Food freshness indicating film and preparation method thereof
By using the preparation method of microencapsulated color-producing particles in the food freshness indicator film, the problem of rapid freshness detection on the food surface in the prior art is solved, and the effect of excellent color development effect and short color development time is achieved.
Patent Information
- Application Number
- CN202411834894.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-13
- Publication Date
- 2025-02-25
AI Technical Summary
The prior art is difficult to directly conduct rapid freshness detection on the food surface, and the indicator film has poor color rendering effect and has a long color rendering time.
Using the preparation method of microencapsulated color-developing particles, black wolfberry anthocyanins are mixed with disintegrant, polylactic acid solution and bisaldehyde starch, and microencapsulated color-developing particles are obtained by emulsification and spray granulation, and mixed with film forming matrix and plasticizing solution to obtain the indicator film by casting.
The indicator film can be directly placed on the surface of meat for freshness detection, with good color rendering effect, distinguishable by the naked eye, and short color rendering time, and the results can be presented in only about 30 seconds.
Smart Images
Figure CN119505319A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of thin films, and more specifically, to a food freshness indicator film and a preparation method thereof. Background Art
[0003] In the related art, for example, the patent application with publication number CN114034697A discloses a method for preparing anthocyanin-betainin-k-carrageenan freshness indicator film, which includes the following steps: Step 1, extraction of raw materials: extraction of anthocyanin, extraction of betaine, drying for standby use; Step 2, preparation of freshness indicator film: magnetically stirring anthocyanin, betaine and 1.5g k-carrageenan, pouring on a polyethylene tetrafluoroethylene plate, and drying. Although the freshness indicator film obtained by the above method can monitor the freshness and corruption of packaged products, it cannot be directly used for rapid detection on the surface of food. Summary of the invention
[0004] The present application provides a food freshness indicator film and a preparation method thereof. The obtained indicator film can be directly placed on the surface of meat for freshness detection, has a good color development effect, is discernible by the naked eye, and has a short color development time.
[0005] In the first aspect, the food freshness indicator film provided in the present application adopts the following technical solution:
[0006] A method for preparing a food freshness indicator film comprises the following steps:
[0007] Preparation of microencapsulated color-developing particles: adding a disintegrating agent to the black wolfberry anthocyanidin, so that the disintegrating agent fully absorbs the black wolfberry anthocyanidin, and then mixing and emulsifying with a polylactic acid solution to obtain a suspension, and then spraying granulating with dialdehyde starch to obtain microencapsulated color-developing particles; the amounts of raw material components used in the microencapsulated color-developing particles are as follows: 0.1-0.5g of disintegrating agent, 1-6mL of black wolfberry anthocyanidin, 5-10mL of polylactic acid solution, and 0.3-0.6g of dialdehyde starch;
[0008] Preparation of the indicator film: mixing the microencapsulated color-developing particles, the film-forming matrix, the plasticizer and water, stirring evenly to obtain a film liquid, casting the film liquid into a film, and obtaining the indicator film;
[0009] Every 80 mL of water contains 0.8-1.5 g of microencapsulated color-developing particles, 0.8-2 g of film-forming matrix, and 0.2-0.8 g of plasticizer.
[0010] Furthermore, the mass fraction of the polylactic acid solution is 15-25%.
[0011] By adopting the above technical solution, the obtained indicator film can be directly placed on the surface of meat for freshness detection. This not only can detect the freshness of the meat during the sales process so that buyers can determine the quality of the goods, but also is convenient for users to detect at home when they are not sure whether the meat has gone bad, so as to facilitate home use. The indicator film has good color development effect, can be distinguished by the naked eye, and has a short color development time.
[0012] In the preparation process of microencapsulated color-developing particles, a disintegrant is used to fully absorb the black wolfberry anthocyanidin, emulsify it under the action of polylactic acid solution, and spray granulate it with dialdehyde starch, which can not only improve the stability of black wolfberry anthocyanidin in the indicator film and effectively prevent it from denaturing during processing; it can also effectively prevent the black wolfberry anthocyanidin from migrating and dissolving into the environment when the indicator film is not in use, significantly improve the color development effect of the indicator film, and then coordinate the dosage of each component to control the water content of the indicator film, improve the flexibility and storage stability of the indicator film, and thus ensure the color development effect of the indicator film. Moreover, when using the indicator film, the user only needs to rub the indicator film so that the microencapsulation coating wall material of the microencapsulated color-developing particles is destroyed during the rubbing process, and then place the indicator film on the surface of the food to absorb the surface juice. Under the action of the disintegrant, the black wolfberry anthocyanidin in the microencapsulated color-developing particles is quickly and evenly released and color is developed, which greatly shortens the color development time, and the results can be presented in about 30 seconds.
