing 0.8g of potassium persulfate, and preparing a potassium persulfate solution by using 20mL of distilled water for later use;
(4) adding 100mL of distilled water and 2g of carboxymethyl starch (the mass ratio of the carboxymethyl starch to the distilled water is 1:50) into a three-neck flask, magnetically stirring to uniformly disperse the starch, placing the starch into a water bath kettle, gelatinizing for 0.5h at 90 ℃, and cooling to the reaction temperature of 70 ℃ after gelatinization to obtain gelatinized carboxymethyl starch;
(5) adding potassium persulfate solution (initiator) into gelatinized carboxymethyl starch to activate starch hydroxyl groups to generate free radicals, wherein the activation time is 0.5h, and the reaction temperature is 70 ℃;
(6) slowly adding methacrylic acid neutralization solution (PMAA) after activation, and carrying out free radical graft copolymerization under the catalysis of an initiator (potassium persulfate solution), wherein nitrogen is introduced into the whole reaction system to remove oxygen interference, the reaction temperature is 70 ℃, and the reaction time is 2 hours; sequentially carrying out deionized water and ethanol precipitation on the product after the reaction, removing monomers and homopolymers by suction filtration, drying and sieving the product to obtain grafted starch (CMS-PMAA);
step two, weighing 10g of grafted starch and 2g of beta-cyclodextrin, putting the grafted starch and the beta-cyclodextrin into 50mL of alkali liquor, slowly stirring at 40 ℃ (the concentration of the grafted starch is 0.2g/mL; the concentration of sodium hydroxide in the alkali liquor is 0.01 g/mL), slowly adding 2g of cross-linking agent sodium trimetaphosphate, reacting for 1h to obtain massive gel, crushing the massive gel, sequentially washing and drying the massive gel with deionized water, ethanol and acetone, and sieving (the drying temperature is 40 ℃, sieving by 200 meshes) to obtain the pH sensitive starch-based carrier { or title: grafted cross-linked starch (CMS-PMAA-beta-CD).
The application { embedded curcumin (Cur) } of the pH-sensitive starch-based carrier obtained by the preparation method comprises the following steps: step 1), preparing a curcumin/ethanol solution with the concentration of 2.5 mg/mL; step 2), preparing a carrier solution with the concentration of 10mg/mL by using deionized water for the pH sensitive starch-based carrier, and stirring and gelatinizing in a boiling water bath for 30min; cooling to 40 ℃ after gelatinization, and adjusting the pH value of the solution to 8 to obtain carrier suspension; the mass ratio of curcumin to pH sensitive starch-based carrier is 1: and 10, dropwise adding curcumin/ethanol solution into a carrier suspension under water bath heating, reacting and stirring for 3 hours, wherein light shielding is needed in the whole process, ethanol is removed by rotary evaporation after the reaction is finished (rotary evaporation time is 0.5h, temperature is 40 ℃, centrifugal speed is 1000r/min, centrifugal time is 10 min), unencapsulated curcumin is removed by centrifugation, and supernatant is freeze-dried to obtain the starch-curcumin compound (St-Cur).
Example 5
A method for preparing a pH sensitive starch-based carrier, which differs from example 1 in that:
in the step (4), 20mL of distilled water and 2g of carboxymethyl starch (the mass ratio of the carboxymethyl starch to the distilled water is 1:10) are added into a three-neck flask;
weighing 2g of grafted starch and 1g of beta-cyclodextrin (the mass ratio of the beta-cyclodextrin to the grafted starch is 1:2), and 0.2g of sodium trimetaphosphate (the mass ratio of the sodium trimetaphosphate to the grafted starch is 1:10);
otherwise, as in example 1, a pH sensitive starch-based carrier { or: grafted cross-linked starch (CMS-PMAA-beta-CD).
