A composite fresh-keeping film containing ethyl maltol and preparation method thereof

Abstract

This invention relates to the field of edible fungus preservation research, specifically to a composite preservation film containing ethyl maltol and its preparation method. The purpose of this invention is to produce a traditional Chinese medicine composite preservation film containing ethyl maltol with CMC-Na as a carrier. This composite preservation film, due to the presence of ethyl maltol, which significantly inhibits mold growth, combined with the antibacterial effect of *Trametes versicolor* polysaccharide, provides significant mold prevention while preserving freshness. The traditional Chinese medicine composite preservation film obtained by this invention is uniform, aesthetically pleasing, and breathable, with a thickness of only 0.1-0.2 mm. Using it to preserve *Pleurotus ostreatus* at room temperature extends the preservation time to more than 9 days. It is simple and convenient, with no direct contact between chemical reagents or other liquids and the surface of the edible fungus, and it can be reused.

Description

Technical Field

[0001] This invention relates to the field of edible fungi preservation application research, specifically to a composite preservation film containing ethyl maltol and its preparation method. Background Technology

[0002] Ethyl maltol, chemically named 3-hydroxy-2-ethyl-4-pyrrolidone, has a relative molecular mass of 140.11. It is a white crystalline powder with a melting point of 89-93℃, readily soluble in hot water, and is a commonly used and safe additive for enhancing the flavor of food. GB2760-2014 National Food Safety Standard – Standard for the Use of Food Additives, Appendix B.2.3, lists ethyl maltol as a permitted synthetic flavoring agent for food (FEMA No.: 3487). The US Food Standards stipulate that the limit for ethyl maltol as a food flavoring agent is 100 mg / L (BATF-27 CFR §240.1051). Yunzhi polysaccharides, extracted from the traditional Chinese medicine Yunzhi, possess certain antibacterial activity and a broad antibacterial spectrum. This invention further explores new applications of ethyl maltol, a safe and traditional food flavoring agent, for antibacterial, antiseptic, and preservation purposes. It combines ethyl maltol with Coriolus versicolor polysaccharide to prepare a traditional Chinese medicine composite preservation film with sodium carboxymethyl cellulose (CMC-Na) as the carrier, which is then applied to the preservation of edible fungi. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0004] A method for preparing a composite food preservation film containing ethyl maltol includes the following steps:

[0005] (1) Weigh 2-3g of CMC-Na powder into a beaker, add an appropriate amount of distilled water (1g:100mL), and stir with a stirrer in a constant temperature water bath at 55-65℃ for 30-40min until CMC-Na is completely dissolved.

[0006] (2) Weigh 4-6g of Ganoderma lucidum (Yunzhi) medicinal material, crush it into coarse powder and place it in an Erlenmeyer flask. Add water (the mass-volume ratio of Yunzhi powder to water is 1g:24mL), and heat under reflux for 1 hour. Repeat the operation once, extracting twice in total. Collect the extract and concentrate it in a water bath to obtain 8-12mL of concentrated solution. The drug-to-liquid ratio is 1:2 (g:mL). Add the concentrated solution to the above solution and stir evenly in a constant temperature water bath at 55-65℃.

[0007] (3) Accurately weigh 0.009-0.011 g of ethyl maltol, dissolve it in 5 mL of double-distilled water at room temperature (not lower than 25℃), stir and dissolve thoroughly, and add the above mixture.

[0008] (4) Finally, add 0.1% zinc sulfate, mix well, and let the mixture stand for 12 hours to remove bubbles before use.

[0009] (5) Use a pipette to draw 55-65mL of the above medicine solution and pour it onto a clean glass plate (35cm*35cm). Spread it evenly and let it air dry horizontally until it is half dry. Dry it in an oven at 30-40℃ for about 10-12 hours. Carefully peel off the composite film and seal it in a plastic bag.

