Nanoparticles for improving water solubility and permeability of fat-soluble rosemary extract as well as preparation method and application of nanoparticles

Abstract

The invention discloses nanoparticles for improving water solubility and permeability of a fat-soluble rosemary extract as well as a preparation method and application of the nanoparticles. The preparation method of the nanoparticles comprises the following steps: (1) respectively preparing a chitosan (CS) solution, a rosemary extract (RE) solution, a sodium hexametaphosphate (SHMP) solution and a tannic acid (TA) solution; (2) slowly dropwise adding the RE solution into the CS solution, and continuously stirring for 30 minutes; then sequentially dropwise adding an SHMP solution and a TA solution, and continuously stirring for 30 to 50 minutes, so as to obtain RE-TA-CS turbid liquid; and (3) centrifuging the RE-TA-CS suspension, pouring out the supernatant, collecting the precipitate, and freeze-drying the precipitate to obtain the RE-TA-CS nanoparticles (RE-TA-CSNPs). The particle size of the RE-TA-CSNPs prepared by the preparation method disclosed by the invention is 279.5 to 354.8 nm, the encapsulation efficiency of the RE-TA-CSNPs is 70.6 to 78.1 percent, and the contact angle of the RE-TA-CSNPs is 65.2 to 66.1 degrees; the nano particles have good stability, permeability and antioxidant activity in boiled seed foods such as sunflower seeds and pumpkin seeds, oxidation of the seed foods is effectively inhibited, and the shelf life of the seed foods is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of antioxidant modification and food preservation. Specifically, this invention relates to a nanoparticle for improving the water solubility and permeability of fat-soluble rosemary extract, its preparation method and application, and the application of the nanoparticle in the preservation of cooked seed foods. Background Technology

[0002] GB / T 22165-2022, "General Standard for Quality of Nuts and Seeds," defines seeds as the edible parts of seeds from plants such as melons, fruits, vegetables, and oilseeds. GB 19300-2014, "National Food Safety Standard - Nuts and Seeds," defines seeds as the edible seeds of non-woody plants such as melons, fruits, vegetables, and oilseeds. In this invention, seeds refer to edible seeds rich in unsaturated fatty acids, such as sunflower seeds, pumpkin seeds, peanuts, and pine nuts. Seeds are highly susceptible to lipid oxidation during processing and storage, leading to rancidity and spoilage, and even the production of toxic and harmful substances that affect human health, causing significant economic losses. Currently, the industry mainly uses synthetic antioxidants with good fat solubility, such as BHT (di-tert-butyl-p-cresol) and TBHQ (tert-butylhydroquinone), to delay oil oxidation. While effective, long-term intake of these antioxidants may damage liver function, failing to meet consumers' growing demand for healthy foods. Meanwhile, although boiled seeds are milder in nature than roasted seeds, their shelf life is significantly shortened because of the lower content of Maillard reaction products with preservative activity produced during processing. Therefore, how to extend the shelf life of boiled seed products has always been a problem that has received much attention and urgently needs to be solved.

[0003] Rosemary extract (RE) is a mixture of active ingredients extracted from the rosemary plant, possessing antioxidant, antibacterial, and flavoring properties. It is now listed as a food additive. Its main active ingredient, carrageenan, exhibits superior antioxidant capacity compared to BHT and TBHQ, and demonstrates excellent thermal stability. However, it is almost insoluble in water (<0.01 g / 100 mL, 25℃), which severely limits its application in water-based food processing systems (such as cooking). To address the challenge of RE's effectiveness in water-based food processing systems, researchers have explored various delivery systems, including liposomes, emulsions, and microcapsules loaded with RE. However, these carrier systems all have limitations: while liposomes can improve the stability of rosemary extract, their preparation process is complex and costly, and they are prone to breakage and failure during food processing. Emulsion carriers suffer from phase separation and poor thermal stability. Microcapsule technology, while providing some protection, suffers from low encapsulation efficiency and poor release control. The existing patent with publication number CN112915040A improves the water solubility of RE through steps such as acidic solution extraction, decolorization, pH adjustment, resin purification, concentration, deodorization, and drying, but it can only prepare an aqueous solution of RE with a concentration of 0.1% (m / v). Patent publication number CN119678976A discloses a water-soluble rosemary antioxidant, its preparation method, and its application. This antioxidant is prepared by mixing RE, edible oil, protein aqueous solution, and polysaccharide aqueous solution, but its actual RE content is extremely low.

