Light-operated near-infrared response juicy peach fresh-keeping coating system and use method thereof

Abstract

According to the light-controlled near-infrared response juicy peach fresh-keeping coating system and the using method thereof, ZnONPs is accurately triggered to generate heat through near-infrared light, then movement of a chitosan oligosaccharide molecular chain is promoted, coating pores are expanded, on-demand release of an antibacterial agent thymol is achieved, the utilization rate of a medicament is increased, waste is reduced, and the environment-friendly effect is achieved. And the problem of drug residue caused by continuous release of a traditional coating film is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of honey peach preservation, and specifically to a light-controlled near-infrared responsive honey peach preservation coating system and its usage method. Background Art

[0002] In the field of fruit preservation, traditional methods mostly rely on chemical preservatives or physical refrigeration means. Although chemical preservatives can effectively extend the shelf life of fruits, long-term use may lead to drug residues, affecting consumer health and fruit quality. Physical refrigeration is relatively safe, but the preservation effect is limited and the energy consumption is high. In recent years, with the development of nanotechnology and intelligent materials, intelligent responsive preservation coatings have gradually become a research hotspot. Such coatings can intelligently adjust their structure and function according to changes in environmental conditions (such as temperature, humidity, light, etc.), so as to achieve precise preservation of fruits.

[0003] However, there are still some problems with existing intelligent responsive preservation coatings. For example, although some coatings can respond to environmental changes, their response mechanism is not precise enough, resulting in uncontrolled drug release, causing waste or poor effects. In addition, some coating materials are not environmentally friendly and are difficult to degrade, posing a potential threat to the environment. Therefore, developing an intelligent responsive preservation coating that is both precise and environmentally friendly has become an urgent technical problem to be solved in the current fruit preservation field. Summary of the Invention

[0004] The purpose of the present invention is to provide a light-controlled near-infrared responsive honey peach preservation coating system and its usage method.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A light-controlled near-infrared responsive honey peach preservation coating system, including core components and formulations, the core components and formulations include: a) A photothermal conversion material, selected from food-grade zinc oxide nanoparticles or carbon quantum dots, with a content range of 0.05 - 0.3 wt%; b) A responsive carrier, which is chitosan oligosaccharide, with a molecular weight ≤ 5 kDa and a deacetylation degree ≥ 90%, and a content range of 85 - 95 wt%; c) An antibacterial agent, selected from food-grade thymol or ε-polylysine, with a content range of 2 - 8 wt%; d) An antioxidant, which is tea polyphenol, with a purity ≥ 98% and a content range of 1 - 3 wt%; e) A humectant, selected from food-grade glycerol or trehalose, with a content range of 1 - 5 wt%; f) A stabilizer, which is food-grade Tween-80, with a content range of 0.5 - 2 wt%.

[0006] Preferably, the photothermal conversion material is zinc oxide nanoparticles with a particle size of 20 - 50 nm.

[0007] Preferably, it further includes a processing technology, which includes: a) Dissolve chitosan oligosaccharide in 1% acetic acid solution, adjust the pH value to 4.5 and continuously stir until completely dissolved; b) Sequentially add an antibacterial agent, an antioxidant, a humectant, and a stabilizer to the chitosan oligosaccharide solution, and fully stir after adding each component; c) Add the photothermal conversion material to the above mixed solution and ultrasonically disperse it using an ultrasonic dispersion device; d) Place the ultrasonically dispersed mixed solution on a magnetic stirrer and stir; e) After the stirring ends, store the composite coating solution in a dark and cool place.

[0008] Preferably, the frequency of the ultrasonic dispersion device is 40 kHz, the power is 200 W, and the ultrasonic dispersion time is 30 minutes.

[0009] Preferably, the speed of the magnetic stirring is 500 rpm, the stirring time is 2 hours, and the light - shielding environment is maintained during the stirring process.