The application { embedded curcumin (Cur) } of the pH-sensitive starch-based carrier obtained by the preparation method comprises the following steps: step 1), preparing a curcumin/ethanol solution with the concentration of 2.5 mg/mL; step 2), preparing a carrier solution with the concentration of 20mg/mL by using deionized water for the pH sensitive starch-based carrier, and stirring and gelatinizing in a boiling water bath for 60min; cooling to 50 ℃ after gelatinization, and adjusting the pH value of the solution to 7 to obtain a carrier suspension; the mass ratio of curcumin to pH sensitive starch-based carrier is 1:50, dropwise adding curcumin/ethanol solution into carrier suspension under water bath heating, stirring for 5h, keeping away from light in the whole process, removing ethanol by rotary evaporation (rotary evaporation time is 0.5h, temperature is 40 ℃, centrifugal speed is 1000r/min, centrifugal time is 10 min), centrifuging to remove unencapsulated curcumin, and lyophilizing supernatant to obtain starch-curcumin compound (St-Cur).
The influence of experimental conditions on the pH sensitivity of the grafted product and the grafted cross-linked product is shown in figure 1, carboxymethyl starch grafted methacrylic acid is a free radical polymerization reaction, and the proportion of starch to methacrylic acid, the concentration of an initiator, the neutralization degree of methacrylic acid, the reaction temperature and the reaction time all influence the receiving reaction, so that the pH sensitivity of the carboxymethyl starch grafted methacrylic acid is changed. At the same time, crosslinking beta-CD has a certain influence on the carboxyl content. The product obtained in example 4 was the best synthesis conditions, since it had the best pH sensitivity. The following data are based on the product obtained in example 4.
FIG. 2 is an infrared spectrum of the raw material and modified starch with CMS-PMAA at 1692cm -1 The strong absorption occurs, and the carbonyl absorption peak corresponding to PMAA is 1257cm -1 The grafting success can be preliminarily proved by the property change of the combination product and the infrared spectrum for the stretching vibration of the acrylic acid. CMS-PMAThe A-. Beta. -CD carbonyl absorption peak vs. CMS-PMAA shifted to 1729cm right -1 beta-CD cross-links with the grafted product at 1600cm -1 A typical absorption peak with a new peak of beta-CD appears at 1257cm -1 The stretching vibration of the acrylic acid is weakened, the hydroxyl peak is right shifted and widened, and 2932cm -1 the-CH 2 peak is stronger than CMS-PMAA, indicating that the crosslinked cyclodextrin incorporates more-CH 2, while the incorporated β -CD provides more hydroxyl groups, combined with the infrared spectrum changes, indicating that the product was successfully synthesized.
Fig. 3 is the effect of experimental conditions on the entrapment rate and loading of curcumin, with the entrapment rate decreasing and loading increasing with increasing amounts of curcumin added, 1: the maximum loading at 10 is 51.16ug/mg, and the embedding rate at this time is 76.88%; the reaction pH and the reaction time have a great influence on the embedding rate, and the embedding rate and the loading capacity are the highest when the pH is 6.5 and the reaction time is 3 hours.
The stability changes before and after embedding of curcumin are shown in table 1, the curcumin loss rate is continuously increased along with the rise of the storage time and temperature, because the curcumin is unstable in air and can be decomposed at high temperature when meeting oxygen, the loss rate of the embedded starch-curcumin compound is obviously reduced, the curcumin loss rate is 9.84% after storage for 288 hours, the starch-curcumin is only 1.88%, the curcumin loss rate is 10.64% when the temperature is increased to 80 ℃, the starch-curcumin is 2.03%, the thermal stability and the storage time stability of the embedded curcumin are improved, and the loss rate of the curcumin is lower, so that the modified starch can be used as an embedding agent to provide a physical barrier for the curcumin and protect the curcumin from being decomposed by light, oxygen and the like.
TABLE 1 stability Change before and after curcumin embedding
Comparative example 1
A curcumin/ethanol solution of 2.5mg/mL is prepared, and the beta-cyclodextrin is prepared into a carrier suspension with the concentration of 10mg/mL by deionized water, stirred and gelatinized in a boiling water bath for 30min. Cooling to 40 ℃ after gelatinization, adjusting the pH of the solution to 7, and dropwise adding curcumin/ethanol solution into a carrier suspension under water bath heating, wherein the mass ratio of curcumin to carrier is 1:20, stirring for 2h, removing light in the whole process, removing ethanol by rotary evaporation after the reaction is finished, centrifuging to remove unencapsulated curcumin, and freeze-drying supernatant to obtain the beta-cyclodextrin-curcumin complex.
