Edible preservative film as well as preparation method and application thereof

Abstract

The invention relates to the technical field of food packaging, and particularly discloses an edible preservative film as well as a preparation method and application thereof. The edible preservative film comprises the following raw materials: gelatin, Sanzan gum, hydrogenated starch hydrolysate and boxthorn leaf water extract. The tensile strength of the prepared edible preservative film is 23-27 MPa, the elongation at break is 40%-58%, the water vapor transmission rate is 22-30 g / (m.Pa.s), the transparency is 21-24 A600 / mm, and the edible preservative film has a certain antibacterial effect on escherichia coli and staphylococcus aureus. When the edible preservative film is applied to preservation of sauce braised meat products, organic combination of physical isolation and active antibiosis can be realized, oxidation can be effectively delayed, decay can be inhibited, moisture and texture can be maintained, the shelf life is remarkably prolonged, the safety of the products is improved, and the edible preservative film has important market application value.

Description

Technical Field

[0001] This invention relates to the field of food packaging technology, and in particular to an edible preservation film, its preparation method, and its application. Background Technology

[0002] Food preservation is a crucial step in ensuring food quality, extending shelf life, and reducing food waste. Plastic wrap, a commonly used food preservation material, is widely used in households, the catering industry, and food processing and distribution. Its core function is to form a barrier layer on the surface of food, inhibiting moisture evaporation and isolating oxygen and microorganisms, thereby slowing down the process of food oxidation, spoilage, and decay.

[0003] Most mainstream plastic wraps on the market are made from petroleum-based polymers such as polyethylene (PE), polyvinyl chloride (PVC), and polyvinylidene chloride (PVDC). While these traditional plastic wraps offer good barrier properties and processability, their inherent drawbacks are becoming increasingly apparent: Firstly, petroleum resources are non-renewable, and relying on them to produce plastic wrap does not align with the needs of sustainable resource development; secondly, plastic wrap is difficult to degrade in the natural environment, causing long-term harm to soil, water bodies, and ecosystems. Furthermore, some plastic wraps may pose a risk of chemical additive migration when in contact with oily foods or under high temperatures, posing a potential threat to food safety.

[0004] Edible plastic wrap primarily uses natural edible biomolecules such as polysaccharides, proteins, and lipids. These materials are widely available, renewable, and possess good biocompatibility and biodegradability. After use, they can be digested and absorbed by the human body or rapidly degraded in the natural environment, fundamentally solving the pollution problem caused by plastic packaging. Furthermore, the raw materials of edible plastic wrap are mostly food-grade components, ensuring high safety and allowing direct contact with food surfaces, effectively avoiding the risk of chemical migration. However, existing edible plastic wraps suffer from insufficient mechanical properties and antibacterial activity, unstable barrier properties, and high costs, which are significant limiting factors for their large-scale development.

[0005] Therefore, developing an edible preservation film that is widely available in raw materials, inexpensive, and possesses good mechanical strength, barrier properties, and antibacterial properties is of great practical significance for promoting the green transformation of the food packaging industry, ensuring food safety, and achieving sustainable resource utilization. Summary of the Invention

[0006] To address the problems of insufficient mechanical properties and antibacterial properties, unstable barrier properties, and high costs of traditional edible preservation films, this invention provides an edible preservation film and its preparation method.

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: An edible food preservation film, the raw materials of which include gelatin, triacin, hydrogenated starch hydrolysate and wolfberry leaf aqueous extract; wherein the wolfberry leaf aqueous extract is obtained by microwave-assisted extraction of wolfberry leaves in water.

[0008] Compared to existing technologies, the edible food preservation film provided by this invention uses gelatin and triazine as the core film-forming substrates. These materials are tightly bonded through intermolecular hydrogen bonding and electrostatic interactions, forming a stable and dense gel network that enhances the mechanical strength of the film. Hydrogenated starch hydrolysate, acting as a plasticizer and humectant, allows its molecules to insert between polymer molecular chains, reducing intermolecular forces and thus lowering the film's rigidity. This improves the film's flexibility and extensibility, and effectively maintains stable moisture content within the film, preventing it from becoming brittle and cracking due to water loss during storage or use. Furthermore, the hydrogenated starch hydrolysate further fills the microscopic gaps between the gel network formed by gelatin and triazine, further densifying the film structure and significantly improving its barrier properties.