[0013] During the film casting process, the dosage of microencapsulated color-developing particles, film-forming matrix, plasticizer and water is strictly controlled to control the degree of cross-linking between the microencapsulated color-developing particles and the film-forming matrix, so as to obtain an indicator film with a moderate water content. At the same time, the microencapsulated color-developing particles are kept in a relatively stable state in the indicator film, thereby further improving the color development effect.
[0014] Preferably, in the step of preparing microencapsulated color-developing particles, the conditions for mixing and emulsifying with the polylactic acid solution include: mixing using ultrasonic oscillation, stirring at 100-150 r / min at a temperature of 30-45° C., and emulsifying for 20-40 min.
[0015] The above technical solution uses ultrasonic oscillation mixing and emulsification, which is beneficial to the uniform distribution of black wolfberry anthocyanins, thereby helping to obtain a uniformly dispersed suspension, optimize the temperature and stirring rate, and further improve the uniformity of the microencapsulated color-developing particles.
[0016] Preferably, the film-forming matrix is one or more of k-carrageenan, gelatin and xanthan gum.
[0017] As a further preferred embodiment of the film-forming matrix, the film-forming matrix is k-carrageenan.
[0018] By adopting the above technical solution, k-carrageenan is selected as the main film-forming matrix to play the role of gel and thickening, and is combined with the plasticizer to improve the water content of the indicator film to obtain an indicator film with better comprehensive performance.
[0019] Preferably, the plasticizer is glycerol.
[0020] By adopting the above technical solution and using glycerin as a plasticizer, the flexibility of the indicator film can be improved while giving the indicator film a certain water retention performance, thereby assisting in improving the water content of the indicator film and improving the overall quality of the indicator film.
[0021] Preferably, the disintegrant is one of cross-linked polyvinyl pyrrolidone, magnesium aluminum silicate, and sodium carboxymethyl starch.
[0022] Furthermore, magnesium aluminum silicate is selected as a disintegrating agent.
[0023] By adopting the above technical scheme, when the indicator film is rubbed, the microencapsulated coating wall material of the microencapsulated color-developing particles is destroyed. After the indicator film is placed on the surface of the food to absorb the surface juice, under the action of the disintegrator, the black wolfberry anthocyanins in the microencapsulated color-developing particles are quickly and evenly released and colored, which greatly shortens the color development time and helps to improve the color development effect.
[0024] Preferably, in the step of preparing the indicator film, the stirring to obtain the film liquid comprises: stirring by ultrasonication for 30-40 minutes at 40-50°C.
[0025] By adopting the above technical solution, ultrasonic stirring is used to help mix the raw material components evenly, and to optimize the stirring temperature during the formation of the membrane liquid, which helps to reduce the formation of bubbles and obtain an indicator membrane with a uniform texture.
[0026] In a second aspect, the present application provides a food freshness indicator film, which adopts the following technical solution:
[0027] A food freshness indicator film is prepared by the above-mentioned method for preparing the food freshness indicator film.
[0028] In summary, this application has the following beneficial effects:
[0029] 1. In the preparation process of microencapsulated color-developing particles, a disintegrant is used to fully absorb the black wolfberry anthocyanidin, emulsify it under the action of polylactic acid solution, and spray granulate it with dialdehyde starch, which can not only improve the stability of black wolfberry anthocyanidin in the indicator film and effectively prevent it from denaturing during processing; it can also effectively prevent the black wolfberry anthocyanidin from migrating and dissolving into the environment when the indicator film is not in use, significantly improve the color development effect of the indicator film, and then coordinate the dosage of each component to control the water content of the indicator film, improve the flexibility and storage stability of the indicator film, and thus ensure the color development effect of the indicator film. When using the indicator film, the user only needs to rub the indicator film so that the microencapsulation coating wall material of the microencapsulated color-developing particles is destroyed during the rubbing process, and then place the indicator film on the surface of the food to absorb the surface juice. Under the action of the disintegrant, the black wolfberry anthocyanidin in the microencapsulated color-developing particles is quickly and evenly released and color is developed, which greatly shortens the color development time, and the results can be presented in about 30 seconds.