[0004] In summary, there is an urgent need to find a carrier that can effectively deliver the fat-soluble natural antioxidant RE, solve the problems of weak water solubility and poor permeability of RE, and realize its antioxidant application in water-based food processing systems and solid / semi-solid foods. Summary of the Invention

[0005] To address the aforementioned issues and improve the water solubility of resin (RE) and its permeability in cooked (semi-)solid foods, thereby expanding its application areas, this invention uses chitosan (CS) as a carrier and prepares chitosan nanoparticles (CSNPs) through cross-linking with sodium hexametaphosphate (SHMP) and tannic acid (TA). RE is then loaded into RE-TA-CSNPs and applied to the storage and preservation of boiled sunflower seeds and other seed foods to inhibit lipid oxidation and extend their shelf life.

[0006] To achieve the above and other related objectives, the technical solution provided by this invention is: nanoparticles for improving the water solubility and permeability of fat-soluble rosemary extract, wherein the chemical structure of the nanoparticles is as follows:

[0007] .

[0008] The preferred technical solution is that the basic characteristic parameters of the nanoparticles are as follows: encapsulation efficiency greater than 70%, loading rate greater than 20%, particle size of 279~355 nm, PDI value of 0.20~0.28, Zeta potential of 45~50 mV, and water contact angle of 60.0~66.5°.

[0009] To achieve the above and other related objectives, the technical solution provided by this invention is: a method for preparing nanoparticles that improve the water solubility and permeability of fat-soluble rosemary extract, comprising the following steps:

[0010] S1. Preparation of chitosan solution: Add chitosan to an aqueous acetic acid solution, stir, and adjust the pH to 4.5-5.5 to obtain a chitosan solution;

[0011] S2. Preparation of sodium hexametaphosphate solution: Sodium hexametaphosphate is added to deionized water to obtain a sodium hexametaphosphate solution of 0.9-1.2 mg / mL;

[0012] S3. Preparation of tannic acid solution: Add tannic acid to deionized water to obtain tannic acid solution;

[0013] S4. Preparation of rosemary extract solution: Rosemary extract was added to edible alcohol to obtain a rosemary extract solution with a concentration of 1.0-2.0 mg / mL.

[0014] S5. Preparation of RE-loaded chitosan nanoparticles: Under stirring and room temperature conditions, rosemary extract solution was added to chitosan solution at a chitosan to rosemary extract mass ratio of 1-3:1, and stirred to obtain RE-CS mixture; then sodium hexametaphosphate solution and tannic acid solution were added to RE-CS mixture sequentially, with the mass ratios of sodium hexametaphosphate and tannic acid to chitosan being 1:5-8 and 1:8-12, respectively, and stirring continued to obtain RE-TA-CS suspension; the RE-TA-CS suspension was centrifuged at 8000-10000g for 25-30 min, the supernatant was discarded, the precipitate was collected and washed with deionized water, and dried to obtain RE-TA-CSNPs.

[0015] The preferred technical solution is that in the RE-TA-CS suspension, the mass ratio of chitosan to sodium hexametaphosphate is 6:1, the mass ratio of chitosan to tannic acid is 10:1, and the mass ratio of chitosan to rosemary extract is 1:1-3:1.

[0016] To achieve the above and other related objectives, the technical solution provided by this invention is: the application of the nanoparticles that improve the water solubility and permeability of fat-soluble rosemary extract in the preservation of boiled seed foods such as sunflower seeds, pumpkin seeds, and peanuts.

[0017] The preferred technical solution is as follows: the prepared nanoparticles are dispersed in distilled water to obtain a 0.3-0.5 g / kg RE-TA-CSNPs working solution. The seeds are added to the working solution at a mass-to-volume ratio of 1:4-6 (sunflower seeds, pumpkin seeds, or peanut seeds to the working solution) and cooked for 70-80 minutes. The seeds are then removed and placed in an oven at 110-120℃ for 3.0-3.5 hours to obtain RE-TA-CSNPs-preserved cooked seeds.

