A high hydrophobic UV barrier starch film with nanoparticle-reinforced complex network and its preparation method

Abstract

This invention discloses a highly hydrophobic UV-blocking starch film with a nanoparticle-reinforced complex network and its preparation method, belonging to the field of starch-based biodegradable film technology. The preparation of the highly hydrophobic UV-blocking starch-based food packaging film with a nanoparticle-reinforced complex network of this invention includes: using pea starch, soy protein isolate, and zein nanoparticles as raw materials, followed by gelatinization, cooling, addition of zein nanoparticles, uniform mixing, casting, drying, and equilibration to prepare a starch-based biodegradable film with highly hydrophobic and high UV-blocking functions. This starch-based film exhibits high hydrophobicity and excellent UV-blocking performance at room temperature, which can expand the application range of starch-based biodegradable films in functional food packaging, maintain the nutritional quality of food during transportation and storage, and extend the shelf life of food.

Description

Technical Field

[0001] This invention relates to a highly hydrophobic ultraviolet-barrier starch film with a nanoparticle-reinforced complex network and its preparation method, belonging to the field of starch-based biodegradable film technology. Background Technology

[0002] The mass production and use of plastics has caused serious environmental pollution. The escalating environmental problems have made people aware of the hazards of chemically synthesized plastics. To address this issue, starch-based biodegradable films are considered an ideal alternative to plastic packaging. However, currently prepared starch-based biodegradable films have poor hydrophobicity and are easily dissolved in water, which severely limits their application in real life. Furthermore, continuous ultraviolet (UV) radiation can negatively impact food quality. For example, UV radiation can cause degradation reactions of nutrients and natural pigments in food, reducing its nutritional value. Simultaneously, UV radiation can promote lipid oxidation in food, producing harmful substances that pose a potential threat to human health.

[0003] To address the aforementioned problems, this invention aims to provide a simple and green novel method for preparing a highly hydrophobic UV-blocking starch film, thereby producing a starch-based biodegradable food packaging film that possesses both high hydrophobicity and UV-shielding properties. In the highly hydrophobic UV-blocking starch film prepared by this invention, pea starch and soy protein isolate form a uniform and stable complex network through non-covalent interactions. Simultaneously, zein nanoparticles in the film, through uniform distribution among pea starch and soy protein isolate molecular chains, reduce the migration rate between non-covalent complex network molecular chains, resulting in a stronger complex network structure formed during film formation, thus enhancing the structural rigidity of the film. Furthermore, while strengthening the internal structure of the film, the zein nanoparticles also enhance the surface roughness and internal light scattering of the starch film, thereby giving the starch-based film obtained by this invention high hydrophobicity and excellent UV-shielding performance. Based on the above phenomena, this invention establishes a method for preparing a highly hydrophobic UV-blocking starch film with a nanoparticle-reinforced complex network. This invention expands the application scope of starch-based biodegradable films in functional food packaging, maintains the nutritional quality of food during transportation and storage, and extends the shelf life of food, which has significant economic and social value. Summary of the Invention

[0004] Existing starch-based biodegradable films suffer from poor hydrophobicity, limited functionality, and the impact of long-term ultraviolet radiation on the nutritional quality of food.

[0005] To address the aforementioned problems, this invention provides a highly hydrophobic UV-blocking starch film with a nanoparticle-reinforced complex network and its preparation method. In the prepared starch film, pea starch and soy protein isolate form a uniform and stable complex network through non-covalent interactions. Simultaneously, zein nanoparticles in the film, through uniform distribution between pea starch and soy protein isolate molecular chains, reduce the migration rate between the non-covalent complex network molecular chains, resulting in a stronger complex network structure during film formation, thereby enhancing the structural rigidity of the film. Furthermore, while strengthening the internal structure of the film, the zein nanoparticles also enhance the surface roughness and internal light scattering of the starch film, thus giving the obtained starch-based film high hydrophobicity and excellent UV-shielding performance. The preparation method of this invention is simple, green, pollution-free, and low-energy-consumption, resulting in a starch film with improved hydrophobicity and excellent UV-shielding performance.