[0009] The active ingredients in wolfberry leaf extract can exert multiple effects, forming a synergistic effect of preservation and toughening: on the one hand, the polyphenols and flavonoids contained in the extract have good antibacterial activity, which can effectively inhibit the growth of microorganisms on the food surface and significantly extend the food shelf life; on the other hand, the hydroxyl groups of polyphenols can form new hydrogen bonds with the polymer chains of gelatin and triacin, weakening the rigid forces between polymer chains and promoting chain segment sliding. At the same time, the soluble sugars in the extract can enter the gaps between polymer molecular chains, lowering the glass transition temperature of the film, making the film more flexible at room temperature, and ultimately improving the uniformity of the film structure, further enhancing the mechanical properties and elongation at break of the preservation film.

[0010] Through the synergistic effect of the above components, the edible preservation film possesses excellent mechanical strength, flexibility, barrier properties, and antibacterial and preservation performance. Moreover, the raw materials are safe, edible, and widely available, effectively solving many technical bottlenecks of existing edible preservation films and showing broad application prospects.

[0011] Gelatin is a natural polymer material with a protein structure, obtained from the degradation of collagen, which is mainly found in animal skin, muscles, bones, and connective tissue. Sanzan gum is a microbial polysaccharide, an extracellular polysaccharide obtained through metabolism under sufficient oxygen and sterile conditions; its structure consists of sugars, lipids, and polypeptides. Hydrogenated starch hydrolysate mainly consists of sugar alcohols, which play a dual role in plasticizing and moisturizing. Lycium barbarum leaf extract serves as a source of natural active ingredients and is used as a functional additive in this invention, providing antibacterial and toughening effects. All raw materials used in this invention are derived from natural, edible, or biorenewable resources. Through the synergistic intermolecular interactions of the components, a composite film system with good mechanical properties, stable barrier properties, good preservation performance, and complete biodegradability under natural conditions is constructed. This provides an ideal solution to replace traditional plastic food preservation films and is of great significance for promoting the sustainable development of the food packaging industry.

[0012] Furthermore, the edible preservation film comprises the following raw material components at the following concentrations: gelatin 2.5g / L~7.5g / L, triacin 5.0g / L~10.0g / L, hydrogenated starch hydrolysate 10.0g / L~15.0g / L, and wolfberry leaf aqueous extract 15.0mL / L~30.0mL / L.

[0013] Furthermore, the edible preservation film comprises the following raw material components at the following concentrations: gelatin 5.0 g / L, triacin 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L, and wolfberry leaf aqueous extract 20.0 mL / L.

[0014] The optimal concentration of each raw material component creates a synergistic relationship between the mechanical strength, flexibility, barrier properties, and antibacterial and preservation performance of the food preservation film, ultimately achieving an optimized balance of multiple key performance characteristics. This effectively avoids the performance shortcomings of existing edible food preservation films, which are either too strong and brittle, too tough and loose, or unstable in terms of preservation.

[0015] Furthermore, the preparation method of the wolfberry leaf aqueous extract includes the following steps: After crushing the wolfberry leaves, soak them in water, and then microwave extract them at 600W~650W and 20℃~30℃ for 30min~50min. After solid-liquid separation, obtain the wolfberry leaf aqueous extract.

[0016] Furthermore, the mass-to-volume ratio of the wolfberry leaves to water is 1g:(8~12)mL.

[0017] Furthermore, the soaking temperature is 20℃~40℃, and the soaking time is 1h~2h.

[0018] The optimized extraction method can significantly improve the dissolution rate of various active ingredients such as polyphenols and flavonoids, and retain the active ingredients of wolfberry leaves to the greatest extent, thus making it more conducive to exerting its multiple effects such as antibacterial and toughening in plastic wrap.

[0019] Furthermore, the hydrogenated starch hydrolysate comprises the following components in weight percentage: sorbitol 45%~75%, mannitol 3%~5%, maltitol 10%~30%, maltodextrin and above oligosaccharide alcohols 5%~20%.

[0020] Secondly, the present invention also provides a method for preparing the above-mentioned edible preservative film, comprising the following steps: Hydrogenated starch hydrolysate and gelatin are dissolved in water at 40℃~60℃, then trisaccharin is added and mixed evenly. After adding wolfberry leaf extract, the mixture is cooled, cast into a film, dried, and equilibrated to obtain an edible plastic wrap.

[0021] Furthermore, the equilibrium temperature is 20℃~30℃, the relative humidity is 50%~55%, and the equilibrium time is 45h~50h.