[0018] Due to the application of the above technical solution, the advantages of this invention compared with the prior art are:

[0019] Compared with the prior art, the advantages and positive effects of the present invention are as follows: ① The present invention uses SHMP and TA as dual crosslinking agents to load the fat-soluble antioxidant RE into CS, preparing RE-TA-CSNPs loaded with RE, which significantly enhances the hydrophilicity and permeability of RE, further expanding its application in water-based systems and (semi)solid matrices; ② The raw materials required for the preparation of RE-TA-CSNPs by the present invention are stable and readily available. RE, TA, and CS have a positive synergistic effect of antioxidation, which can effectively inhibit oil oxidation and significantly extend the shelf life of cooked seed foods; ③ The preparation process of the present invention is simple, green and safe, and has strong applicability. Attached Figure Description

[0020] Figure 1 A schematic diagram of the chemical structure of RE-TA-CSNPs prepared in Example 1.

[0021] Figure 2 Characterization diagrams of the negative RE-TA-CSNPs prepared in Example 1 (a, Fourier transform infrared spectrum; b, ultraviolet spectrum; c, X-ray diffraction pattern; d, differential scanning calorimetry; e, thermogravimetric analysis; f, differential thermogravimetric curve).

[0022] Figure 3 Transmission electron microscopy and contact angle of RE-TA-CSNPs prepared in Example 1.

[0023] Figure 4 Laser confocal microscopy illustration shows the distribution of RE in boiled sunflower seeds (a, b, c, and d represent the free RE treatment group, the RERE-TA-CSNPs treatment group prepared in Example 1, the RERE-TA-CSNPs treatment group prepared in Example 2, and the RERE-TA-CSNPs treatment group prepared in Example 3, respectively).

[0024] Figure 5 The graph shows the changes in acid value (a) and peroxide value (b) of boiled sunflower seeds during storage.

[0025] Figure 6The graph shows the changes in acid value (a) and peroxide value (b) of boiled pumpkin seeds during storage.

[0026] Figure 7 The graph shows the changes in acid value (a) and peroxide value (b) of cooked peanuts during storage. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in these embodiments.

[0028] Please see Figures 1-7 It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size are not permitted. The following embodiments are provided to better understand the invention, but are not intended to limit it. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials used in the following embodiments were purchased from conventional biochemical reagent stores.

[0029] The sunflower seeds, pumpkin seeds, and peanuts used in the embodiments of this invention were purchased from Zhougutui Wholesale Market in Hefei City; chitosan (deacetylated 90.0%) was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; rosemary extract (caryopic acid content above 95%) was purchased from Shaanxi Mixianer Biotechnology Co., Ltd.; and tannic acid and sodium hexametaphosphate were purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0030] The distribution of RE in preserved sunflower seeds was determined as follows: cooked sunflower seeds preserved with RE-TA-CSNPs were cut into appropriate sizes, moistened in plant fixation solution, and semi-thinned using a microtome. The sections were stained with Naturstoffreagent A (NA, 2-aminoethyl-diphenylborate), incubated for 10 minutes, washed with Milli-Q water, and observed under a focused laser scanning microscope. The excitation wavelength and scanning emission wavelength were set to 405 nm and 412-440 nm, respectively.

[0031] The peroxide value and acid value of seed products were determined according to the first titration method in GB 5009.227-2023 National Food Safety Standard - Determination of Peroxide Value in Food and the first cold solvent indicator titration method in GB-5009.229-2016 National Food Safety Standard - Determination of Acid Value in Food, respectively. Accelerated samples were taken every 7 days for testing.

[0032] Rosemary extract is an ethanol extract of rosemary.

[0033] The technical solution of the present invention will be further described in detail below with reference to examples.

[0034] Example 1: Preparation of RE-TA-CSNPs and their application in the preservation of boiled sunflower seeds

[0035] A nanoparticle for improving the water solubility and permeability of lipid-soluble rosemary extract, wherein the basic characteristic parameters of the nanoparticle are as follows: encapsulation efficiency greater than 70%, loading rate greater than 20%, particle size of 279~355 nm, PDI value of 0.20~0.28, zeta potential of 45~50 mV, water contact angle of 60.0~66.5°, and chemical structure as follows. Figure 1 As shown.