[0006] The first objective of this invention is to provide a method for preparing a highly hydrophobic ultraviolet-barrier starch film with a nanoparticle-reinforced complex network, the method comprising the following steps:

[0007] (1) Preparation of zein nanoparticles:

[0008] Zeatin was dissolved in an ethanol solution. The resulting zeatin ethanol solution was added dropwise to an aqueous solution, and the ethanol in the solution was removed. The volume was then replenished to the original volume using an aqueous solution.

[0009] After centrifuging the sample with the added volume, discard the supernatant, freeze-dry the precipitate, and obtain the prepared zein nanoparticles.

[0010] (2) Preparation of film-forming solution:

[0011] Dissolve starch and soy protein isolate in deionized water, heat to gelatinize, cool, add corn glycerin nanoparticles, and stir evenly.

[0012] (3) Preparation of starch film:

[0013] The film-forming solution obtained in step (2) is poured into a polytetrafluoroethylene plate by casting and dried in an oven at 40°C; a highly hydrophobic UV-blocking starch film with interfacial crosslinking is obtained.

[0014] In one embodiment of the present invention, a balancing step is also included: the balancing step is to peel off the film prepared in step (3) and balance it under a humidity of 53% to obtain a high hydrophobic UV barrier starch-based biodegradable food packaging film.

[0015] In one embodiment of the present invention, in step (1), the volume fraction of ethanol is 75% to 95%.

[0016] In one embodiment of the present invention, the mass ratio of zein to ethanol is 1:100 to 200.

[0017] In one embodiment of the present invention, in step (1), the pH of the aqueous solution is 4 to 6.

[0018] In one embodiment of the present invention, in step (1), the centrifugation rate is 6000-8000 rpm and the centrifugation time is 10-30 min.

[0019] In one embodiment of the present invention, step (1) involves dissolving zein in a 75% ethanol solution, adding the zein ethanol solution dropwise to deionized water, and finally removing the ethanol from the solution using a rotary evaporator (temperature 40°C, vacuum 0.1 MPa), and replenishing the volume with deionized water. Then, the sample with the replenished volume is centrifuged at 4°C, and finally, the freshly prepared sample is freeze-dried to obtain the prepared zein nanoparticles.

[0020] In one embodiment of the present invention, pea starch and soy protein isolate are dissolved in deionized water at a mass ratio of 1:1 to 3, and the total amount of pea starch and soy protein isolate added is at least 4g.

[0021] In one embodiment of the present invention, gelatinization is performed by heating at 90–100°C for 30–50 minutes, followed by cooling to 40–50°C.

[0022] In one embodiment of the present invention, the total amount of pea starch and soy protein isolate and the addition ratio of zein nanoparticles are 1:0.01 to 0.06.

[0023] In one embodiment of the present invention, in step (1), the volume ratio of the zein ethanol solution to the aqueous solution is 1:4 to 6.

[0024] In one embodiment of the present invention, in step (2), pea starch and soy protein isolate are dissolved and gelatinized. After cooling, zein nanoparticles prepared in step (1) are added. Phytic acid may also be added. After stirring evenly, a film-forming solution is prepared.

[0025] The second objective of this invention is to provide a highly hydrophobic ultraviolet-barrier starch film with a nanoparticle-reinforced complex network prepared by the method described above.

[0026] The third objective of this invention is to provide the application of a highly hydrophobic ultraviolet-barrier starch film with a nanoparticle-reinforced complex network as described above in the food and agricultural product fields.

[0027] Beneficial effects

[0028] This invention, based on nanofiller enhancement technology, promotes the formation of non-covalent complex networks between pea starch and soy protein isolate molecular chains. The preparation process is simple, green, non-toxic, harmless, and pollution-free. Furthermore, by changing the concentration of zein nanoparticles, starch-based films with different hydrophobicities and UV blocking properties can be obtained. The starch-based films prepared by this invention possess high hydrophobicity and excellent UV shielding performance, expanding the application range of starch-based biodegradable films in functional food packaging and having significant economic and social value in extending food shelf life. Attached Figure Description

[0029] Figure 1 Test on the hydrophobic properties of starch film.