[0010] Preferably, it further includes a light - controlled release mechanism, which includes: a) Near - infrared triggering parameters: the wavelength is 808 nm, the power density is 0.3 - 0.8 W / cm², and the irradiation mode is pulsed; b) Response release logic: The near - infrared light triggers the photothermal conversion material to generate heat, resulting in enhanced movement of the responsive carrier molecular chains and expansion of the film pores, thereby releasing the antibacterial agent.

[0011] Preferably, the light - controlled release mechanism further includes dynamic regulation, that is, when the fruit maturity increases, the fruit stalk or wound is irradiated directionally by a portable NIR device to increase the release rate of the antibacterial agent.

[0012] A method for using a light - controlled near - infrared responsive peach fresh - keeping coating system includes pretreatment, coating operation, and storage and triggering steps, where: a) The pretreatment step is to wash the peach with 0.1% sodium hypochlorite and air - dry it naturally; b) The coating operation step is to uniformly cover the surface of the peach with the composite coating solution by the dipping method or the spraying method; c) The storage and triggering step is to store the peach at 10 - 12 °C with a humidity of 85 - 90%, and when the fruit respiration intensity is detected to increase, irradiate the fruit stalk with a portable 808 nm laser pen to activate the release of the antibacterial agent.

[0013] Compared with the prior art, the beneficial effects of the present invention are: The present invention provides a light-controlled near-infrared responsive peach preservation coating system and its usage method. By precisely triggering the heat generation of ZnONPs with near-infrared light, the movement of chitosan molecular chains is promoted, the coating pores are enlarged, the on-demand release of the antibacterial agent thymol is achieved, the utilization rate of the agent is improved, waste is reduced, and the problem of drug residue caused by the continuous release of traditional coatings is effectively avoided. Detailed implementation mode

[0014] The technical inventions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0015] The present invention is a light-controlled near-infrared responsive peach preservation coating system, including preparing core components and formulations, preparing photothermal materials, coating and curing peaches, and a light-controlled release mechanism. Among them, the core components and formulations include: a) Photothermal conversion materials, selected from food-grade zinc oxide nanoparticles (ZnONPs) or carbon quantum dots (CQDs), with a content range of 0.05 - 0.3 wt%; b) Responsive carriers, which are chitosan (COS), with a molecular weight ≤ 5 kDa, a deacetylation degree ≥ 90%, and a content range of 85 - 95 wt%; c) Antibacterial agents, selected from food-grade thymol or ε-polylysine, with a content range of 2 - 8 wt%; d) Antioxidants, which are tea polyphenols, with a purity ≥ 98% and a content range of 1 - 3 wt%; e) Humectants, selected from food-grade glycerol or trehalose, with a content range of 1 - 5 wt%; f) Stabilizers, which are food-grade Tween-80, with a content range of 0.5 - 2 wt%. Among them, the processing technology of the photothermal material includes: a) Dissolve chitosan in a 1% acetic acid solution, adjust the pH value to 4.5, and continuously stir until completely dissolved; b) Sequentially add antibacterial agents, antioxidants, humectants, and stabilizers to the chitosan solution, and fully stir after adding each component; c) Add the photothermal conversion material to the above mixed solution, and ultrasonically disperse it for 30 minutes under the conditions of 40 kHz and 200 W using an ultrasonic dispersion device; d) Place the ultrasonically dispersed mixed solution on a magnetic stirrer and stir at a speed of 500 rpm for 2 hours, keeping the environment dark during the stirring process; e) After the stirring is completed, store the composite coating solution in a dark and cool place. Among them, film coating curing: After the peaches are impregnated for 30 seconds, place them in a 10°C cold air drying oven for 20 minutes to cure, forming a transparent film coating (thickness 10 - 20 μm). Among them, the light-controlled release mechanism includes: a) Near-infrared triggering parameters: wavelength is 808 nm, power density is 0.3 - 0.8 W / cm², and the irradiation mode is pulsed; b) Response release logic: The near-infrared light-triggered photothermal conversion material generates heat, resulting in enhanced movement of the responsive carrier molecular chains, expansion of the film coating pores, and thus release of the antibacterial agent; c) Dynamic regulation, that is, when the fruit maturity increases, the fruit stalk or wound is irradiated directionally by a portable NIR device to increase the release rate of the antibacterial agent. The usage method of the light-controlled near-infrared responsive peach fresh-keeping film coating system includes pre-treatment, film coating operation, and storage and triggering steps, among which: a) The pre-treatment step is to wash the peaches with 0.1% sodium hypochlorite and air dry them naturally; b) The film coating operation step is to uniformly cover the surface of the peaches with the composite coating solution by the dipping method or spraying method; c) The storage and triggering step is to store the peaches at 10 - 12°C with a humidity of 85 - 90%, and when the fruit respiration intensity is detected to increase, irradiate the fruit stalk with a portable 808 nm laser pen to activate the release of the antibacterial agent. Examples