[0036] Preparation methods include:

[0037] Preparation of S1 and 1.5 mg / mL CS solution: Weigh 1.5 g of CS. Dissolve it in 1000 mL of 1% (m / v) acetic acid aqueous solution, stir magnetically overnight, and adjust the pH to 5.0 to obtain a 1.5 mg / mL CS solution;

[0038] S2, Preparation of 1.0 mg / mL SHMP solution: Weigh 0.5 g SHMP and dissolve it completely in 500 mL deionized water to obtain a 1.0 mg / mL SHMP solution;

[0039] Preparation of S3, 1.0 mg / mL TA solution: Weigh 0.5 g TA and dissolve it completely in 500 mL of deionized water to obtain a 1.0 mg / mL TA solution;

[0040] Preparation of S4, 1.5 mg / mL RE solution: Weigh 1.5 g RE and dissolve it in 1000 mL of edible alcohol to obtain a 1.5 mg / mL RE solution;

[0041] S5. Preparation of RE-TA-CSNPs loaded with RE: Under magnetic stirring and at room temperature, 500 mL of RE solution was slowly added dropwise to 500 mL of CS solution at a CS solution to RE solution volume ratio of 1:1, and stirred for 30 min to obtain a RE-CS mixture; then 125 mL of SHMP solution and 75 mL of TA solution were added dropwise in sequence, and stirring was continued for 30 min to obtain a RE-TA-CSNPs suspension; the RE-TA-CS suspension was centrifuged at 10000 g for 20 min, the supernatant was discarded, the precipitate was collected and washed three times with deionized water, and then freeze-dried to obtain RE-TA-CSNPs;

[0042] S6. Disperse RE-TA-CSNPs in distilled water to prepare a 0.4 g / kg RE-TA-CSNPs working solution. Add sunflower seeds to the working solution at a mass-to-volume ratio of 1:5 and cook for 80 min. Remove the sunflower seeds and bake them in an oven at 115 ±1℃ for 3.0 h to obtain RE-TA-CSNPs preserved sunflower seeds.

[0043] The encapsulation efficiency, loading rate, particle size, PDI, potential, and water contact angle of the RE-TA-CSNPs prepared in this embodiment are shown in Table 1, and the chemical structure is shown in Appendix. Figure 1 Structural characterization is shown in the appendix. Figure 2 (a, Fourier transform infrared spectrum; b, ultraviolet spectrum; c, XRD pattern; d, differential scanning calorimetry; e, thermogravimetric analysis; f, differential thermogravimetric curve), morphology and contact angle are shown in the appendix. Figure 3 REs that penetrate and disperse in RE-TA-CSNPs for preserving sunflower seed kernels are attached. Figure 4 The storage stability of RE-TA-CSNPs-preserved sunflower seeds is shown in the appendix. Figure 5 .

[0044] Table 1 shows that the encapsulation efficiency of RE-TA-CSNPs for RE was 80.64 ± 1.17%, the loading rate was 34.72 ± 0.24%, the particle size was 354.76 ± 6.71 nm, the PDI value was 0.278 ± 0.008, the Zeta potential was 49.60 ± 0.42 mV, and the water contact angle was 64.9 ± 0.3°. Figure 3 The results show that RE-TA-CSNPs are spherical particles with a contact angle of 66.65 ± 0.45°. These results indicate that RE-TA-CSNPs have good uniformity and strong colloidal stability. Compared with free RE, the RE-TA-CSNPs prepared in this example have improved the scavenging ability of DPPH free radicals and ABTS free radicals by 15.4% and 21.5%, respectively.

[0045] Encapsulation efficiency: The percentage of drug encapsulated inside the nanoparticles relative to the total amount of drug applied; Loading rate: The percentage of encapsulated drug relative to the total mass of the nanoparticles (carrier + drug).