[0030] Figure 2 : Test of ultraviolet blocking performance of starch film. Detailed Implementation

[0031] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0032] The pea starch used in the following examples was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; the soy protein isolate and zein were purchased from Shanghai Titan Technology Co., Ltd.; and the citric acid and tannic acid were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0033] The test methods involved in the following embodiments:

[0034] 1. Hydrophobicity test

[0035] The hydrophobicity of starch-based films was tested using a video optical contact angle meter.

[0036] 2. Ultraviolet blocking test

[0037] The transmission spectra of starch-based films were measured using a spectrophotometer, ranging from 200 nm to 1000 nm.

[0038] Example 1: Preparation of a highly hydrophobic UV-barrier starch-based food packaging film

[0039] Specifically, the steps include the following:

[0040] (1) Preparation of zein nanoparticles:

[0041] Dissolve 0.4g of zein in 40mL of 75% ethanol solution. Add the resulting zein ethanol solution dropwise to 160mL of deionized water (adjust the pH of the deionized water to 4.0 first). Finally, use a rotary evaporator (temperature 40℃, vacuum degree 0.1MPa) to remove the ethanol from the solution, and add deionized water (adjust the pH of the deionized water to 4.0 first) to make up the volume to 200mL.

[0042] Then, the sample after the above-mentioned volume replenishment was centrifuged at 6000 rpm and 4℃, the supernatant was discarded, and the obtained precipitate was freeze-dried to obtain the prepared zein nanoparticles.

[0043] (2) Preparation of film-forming solution:

[0044] Add 2g of pea starch and 2g of soy protein isolate to 100mL of deionized water, and heat with magnetic stirring at 90℃ and 600rpm for 30min to gelatinize. After cooling to 50℃, add 0.02g of zein nanoparticles prepared in step (1), stir evenly, and prepare a film-forming solution.

[0045] (3) Preparation of starch film:

[0046] 30 mL of the film-forming solution obtained in step (2) was poured into a polytetrafluoroethylene plate by casting and dried in an oven at 40°C to obtain a film.

[0047] (4) Balance:

[0048] The film prepared in step (3) is peeled off and equilibrated at a humidity of 53% to obtain a high hydrophobic UV barrier starch-based food packaging film.

[0049] Example 2: Preparation of a highly hydrophobic UV-barrier starch-based food packaging film

[0050] The specific implementation method is the same as in Example 1, except that the amount of zein nanoparticles added in step (2) of Example 1 is adjusted to 0.04g.

[0051] Step (2) specifically involves:

[0052] Add 2g of pea starch and 2g of soy protein isolate to 100mL of deionized water, heat at 90℃ for 30min to gelatinize, cool to 50℃, add 0.04g of zein nanoparticles prepared in step (1), stir evenly, and prepare a film-forming solution.

[0053] All other parameters and conditions remained the same as in Example 1, resulting in a starch-based food packaging film with high hydrophobic UV barrier properties.

[0054] Example 3: Preparation of a highly hydrophobic UV-barrier starch-based food packaging film

[0055] The specific implementation method is the same as in Example 1, except that the amount of zein nanoparticles added in step (2) of Example 1 is adjusted to 0.08g.

[0056] Step (2) specifically involves:

[0057] Add 2g of pea starch and 2g of soy protein isolate to 100mL of deionized water, heat at 90℃ for 30min to gelatinize, cool to 50℃, add 0.08g of zein nanoparticles prepared in step (1), stir evenly, and prepare a film-forming solution.

[0058] All other parameters and conditions remained the same as in Example 1, resulting in a starch-based food packaging film with high hydrophobic UV barrier properties.