[0010] The beneficial effects of this invention are:

[0011] This invention discloses a composite preservation film for traditional Chinese medicine containing ethyl maltol with CMC-Na as a carrier. Due to the presence of ethyl maltol, which significantly inhibits mold growth, and the antibacterial effect of *Trametes versicolor* polysaccharide, this composite preservation film provides significant mold prevention while preserving freshness. The resulting composite preservation film is uniform, aesthetically pleasing, and breathable, with a thickness of only 0.1-0.2 mm. Using it to preserve *Pleurotus ostreatus* at room temperature extends the shelf life to over 9 days. It is simple and convenient, with no direct contact between chemical reagents or other liquids and the surface of the edible fungus, and it is reusable. Attached Figure Description

[0012] Figure 1 The bacterial colony count for each treatment group is shown below (from left to right: A - treatment group, B - PE preservation group, C - composite preservation film group; bacterial suspension concentration is 10). -5 ). Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0014] The purpose of this invention is to produce a composite preservation film for traditional Chinese medicine containing ethyl maltol with CMC-Na as a carrier. This composite preservation film, due to the presence of ethyl maltol, which significantly inhibits mold growth, combined with the antibacterial effect of *Trametes versicolor* polysaccharide, provides significant mold prevention while preserving freshness. The composite preservation film obtained by this invention is uniform, aesthetically pleasing, and breathable, with a thickness of only 0.1-0.2 mm. Using it to preserve *Pleurotus ostreatus* at room temperature extends the shelf life to over 9 days. It is simple and convenient, with no direct contact between chemical reagents or other liquids and the surface of the edible fungus, and it is reusable.

[0015] Example 1: Preparation method of traditional Chinese medicine preservation film

[0016] 1. Weigh 2g of CMC-Na powder into a beaker, add an appropriate amount of distilled water (1g:100mL), and stir with a stirrer in a 55℃ constant temperature water bath for 30min until CMC-Na is completely dissolved.

[0017] 2. Weigh 4g of Ganoderma lucidum (Yunzhi) medicinal material, crush it into coarse powder, place it in an Erlenmeyer flask, add water and reflux to extract Ganoderma lucidum polysaccharides. After extraction twice, collect the extract and concentrate it in a water bath, finally obtaining 8mL of concentrated solution with a drug-to-liquid ratio of 1:2 (g:mL). Add the concentrated solution to the above solution and stir evenly in a 55℃ constant temperature water bath.

[0018] 3. Accurately weigh 0.009 g of ethyl maltol, dissolve it in 5 mL of double-distilled water at room temperature (not lower than 25℃), stir and dissolve thoroughly, and add it to the above mixture.

[0019] 4. Finally, add 0.1% zinc sulfate, mix well, and let the mixture stand for 12 hours to remove bubbles before use.

[0020] 5. Use a pipette to draw 55mL of the above-mentioned liquid and pour it onto a clean glass plate (35cm*35cm). Spread it evenly and let it air dry horizontally until it is semi-dry. Dry it in an oven at 30℃ for about 10 hours. Carefully peel off the composite film and seal it in a plastic bag.

[0021] Example 2: Preparation method of traditional Chinese medicine preservation film

[0022] 1. Weigh 2.5g of CMC-Na powder into a beaker, add an appropriate amount of distilled water (1g:100mL), and stir with a stirrer in a 60℃ constant temperature water bath for 36min until CMC-Na is completely dissolved.

[0023] 2. Weigh 5g of Ganoderma lucidum (Yunzhi) medicinal material, crush it into coarse powder, place it in an Erlenmeyer flask, add water and reflux to extract Ganoderma lucidum polysaccharides. After extraction twice, collect the extract and concentrate it in a water bath, finally obtaining 10mL of concentrated solution with a drug-to-liquid ratio of 1:2 (g:mL). Add the concentrated solution to the above solution and stir evenly in a 61℃ constant temperature water bath.

[0024] 3. Accurately weigh 0.010 g of ethyl maltol, dissolve it in 5 mL of double-distilled water at room temperature (not lower than 25℃), stir and dissolve thoroughly, and add it to the above mixture.