[0016] Prepare the core components and formula: a) Photothermal conversion material, selected from food-grade zinc oxide nanoparticles, with a content range of 0.2 wt%; b) Responsive carrier, which is chitosan oligosaccharide with a molecular weight of 3 kDa and a degree of deacetylation of 95%, with a content range of 90 wt%; c) Antibacterial agent, selected from food-grade thymol, with a content range of 4 wt%; d) Antioxidant, which is tea polyphenol with a purity of 98%, with a content range of 1 wt%; e) Humectant, selected from food-grade glycerol, with a content range of 2 wt%; f) Stabilizer, which is food-grade Tween-80, with a content range of 1 wt%.

[0017] Processing of the photothermal material: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion material in a 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0018] Add functional components: Add antibacterial agent, antioxidant, humectant, and Tween-80 in sequence, and stir for 10 minutes at intervals for each component.

[0019] Disperse the photothermal material: Add the photothermal material, and perform ultrasonic dispersion (40 kHz, 200 W, 30 min), then stir in the dark for 2 h.

[0020] Coating curing: Immerse the peach in water for 30 s, then dry it with cold air at 10 °C for 20 min. Storage conditions: Refrigerate at 10 - 12 °C, humidity 85 - 90%, and in a light-proof environment.

[0021] Photocontrol release mechanism Trigger device: A portable 808 nm near-infrared laser pen (power density 0.5 W / cm², pulse mode: 5 s on / 10 s off).

[0022] Initial state: The pore diameter of the coating film is about 10 nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0023] Near-infrared triggering: After irradiation, the local temperature at the fruit stalk rises to 45 - 50 °C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50 nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0024] Dynamic regulation: According to the respiratory intensity (CO 2 monitor) adjust the irradiation duration (increase the irradiation by 10 s for every 10% increase in respiratory intensity). Examples

[0025] Prepare the core components and formula: a) Photothermal conversion material, selected from food-grade zinc oxide nanoparticles, with a content range of 0.2 wt%; b) Responsive carrier, which is chitosan oligosaccharide with a molecular weight of 3 kDa and a deacetylation degree of 95%, with a content range of 90 wt%; c) Antibacterial agent, selected from food-grade thymol, with a content range of 4 wt%; d) Antioxidant, which is tea polyphenol with a purity of 98%, with a content range of 1 wt%; e) Humectant, selected from food-grade glycerol, with a content range of 2 wt%; f) Stabilizer, which is food-grade Tween-80, with a content range of 1 wt%.

[0026] Processing of the photothermal material: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion material in 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0027] Add functional components: Add antibacterial agent, antioxidant, humectant, and Tween-80 in sequence, and stir for 10 minutes at intervals for each component.

[0028] Dispersed photothermal material: Add photothermal material, ultrasonically disperse (40 kHz, 200 W, 30 min), and stir in the dark for 2 h.

[0029] Coating curing: Immerse in peach for 30 seconds, dry with cold air at 10 °C for 20 minutes. Storage conditions: Refrigerate at 10 - 12 °C, humidity 85 - 90%, in a light-proof environment.

[0030] Light-controlled release mechanism Trigger device: Portable 808 nm near-infrared laser pen (power density 0.5 W / cm², pulse mode: 5 s on / 10 s off).