[0022] As one possible embodiment of the present invention, the preparation method of the above-mentioned edible preservation film specifically includes the following steps: Hydrogenated starch hydrolysate and gelatin are added to water at 40℃~60℃. After the gelatin is completely dissolved, triglycerides are added and dissolved evenly. Then, wolfberry leaf extract is added and stirred for 30min~40min. The dissolved film solution is cooled to room temperature and cast onto an acrylic plate. The plate is left to stand for 10min~15min. The acrylic plate is then placed in an oven at 40℃~60℃ and dried for 5h~6h. The film is then removed and placed in an environment at 20℃~30℃ and relative humidity of 50%~55% for equilibration for 45h~50h to obtain an edible preservation film.

[0023] Thirdly, the present invention also provides the application of the above-mentioned edible preservation film in the preservation of braised meat products.

[0024] Specifically, the braised meat products include, but are not limited to, braised chicken, braised pork, and braised beef.

[0025] It should be noted that the edible preservation film provided by this invention can be prepared into a solution and formed into a uniform and dense edible protective film on the surface of braised meat products by means of impregnation, spraying or coating; it can also be directly made into a flexible film for skin packaging.

[0026] Tests showed that the edible food preservation film prepared by this invention has a tensile strength of 23-27 MPa, an elongation at break of 40%-58%, a water vapor transmission rate of 22-30 g / (m·Pa·s), and a transparency of 21-24 Å. 600 / mm, exhibiting a certain antibacterial effect against Escherichia coli and Staphylococcus aureus. Applying this edible preservative film to the preservation of braised meat products achieves an organic combination of physical isolation and active antibacterial action. It effectively delays oxidation, inhibits spoilage, and maintains moisture and texture, significantly extending shelf life while improving product safety, thus possessing significant market application value. Attached Figure Description

[0027] Figure 1 A photograph of the edible preservation film prepared in Example 1 of this invention; Figure 2 This is a SEM image of the edible preservation film prepared in Example 1 of the present invention; Figure 3 Fourier transform infrared spectrum of the edible preservation film prepared in Example 1 of this invention; Figure 4 To illustrate the change curve of total bacterial count during the storage period of the edible preservation film prepared in Example 1 of this invention when applied to the packaging of braised chicken; Figure 5 To illustrate the variation curve of total bacterial count during the storage period of the edible preservation film prepared in Example 1 of this invention when applied to the packaging of braised beef; Figure 6 To illustrate the change curve of total bacterial count during the storage period of the edible preservation film prepared in Example 1 of this invention when applied to the packaging of braised pork; Figure 7 To illustrate the pH change curve during the storage period of the edible preservation film prepared in Example 1 of this invention when applied to the packaging of braised chicken; Figure 8 To illustrate the pH change curve during the storage period of the edible preservation film prepared in Example 1 of this invention when applied to the packaging of braised beef; Figure 9 To illustrate the pH change curve during the storage period of the edible preservation film prepared in Example 1 of this invention when applied to the packaging of braised pork; Figure 10 A photograph of the edible plastic wrap prepared for Comparative Example 1; Figure 11 Photograph of the edible plastic wrap prepared for Comparative Example 2; Figure 12 Photograph of the edible plastic wrap prepared for Comparative Example 3; Figure 13 A photograph of the edible plastic wrap prepared for Comparative Example 4; Figure 14 A photograph of the edible plastic wrap prepared for Comparative Example 5; Figure 15 Photograph of the edible plastic wrap prepared for Comparative Example 6; Figure 16A photograph of the edible plastic wrap prepared for Comparative Example 7; Figure 17 Photograph of the edible plastic wrap prepared for Comparative Example 8; Figure 18 A photograph of the edible plastic wrap prepared for Comparative Example 9; Figure 19 A photograph of the edible plastic wrap prepared for Comparative Example 10; Figure 20 Photograph of the edible plastic wrap prepared with 20 mL / L of wolfberry fruit water extract in Comparative Example 11; Figure 21 Photograph of the edible plastic wrap prepared with 15 mL / L of wolfberry fruit water extract in Comparative Example 11; Figure 22 Photograph of the edible plastic wrap prepared with 30 mL / L of wolfberry fruit water extract in Comparative Example 11; Figure 23 Photograph of the edible plastic wrap prepared with 10.0 g / L of Lycium barbarum polysaccharide in Comparative Example 12; Figure 24 Photograph of the edible plastic wrap prepared with 150 g / L of Lycium barbarum polysaccharide in Comparative Example 12; Figure 25 Photograph of the edible plastic wrap prepared in Comparative Example 12 with an addition amount of 300 g / L of Lycium barbarum polysaccharide. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] To better illustrate the present invention, further examples are provided below.