[0046] Table 1 Encapsulation efficiency, loading rate, particle size, PDI, potential, and water contact angle of RE-TA-CSNPs prepared in Examples 1-3

[0047]

[0048] Appendix Figure 2 Structural characterization results show that the Fourier transform infrared spectra of RE-TA-CSNPs (with appendix) Figure 2In (a), the introduction of crosslinking agents SHMP and TA enhances the hydrogen bonding effect, leading to a broadening and redshift of the -OH absorption peak, and the presence of electrostatic interactions. Simultaneously, the disappearance of the RE peak in the broad bandwidth from 1652.2 to 1272.1 cm⁻¹ indicates that rosemary extract has been encapsulated within nanoparticles. (Appendix) Figure 2 Figure b shows that the UV absorption peaks of RE were retained in both RE-CSNPs and RE-TA-CSNPs, indicating that the nano-encapsulation process did not destroy the conjugated system and molecular structure of RE. (See attached image) Figure 2 The XRD pattern of c further indicates that the main active component of RE, sarsaparilla oxalate, forms a partially ordered arrangement with CS through intermolecular hydrogen bonding. Differential scanning calorimetry (see Appendix 2, d) and thermogravimetric analysis (see Appendix 2) further demonstrate this. Figure 2 e) and appendix Figure 2 The differential thermogravimetric curves of f indicate that RE-TA-CSNPs possess strong thermal and storage stability. (See Table 1 and Appendix...) Figure 2 Based on the structural characterization results, the chemical structures of RE-TA-CSNPs are inferred as shown in the attached figure. Figure 1 As shown.

[0049] Appendix Figure 4 The results showed that the blue fluorescence intensity of sunflower seed kernels preserved with RE-TA-CSNPs was significantly higher than that of the free RE group. This indicates that the RE loaded in RE-TA-CSNPs penetrated into the sunflower seed kernels preserved with RE-TA-CSNPs during the cooking process and was evenly distributed. In other words, RE-TA-CSNPs help promote the penetration and dispersion of RE in sunflower seed tissue, achieving continuous and uniform distribution of antioxidants in the fat layer, thereby enhancing the antioxidant properties of sunflower seeds. (Appendix) Figure 5 a and append Figure 5 b further demonstrates that cooked sunflower seeds preserved with RE-TA-CSNPs had lower acid values ​​and peroxide values ​​during storage than the free RE-treated group and the control group.

[0050] Example 2: Preparation of RE-TA-CSNPs and their application in the preservation of boiled pumpkin seeds

[0051] Preparation of S1 and 1.0 mg / mL CS solution: Weigh 1.0 g CS. Dissolve it in 1000 mL of 1% (m / v) acetic acid aqueous solution, stir magnetically overnight, and adjust the pH to 4.0 to obtain a 1.5 mg / mL CS solution;

[0052] Preparation of S2, 0.9 mg / mL SHMP solution: Weigh 0.45 g SHMP and dissolve it completely in 500 mL deionized water to obtain a 1.0 mg / mL SHMP solution;

[0053] Preparation of S3, 0.8 mg / mL TA solution: Weigh 0.4 g TA and dissolve it completely in 500 mL of deionized water to obtain a 1.0 mg / mL TA solution;

[0054] Preparation of S4, 1.0 mg / mL RE solution: Weigh 1.0 g RE and dissolve it in 1000 mL of edible alcohol to obtain a 1.5 mg / mL RE solution;

[0055] S5. Preparation of RE-TA-CSNPs loaded with RE: Under magnetic stirring and at room temperature, 500 mL of RE solution was slowly added dropwise to 1000 mL of CS solution at a CS solution to RE solution volume ratio of 2:1, and stirred for 30 min to obtain a RE-CS mixture; then 225 mL of SHMP solution and 155 mL of TA solution were added dropwise in sequence, and stirring was continued for 30 min to obtain a RE-TA-CSNPs suspension; the RE-TA-CS suspension was centrifuged at 8000 g for 30 min, the supernatant was discarded, the precipitate was collected and washed 5 times with deionized water, and then freeze-dried to obtain RE-TA-CSNPs;

[0056] S6. Disperse RE-TA-CSNPs in distilled water to prepare a 0.3 g / kg RE-TA-CSNPs working solution. Add sunflower seeds to the working solution at a mass-to-volume ratio of 1:5 and cook for 70 min. Remove the sunflower seeds and bake them in an oven at 120 ± 1 ℃ for 3.0 h to obtain RE-TA-CSNPs preserved sunflower seeds.