[0030] 2. During the film casting process, the dosage of microencapsulated color-developing particles, film-forming matrix, plasticizer and water is strictly controlled to control the degree of cross-linking between the microencapsulated color-developing particles and the film-forming matrix, and obtain an indicator film with a moderate water content. At the same time, the microencapsulated color-developing particles are kept in a relatively stable state in the indicator film, further improving the color development effect.
[0031] 3. The indicator film obtained in the present application can be directly placed on the surface of meat for freshness detection. This not only can detect the freshness of the meat during the sales process so that buyers can determine the quality of the goods, but also is convenient for users to detect at home when they are not sure whether the meat has gone bad, so as to facilitate home use. The indicator film has good color development effect, can be distinguished by the naked eye, and has a short color development time. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 This is a photo of Example 1 after it was placed directly on the surface of spoiled meat for testing;
[0033] Figure 2 The diagram is a color development diagram of the indicator film of Example 1 in solutions with different pH values. DETAILED DESCRIPTION
[0034] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. The specific conditions not specified in the examples are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially. Among them, k-carrageenan was purchased from Qinghai Laiyiner Biotechnology Co., Ltd.; black wolfberry anthocyanin was purchased from Shaanxi Baicao Xintian Biotechnology Co., Ltd., product number: bc-hqs-0678.
[0035] Example
[0036] Example 1
[0037] A method for preparing a food freshness indicator film comprises the following steps:
[0038] Preparation of microencapsulated color-developing particles: Add 0.2 g of magnesium aluminum silicate, a disintegrating agent, to 3 mL of black wolfberry anthocyanin to allow the disintegrating agent to fully absorb the black wolfberry anthocyanin, and then mix with 8 mL of a polylactic acid solution with a mass fraction of 18% by ultrasonic oscillation, stir at 120 r / min at a temperature of 40°C, emulsify for 30 min to obtain a suspension, and then spray granulate with 0.4 g of dialdehyde starch to obtain microencapsulated color-developing particles;
[0039] Preparation of indicator film: Mix 1 g of microencapsulated color-developing particles, 1 g of k-carrageenan, 0.6 g of glycerol and 80 mL of water, stir ultrasonically for 40 min at 45 °C to obtain a membrane liquid, cast the membrane liquid into a film, and store it at room temperature away from light for 24 h to obtain an indicator film.
[0040] Example 2
[0041] The difference from Example 1 is that the microencapsulated color-developing particles are prepared by adding 0.1 g of magnesium aluminum silicate, a disintegrating agent, to 1 mL of black wolfberry anthocyanidin, so that the disintegrating agent fully absorbs the black wolfberry anthocyanidin, and then mixing with 5 mL of a 25% by mass polylactic acid solution by ultrasonic oscillation, stirring at 100 r / min at a temperature of 45° C., emulsifying for 20 min to obtain a suspension, and then spraying granulating with 0.3 g of dialdehyde starch to obtain microencapsulated color-developing particles;
[0042] The rest are the same as in Example 1.
[0043] Example 3
[0044] The difference from Example 1 is that the microencapsulated color-developing particles are prepared by adding 0.5 g of magnesium aluminum silicate, a disintegrating agent, to 6 mL of black wolfberry anthocyanidin, so that the disintegrating agent fully absorbs the black wolfberry anthocyanidin, and then mixing with 10 mL of a 15% by mass polylactic acid solution by ultrasonic oscillation, stirring at 150 r / min at a temperature of 30° C., emulsifying for 40 min to obtain a suspension, and then spraying granulating with 0.6 g of dialdehyde starch to obtain microencapsulated color-developing particles;
[0045] The rest are the same as in Example 1.
[0046] Example 4
[0047] The difference from Example 1 is that in the step of preparing microencapsulated color-developing particles, the disintegrant is cross-linked polyvinyl pyrrolidone, and the mass fraction of the polylactic acid solution is 10%; the rest is the same as Example 1.
[0048] Example 5
[0049] The difference from Example 1 is that the microencapsulated color-developing particles are prepared as follows: 0.2 g of sodium carboxymethyl starch as a disintegrating agent is added to 3 mL of black wolfberry anthocyanin to allow the disintegrating agent to fully absorb the black wolfberry anthocyanin, and then the mixture is ultrasonically mixed with 6 mL of a 18% polylactic acid solution, stirred at 120 r / min at room temperature, emulsified for 10 min to obtain a suspension, and then spray-granulated with 0.4 g of dialdehyde starch to obtain microencapsulated color-developing particles; the rest is the same as Example 1.