[0030] The hydrogenated starch hydrolysate used in the following examples and comparative examples was purchased from Suzhou Kening Polyol Co., Ltd. The hydrogenated starch hydrolysate comprises the following components in mass percentage: sorbitol 45%~75%, mannitol 3%~5%, maltitol 10%~30%, maltotriol and above oligosaccharide alcohols 5%~20%.

[0031] The wolfberry leaves were purchased from Zhongwei City, Ningxia Hui Autonomous Region.

[0032] Example 1 This invention provides an edible food preservation film comprising the following raw material components at the following concentrations: Gelatin 5.0 g / L, triglyceride 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L and wolfberry leaf aqueous extract 20.0 mL / L.

[0033] The preparation method of wolfberry leaf aqueous extract includes the following steps: Fresh wolfberry leaves are dried outdoors to make dried wolfberry leaves. The dried wolfberry leaves are then crushed to obtain wolfberry leaf powder. Add wolfberry leaf powder to distilled water at a material-to-liquid ratio of 1g:10mL, mix well, and then add to a microwave extractor. Soak at room temperature for 1 hour, set microwave power to 630W, temperature to 25℃, microwave extract for 40 minutes, centrifuge at 3500r / min for 10 minutes, and take the supernatant to obtain wolfberry leaf aqueous extract.

[0034] The preparation method of the above-mentioned edible plastic wrap includes the following steps: Hydrogenated starch hydrolysate and gelatin were added to water at 50°C. After the gelatin was completely dissolved, triglycerides were added and dissolved evenly. Then, wolfberry leaf extract was added and stirred for 30-40 minutes. The dissolved film solution was cooled to room temperature and cast onto an acrylic plate at a rate of 40 mL / plate. The plate was allowed to stand for 10 minutes, and then placed in an oven at 50°C for 5 hours to dry. The film was then removed and placed in an environment at 25°C and 53% relative humidity for 48 hours to equilibrate, thus obtaining an edible preservation film.

[0035] The photographs and SEM images of the edible preservative film prepared in this embodiment are shown below. Figures 1-2 As shown in the figure, its shape and appearance are flat and smooth, its color is relatively transparent, and it is free of foreign objects and damage.

[0036] The Fourier transform infrared spectrum of the edible preservation film prepared in this embodiment is as follows: Figure 3 As shown in the figure, compared with the edible plastic wrap without the addition of wolfberry leaf extract, the edible plastic wrap prepared in this embodiment originally located at 1592.5 cm -1 The characteristic absorption peak is significantly blue-shifted to 1641.4 cm⁻¹. -1 The study confirmed that the polar groups (such as hydroxyl and carboxyl groups) in the active components of the wolfberry leaf aqueous extract formed a strong hydrogen bond network with the ether or hydroxyl groups of the matrix material, which may be the reason for the significant increase in elongation at break after the addition of wolfberry leaf aqueous extract.

[0037] Example 2 This invention provides an edible food preservation film comprising the following raw material components at the following concentrations: Gelatin 2.5 g / L, Triamcinolone acetonide 10.0 g / L, hydrogenated starch hydrolysate 15.0 g / L and Lycium barbarum leaf aqueous extract 15.0 mL / L.

[0038] The preparation method of wolfberry leaf aqueous extract includes the following steps: Fresh wolfberry leaves are dried outdoors to make dried wolfberry leaves. The dried wolfberry leaves are then crushed to obtain wolfberry leaf powder. Add wolfberry leaf powder to distilled water at a material-to-liquid ratio of 1g:8mL, mix well, and then add to a microwave extractor. Soak at room temperature for 2 hours, set microwave power to 600W, temperature to 30℃, microwave extract for 50 minutes, centrifuge at 3500r / min for 10 minutes, and take the supernatant to obtain wolfberry leaf aqueous extract.

[0039] The preparation method of the above-mentioned edible plastic wrap includes the following steps: Hydrogenated starch hydrolysate and gelatin were added to water at 40°C. After the gelatin was completely dissolved, triglycerides were added and dissolved evenly. Then, wolfberry leaf extract was added and stirred for 30-40 minutes. The dissolved film solution was cooled to room temperature and cast onto an acrylic plate at a rate of 40 mL / plate. The plate was allowed to stand for 10 minutes, and then placed in an oven at 40°C for 6 hours to dry. The film was then removed and placed in an environment at 20°C and 50% relative humidity for 50 hours to equilibrate, thus obtaining an edible preservation film.