[0059] Example 4: Preparation of a highly hydrophobic UV-barrier starch-based food packaging film

[0060] The specific implementation method is the same as in Example 1, except that the amount of zein nanoparticles added in step (2) of Example 1 is adjusted to 0.12g.

[0061] Step (2) specifically involves:

[0062] Add 2g of pea starch and 2g of soy protein isolate to 100mL of deionized water, heat at 90℃ for 30min to gelatinize, cool to 50℃, add 0.12g of zein nanoparticles prepared in step (1), stir evenly, and prepare a film-forming solution.

[0063] All other parameters and conditions remained the same as in Example 1, resulting in a starch-based food packaging film with high hydrophobic UV barrier properties.

[0064] Comparative Example 1: Preparation of pure pea starch-based food packaging film

[0065] The specific implementation method is the same as in Example 1, except that step (1) in Example 1 is omitted, and 2g of pea starch and 2g of soy protein isolate in step (2) are replaced with 4g of pea starch. No zein nanoparticles are added. All other parameters and conditions are the same as in Example 1.

[0066] In other words, the specific steps are as follows:

[0067] (1) Dissolve 4g of pea starch in 100mL of deionized water, heat at 90℃ for 30min to gelatinize, and cool to prepare a film-forming solution.

[0068] (2) Preparation of starch film:

[0069] 30 mL of the film-forming solution obtained in step (1) was poured into a polytetrafluoroethylene plate by casting and dried in an oven at 40°C to obtain a film.

[0070] (3) Balance:

[0071] The film prepared in step (2) is peeled off and equilibrated at a humidity of 53% to obtain a food packaging film.

[0072] Comparative Example 2: Preparation of Starch-Based Food Packaging Film Without Added Zein Nanoparticles

[0073] The only difference from Example 1 is that step (1) in Example 1 is omitted and zein nanoparticles are not added to the film-forming solution. All other parameters and conditions are the same as in Example 1.

[0074] In other words, the specific steps are as follows:

[0075] (1) Dissolve 2g of pea starch and 2g of soy protein isolate in 100mL of deionized water, heat at 90℃ for 30min to gelatinize, and after cooling, prepare a film-forming solution.

[0076] (2) Preparation of starch film:

[0077] 30 mL of the film-forming solution obtained in step (1) was poured into a polytetrafluoroethylene plate by casting and dried in an oven at 40°C to obtain a film.

[0078] (3) Balance:

[0079] The film prepared in step (2) is peeled off and equilibrated at a humidity of 53% to obtain a food packaging film.

[0080] Comparative Example 3: Preparation of starch-based food packaging films with different proportions of pea starch and soy protein isolate

[0081] The specific implementation method is the same as in Example 1, except that the addition ratio of pea starch and soy protein isolate in step (2) is adjusted to 1:3.

[0082] In other words, the specific steps are as follows:

[0083] (1) Preparation of zein nanoparticles:

[0084] Dissolve 0.4g of zein in 40mL of 75% ethanol solution. Add the resulting zein ethanol solution dropwise to 160mL of deionized water (adjust the pH of the deionized water to 4.0 first). Finally, use a rotary evaporator (temperature 40℃, vacuum degree 0.1MPa) to remove the ethanol from the solution, and add deionized water (adjust the pH of the deionized water to 4.0 first) to make up the volume to 200mL.

[0085] Then, the sample after the above-mentioned volume replenishment was centrifuged at 6000 rpm and 4℃, the supernatant was discarded, and the obtained precipitate was freeze-dried to obtain the prepared zein nanoparticles.

[0086] (2) Add 1g of pea starch and 3g of soy protein isolate to 100mL of deionized water, and heat with magnetic stirring at 90℃ and 600rpm for 30min to gelatinize. After cooling to 50℃, add 0.12g of zein nanoparticles prepared in step (1), stir evenly, and prepare a film-forming solution.

[0087] (3) Preparation of starch film:

[0088] 30 mL of the film-forming solution obtained in step (2) was poured into a polytetrafluoroethylene plate by casting and dried in an oven at 40°C to obtain a film.

