Composite preservative film containing ethyl maltol and preparation method thereof

Abstract

The invention relates to the field of edible mushroom fresh-keeping application research, in particular to a composite fresh-keeping film containing ethyl maltol and a preparation method of the composite fresh-keeping film. The invention aims to prepare a traditional Chinese medicine composite preservative film containing ethyl maltol and taking CMC-Na as a carrier. The composite preservative film contains ethyl maltol capable of obviously inhibiting mould, and the coriolus versicolor polysaccharide has an antibacterial effect, so that the composite preservative film has an obvious mould-proof effect while keeping fresh. The obtained traditional Chinese medicine composite preservative film is uniform, attractive and breathable, the thickness is only 0.1-0.2 mm, the normal-temperature preservation time of pleurotus pulmonarius preserved by the traditional Chinese medicine composite preservative film is prolonged to 9 days or above, the traditional Chinese medicine composite preservative film is simple and convenient, no chemical reagent or other liquid medicine makes direct contact with the surfaces of edible mushrooms, and the traditional Chinese medicine composite preservative film can be repeatedly used.

Description

Technical Field

[0001] The invention relates to the research field of edible fungus preservation application, and in particular to a composite fresh-keeping film containing ethyl maltol and a preparation method thereof. Background Art

[0002] Ethyl maltol (ethylmaltltol), chemical name 3-hydroxy-2-ethyl-4-pyrrolidone, relative molecular mass 140.11, white crystalline powder, melting point 89-93℃, easily soluble in hot water, is one of the commonly used and safe additives for food flavoring. GB2760-2014 National Food Safety Standard-Food Additives Usage Standard Appendix B.2.3 lists ethyl maltol as a synthetic flavoring agent for food that can be used (FEMA No.: 3487). The US food standard stipulates that the limit standard for ethyl maltol as a food flavoring agent is 100 mg / L (BATF-27CFR§240.1051). Yunzhi polysaccharide is extracted from the traditional Chinese medicine Yunzhi medicinal material, which has certain antibacterial activity and a wide antibacterial spectrum. The present invention further explores the new application of ethyl maltol, a safe and traditional food flavoring agent, in antibacterial, antiseptic and preservation. Ethyl maltol is combined with versicolor polysaccharide to prepare a traditional Chinese medicine composite preservative film with sodium carboxymethyl cellulose (CMC-Na) as a carrier and applied to the preservation of edible fungi. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0004] A method for preparing a composite fresh-keeping film containing ethyl maltol comprises the following steps:

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

[0006] (2) Medicinal Materials Weigh 4-6 g of Yunzhi medicinal materials, grind them into coarse powder and place them in a conical flask. Add water (the mass volume ratio of Yunzhi medicinal powder to water is 1 g: 24 mL) and heat under reflux for 1 hour. Repeat the operation once. After extracting twice, collect the extract and concentrate it in a water bath. Finally, 8-12 mL of concentrated solution is obtained, and the drug-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°C.

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

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

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

[0010] Beneficial effects of the present invention:

[0011] The invention discloses a traditional Chinese medicine composite fresh-keeping film containing ethyl maltol and using CMC-Na as a carrier. The composite fresh-keeping film contains ethyl maltol which can obviously inhibit mold, and the antibacterial effect of Coriolus versicolor polysaccharide is added, so the composite fresh-keeping film can obviously prevent mold while preserving. The traditional Chinese medicine composite fresh-keeping film obtained by the invention is uniform, beautiful and breathable, with a thickness of only 0.1-0.2 mm. The storage time of Pleurotus pulmonarius at room temperature can be extended to more than 9 days by using the composite fresh-keeping film. The film is simple and convenient, and no chemical reagent or other liquid medicine directly contacts the surface of edible fungi, and the film can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The colony of each treatment group (from left to right: A-treatment group, B-PE preservation group, C-composite preservation film group, bacterial suspension concentration is 10 -5 ). DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] The purpose of the present invention is to prepare a traditional Chinese medicine composite fresh-keeping film containing ethyl maltol and using CMC-Na as a carrier. The composite fresh-keeping film contains ethyl maltol which can obviously inhibit mold, and the antibacterial effect of Coriolus versicolor polysaccharide is added, so that the composite fresh-keeping film can obviously prevent mold while preserving. The traditional Chinese medicine composite fresh-keeping film obtained by the present invention is uniform, beautiful and breathable, with a thickness of only 0.1-0.2 mm. The storage time of Pleurotus pulmonarius at room temperature can be extended to more than 9 days by using the composite fresh-keeping film, which is simple and convenient, has no direct contact between chemical reagents or other liquid medicines and the surface of edible fungi, and can be reused.