[0040] Example 3 This invention provides an edible food preservation film comprising the following raw material components at the following concentrations: Gelatin 7.5 g / L, triglyceride 5.0 g / L, hydrogenated starch hydrolysate 10.0 g / L and wolfberry leaf aqueous extract 30.0 mL / L.

[0041] The preparation method of wolfberry leaf aqueous extract includes the following steps: Fresh wolfberry leaves are dried outdoors to make dried wolfberry leaves. The dried wolfberry leaves are then crushed to obtain wolfberry leaf powder. Add wolfberry leaf powder to distilled water at a material-to-liquid ratio of 1g:12mL, mix well, and then add to a microwave extractor. Soak at room temperature for 1 hour, set microwave power to 650W, temperature to 20℃, microwave extract for 30 minutes, centrifuge at 3500r / min for 10 minutes, and take the supernatant to obtain wolfberry leaf aqueous extract.

[0042] The preparation method of the above-mentioned edible plastic wrap includes the following steps: Hydrogenated starch hydrolysate and gelatin were added to water at 60°C. After the gelatin was completely dissolved, triglycerides were added and dissolved evenly. Then, wolfberry leaf extract was added and stirred for 30-40 minutes. The dissolved film solution was cooled to room temperature and cast onto an acrylic plate at a rate of 40 mL / plate. The plate was allowed to stand for 15 minutes, and then placed in an oven at 60°C for 5 hours to dry. The film was then removed and placed in an environment at 30°C and 55% relative humidity for 45 hours to equilibrate, thus obtaining an edible preservation film.

[0043] Performance testing 1. Mechanical property testing Film thickness test: According to the national standard GB / T 6672-2001 Determination of film thickness, use a digital micrometer to randomly select 5 points on the film and accurately measure the film thickness, and take the average value.

[0044] Tensile strength and elongation at break tests: The tensile strength and elongation at break of the cling film were measured using a tensile testing machine. Following the guidelines of GB / T 1.40.3-2006 "Tension Testing of Films and Sheets", long strip samples were taken, and the testing speed was 25 mm / min. Three samples were taken for each measurement, and the result was the average of the three samples. Tensile strength is expressed in MPa, and elongation at break is expressed as %.

[0045] Water vapor transmission rate (WVP) test: Add 20 g of anhydrous calcium chloride powder to a test cup, ensuring the distance between the powder and the edge of the cup is less than 5 mm. Place the cup in a constant temperature chamber at 25 ℃ and 75% relative humidity, maintaining a known water vapor pressure difference between the inside and outside of the membrane. Remove the cup and weigh it every 12 hours. Each measurement is repeated three times. WVP is calculated using the following formula:

[0046] In the formula: m is the mass of water permeating the membrane (g), and A is the permeation area (m²). 2 L is the membrane thickness (mm), t is the permeation time (s), and ΔP is the pressure difference across the membrane (Pa).

[0047] Transparency (Op) test: Cut the balanced antibacterial plastic wrap into strips of 30 mm × 10 mm and attach them to the surface of a cuvette. Measure the absorbance at 600 nm, using an empty cuvette as a blank control. The opacity (Op) of the film is calculated using the following formula:

[0048] In the formula: A 600 X represents the absorbance of the sample at 600 nm; X represents the film thickness (mm).

[0049] The test results are shown in Table 1.

[0050] Table 1

[0051] 2. Application Research in Braised Meat Products 2.1 Changes in total bacterial count The edible preservative film prepared in Example 1 was used in the packaging of braised chicken, braised pork, and braised beef, respectively. After packaging, the products were stored at 4°C. A blank control group without any packaging treatment and a commercially available group (PE preservative film) were also included. The product's manufacturing date was defined as day 0. At days 0, 2, 4, 6, and 8, 10 g of meat samples were taken, minced, and mixed with 90 mL of physiological saline. The mixture was homogenized using a beater for 1 min, and the supernatant was discarded after standing. The total bacterial count was determined according to GB4789.2-2016 "Determination of Total Bacterial Count". The pH value was determined according to GB5009.237-2016 "Determination of pH in Food". Each sample was measured three times, and the average value was taken. The results are as follows: Figures 4-6 As shown.