[0089] (4) Balance:

[0090] The film prepared in step (3) is peeled off and equilibrated at a humidity of 53% to obtain a food packaging film.

[0091] Comparative Example 4: Preparation of starch-based food packaging film crosslinked with citric acid

[0092] The specific implementation method is the same as in Example 1, except that in step (2), an additional crosslinking agent is added: citric acid.

[0093] In other words, the specific steps are as follows:

[0094] (1) Preparation of zein nanoparticles:

[0095] Dissolve 0.4g of zein in 40mL of 75% ethanol solution. Add the resulting zein ethanol solution dropwise to 160mL of deionized water (adjust the pH of the deionized water to 4.0 first). Finally, use a rotary evaporator (temperature 40℃, vacuum degree 0.1MPa) to remove the ethanol from the solution, and add deionized water (adjust the pH of the deionized water to 4.0 first) to make up the volume to 200mL.

[0096] Then, the sample after the above-mentioned volume replenishment was centrifuged at 6000 rpm and 4℃, the supernatant was discarded, and the obtained precipitate was freeze-dried to obtain the prepared zein nanoparticles.

[0097] (2) Add 2g of pea starch and 2g of soy protein isolate to 100mL of deionized water simultaneously, and incubate at 90℃ and 600℃.

[0098] Gelatinization was carried out by magnetic stirring and heating for 30 minutes under rpm conditions. After cooling to 50℃, 0.12g of zein nanoparticles and 0.1g of citric acid prepared in step (1) were added and stirred evenly to prepare a film-forming solution.

[0099] (3) Preparation of starch film:

[0100] 30 mL of the film-forming solution obtained in step (2) was poured into a polytetrafluoroethylene plate by casting and dried in an oven at 40°C to obtain a film.

[0101] (4) Balance:

[0102] The film prepared in step (2) is peeled off and equilibrated at a humidity of 53% to obtain a food packaging film.

[0103] Comparative Example 5: Preparation of starch-based food packaging film crosslinked with tannins

[0104] The specific implementation method is the same as in Example 1, except that in step (2), an additional crosslinking agent is added: tannic acid.

[0105] In other words, the specific steps are as follows:

[0106] (1) Preparation of zein nanoparticles:

[0107] Dissolve 0.4g of zein in 40mL of 75% ethanol solution. Add the resulting zein ethanol solution dropwise to 160mL of deionized water (adjust the pH of the deionized water to 4.0 first). Finally, use a rotary evaporator (temperature 40℃, vacuum degree 0.1MPa) to remove the ethanol from the solution, and add deionized water (adjust the pH of the deionized water to 4.0 first) to make up the volume to 200mL.

[0108] Then, the sample after the above-mentioned volume replenishment was centrifuged at 6000 rpm and 4℃, the supernatant was discarded, and the obtained precipitate was freeze-dried to obtain the prepared zein nanoparticles.

[0109] (2) Add 2g of pea starch and 2g of soy protein isolate to 100mL of deionized water at the same time. Stir and heat magnetically at 90℃ and 600rpm for 30min to gelatinize. After cooling to 50℃, add 0.12g of zein nanoparticles and 0.1g of tannic acid prepared in step (1). Stir evenly to prepare a film-forming solution.

[0110] (3) Preparation of starch film:

[0111] 30 mL of the film-forming solution obtained in step (2) was poured into a polytetrafluoroethylene plate by casting and dried in an oven at 40°C to obtain a film.

[0112] (4) Balance:

[0113] The film prepared in step (3) is peeled off and equilibrated at a humidity of 53% to obtain a food packaging film.

