A method for prolonging the shelf life of cured meat products by using natural edible coatings

Abstract

The present invention discloses a method for prolonging the shelf life of cured meat products by using a natural edible coating film. The method uses a coating agent prepared by mixing okra extract, honeysuckle extract, artemisia annua extract, gelatin powder and distilled water and homogenizing them, and evenly applying the coating agent to the surface of meat pieces when the meat pieces are air-dried. During the air-drying and dehydration process, the coating agent adheres tightly to the surface of the meat pieces to form an antibacterial and antioxidant protective film. This protective film isolates the meat pieces from the outside world, thus avoiding the oxidation and deterioration of cured meat products. At the same time, the gelatin layer of this film enables the okra extract, honeysuckle extract and artemisia annua extract to slowly release and penetrate into the interior of the meat products, playing a role in anti-corrosion and freshness preservation, so as to prolong the shelf life of cured meat products without affecting the original flavor and taste inside the meat products.

Description

Technical Field

[0001] The present invention relates to a method for extending the shelf life of cured and dried meat products, and particularly to a method for extending the shelf life of cured and dried meat products by using a natural edible coating film. Background Art

[0002] Cured and dried meat products are one of the traditional meat products in China. They are raw meat products processed from raw meat and its edible by-products through processes such as pretreatment, curing, sauce-making, and air-drying. They need to be cooked before consumption. The main types include: cured meat, pressed duck, cured chicken, wind goose, sausage, ham, etc. Cured and dried meat products have the characteristics of being easy to process, having a prominent cured flavor, firm and solid texture, distinct red and white color, salty and delicious taste, unique flavor, being convenient to carry and store, etc.

[0003] However, due to the relatively high lipid content in cured and dried meat products, it is easy to cause oxidation and rancidity during the ripening and storage processes of the products. If the products are not stored properly, an unpleasant rancid smell is likely to occur. Moreover, during the processing of cured and dried meat products, the surface of the meat blocks is inevitably contaminated by a large number of harmful microorganisms, resulting in spoilage and deterioration of the products during processing and storage, and even the growth of residual pathogenic bacteria leading to food poisoning. At present, some cured and dried meat products use chemical food preservatives and antioxidants such as nitrite and potassium sorbate to inhibit fatty acid rancidity and the growth of harmful bacteria, which can extend the shelf life of cured and dried meat products to a certain extent. However, chemical preservatives have certain safety risks and are harmful to the body if consumed for a long time. Other methods for extending the shelf life of cured and dried meat products, although having less potential safety hazards, have poor effects. Therefore, it is necessary to seek a safer and more efficient method for extending the shelf life of cured and dried meat products. Summary of the Invention

[0004] The object of the present invention is to provide a method for extending the shelf life of cured and dried meat products by using a natural edible coating film in view of the deficiencies of the prior art. By applying a coating agent with antioxidant and antibacterial functions to the surface of the meat blocks, this method can effectively extend the shelf life of cured and dried meat products and meet the current consumers' demand for natural and green foods.

[0005] To achieve the above object, the method for extending the shelf life of cured meat products by using natural edible coatings provided by the present invention is to marinate livestock and poultry meat and then hang it to dry. Then, the pre-prepared coating agent is evenly applied to the surface of the meat blocks, and then air-dried and dehydrated. During the air-drying and dehydration process, the coating agent adheres tightly to the surface of the meat blocks to form a dense antioxidant and antibacterial coating; the coating agent is made by mixing, homogenizing okra extract, honeysuckle extract, artemisia annua extract, gelatin powder and distilled water. The weight ratio of each component is: 20-22 parts of gelatin powder, 15-20 parts of okra extract, 15-20 parts of honeysuckle extract, 4-5 parts of artemisia annua extract, and 900-1000 parts of distilled water. Among them, okra extract, honeysuckle extract and artemisia annua extract have a synergistic effect in antibacterial and antioxidant aspects.

[0006] Further, the preparation method of the okra extract is: wash the okra, cut it into pieces, add water and homogenize it with a grinder, filter it and refrigerate it for 18-24 hours, then remove the water-insoluble substances and centrifuge it at a high speed of 1000-12000 r / min. Concentrate the clear liquid to obtain the okra extract, and store it at -18°C before use.