[0031] Initial state: The pore diameter of the coating is about 10 nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0032] Near-infrared triggering: After irradiation, the local temperature at the fruit stalk rises to 45 - 50 °C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50 nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0033] Dynamic regulation: According to the respiratory intensity (CO 2 monitor) adjust the irradiation duration (increase the irradiation by 10 s for every 10% increase in respiratory intensity). Examples

[0034] Prepare the core components and formula: a) Photothermal conversion material, selected from food-grade zinc oxide nanoparticles, with a content range of 0.2 wt%; b) Responsive carrier, chitosan oligosaccharide with a molecular weight of 3 kDa and a deacetylation degree of 95%, with a content range of 90 wt%; c) Antibacterial agent, selected from food-grade thymol, with a content range of 4 wt%; d) Antioxidant, tea polyphenol with a purity of 98%, with a content range of 1 wt%; e) Humectant, selected from food-grade glycerol, with a content range of 2 wt%; f) Stabilizer, food-grade Tween-80, with a content range of 1 wt%.

[0035] Processing of photothermal material: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion material in 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0036] Add functional components: Add the antibacterial agent, antioxidant, humectant, and Tween-80 in sequence, and stir for 10 minutes at each interval.

[0037] Dispersed photothermal material: Add photothermal material, ultrasonically disperse (40 kHz, 200 W, 30 min), and stir in the dark for 2 h.

[0038] Coating curing: Soak in peach for 30 seconds, dry with cold air at 10 °C for 20 minutes. Storage conditions: Refrigerate at 10 - 12 °C, humidity 85 - 90%, in a dark environment.

[0039] Photocontrol release mechanism Trigger device: Portable 808 nm near-infrared laser pen (power density 0.5 W / cm², pulse mode: 5 s on / 10 s off).

[0040] Initial state: The pore diameter of the coating film is about 10 nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0041] Near-infrared trigger: After irradiation, the local temperature at the fruit stalk rises to 45 - 50 °C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50 nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0042] Dynamic regulation: According to the respiration intensity (CO 2 Monitor) adjust the irradiation duration (increase the irradiation by 10 s for every 10% increase in respiration intensity). Examples

[0043] Prepare the core components and formula: a) Photothermal conversion material, select carbon quantum dots, content range is 0.2 wt%; b) Responsive carrier, is chitosan oligosaccharide with a molecular weight of 3 kDa and a deacetylation degree of 95%, content range is 90 wt%; c) Antibacterial agent, select ε-polylysine, content range is 6 wt%; d) Antioxidant, is tea polyphenol with a purity of 98%, content range is 1 wt%; e) Humectant, select trehalose, content range is 3 wt%; f) Stabilizer, is food-grade Tween-80, content range is 1 wt%.

[0044] Processing of photothermal material: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion material in 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0045] Add functional components: Add the antibacterial agent, antioxidant, humectant, and Tween-80 in sequence, and stir for 10 minutes at each interval.

[0046] Dispersed photothermal material: Add photothermal material, ultrasonically disperse (40 kHz, 200 W, 30 min), and stir in the dark for 2 h.

[0047] Coating curing: Soak in peach juice for 30 seconds, dry with cold air at 10°C for 20 minutes. Storage conditions: refrigerate at 10 - 12°C, humidity 85 - 90%, light - proof environment.

[0048] Light - controlled release mechanism Trigger device: Portable 808nm near - infrared laser pen (power density 0.5W / cm², pulse mode: 5 seconds on / 10 seconds off).