FIG. 4 shows the release behavior of the products of example 4 and comparative example 1 at different pH values (A: starch-curcumin complex:, B: beta-cyclodextrin-curcumin complex), the starch-curcumin complex having pH-sensitive release behavior, the release rate increasing with increasing pH, the release rates of the complex being 27.87%, 42.06%, 51.57%, 55.68%, 56.76% at pH values of 6, 6.5, 7, 7.5 and 8, respectively, since starch swells at different pH values, the swelling degree under alkaline conditions is higher, and the curcumin release rate is also higher. The release rate of the beta-cyclodextrin-curcumin complex is obviously higher than that of the starch-curcumin complex, because the beta-cyclodextrin and the curcumin are simple host-guest functions, and besides the host-guest functions, the starch embedded curcumin has hydrogen bonds or other functions between curcumin molecules and starch, so that the structure is more compact, and the release rate is lower. The release rate of the beta-cyclodextrin-curcumin compound is higher than that of the beta-cyclodextrin-curcumin compound under the alkaline condition, and the release rate of the beta-cyclodextrin-curcumin compound is 73.46%, 75.68%, 82.26%, 83.64% and 85.12% respectively at the pH values of 6, 6.5, 7, 7.5 and 8, and the curcumin molecules are ionized under the alkaline condition to promote the dissolution of the curcumin, so that the release rate under the alkaline condition is higher, but the carrier does not have pH sensitivity.
The above examples are only preferred embodiments of the present invention and do not limit the scope of the invention, and the present invention may be modified and varied in various experimental conditions for other researchers in the field. Any modifications or improvements made within the spirit and principles of the invention are within the scope of the invention.
Claims (10)
1. A pH-sensitive starch-based carrier composite, characterized by comprising the steps of:
step one, (1) selecting raw materials: the mass ratio of potassium persulfate to methacrylic acid is 2-10 percent, and the weight ratio of the potassium persulfate to the methacrylic acid is as follows: methacrylic acid mass is 1: 2-1: 6, selecting carboxymethyl starch, potassium persulfate, methacrylic acid and sodium hydroxide for later use according to the mass ratio of 10% -30% of sodium hydroxide to methacrylic acid;
(2) methacrylic acid neutralization solution: weighing sodium hydroxide, dissolving in 10mL of distilled water to prepare sodium hydroxide solution, and mixing with methacrylic acid to obtain a neutralization solution for later use;
(3) potassium persulfate solution: preparing a potassium persulfate solution with 20mL of distilled water for later use;
(4) according to carboxymethyl starch: the mass ratio of distilled water is 1:10 to 1:50, adding distilled water and carboxymethyl starch into a three-neck flask, and magnetically stirring to uniformly disperse the carboxymethyl starch; placing the mixture into a water bath kettle to be gelatinized for 0.5 to 1 hour at the temperature of 50 to 90 ℃, and cooling the mixture to the reaction temperature after the gelatinization to obtain gelatinized carboxymethyl starch;
(5) adding potassium persulfate solution into gelatinized carboxymethyl starch to activate starch hydroxyl groups to generate free radicals, wherein the activation time is 0.5-1 h, and the reaction temperature is 50-80 ℃;
(6) slowly adding methacrylic acid neutralization solution after activation, and carrying out free radical graft copolymerization under the catalysis of potassium persulfate solution, wherein nitrogen is introduced into the whole reaction system to remove oxygen interference, the reaction temperature is 50-80 ℃, and the reaction time is 1-3 h; sequentially carrying out deionized water and ethanol precipitation on the product after the reaction, removing monomers and homopolymers by suction filtration, drying and sieving the product to obtain grafted starch;