[0052] Figures 4-6 The graphs show the changes in total bacterial count during the 8-day storage period for braised chicken, braised beef, and braised pork. Overall, the total bacterial count showed an increasing trend with sampling time (except for the braised beef group packaged with the preservation film prepared in Example 1 of this invention). The total bacterial count in the unpackaged blank control group was significantly higher than the other two groups, demonstrating that the packaging material has a certain inhibitory effect on the proliferation of microorganisms in braised chicken, braised beef, and braised pork. Furthermore, the preservation film prepared in Example 1 of this invention showed better antibacterial activity than commercially available PE preservation film, reducing the total bacterial count of braised chicken, braised beef, and braised pork by 3.0 log(CFU / g), 4.5 log(CFU / g), and 3.3 log(CFU / g), respectively, during the 8-day storage period. Specifically, when the preservation film prepared in Example 1 of this invention was used in the packaging of braised beef, the total bacterial count showed a trend of first increasing and then decreasing during the storage period, possibly due to the slow-release bactericidal effect of the main components in the preservation film.

[0053] 2.2 pH Changes The pH changes of the braised meat during the above-mentioned storage process are shown in the following figures. Figures 7-9 As shown in the figure, the pH changes under different packaging conditions all exhibit a trend of first decreasing and then increasing. It is speculated that the initial pH decrease is likely due to the fermentation of carbohydrates by microorganisms such as lactic acid bacteria during the early stages of storage, producing organic acids such as lactic acid, leading to a decrease in pH; and the decomposition of proteins and fats by endogenous enzymes in meat products (such as proteases and lipases), generating acidic substances that further lower the pH. In the later stages of storage, the microbial community changes, with acid-tolerant bacteria (such as Pseudomonas and Bacillus) proliferating, decomposing organic acids and producing alkaline metabolites, causing the pH to rise again. Furthermore, with prolonged storage, proteins further degrade, generating alkaline substances (such as ammonia and amines), leading to an increase in pH.

[0054] Take braised chicken as an example ( Figure 7The lowest pH values ​​for the unpackaged blank group and the commercially available PE plastic wrap-wrapped group were on day 4 and day 2, respectively. This means that significant rancidity occurred in the unpackaged blank group on day 4, while the use of PE plastic wrap accelerated the rancidity process. In contrast, the pH change of the braised chicken using the edible plastic wrap obtained in Example 1 of this invention was slower, reaching a pH level similar to that of the blank group on day 4 and the commercially available plastic wrap group on day 2 only on day 8 of the storage period, significantly delaying the spoilage of the braised chicken. Braised beef ( Figure 8 ) and braised pork ( Figure 9 Similar results were obtained in ( ).

[0055] Comparative Example 1 This comparative example provides an edible preservation film, which differs from Example 1 only in that the hydrogenated starch hydrolysate is replaced with an equal amount of glycerol, and the wolfberry leaf extract is not added. The specific formula is as follows: Gelatin 5.0g / L, Triamcinolone 7.5g / L, Glycerin 12.5g / L.

[0056] Edible plastic wrap was prepared using the same method as in Example 1, and will not be described again here.

[0057] The prepared cling film has a smooth, bubble-free surface and can be peeled off completely; however, it is quite sticky and easily breaks. A picture of the prepared cling film is shown below. Figure 10 As shown.

[0058] Comparative Example 2 This comparative example provides an edible food preservation film, which differs from Example 1 only in that the triazine gum is replaced with an equal amount of xanthan gum, and no wolfberry leaf extract is added. The specific formula is as follows: Gelatin 5.0 g / L, xanthan gum 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L.

[0059] Edible plastic wrap was prepared using the same method as in Example 1, and will not be described again here.

[0060] During the preparation process, numerous air bubbles were observed on the acrylic sheet, making it difficult to peel off the complete film. Figure 11 As shown.

[0061] Comparative Example 3 This comparative example provides an edible food preservation film, which differs from Example 1 only in that the triazine gum is replaced with an equal amount of xanthan gum. The specific formula is as follows: Gelatin 5.0 g / L, xanthan gum 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L, wolfberry leaf aqueous extract 20.0 mL / L.

[0062] The preparation method of the aqueous extract of wolfberry leaves is exactly the same as that in Example 1, and will not be repeated here.

[0063] An edible preservation film was prepared using the same method as in Example 1.

[0064] During the preparation process, numerous air bubbles can be observed on the acrylic plate, preventing film formation. Figure 12 As shown.