[0007] Further, the preparation method of the honeysuckle extract is: wash the honeysuckle with distilled water, dry it at 45-55°C and grind it into fine powder. After passing the fine powder through a 20-mesh sieve, perform ultrasonic extraction for 1-1.5 h with edible alcohol in a ratio of (45-55):(750-850). After removing the insoluble substances, rotate and dry the solution with a rotary evaporator to obtain the honeysuckle extract. The preparation method of the artemisia annua extract is the same as that of the honeysuckle extract. Store the honeysuckle extract and artemisia annua extract at -18°C before use.

[0008] Further, the preparation method of the coating agent is: first completely dissolve the gelatin powder with distilled water, then add okra extract, honeysuckle extract and artemisia annua extract and dissolve them, then add an appropriate amount of water to adjust the viscosity of the coating agent, and finally homogenize it with a homogenizer to obtain the coating agent.

[0009] Further, the gelatin powder and distilled water are completely dissolved by the microwave method.

[0010] Further, the number of homogenization times is 2 times.

[0011] When determining the solution, the present invention conducted antibacterial and antioxidant experiments on a large number of plant extracts, and confirmed and found that in addition to the usual lipid-lowering, health-care, anti-cancer and other effects, these three plant extracts of okra, honeysuckle and artemisia annua also have outstanding antibacterial and antioxidant functions in meat products, specifically as follows:

[0012] Okra extract: It can prevent the peroxidative decomposition of fat caused by oxygen attacking the double bond of fatty acid; it can form a dense film through hydrogen bonding with the gelatin film matrix, thereby isolating the contact between oxygen and meat products. Experiments have shown that when the okra extract and gelatin composite film are coated on meat pieces, the TBARS value of the meat product drops from 1.57 to 0.19 mg MDA eq·kg on the 8th day. -1 In addition, experiments have found that okra extract has inhibitory effects on Bacillus subtilis, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa.

[0013] Honeysuckle extract: In vitro antibacterial experiments have shown that honeysuckle extract has inhibitory effects on foodborne Escherichia coli, Staphylococcus aureus, Shigella dysenteriae, Salmonella typhimurium, Penicillium, Aspergillus niger, Aspergillus flavus, and Saccharomyces cerevisiae, and the MIC values are (μg / mL): 100, 50, 41, 1000, 250, 62.5, 250, 250 respectively. Among them, it has significant antibacterial effects on Escherichia coli, Staphylococcus aureus, Shigella dysenteriae, and Aspergillus niger.

[0014] Artemisia annua extract: In vitro antibacterial experiments have shown that it has inhibitory effects on foodborne Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Saccharomyces cerevisiae, and Aspergillus niger, and the MIC values are (μg / mL): 48.5, 194.2, 194.2, 48.5, 194.2 respectively. Among them, the inhibitory effects on Staphylococcus aureus and Saccharomyces cerevisiae are particularly significant.

[0015] Through a large number of compound experiments, it has been found that 15 - 20 parts of okra extract, 15 - 20 parts of honeysuckle extract, and 4 - 5 parts of Artemisia annua extract have synergistic antibacterial and antioxidant effects.

[0016] The coating agent of the present invention is prepared by mixing and homogenizing okra extract, honeysuckle extract, Artemisia annua extract, gelatin powder, and distilled water, and is evenly applied to the surface of meat pieces when the meat pieces are air-dried. During the air-drying and dehydration process, the coating agent adheres tightly to the surface of the meat pieces to form an antibacterial and antioxidant protective film. This protective film isolates the meat pieces from the outside world, thereby avoiding the oxidative deterioration of cured meat products. At the same time, the gelatin layer of the film enables the okra extract, honeysuckle extract, and Artemisia annua extract to slowly release and penetrate into the interior of the meat products, playing a role in anti-corrosion and preservation, so as to extend the shelf life of cured meat products without affecting the original flavor and taste inside the meat products. In addition, due to the synergistic effect of the okra extract, honeysuckle extract, and Artemisia annua extract in the coating agent in terms of antibacterial and antioxidant effects, a smaller amount of the coating agent can achieve the purpose of extending the shelf life of cured meat products. Moreover, since the coating agent is made of natural edible okra extract, honeysuckle extract, Artemisia annua extract, and gelatin powder, it ensures that the meat products are convenient for immediate consumption and have certain health care functions. Compared with traditional methods of extending the shelf life, the present invention can generally extend the shelf life of cured meat products by 2 - 3 times. Detailed implementation mode

[0017] The present invention will be further described in detail below with reference to embodiments.