[0050] Example 6
[0051] The difference from Example 1 is that the indicator film is prepared by mixing 1.5 g of microencapsulated color particles, 2 g of gelatin, 0.2 g of glycerol and 80 mL of water, stirring by ultrasonic for 40 min at 40° C. to obtain a film liquid, casting the film liquid into a film, and storing it at room temperature in the dark for 24 h to obtain an indicator film;
[0052] The rest are the same as in Example 1.
[0053] Example 7
[0054] The difference from Example 1 is that the indicator film is prepared by mixing 0.8 g of microencapsulated color particles, 0.8 g of xanthan gum, 0.8 g of glycerol and 80 mL of water, stirring by ultrasonic for 30 min at 50° C. to obtain a film liquid, casting the film liquid into a film, and storing it at room temperature in the dark for 24 h to obtain an indicator film;
[0055] The rest are the same as in Example 1.
[0056] Comparative Example
[0057] Comparative Example 1
[0058] The difference from Example 1 is that the amounts of raw material components used in the microencapsulated color-developing particles are as follows: 0.05 g of disintegrating agent, 2 mL of black wolfberry anthocyanin, 20 mL of polylactic acid solution, and 1.2 g of dialdehyde starch; the rest are the same as in Example 1.
[0059] Comparative Example 2
[0060] The difference from Example 1 is that a color developing solution is used instead of microencapsulated color developing particles, and the steps of preparing the color developing solution include: adding 8 mL of a polylactic acid solution with a mass fraction of 18% to 3 mL of black wolfberry anthocyanin, mixing by ultrasonic oscillation, stirring at 120 r / min at a temperature of 40° C., and emulsifying for 30 minutes to obtain a color developing solution;
[0061] The rest are the same as in Example 1.
[0062] Comparative Example 3
[0063] The difference from Example 1 is that color-developing particles are used instead of microencapsulated color-developing particles, and the preparation steps of the color-developing particles include: adding 0.2 g of magnesium aluminum silicate, a disintegrating agent, to 3 mL of black wolfberry anthocyanin, so that the disintegrating agent fully absorbs the black wolfberry anthocyanin to obtain color-developing particles;
[0064] The rest are the same as in Example 1.
[0065] Comparative Example 4
[0066] The difference from Example 1 is that in the step of preparing the indicator film, 0.3 g of microencapsulated color-developing particles, 0.5 g of chitosan, and 2 g of glycerol are used, and the rest are the same as in Example 1.
[0067] Performance testing
[0068] The thickness and moisture content of the indicator films prepared in Examples 1-7 and Comparative Examples 1-4 were measured. The results are shown in Table 1.
[0069] Thickness measurement method: Use an electronic digital micrometer and adopt a five-point measurement method to measure the thickness of the indicator film: adjust the electronic digital micrometer to zero, take out the indicator film and place it flat on A4 paper, select the center and four test points around it for thickness measurement, and take the average value of the thickness data to get the average thickness.
[0070] Determination of moisture content: Place the indicator film with a mass of C1 (g) in an oven and dry it at 105°C until it reaches a constant weight, at which point the mass of the indicator film is C2 (g). Repeat three times, take the average value, and calculate the moisture content according to formula (1).
[0071]
[0072] The indicator films prepared in Examples 1-7 and Comparative Examples 1-4 were placed on the surface of spoiled pork for detection. From the time of placement on the pork surface to the time when the indicator film showed color, the color development time was recorded and the color development effect was observed. The results are recorded in Table 1. The color development of the indicator film in Example 1 is shown in Table 1. Figure 1 shown.
[0073] Table 1
[0074] Thickness / mm Moisture content / % Color development time / s Color rendering effect Example 1 33.36 40.41 26 Can be quickly identified by naked eyes Example 2 42.85 30.54 32 Can be quickly identified by naked eyes Example 3 53.14 36.19 31 Can be quickly identified by naked eyes Example 4 63.09 38.64 28 Can be quickly identified by naked eyes Example 5 42.47 43.11 33 Can be quickly identified by naked eyes Example 6 39.21 46.94 29 Can be quickly identified by naked eyes Example 7 50.15 42.72 30 Can be quickly identified by naked eyes Comparative Example 1 32.85 24.39 71 The color is slightly lighter and can be distinguished by the naked eye Comparative Example 2 33.09 60.21 96 Light color, can be distinguished by naked eyes Comparative Example 3 33.14 53.03 84 Light color, can be distinguished by naked eyes Comparative Example 4 34.22 57.26 53 The color is slightly lighter and can be distinguished by the naked eye
[0075] Sensitivity verification: The indicator film prepared in Example 1 was placed in solutions with pH 3 (glass bottle No. 1), pH 3.5 (glass bottle No. 2), pH 4 (glass bottle No. 3), pH 4.5 (glass bottle No. 4), and pH 5 (glass bottle No. 5), and the color changes were observed. The results are as follows: Figure 2 shown.