[0025] 4. Finally, add 0.1% zinc sulfate, mix well, and let the mixture stand for 12 hours to remove bubbles before use.

[0026] 5. Use a pipette to draw 50mL of the above-mentioned liquid and pour it onto a clean glass plate (35cm*35cm). Spread it evenly and let it air dry horizontally until it is semi-dry. Dry it in an oven at 35℃ for about 11 hours. Carefully peel off the composite film and seal it in a plastic bag.

[0027] Example 3: Preparation method of traditional Chinese medicine preservation film

[0028] 1. Weigh 3g of CMC-Na powder into a beaker, add an appropriate amount of distilled water (1g:100mL), and stir with a stirrer in a 65℃ constant temperature water bath for 40min until CMC-Na is completely dissolved.

[0029] 2. Weigh 6g of *Trametes versicolor* (Yunzhi) medicinal material, crush it into coarse powder, place it in an Erlenmeyer flask, add water, and reflux to extract *Trametes versicolor* polysaccharides. After extraction twice, collect the extract and concentrate it in a water bath, finally obtaining 12mL of concentrated solution with a drug-to-liquid ratio of 1:2 (g:mL). Add the concentrated solution to the above solution and stir evenly in a 65℃ constant temperature water bath.

[0030] 3. Accurately weigh 0.011g of ethyl maltol, dissolve it in 5mL of double-distilled water at room temperature (not lower than 25℃), stir and dissolve thoroughly, and add it to the above mixture.

[0031] 4. Finally, add 0.1% zinc sulfate, mix well, and let the mixture stand for 12 hours to remove bubbles before use.

[0032] 5. Use a pipette to draw 65mL of the above-mentioned liquid and pour it onto a clean glass plate (35cm*35cm). Spread it evenly and let it air dry horizontally until it is semi-dry. Dry it in an oven at 40℃ for about 12 hours. Carefully peel off the composite film and seal it in a plastic bag.

[0033] Application examples

[0034] Sixty fresh, uniformly sized *Pleurotus ostreatus* fruiting bodies were collected and divided into three groups: untreated group (Group A), PE preservation film control group (Group B), and composite preservation film group (Group C, prepared in Example 1). The fruiting bodies were wrapped and stored at room temperature. Physiological indicators of each group were measured after 5 days, with three replicates for each measurement.

[0035] 1. Mass loss rate: determined by weighing method;

[0036] 2. Hardness of the fruiting body: measured using two different hardness testers;

[0037] 3. Soluble solids content: determined using a handheld refractometer;

[0038] 4. Respiratory intensity: Measured using the static method;

[0039] 5. Malondialdehyde (MDA) content: determined by the thiobarbituric acid (TBA) method;

[0040] 6. Polyphenol oxidase (PPO) activity: determined by the catechol method.

[0041] 7. Decay Index: The degree of decay of the fruiting body is divided into 5 levels. Level 0: No decay; Level 1: 1-3 small rotten spots appear; Level 2: Decayed area is between 1 / 4 and 1 / 2; Level 3: Decayed area is between 1 / 2 and 3 / 4; Level 4: Decayed area > 3 / 4. The decay index is calculated using the following formula: Decay Index = [∑(Level × Number of corresponding decayed fruiting bodies)] / Total number of fruiting bodies in the group.

[0042] 8. Evaluation of Anti-mold and Antibacterial Properties: After 5 days of storage, use a sterile cotton swab to brush the surface of the fruiting body, covering approximately 5 points. Then, immerse the sample in a test tube containing 9 mL of sterile water and vortex to disperse the sample evenly. Next, transfer 1 mL of the above liquid into a test tube containing 9 mL of sterile water, and mix thoroughly by pipetting. Repeat this process to prepare 10 samples. -1 10 -2 10 -3 10 -4 and 10 -5 Five test tubes containing bacterial suspensions of various concentrations. Take the above 10... -1 10 -3 10 -5 In each of the three concentration test tubes, 50 μL of the inoculum was spread to prepare plates, with three replicates for each concentration. The plates were incubated upside down at 25°C for 48 hours.