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

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

[0017] 2. Weigh 4g of Yunzhi medicinal material, crush it into coarse powder, put it in a conical flask, add water and reflux to extract Yunzhi polysaccharide, extract twice, collect the extract and concentrate it in a water bath, and finally obtain 8mL of concentrated solution, with a drug-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 less than 25°C), stir and dissolve it thoroughly, and add the above mixed solution.

[0019] 4. Finally, add 0.1% zinc sulfate, mix well, let the mixture stand and degas for 12 hours, and then set aside.

[0020] 5. Use a pipette to absorb 55 mL of the above solution, pour it onto a clean glass plate (35 cm * 35 cm), spread it evenly, dry it horizontally until it is half dry, and dry it in an oven at 30°C for about 10 hours. Carefully peel off the composite film and seal it in a plastic bag.

[0021] Embodiment 2 Preparation method of traditional Chinese medicine preservative film

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

[0023] 2. Weigh 5g of Yunzhi medicinal material, crush it into coarse powder, put it in a conical flask, add water and reflux to extract Yunzhi polysaccharide, extract twice, collect the extract and concentrate it in a water bath, and finally obtain 10mL of concentrated solution, with a drug-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 less than 25°C), stir and dissolve it thoroughly, and add the above mixed solution.

[0025] 4. Finally, add 0.1% zinc sulfate, mix well, let the mixture stand and degas for 12 hours, and then set aside.

[0026] 5. Use a pipette to absorb 50 mL of the above solution, pour it onto a clean glass plate (35 cm * 35 cm), spread it evenly, dry it horizontally until it is half dry, and dry it in an oven at 35°C 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 preservative film

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

[0029] 2. Weigh 6g of Yunzhi medicinal material, crush it into coarse powder, put it in a conical flask, add water and reflux to extract Yunzhi polysaccharide, extract twice, collect the extract and concentrate it in a water bath, and finally obtain 12mL of concentrated solution, with a drug-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 0.011 g of ethyl maltol, dissolve it in 5 mL of double distilled water at room temperature (not less than 25°C), stir and dissolve it thoroughly, and add the above mixed solution.

[0031] 4. Finally, add 0.1% zinc sulfate, mix well, let the mixture stand and degas for 12 hours, and then set aside.

[0032] 5. Use a pipette to absorb 65 mL of the above solution, pour it onto a clean glass plate (35 cm * 35 cm), spread it evenly, dry it horizontally until it is half dry, and dry it in an oven at 40°C for about 12 hours. Carefully peel off the composite film and seal it in a plastic bag.

[0033] Application Examples

[0034] 60 fresh, uniform-sized Pleurotus pulmonarius fruiting bodies were divided into 3 groups: an untreated group (Group A), a PE cling film control group (Group B), and a composite cling film group (Group C, prepared in Example 1), and stored at room temperature. After 5 days, the physiological indexes of the fruiting bodies of each group were measured, and 3 replicates were performed each time.

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

[0036] 2. Fruiting body hardness: measured using two hardness testers;

[0037] 3. Soluble solid content: measured by handheld refractometer;

[0038] 4. Respiratory intensity: measured by static method;

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

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

[0041] 7. Decay index: The degree of fruit body decay is divided into 5 levels. Level 0: no decay; Level 1: 1 to 3 small rotten spots; Level 2: the decay area is between 1 / 4 and 1 / 2; Level 3: the decay area is between 1 / 2 and 3 / 4; Level 4: the decay area is >3 / 4. The decay index is calculated according to the following formula: Decay index = [∑ (level × corresponding number of decayed fruit bodies)] / total number of fruit bodies in the group.