[0114] Example 5: Starch film obtained by adding phytic acid and its performance determination

[0115] Specifically, the steps include the following:

[0116] 1. Preparation of starch film

[0117] (1) Preparation of zein nanoparticles:

[0118] Dissolve 0.4g of zein in 40mL of 75% ethanol solution. Add the resulting zein ethanol solution dropwise to 160mL of deionized water (adjust the pH of the deionized water to 4.0 first). Finally, use a rotary evaporator (temperature 40℃, vacuum degree 0.1MPa) to remove the ethanol from the solution, and add deionized water (adjust the pH of the deionized water to 4.0 first) to make up the volume to 200mL.

[0119] Then, the sample after the above-mentioned volume replenishment was centrifuged at 6000 rpm and 4℃, the supernatant was discarded, and the obtained precipitate was freeze-dried to obtain the prepared zein nanoparticles.

[0120] (2) Preparation of film-forming solution:

[0121] Add 2g of pea starch and 2g of soy protein isolate to 100mL of deionized water, and heat with magnetic stirring at 90℃ and 600rpm for 30min to gelatinize. After cooling to 50℃, add 0.04g of zein nanoparticles and 0.1g of phytic acid prepared in step (1), stir evenly, and prepare a film-forming solution.

[0122] (3) Preparation of starch film:

[0123] 30 mL of the film-forming solution obtained in step (2) was poured into a polytetrafluoroethylene plate by casting and dried in an oven at 40°C to obtain a film.

[0124] (4) Balance:

[0125] The film prepared in step (3) is peeled off and equilibrated at a humidity of 53% to obtain a high hydrophobic UV barrier starch-based food packaging film.

[0126] Example 6: Result Determination

[0127] The properties of the starch films obtained in Examples 1-5 and Comparative Examples 1-5 were measured.

[0128] (1) Hydrophobic properties

[0129] Depend on Figure 1 It can be seen that the water contact angles of the starch films prepared in Examples 1-5 are 94.48°, 97.99°, 102.71°, 108.75°, and 89.02°, respectively. It can be seen that the water contact angle of the starch films prepared in Examples 1-4 increases from 94.48° to 108.75°, and the water contact angle of the starch film with added phytic acid crosslinking agent in Example 5 is 89.02°. This indicates that the starch films with nanoparticle-reinforced complex networks prepared in Examples 1-5 all have good hydrophobicity. The water contact angle of the film prepared in Example 4 is increased by 52.06% compared with the pure starch film (Comparative Example 1). At the same time, the hydrophobicity of the film increases with the increase of the amount of nanoparticles added.

[0130] The surface water contact angle of the pure pea starch film prepared in Comparative Example 1 was only 71.52°; the surface water contact angle of the starch film without nanoparticles prepared in Comparative Example 2 was 83.2°; the surface water contact angle of the starch films prepared in Comparative Example 3 with different proportions of pea starch and soy protein isolate was 87.4°; the surface water contact angle of the citric acid cross-linked starch film prepared in Comparative Example 4 was 68.7°; and the surface water contact angle of the tannic acid cross-linked starch film prepared in Comparative Example 5 was 59.85°.

[0131] The hydrophobicity of the films prepared in Comparative Examples 1-5 is weaker than that in Examples 1-5, indicating that the nanoparticle-reinforced complex network starch film prepared in this invention has high hydrophobicity and is superior to chemically cross-linked starch films.

[0132] (2) Ultraviolet blocking performance

[0133] Depend on Figure 2It can be seen that the starch film prepared in Example 1 can adsorb ultraviolet light in the wavelength range below 353 nm, the starch film prepared in Example 2 can adsorb ultraviolet light in the wavelength range below 355 nm, the starch film prepared in Example 3 can adsorb ultraviolet light in the wavelength range below 359 nm, the starch film prepared in Example 4 can adsorb ultraviolet light in the wavelength range below 373 nm, and the starch film prepared in Example 5 can adsorb ultraviolet light in the wavelength range below 364 nm. It can be seen that the starch films prepared in Examples 1-5 can adsorb ultraviolet light in the wavelength range below 353-373 nm, indicating that the starch films prepared in Examples 1-5 have excellent ultraviolet blocking performance, and the ultraviolet blocking performance is enhanced with the increase of the amount of nanoparticles added.