[0049] Initial state: The pore diameter of the coating film is about 10nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0050] Near - infrared trigger: After irradiation, the local temperature at the fruit stalk rises to 45 - 50°C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0051] Dynamic regulation: Adjust the irradiation duration according to the respiration intensity (CO 2 monitor) (for every 10% increase in respiration intensity, increase the irradiation by 10 seconds). Examples

[0052] Prepare the core components and formula: a) Photothermal conversion material, select carbon quantum dots, content range is 0.2wt%; b) Responsive carrier, is chitosan oligosaccharide with molecular weight 3kDa, deacetylation degree 95%, content range is 90wt%; c) Antibacterial agent, select ε - polylysine, content range is 6wt%; d) Antioxidant, is tea polyphenol with purity 98%, content range is 1wt%; e) Humectant, select trehalose, content range 3wt%; f) Stabilizer, is food - grade Tween - 80, content range is 1wt%.

[0053] Processing of photothermal material: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion material in 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0054] Add functional components: Add antibacterial agent, antioxidant, humectant, Tween - 80 in sequence, and stir for 10 minutes at each interval.

[0055] Disperse the photothermal material: Add the photothermal material, ultrasonically disperse (40kHz, 200W, 30min), and stir in the dark for 2h.

[0056] Coating curing: The peaches are soaked for 30 seconds and then dried with cold air at 10°C for 20 minutes. Storage conditions: refrigeration at 10 - 12°C, humidity 85 - 90%, and in a light - proof environment.

[0057] Light - controlled release mechanism Trigger device: a portable 808nm near - infrared laser pen (power density 0.5W / cm², pulse mode: 5 seconds on / 10 seconds off).

[0058] Initial state: The pore diameter of the coating film is about 10nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0059] Near - infrared triggering: After irradiation, the local temperature at the fruit stalk rises to 45 - 50°C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0060] Dynamic regulation: According to the respiratory intensity (CO 2 monitor) to adjust the irradiation duration (for every 10% increase in respiratory intensity, increase the irradiation by 10 seconds). Examples

[0061] Prepare the core components and formula: a) Photothermal conversion material, select carbon quantum dots, with a content range of 0.2wt%; b) Responsive carrier, is chitosan oligosaccharide with a molecular weight of 3kDa and a deacetylation degree of 95%, with a content range of 90wt%; c) Antibacterial agent, select ε - polylysine, with a content range of 6wt%; d) Antioxidant, is tea polyphenol with a purity of 98%, with a content range of 1wt%; e) Humectant, select trehalose, with a content range of 3wt%; f) Stabilizer, is food - grade Tween - 80, with a content range of 1wt%.

[0062] Processing of the photothermal material: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion material in 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0063] Add functional components: Add the antibacterial agent, antioxidant, humectant, and Tween - 80 in sequence, and stir for 10 minutes at each interval.

[0064] Disperse the photothermal material: Add the photothermal material, and perform ultrasonic dispersion (40kHz, 200W, 30min), and stir in the dark for 2h.

[0065] Coating film curing: The peaches are soaked for 30 seconds and then dried with cold air at 10°C for 20 minutes. Storage conditions: refrigeration at 10 - 12°C, humidity 85 - 90%, and in a light - proof environment.

[0066] Optical control release mechanism Trigger device: Portable 808nm near-infrared laser pen (power density 0.5W / cm², pulse mode: 5 seconds on / 10 seconds off).

[0067] Initial state: The pore diameter of the coating film is about 10nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0068] Near-infrared trigger: After irradiation, the local temperature at the fruit stalk rises to 45 - 50°C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0069] Dynamic regulation: Adjust the irradiation duration according to the respiratory intensity (CO 2 monitor) (for every 10% increase in respiratory intensity, increase the irradiation by 10 seconds). Example

[0070] Prepare the core components and formula: a) Photothermal conversion materials, selected from 0.1wt% of food-grade zinc oxide nanoparticles and 0.1wt% of carbon quantum dots; b) Responsive carrier, chitosan oligosaccharide with a molecular weight of 3kDa, deacetylation degree of 95%, and content range of 90wt%; c) Antibacterial agent, selected from 3wt% of food-grade thymol and 3wt% of ε-polylysine; d) Antioxidant, tea polyphenols with a purity of 98% and content range of 3wt%; e) Humectant, selected from 1wt% of food-grade glycerol and 2wt% of trehalose; f) Stabilizer, food-grade Tween-80 with a content range of 1wt%.