[0042] 8. Evaluation of mildew and antibacterial properties: After 5 days of storage, use a sterile cotton swab to brush the surface of the fruiting body, try to cover 5 points, and then immerse it in a test tube containing 9 mL of sterile water, vortex shake to evenly disperse the sample. Then transfer 1 mL of the above liquid into a test tube containing 9 mL of sterile water, blow and beat to mix thoroughly. Repeat this process to make 10 -1 , 10 -2 , 10 -3 , 10 -4 and 10 -5 There are 5 test tubes with bacterial suspensions of various concentrations. -1 , 10 -3 , 10 -5 50 μL of inoculum was applied to each test tube with different concentrations to prepare plates with 3 replicates for each concentration. Incubate the plates upside down at 25°C for 48 h.

[0043] The results showed that compared with group A, the fruiting body mass loss rate of group C was significantly reduced, about -0.69% (P<0.05), and there was no significant difference between groups B and C (P>0.05), indicating that both treatments B and C can effectively maintain the water content of the fruit. After treatment, the fruiting body hardness of group C was the best, reaching 1.9kg / cm 2 , objectively delaying the fruit decay process, and the hardness after treatment A and B was 0.8kg / cm 2 and 1.5kg / cm 2 . From the perspective of soluble solid content and respiration intensity, treatment C can effectively inhibit respiration, slow down the decrease of soluble solid mass fraction, and effectively inhibit the respiration of Pleurotus pulmonarius fruiting bodies. The MDA content in the fruiting bodies of group C was relatively the lowest (0.850 μmol / L), while that of groups A and B was 1.376 μmol / L and 1.109 μmol / L, respectively; and the PPO activity of group C was also relatively the lowest, 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 can effectively inhibit the activity of polyphenol oxidase, thereby delaying browning. From the perspective of decay index, compared with 0.932 in group A and 0.586 in group B, the decay index of group C fruiting bodies was also the lowest (0.283), indicating that treatment C can effectively control the decay of edible fungi fruiting bodies.

[0044] From the results of anti-mold and anti-bacterial Figure 1), the colony of group C was significantly less than that of groups A and B, and there were significant differences between group C and groups A and B (P<0.05), indicating that this composite cling film can significantly inhibit the growth of microorganisms, especially molds.

Claims

1. A composite preservative film containing ethyl maltol, characterized in that: The preparation method of the composite fresh-keeping film comprises the following steps: (1) mixing sodium carboxymethyl starch powder with water, and stirring to obtain a CMC-Na solution; the mass volume ratio of the CMC-Na powder to water is 1 g:100 mL; (2) Preparation of Coriolus versicolor polysaccharide concentrate: Grind Coriolus versicolor medicinal material into coarse powder and place it in a conical flask, add water and heat under reflux for 1 hour, repeat the operation once, and obtain Coriolus versicolor polysaccharide concentrate after the medicinal material is concentrated. Then, add the Coriolus versicolor polysaccharide concentrate into the CMC-Na solution in step (1), and mix well to obtain a mixed solution A; (3) mixing ethyl maltol and water and adding the mixture to the mixed solution A, wherein the mass volume ratio of ethyl maltol to water is: 9-11 g: 5000 mL; (4) adding 0.1% by mass of zinc sulfate to the mixed solution A, mixing well, and allowing to stand to obtain a mixed solution B; (5) pouring the mixed solution B onto a flat plate, wherein the volume area ratio of the mixed solution B to the flat plate is 55-65:122.5, and drying at 30-40° C. for 10-12 h to obtain the composite preservative film containing ethyl maltol.

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

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

4. The composite preservative film of ethyl maltol according to claim 1, characterized in that In step (2), the ratio of the medicinal material of Versicolor to the solvent is 1 g: 2 mL.

5. The composite preservative film of ethyl maltol according to claim 1, characterized in that The specific method of mixing in step (2) is to stir evenly in a constant temperature water bath at 55-65°C.

6. The composite fresh-keeping film of ethyl maltol according to claim 1, characterized in that, The volume of the CMC-Na solution and the Versicolor polysaccharide concentrate is 50-75:2-3.

7. The composite fresh-keeping film of ethyl maltol according to any one of claims 1 to 6, characterized in that: In step (5), the volume area ratio of the mixed solution B to the flat plate is 550-650:1225.

8. Use of the composite preservative film of ethyl maltol according to claim 1 in food preservation and / or preservation.

9. The use according to claim 8, characterized in that The food is edible fungi.

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