[0065] Comparative Example 4 This comparative example provides an edible food preservation film, which differs from Example 1 only in that the tristan gum is replaced with an equal amount of gellan gum, and the wolfberry leaf extract is not added. The specific formula is as follows: Gelatin 5.0 g / L, gellan gum 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L.

[0066] Edible plastic wrap was prepared using the same method as in Example 1, and will not be described again here.

[0067] During the preparation process, numerous air bubbles can be observed on the acrylic plate, preventing film formation. Figure 13 As shown.

[0068] Comparative Example 5 This comparative example provides an edible food preservation film, which differs from Example 1 only in that the triazine gum is replaced with an equal amount of gellan gum. The specific formula is as follows: Gelatin 5.0 g / L, gellan gum 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L, wolfberry leaf aqueous extract 20.0 mL / L.

[0069] The preparation method of the aqueous extract of wolfberry leaves is exactly the same as that in Example 1, and will not be repeated here.

[0070] An edible preservation film was prepared using the same method as in Example 1.

[0071] During the preparation process, numerous air bubbles can be observed on the acrylic plate, preventing film formation. Figure 14 As shown.

[0072] Comparative Example 6 This comparative example provides an edible food preservation film, which differs from Example 1 only in that the trisaccharin is replaced with an equal amount of carrageenan, and the wolfberry leaf extract is not added. The specific formula is as follows: Gelatin 5.0 g / L, carrageenan 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L.

[0073] Edible plastic wrap was prepared using the same method as in Example 1, and will not be described again here.

[0074] The prepared plastic wrap contains a small number of air bubbles, is easily broken, and has high stickiness. Figure 15 As shown.

[0075] Comparative Example 7 This comparative example provides an edible food preservation film, which differs from Example 1 only in that the triazine gum is replaced with an equal amount of carrageenan. The specific formula is as follows: Gelatin 5.0 g / L, carrageenan 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L, wolfberry leaf aqueous extract 20.0 mL / L.

[0076] The preparation method of the aqueous extract of wolfberry leaves is exactly the same as that in Example 1, and will not be repeated here.

[0077] An edible preservation film was prepared using the same method as in Example 1.

[0078] During the preparation process, numerous air bubbles can be observed on the acrylic plate, preventing film formation. Figure 16 As shown.

[0079] Comparative Example 8 This comparative example provides an edible food preservation film, which differs from Example 1 only in that the trisaccharin is replaced with an equal amount of pectin, and no wolfberry leaf extract is added. The specific formula is as follows: Gelatin 5.0 g / L, pectin 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L.

[0080] Edible plastic wrap was prepared using the same method as in Example 1, and will not be described again here.

[0081] During the preparation process, numerous air bubbles can be observed on the acrylic plate, preventing film formation. Figure 17 As shown.

[0082] Comparative Example 9 This comparative example provides an edible preservation film, which differs from Example 1 only in that it does not contain wolfberry leaf extract. The specific formula is as follows: Gelatin 5.0 g / L, Triamcinolone 7.5 g / L, Hydrogenated Starch Hydrolysate 12.5 g / L.

[0083] Edible plastic wrap was prepared using the same method as in Example 1, and will not be described again here.

[0084] The resulting plastic wrap can form a complete film, such as Figure 18 As shown, its elongation at break is only 31.24%, which is significantly lower than that of the embodiments of the present invention.

[0085] Comparative Example 10 This comparative example provides an edible preservation film, which differs from Example 1 only in that the preparation method of the wolfberry leaf extract is replaced by a conventional decoction method. The specific preparation method is as follows: Fresh wolfberry leaves are dried outdoors to make dried wolfberry leaves. The dried wolfberry leaves are then crushed to obtain wolfberry leaf powder. Add wolfberry leaf powder to distilled water at a material-to-liquid ratio of 1g:12mL, soak at room temperature for 1 hour, then place in a water bath, heat to boiling, and reflux for 30 minutes while maintaining a gentle boil. After extraction, allow to cool naturally to room temperature, centrifuge at 3500r / min for 10 minutes, and collect the supernatant to obtain wolfberry leaf aqueous extract.

[0086] The resulting plastic wrap can form a complete film, such as Figure 19 As shown, its elongation at break is only 22.2%, which is far lower than that of the embodiments of the present invention.