[0071] Processing of photothermal materials: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion materials in 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0072] Add functional components: Add the antibacterial agent, antioxidant, humectant, and Tween-80 in sequence, and stir for 10 minutes at each interval.

[0073] Disperse the photothermal materials: Add the photothermal materials, ultrasonically disperse (40kHz, 200W, 30min), and stir in the dark for 2h.

[0074] Coating film curing: Immerse the peaches for 30 seconds, dry in cold air at 10°C for 20 minutes, storage conditions: refrigerate at 10 - 12°C, humidity 85 - 90%, and in a light-proof environment.

[0075] Optical control release mechanism Trigger device: Portable 808nm near-infrared laser pen (power density 0.5W / cm², pulse mode: 5 seconds on / 10 seconds off).

[0076] Initial state: The pore diameter of the coating film is about 10nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0077] Near-infrared triggering: After irradiation, the local temperature at the fruit stalk rises to 45 - 50°C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0078] Dynamic regulation: Adjust the irradiation duration according to the breathing intensity (CO 2 monitor) (for every 10% increase in breathing intensity, increase the irradiation by 10 seconds). Example

[0079] Prepare the core components and formula: a) Photothermal conversion material, selected from 0.1wt% of food-grade zinc oxide nanoparticles and 0.1wt% of carbon quantum dots; b) Responsive carrier, chitosan oligosaccharide with a molecular weight of 3kDa, a degree of deacetylation of 95%, and a content range of 90wt%; c) Antibacterial agent, selected from 3wt% of food-grade thymol and 3wt% of ε-polylysine; d) Antioxidant, tea polyphenol with a purity of 98% and a content range of 3wt%; e) Humectant, selected from 1wt% of food-grade glycerol and 2wt% of trehalose; f) Stabilizer, food-grade Tween-80 with a content range of 1wt%.

[0080] Processing of the photothermal material: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion material in 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0081] Add functional components: Add the antibacterial agent, antioxidant, humectant, and Tween-80 in sequence, and stir for 10 minutes at each interval.

[0082] Disperse the photothermal material: Add the photothermal material, ultrasonically disperse (40kHz, 200W, 30min), and stir in the dark for 2h.

[0083] Coating film curing: Immerse the peaches for 30 seconds, dry them with cold air at 10°C for 20 minutes, storage conditions: refrigerate at 10 - 12°C, humidity 85 - 90%, and in a dark environment.

[0084] Photocontrolled release mechanism Trigger device: Portable 808nm near-infrared laser pen (power density 0.5W / cm², pulse mode: 5 seconds on / 10 seconds off).

[0085] Initial state: The pore diameter of the coating film is about 10nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0086] Near-infrared triggering: After irradiation, the local temperature at the fruit stalk rises to 45 - 50°C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0087] Dynamic regulation: Adjust the irradiation duration according to the respiratory intensity (CO 2 monitor) (for every 10% increase in respiratory intensity, increase the irradiation by 10 seconds). Example

[0088] Prepare the core components and formula: a) Photothermal conversion material, selected from 0.1wt% of food-grade zinc oxide nanoparticles and 0.1wt% of carbon quantum dots; b) Responsive carrier, which is chitosan oligosaccharide with a molecular weight of 3kDa, a deacetylation degree of 95%, and a content range of 90wt%; c) Antibacterial agent, selected from 3wt% of food-grade thymol and 3wt% of ε-polylysine; d) Antioxidant, which is tea polyphenol with a purity of 98% and a content range of 3wt%; e) Humectant, selected from 1wt% of food-grade glycerol and 2wt% of trehalose; f) Stabilizer, which is food-grade Tween-80 with a content range of 1wt%.

[0089] Processing of the photothermal material: Dissolve chitosan oligosaccharide: Dissolve the photothermal conversion material in 1% acetic acid solution, adjust the pH to 4.5, and stir magnetically until transparent.