[0043] The results showed that compared with group A, the fruiting body weight loss rate in group C was significantly reduced to approximately -0.69% (P<0.05), while there was no significant difference between groups B and C (P>0.05), indicating that both treatments B and C effectively maintained the fruit's water content. After treatment, group C showed the best fruiting body firmness, reaching 1.9 kg / cm². 2 Objectively, this slowed down the fruit's decay process, and the firmness of the fruit after treatments A and B was 0.8 kg / cm². 2 and 1.5kg / cm 2 In terms of soluble solids content and respiration intensity, treatment C effectively inhibited respiration, slowed the decrease in soluble solids mass fraction, and significantly suppressed respiration in *Pleurotus ostreatus* fruiting bodies. The MDA content in group C fruiting bodies was the lowest (0.850 μmol / L), compared to 1.376 μmol / L in groups A and 1.109 μmol / L in groups B. Furthermore, group C also exhibited the lowest PPO activity, with the specific activity order being: A (88.130 U / g) > B (63.084 U / g) > C (54.721 U / g), indicating that treatment C effectively inhibited polyphenol oxidase activity, thereby delaying browning. Regarding the decay index, compared to 0.932 in group A and 0.586 in group B, the decay index in group C fruiting bodies was also the lowest (0.283), demonstrating that treatment C effectively controlled the decay of edible fungi fruiting bodies.

[0044] From the results of anti-mold and antibacterial treatment ( Figure 1From the results, the number of colonies in group C was significantly less than that in groups A and B, and there was a significant difference between group C and groups A and B (P<0.05), indicating that this composite preservation film can significantly inhibit the growth of microorganisms, especially molds.

Claims

1. A composite food preservation film containing ethyl maltol, characterized in that, The method for preparing the composite food preservation film includes the following steps: (1) Mix sodium carboxymethyl starch powder with water and stir to obtain a CMC-Na solution; the mass-volume ratio of CMC-Na powder to water is 1g:100mL. (2) Preparation of concentrated Yunzhi polysaccharide solution: Yunzhi medicinal material is crushed into coarse powder and placed in a conical flask. Water is added and the mixture is heated under reflux for 1 hour. The ratio of Yunzhi medicinal material to water is 1g:2mL. The operation is repeated once. After the medicinal material is concentrated, Yunzhi polysaccharide solution is obtained. Then, Yunzhi polysaccharide solution is added to the CMC-Na solution in step (1). The volume ratio of CMC-Na solution to Yunzhi polysaccharide solution is 50-75:2-3. Mix well to obtain mixture A. (3) After mixing ethyl maltol with water, add it to the mixture A. The mass-volume ratio of ethyl maltol to water is 9-11 g: 5000 mL. (4) Add zinc sulfate with a mass fraction of 0.1% to mixture A, mix well, and let stand to obtain mixture B; (5) The mixture B is poured onto a plate, the volume-to-area ratio of the mixture B to the plate is 55-65:122.5, and dried at 30-40℃ for 10-12 hours to obtain the composite preservation film containing ethyl maltol.

2. The ethyl maltol composite preservation film according to claim 1, characterized in that, The specific method of stirring in step (1) is to stir with a stirrer in a constant temperature water bath at 55-65℃ for 30-40 minutes.

3. The ethyl maltol composite preservation film according to claim 1, characterized in that, The reflux extraction in step (2) is performed twice.

4. The ethyl maltol composite preservation film according to claim 1, characterized in that, The specific method for mixing in step (2) is to stir evenly in a constant temperature water bath at 55-65℃.

5. The composite preservation film of ethyl maltol according to any one of claims 1-4, characterized in that, In step (5), the volume-to-area ratio of the mixture B to the plate is 550-650:1225.

6. The application of the ethyl maltol composite preservative film according to claim 1 in the preservation and / or freshness of food.

7. The application according to claim 6, characterized in that, The food in question is edible fungi.

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