[0087] Comparative Example 11 This comparative example provides an edible preservation film, which differs from Example 1 only in that the wolfberry leaf extract is replaced with an equal amount of wolfberry fruit extract. The preparation method of the wolfberry fruit extract is as follows: Add the wolfberry fruit powder to distilled water at a material-to-liquid ratio of 1g:10mL, mix well, and then add to a microwave extractor. Soak at room temperature for 1 hour, set the microwave power to 630W, the temperature to 25℃, microwave extract for 40 minutes, centrifuge at 3500r / min for 10 minutes, and take the supernatant to obtain the wolfberry fruit water extract.

[0088] The resulting plastic wrap can form a complete film, such as Figure 20 As shown, its elongation at break is only 37.7%, which is significantly lower than that of the embodiments of the present invention.

[0089] The amount of wolfberry fruit water extract added was changed to 15 mL / L. Figure 21 ) and 30mL / L ( Figure 22 The resulting plastic wrap had an elongation at break of 34.2% and 30.3%.

[0090] Comparative Example 12 This comparative example provides an edible preservation film, which differs from Example 1 only in that the wolfberry leaf water extract is replaced with wolfberry polysaccharide. The specific formula is as follows: Gelatin 5.0 g / L, Triamcinolone 7.5 g / L, Hydrogenated Starch Hydrolysate 12.5 g / L, Lycium barbarum Polysaccharide 10.0 g / L.

[0091] An edible preservation film was prepared using the same method as in Example 1.

[0092] The resulting plastic wrap can form a complete film, such as Figure 23 As shown, the elongation at break reaches 50.1%, but its film color is too dark and its light transmittance is poor, indicating that it cannot maintain good mechanical properties while also achieving excellent appearance.

[0093] Replace the above-mentioned amount of Lycium barbarum polysaccharide with 150g / L, such as Figure 24 As shown, the acrylic sheet has many cracks, forms a film but lacks toughness, and is easily broken when touched.

[0094] Replace the above-mentioned dosage of Lycium barbarum polysaccharides with 300g / L, such as... Figure 25 As shown, the acrylic sheet film has cracks on its surface and cannot be peeled off.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An edible food preservation film, characterized in that, Its raw materials include gelatin, triacin, hydrogenated starch hydrolysate and wolfberry leaf water extract; the wolfberry leaf water extract is obtained by microwave-assisted extraction of wolfberry leaves in water.

2. The edible preservation film as described in claim 1, characterized in that, The raw material components include the following concentrations: gelatin 2.5 g / L~7.5 g / L, triacin 5.0 g / L~10.0 g / L, hydrogenated starch hydrolysate 10.0 g / L~15.0 g / L, and wolfberry leaf aqueous extract 15.0 mL / L~30.0 mL / L.

3. The edible preservation film as described in claim 2, characterized in that, The raw material components include the following concentrations: gelatin 5.0 g / L, trisaccharin 7.5 g / L, hydrogenated starch hydrolysate 12.5 g / L, and wolfberry leaf aqueous extract 20.0 mL / L.

4. The edible preservation film as described in claim 1, characterized in that, The preparation method of the wolfberry leaf aqueous extract includes the following steps: After crushing the wolfberry leaves, soak them in water, and then microwave extract them at 600W~650W and 20℃~30℃ for 30min~50min. After solid-liquid separation, obtain the wolfberry leaf aqueous extract.

5. The edible preservation film as described in claim 4, characterized in that, The mass-to-volume ratio of wolfberry leaves to water is 1g:(8~12)mL.

6. The edible preservation film as described in claim 4, characterized in that, The soaking temperature is 20℃~40℃, and the soaking time is 1h~2h.

7. The edible preservation film as described in claim 1, characterized in that, The hydrogenated starch hydrolysate comprises the following components in weight percentage: sorbitol 45%~75%, mannitol 3%~5%, maltitol 10%~30%, maltodextrin and above oligosaccharide alcohols 5%~20%.

8. The method for preparing the edible food preservation film according to any one of claims 1 to 7, characterized in that, Includes the following steps: Hydrogenated starch hydrolysate and gelatin are dissolved in water at 40℃~60℃, then trisaccharin is added and mixed evenly. After adding wolfberry leaf extract, the mixture is cooled, cast into a film, dried, and equilibrated to obtain an edible plastic wrap.

9. The method for preparing the edible preservation film as described in claim 8, characterized in that, The equilibrium temperature is 20℃~30℃, the relative humidity is 50%~55%, and the equilibrium time is 45h~50h.

10. The application of the edible preservation film according to any one of claims 1 to 7 in the preservation of braised meat products.

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