[0090] Add functional components: Add the antibacterial agent, antioxidant, humectant, and Tween-80 in sequence, and stir for 10 minutes at each interval.

[0091] Disperse the photothermal material: Add the photothermal material, and disperse it by ultrasonic wave (40kHz, 200W, 30min), and stir in the dark for 2h.

[0092] Coating film curing: Immerse the peach for 30 seconds, dry it with cold air at 10°C for 20 minutes, storage conditions: refrigerate at 10 - 12°C, humidity 85 - 90%, and in a light-proof environment.

[0093] Photocontrol release mechanism Trigger device: Portable 808nm near-infrared laser pen (power density 0.5W / cm², pulse mode: 5 seconds on / 10 seconds off).

[0094] Initial state: The pore diameter of the coating film is about 10nm, and the antibacterial agent is embedded in the chitosan oligosaccharide network.

[0095] Near-infrared triggering: After irradiation, the local temperature at the fruit stalk rises to 45 - 50°C, the molecular chain movement of chitosan oligosaccharide intensifies, the pores expand to 30 - 50nm, and the release rate of thymol increases by 3 times (detected by HPLC).

[0096] Dynamic regulation: According to the respiratory intensity (CO 2 monitor), adjust the irradiation duration (for every 10% increase in respiratory intensity, increase the irradiation by 10 seconds). Example

[0097] For the control group, there is a coating film without light control.

[0098] Examples 1 - 10 of the present invention use peaches of the variety "Yuanmeng". The selected peach fruits are about eight - ripe, with similar colors, the same size and shape, and no mechanical damage or pests and diseases; the antibacterial rate, DPPH scavenging rate, weight loss rate, release response time, and degradability of the peaches in each example are tested, and the performance test results are shown in Table 1 below: Example Bacteriostatic rate (%) DPPH scavenging rate (%) Weight loss rate (%) Release response time (min) Degradability (28 days %) 1 92.3 78.6 2.9 5.2 91.5 2 88.7 82.1 3.1 6.8 92 3 94.5 85.3 2.5 4.5 90.8 4 86.2 76.4 3.3 7.5 93.2 5 89.8 80.9 2.8 6 91.7 6 95.1 88.7 2.1 3.8 92.5 7 93.6 84.2 2.3 4.2 90.5 8 97.4 89.5 1.8 2.9 93.8 9 90.3 83.6 2.7 5.5 92.1 10 72.5 83.6 7.6 / / Table 1 Embodiment of the core beneficial effects Through the combination of precise light - controlled release and natural antibacterial agents, the present invention overcomes the pain point of "drug residue caused by continuous release" in traditional coating films, providing a new paradigm for intelligent preservation of delicate fruits such as peaches.

[0099] The light - controlled near - infrared responsive peach preservation coating film system proposed by the present invention, aiming at the pain points in the prior art, realizes the following beneficial effects: Precise release and reduction of drug residue: Near - infrared light precisely triggers the heat generation of ZnONPs, which in turn promotes the molecular chain movement of chitosan oligosaccharide, expands the pores of the coating film, and realizes the on - demand release of the antibacterial agent thymol. This method not only improves the utilization rate of the drug, reduces waste, but also effectively avoids the problem of drug residue caused by the continuous release of traditional coating films.

[0100] Adaptive preservation and balanced gas exchange: The pores of the coating film can be dynamically adjusted according to the change of the fruit's respiratory intensity, which not only ensures the normal gas exchange of the fruit, but also can quickly release the antibacterial agent when needed, realizing the balance between the preservation effect and the physiological needs of the fruit.

[0101] Environmentally friendly and biodegradable: All components are food - grade safe materials, and the coating film has good natural degradability, meeting environmental protection requirements and reducing the impact on the environment.

[0102] Simple operation and intelligence: The film coating operation is simple. The dipping method or spraying method can be used, which is suitable for fresh-keeping requirements of different scales. At the same time, through the directional irradiation of a portable NIR device, intelligent light-controlled activation is realized, improving the fresh-keeping efficiency and convenience.