[0057] The encapsulation efficiency, loading rate, particle size, PDI, potential, and water contact angle of the RE-TA-CSNPs prepared in this embodiment are shown in Table 1; the stability of RE-TA-CSNPs in preserving pumpkin seeds is shown in Appendix. Figure 6 .

[0058] Table 1 shows that the RE encapsulation efficiency of RE by RE-TA-CSNPs was 8.04 ± 1.95%, the loading rate was 26.26 ± 0.41%, the particle size was 323.83 ± 7.88 nm, the PDI value was 0.253 ± 0.018, the Zeta potential was 47.40 ± 1.36 mV, and the water contact angle was 62.5 ± 0.1°. Compared with free RE, the RE-TA-CSNPs prepared in this example showed an increase of 18.2% and 25.1% in scavenging ability against DPPH and ABTS radicals, respectively. (Appendix) Figure 6 The results showed that cooked pumpkin seeds preserved with RE-TA-CSNPs had lower acid values ​​and peroxide values ​​during storage than those in the free RE treatment group and the control group, indicating higher storage stability.

[0059] Example 3: Preparation of RE-TA-CSNPs and their application in the preservation of boiled peanuts

[0060] Preparation of S1 and 2.0 mg / mL CS solution: Weigh 2.0 g of CS. Dissolve it in 1000 mL of 1% (m / v) acetic acid aqueous solution, stir magnetically overnight, and adjust the pH to 4.3 to obtain a 2.0 mg / mL CS solution;

[0061] Preparation of S2, 1.2 mg / mL SHMP solution: Weigh 0.6 g SHMP and dissolve it completely in 500 mL deionized water to obtain a 1.0 mg / mL SHMP solution;

[0062] Preparation of S3, 1.1 mg / mL TA solution: Weigh 0.55 g TA and dissolve it completely in 500 mL of deionized water to obtain a 1.0 mg / mL TA solution;

[0063] Preparation of S4, 2.0 mg / mL RE solution: Weigh 2.0 g RE and dissolve it in 1000 mL of edible alcohol to obtain a 1.5 mg / mL RE solution;

[0064] S5. Preparation of RE-TA-CSNPs loaded with RE: Under magnetic stirring and at room temperature, 250 mL of RE solution was slowly added dropwise to 750 mL of CS solution at a CS solution to RE solution volume ratio of 3:1, and stirred for 30 min to obtain a RE-CS mixture; then 155 mL of SHMP solution and 115 mL of TA solution were added dropwise in sequence, and stirring was continued for 30 min to obtain a RE-TA-CSNPs suspension; the RE-TA-CS suspension was centrifuged at 9000 g for 25 min, the supernatant was discarded, the precipitate was collected and washed 4 times with deionized water, and then freeze-dried to obtain RE-TA-CSNPs;

[0065] S6. Disperse RE-TA-CSNPs in distilled water to prepare a 0.5 g / kg RE-TA-CSNPs working solution. Add sunflower seeds to the working solution at a mass-to-volume ratio of 1:5 and cook for 75 min. Remove the sunflower seeds and bake them in an oven at 110 ± 1 ℃ for 3.5 h to obtain RE-TA-CSNPs preserved sunflower seeds.

[0066] The encapsulation efficiency, loading rate, particle size, PDI, potential, and water contact angle of the RE-TA-CSNPs prepared in this embodiment are shown in Table 1; the storage stability of RE-TA-CSNPs for preserving fresh flowers is shown in Appendix. Figure 7 .

[0067] Table 1 shows that the encapsulation efficiency of RE-TA-CSNPs for RE was 74.46 ± 0.28%, the loading rate was 20.61 ± 0.08%, the particle size was 279.53 ± 4.08 nm, the PDI value was 0.266 ± 0.008, the Zeta potential was 49.83 ± 1.37 mV, and the water contact angle was 63.7 ± 0.2°. Figure 3 The results show that RE-TA-CSNPs are spherical particles with a contact angle of 66.65 ± 0.45°; these results indicate that RE-TA-CSNPs have good uniformity and strong colloidal stability; compared with free RE, the RE-TA-CSNPs prepared in this example have improved scavenging abilities against DPPH radicals and ABTS radicals by 14.9% and 22.5%, respectively. (See attached image) Figure 7 This indicates that cooked peanuts preserved with RE-TA-CSNPs have lower acid values ​​and peroxide values ​​during storage than those in the free RE-treated group and the control group, resulting in a longer shelf life.