step two, crosslinking the grafted starch obtained in the step one with beta-cyclodextrin: the mass ratio of the beta-cyclodextrin to the grafted starch is 1:10 to 1:2, grafting starch: alkali liquor=0.1 to 0.2g:1mL, the mass ratio of sodium trimetaphosphate to grafted starch is 1: 10-3: 10; weighing grafted starch and beta-cyclodextrin, placing the grafted starch and the beta-cyclodextrin into alkali liquor prepared from sodium hydroxide, stirring at 40 ℃, adding a cross-linking agent sodium trimetaphosphate, reacting for 1-2 hours to obtain massive gel, crushing the massive gel, sequentially washing and drying the massive gel with deionized water, ethanol and acetone, and sieving to obtain the pH sensitive starch-based carrier;
the application of the obtained pH sensitive starch-based carrier comprises the following steps: the curcumin/ethanol solution prepared in the step 1); step 2), preparing a carrier solution of the pH sensitive starch-based carrier by deionized water, stirring and gelatinizing in a boiling water bath for 30-60 min; cooling to 40-50 ℃ after gelatinization, and adjusting the pH value of the solution to 7-9 to obtain carrier suspension; the mass ratio of curcumin to pH sensitive starch-based carrier is 1: 50-1: and 10, dropwise adding curcumin/ethanol solution into the carrier suspension under water bath heating, stirring for 2-5h, removing ethanol by rotary evaporation after the whole process is finished, centrifuging to remove unencapsulated curcumin, and freeze-drying the supernatant to obtain the starch-curcumin compound.
2. The pH-sensitive starch-based carrier composite according to claim 1, wherein the concentration of sodium hydroxide solution in step one is 0.1-0.3 g/mL; the concentration of the potassium persulfate solution in the first step is 0.004-0.048 g/mL.
3. A pH sensitive starch-based carrier composite according to claim 1 wherein in step one the product is dried and sieved: the drying temperature is 40 ℃, and the sieving is 200 meshes.
4. The pH-sensitive starch-based carrier composition according to claim 1, wherein the concentration of sodium hydroxide in the alkaline solution in step two is 0.01-0.02 g/mL.
5. The pH-sensitive starch-based carrier composite according to claim 1, wherein the reaction pH in step two is 8-9.
6. A pH sensitive starch-based carrier composite according to claim 1 wherein in step two, the composite is dried and then screened: the drying temperature is 40 ℃, and the sieving is 200 meshes.
7. Use of a pH-sensitive starch-based carrier in a complex of pH-sensitive starch-based carriers according to claim 1, characterized in that it comprises the steps of: the curcumin/ethanol solution prepared in the step 1); step 2), preparing a carrier solution of the pH sensitive starch-based carrier by deionized water, stirring and gelatinizing in a boiling water bath for 30-60 min; cooling to 40-50 ℃ after gelatinization, and adjusting the pH value of the solution to 7-9 to obtain carrier suspension; the mass ratio of curcumin to pH sensitive starch-based carrier is 1: 50-1: and 10, dropwise adding curcumin/ethanol solution into the carrier suspension under water bath heating, stirring for 2-5h, removing ethanol by rotary evaporation after the whole process is finished, centrifuging to remove unencapsulated curcumin, and freeze-drying the supernatant to obtain the starch-curcumin compound.
8. The use according to claim 7, wherein the concentration of curcumin/ethanol solution in step 1) is 2.5mg/mL.
9. The use according to claim 7, wherein the carrier suspension in step 2) has a concentration of 10 to 20mg/mL.
10. The method according to claim 7, wherein the spin-steaming time in step 2) is 0.5h, the temperature is 40 ℃, the centrifugation speed is 1000r/min, and the centrifugation time is 10min.
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| CN114588129A (en) * | 2022-02-08 | 2022-06-07 | 华南理工大学 | Curcumin-loaded composite gel microspheres prepared from crosslinked corn porous starch and preparation method of curcumin-loaded composite gel microspheres |
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| CN113575951A (en) * | 2021-08-06 | 2021-11-02 | 合肥工业大学 | Starch-based double-load functional nano-particles, and preparation method and application thereof |
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