[0103] In summary, the light-controlled near-infrared responsive peach fresh-keeping film coating system of the present invention not only solves the problems existing in traditional film coatings, but also realizes multiple beneficial effects such as precise release, adaptive fresh-keeping, environmental protection and degradability, and intelligent operation.

[0104] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. And the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0105] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made in these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A light-controlled near-infrared response peach preservation coating system, characterized in that: It includes core components and formula, and the core components and formula include: a) light-to-heat conversion material, selected from food-grade zinc oxide nanoparticles or carbon quantum dots, with a content ranging from 0.05 to 0.3 wt%; b) The responsive carrier is chitosan oligosaccharide with a molecular weight of ≤5 kDa, a deacetylation degree of ≥90%, and a content range of 85-95 wt%; c) an antimicrobial agent selected from food grade thymol or ε-polylysine, with a content ranging from 2 to 8 wt %; d) Antioxidant, which is tea polyphenols, with a purity of ≥98% and a content range of 1-3wt%; e) a humectant selected from food grade glycerin or trehalose, with a content ranging from 1 to 5 wt %; f) Stabilizer: food grade Tween-80, with a content ranging from 0.5 to 2 wt%.

2. The light-controlled near-infrared response peach preservative coating system according to claim 1, characterized in that: The photothermal conversion material is zinc oxide nanoparticles with a particle size of 20-50 nm.

3. The light-controlled near-infrared response peach preservative coating system according to claim 1 or 2, characterized in that: It also includes a processing technology for photothermal materials, and the processing technology includes: a) Dissolve chitosan oligosaccharide in 1% acetic acid solution, adjust the pH to 4.5 and continue stirring until completely dissolved; b) adding an antibacterial agent, an antioxidant, a humectant and a stabilizer to the chitosan oligosaccharide solution in sequence, and stirring thoroughly after each component is added; c) adding the photothermal conversion material to the mixed solution and dispersing it ultrasonically using an ultrasonic dispersing device; d) placing the mixed solution after ultrasonic dispersion on a magnetic stirrer for stirring; e) After stirring, store the composite coating liquid in a dark, cool place.

4. The light-controlled near-infrared response peach preservation coating system according to claim 3, characterized in that: The frequency of the ultrasonic dispersion equipment is 40 kHz, the power is 200 W, and the ultrasonic dispersion time is 30 minutes.

5. The light-controlled near-infrared response peach preservation coating system according to claim 4, characterized in that: The speed of the magnetic stirring was 500 rpm, the stirring time was 2 hours, and the environment was kept away from light during the stirring process.

6. The light-controlled near-infrared response peach preservation coating system according to any one of claims 1 to 5, characterized in that: Also included is a light-controlled release mechanism, the light-controlled release mechanism comprising: a) Near infrared trigger parameters: wavelength is 808nm, power density is 0.3-0.8W / cm², irradiation mode is pulsed; b) Responsive release logic: Near-infrared light triggers the photothermal conversion material to generate heat, resulting in enhanced movement of the responsive carrier molecular chains and expansion of the coating pores, thereby releasing the antibacterial agent.

7. The light-controlled near-infrared response peach preservation coating system according to claim 6, characterized in that: The light-controlled release mechanism also includes dynamic regulation, that is, when the fruit maturity increases, the fruit stalk or wound is irradiated in a direction by a portable NIR device to increase the release rate of the antibacterial agent.

8. The method for using the light-controlled near-infrared response peach preservation coating system according to claim 7, characterized in that: It includes pretreatment, coating operation, storage and triggering steps, in which: a) The pretreatment step is to wash the peaches with 0.1% sodium hypochlorite and dry them naturally; b) The coating operation step is to evenly cover the surface of the peach with the composite coating liquid by dipping or spraying; c) The storage and triggering step is to place the peaches in a cold storage at 10-12°C and a humidity of 85-90%, and when the respiration intensity of the fruit is detected to be increased, a portable 808nm laser pen is used to illuminate the fruit stalk to activate the release of the antimicrobial agent.