[0076] Through Example 1 and combined Figure 1 and Figure 2 It can be seen that the indicator film obtained in Example 1 can show a color change that can be quickly distinguished by the naked eye in a very short time, and has a good color development effect. It can also show obvious color changes in solutions with slight changes in pH value, and has excellent color development sensitivity.
[0077] Through Examples 1-7 and Table 1, it can be seen that the indicator film obtained by the method of the present application has a thickness controlled between 0.3-0.7 mm and a moisture content controlled between 25%-50%. When placed directly on the surface of meat for freshness detection, the indicator film has a good color development effect, can be quickly identified by the naked eye, and has a color development time of about 30 seconds, which is a short color development time.
[0078] Through Example 1 and Comparative Examples 1-4 and combined with Table 1, it can be seen that the amount relationship of the raw material components used in the microencapsulated color-developing particles in Comparative Example 1 is unbalanced, while in Comparative Example 2, the black wolfberry anthocyanidin is directly treated with the polylactic acid solution, and in Comparative Example 3, only magnesium aluminum silicate is used to adsorb the black wolfberry anthocyanidin, and in Comparative Example 4, chitosan is selected as the film-forming matrix, and the ratio with the microencapsulated color-developing particles and glycerol is unbalanced; even if the thickness of the indicator film of Comparative Examples 1-4 is roughly the same as that of Example 1, the color development time of the obtained indicator film is significantly prolonged, and the color development effect is also significantly reduced. It can be seen that the preparation method and raw material components of the indicator film of the present application complement each other, and only by cooperating with each other can an indicator film with excellent comprehensive performance be obtained.
[0079] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.
Claims
1. A method for preparing a food freshness indicator film, characterized in that: The following steps are involved: Preparation of microencapsulated color-developing particles: adding a disintegrating agent to the black wolfberry anthocyanidin, so that the disintegrating agent fully absorbs the black wolfberry anthocyanidin, and then mixing and emulsifying with a polylactic acid solution to obtain a suspension, and then spraying granulating with dialdehyde starch to obtain microencapsulated color-developing particles; the amounts of raw material components used in the microencapsulated color-developing particles are as follows: 0.1-0.5g of disintegrating agent, 1-6mL of black wolfberry anthocyanidin, 5-10mL of polylactic acid solution, and 0.3-0.6g of dialdehyde starch; Preparation of the indicator film: mixing the microencapsulated color-developing particles, the film-forming matrix, the plasticizer and water, stirring evenly to obtain a film liquid, casting the film liquid into a film, and obtaining the indicator film; Every 80 mL of water contains 0.8-1.5 g of microencapsulated color-developing particles, 0.8-2 g of film-forming matrix, and 0.2-0.8 g of plasticizer.
2. The method for preparing the food freshness indicator film according to claim 1, characterized in that: In the step of preparing microencapsulated color-developing particles, the conditions for mixing and emulsifying with the polylactic acid solution include: mixing with ultrasonic oscillation, stirring at 100-150 r / min at a temperature of 30-45° C., and emulsifying for 20-40 minutes.
3. The method for preparing the food freshness indicator film according to claim 1, characterized in that: The film-forming matrix is one or more of k-carrageenan, gelatin and xanthan gum.
4. The method for preparing the food freshness indicator film according to claim 3, characterized in that: The film-forming matrix is k-carrageenan.
5. The method for preparing the food freshness indicator film according to claim 1, characterized in that: The plasticizer is glycerol.
6. The method for preparing a food freshness indicator film according to claim 1, characterized in that: The disintegrant is one of cross-linked polyvinyl pyrrolidone, magnesium aluminum silicate, and sodium carboxymethyl starch.
7. The method for preparing a food freshness indicator film according to claim 1, characterized in that: In the step of preparing the indicator film, the stirring to obtain the film liquid comprises: stirring by ultrasonic wave for 30-40 minutes at 40-50°C.
8. A food freshness indicator film, characterized in that: The food freshness indicator film is prepared by the method for preparing the food freshness indicator film according to any one of claims 1 to 7.
Citation Information
Patent Citations
Preparation method of anthocyanin-beet element-k-carrageenan freshness indicating film
CN114034697A