[0068] In summary, the RE-TA-CSNPs prepared by heterogeneous reaction for ion aggregation have advantages such as high stability, good uniformity, and strong permeability. They can realize the antioxidant activity of RE in the preservation of cooked seed foods, thereby extending the shelf life of seed foods and have broad application prospects.

[0069] The above description is merely a preferred embodiment for explaining the present invention and is not intended to limit the present invention in any way. Therefore, any modifications or changes made to the present invention under the same inventive spirit should still be included within the scope of protection intended by the present invention.

Claims

1. A nanoparticle for improving the water solubility and permeability of fat-soluble rosemary extract, characterized in that, The chemical structure of the nanoparticles is as follows: 。 2. The nanoparticles for improving the water solubility and permeability of fat-soluble rosemary extract according to claim 1, characterized in that, The basic characteristic parameters of the nanoparticles are as follows: encapsulation efficiency greater than 70%, loading rate greater than 20%, particle size of 279~355 nm, PDI value of 0.20~0.28, Zeta potential of 45~50 mV, and water contact angle of 60.0~66.5°.

3. The method for preparing nanoparticles that improve the water solubility and permeability of fat-soluble rosemary extract according to claim 1 or 2, characterized in that, Includes the following steps: S1. Preparation of chitosan solution: Add chitosan to an aqueous acetic acid solution, stir, and adjust the pH to 4.5-5.5 to obtain a chitosan solution; S2. Preparation of sodium hexametaphosphate solution: Sodium hexametaphosphate is added to deionized water to obtain a sodium hexametaphosphate solution of 0.9-1.2 mg / mL; S3. Preparation of tannic acid solution: Add tannic acid to deionized water to obtain tannic acid solution; S4. Preparation of rosemary extract solution: Rosemary extract was added to edible alcohol to obtain a rosemary extract solution with a concentration of 1.0-2.0 mg / mL. S5. Preparation of RE-loaded chitosan nanoparticles: Under stirring and room temperature conditions, rosemary extract solution was added to chitosan solution at a chitosan to rosemary extract mass ratio of 1-3:1, and stirred to obtain RE-CS mixture; then sodium hexametaphosphate solution and tannic acid solution were added to RE-CS mixture sequentially, with the mass ratios of sodium hexametaphosphate and tannic acid to chitosan being 1:5-8 and 1:8-12, respectively, and stirring continued to obtain RE-TA-CS suspension; the RE-TA-CS suspension was centrifuged at 8000-10000g for 25-30 min, the supernatant was discarded, the precipitate was collected and washed with deionized water, and dried to obtain RE-TA-CSNPs.

4. The method for preparing nanoparticles that improve the water solubility and permeability of fat-soluble rosemary extract according to claim 3, characterized in that, In the RE-TA-CS suspension, the mass ratio of chitosan to sodium hexametaphosphate was 6:1, the mass ratio of chitosan to tannic acid was 10:1, and the mass ratio of chitosan to rosemary extract was 1:1-3:

1.

5. The application of the nanoparticles described in claim 3 for improving the water solubility and permeability of fat-soluble rosemary extract in the preservation of boiled seed foods such as sunflower seeds, pumpkin seeds, and peanuts.

6. The application of the nanoparticles described in claim 5, which improve the water solubility and permeability of fat-soluble rosemary extract, in the preservation of boiled sunflower seeds, pumpkin seeds, and peanuts, is characterized in that: The prepared nanoparticles were dispersed in distilled water to obtain a 0.3-0.5 g / kg RE-TA-CSNPs working solution. The seeds were added to the working solution at a mass-to-volume ratio of 1:4-6 (sunflower seeds, pumpkin seeds, or peanut seeds to the working solution) and cooked for 70-80 minutes. The seeds were then removed and placed in an oven at 110-120℃ for 3.0-3.5 hours to obtain RE-TA-CSNPs-preserved cooked seeds.

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