[0134] The pure starch film prepared in Comparative Example 1 had no blocking effect on ultraviolet light; the starch film without nanoparticles prepared in Comparative Example 2 could adsorb ultraviolet light in the wavelength range below 312 nm; the starch films prepared in Comparative Example 3 with different proportions of pea starch and soy protein isolate could adsorb ultraviolet light in the wavelength range below 289 nm; the citric acid cross-linked starch film prepared in Comparative Example 4 could adsorb ultraviolet light in the wavelength range below 271 nm; and the tannic acid cross-linked starch film prepared in Comparative Example 5 could adsorb ultraviolet light in the wavelength range below 323 nm.

[0135] The ultraviolet blocking performance of the films prepared in Comparative Examples 1-5 is weaker than that in Examples 1-5, indicating that the nanoparticle-reinforced complex network starch film prepared in this invention has excellent ultraviolet blocking performance and is superior to chemically cross-linked starch films.

[0136] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A highly hydrophobic ultraviolet-barrier starch film with a nanoparticle-reinforced complex network, characterized in that, The highly hydrophobic ultraviolet-barrier starch film was prepared according to the following steps: (1) Preparation of zein nanoparticles: Zeat protein was dissolved in an ethanol solution. The resulting zeat protein ethanol solution was added dropwise to an aqueous solution. The ethanol in the solution was then removed, and the volume was replenished to the original volume using an aqueous solution. After centrifuging the sample with the added volume, discard the supernatant, freeze-dry the precipitate, and obtain the prepared zein nanoparticles. (2) Preparation of film-forming solution: Pea starch and soy protein isolate were dissolved in a mass ratio of 1:1 and gelatinized. After cooling, the zein nanoparticles prepared in step (1) were added and stirred evenly to prepare a film-forming solution. (3) Preparation of starch film: The film-forming solution obtained in step (2) was poured into a polytetrafluoroethylene plate by casting and dried to obtain a highly hydrophobic ultraviolet barrier starch film with a nanoparticle-reinforced complex network.

2. The highly hydrophobic ultraviolet-barrier starch film according to claim 1, characterized in that, In step (1), the volume fraction of ethanol is 75% to 95%.

3. The highly hydrophobic ultraviolet-barrier starch film according to claim 1, characterized in that, The mass ratio of zein to ethanol is 1:100 to 200.

4. The highly hydrophobic ultraviolet-barrier starch film according to any one of claims 1 to 3, characterized in that, In step (1), the pH of the aqueous solution is 4 to 6.

5. The highly hydrophobic ultraviolet-barrier starch film according to claim 4, characterized in that, The total amount of pea starch and soy protein isolate added should be at least 4g.

6. The highly hydrophobic ultraviolet-barrier starch film according to claim 5, characterized in that, In step (2), the gelatinization is carried out by heating at 90-100℃ for 30-50 minutes and then cooled to 40-50℃.

7. The highly hydrophobic ultraviolet-barrier starch film according to claim 6, characterized in that, In step (2), the total amount of pea starch and soy protein isolate and the addition ratio of zein nanoparticles are 1:0.01 to 0.

06.

8. The highly hydrophobic ultraviolet-barrier starch film according to claim 7, characterized in that, In step (1), the volume ratio of the zein ethanol solution to the aqueous solution is 1:4 to 6.

9. The high hydrophobic UV-blocking starch film according to claim 8, characterized in that, In step (1), the centrifugation rate is 6000-8000 rpm and the centrifugation time is 10-30 min.

10. The high hydrophobic UV-blocking starch film according to claim 9, characterized in that, In step (2), pea starch and soy protein isolate are dissolved and gelatinized. After cooling, zein nanoparticles prepared in step (1) are added, phytic acid is added, and the mixture is stirred evenly to prepare a film-forming solution.

11. The application of the highly hydrophobic ultraviolet-barrier starch film according to any one of claims 1 to 10 in the food and agricultural product fields.

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