[0018] Embodiment 1 Method for prolonging the shelf life of bacon using a natural edible coating

[0019] The method for prolonging the shelf life of bacon using a natural edible coating provided in this embodiment includes the following steps:

[0020] (1) Raw material treatment: Cut 30 kg of fresh meat with hind legs into meat strips with a length of 25 cm, a width of 5 cm, and a thickness of 6 cm, and cool them in a cold storage to 2°C;

[0021] (2) Pickling: Evenly apply 3.5% salt and 1.5% white sugar by weight of the meat on the surface of the meat blocks. After even application, place them under a lid and pickle at 4°C for 72 h;

[0022] (3) Coating: Let the pickled meat blocks air-dry naturally for 2 d, and then apply the pre-prepared coating agent on the surface of the meat blocks. The preparation method of the coating agent is as follows: First, completely dissolve gelatin powder and distilled water by microwave method, then add okra extract, honeysuckle extract, and artemisia annua extract and dissolve them, then add an appropriate amount of water to adjust the viscosity of the coating agent, and finally homogenize it twice with a homogenizer to obtain the coating agent;

[0023] (4) Air-drying: Place the coated meat blocks in an intelligent control natural-like air-drying device and air-dry them under natural-like conditions. The air-drying conditions are a wind speed of 1 - 2 m / s, a relative humidity of 60%, and a temperature of 8°C - 12°C, alternating and circulating every 12 h. Air-dry until the dehydration rate is about 30% to obtain the finished product;

[0024] The preparation method of the okra extract in step (3) is as follows: Wash the okra, cut it into pieces, add water and homogenize it with a grinder, filter it and refrigerate it for 20 hours, then remove the water-insoluble substances and centrifuge it at 1000 r / min at high speed. Concentrate the clear liquid to obtain the okra extract, and store it at -18°C before use.

[0025] The preparation method of the honeysuckle extract is as follows: Wash the honeysuckle with distilled water, dry it at 50°C and grind it into fine powder. After passing the fine powder through a 20-mesh sieve, ultrasonically extract it with edible alcohol at a ratio of 50:800 for 1 h. After removing the insoluble substances, rotate and dry the solution with a rotary evaporator to obtain the honeysuckle extract, and store it at -18°C before use.

[0026] The preparation method of the artemisia annua extract is the same as that of the honeysuckle extract, and it is stored at -18°C before use.

[0027] Next, the characteristics tests of the cured meat products were carried out by using different coating agents or adding other preservatives and without adding preservatives and coating agents respectively in step (3).

[0028] Experimental group 1: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 20 parts of okra extract, 15 parts of honeysuckle extract, 4 parts of artemisia annua extract, and 950 parts of distilled water.

[0029] Experimental group 2: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of okra extract, 15 parts of honeysuckle extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0030] Experimental group 3: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of okra extract, 20 parts of honeysuckle extract, 5 parts of artemisia annua extract, and 960 parts of distilled water.

[0031] Experimental group 4: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of aloe extract, 15 parts of honeysuckle extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0032] Experimental group 5: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of konjac extract, 15 parts of honeysuckle extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0033] Experimental group 6: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of tremella extract, 15 parts of honeysuckle extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0034] Experimental group 7: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of okra extract, 15 parts of feverfew extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0035] Experimental group 8: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of okra extract, 15 parts of bitter orange flower extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0036] Experimental group 9: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of okra extract, 15 parts of white hyacinth bean flower extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0037] Experimental group 10: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of okra extract, 15 parts of honeysuckle extract, 4 parts of fritillaria thunbergii extract, and 900 parts of distilled water.

[0038] Experimental group 11: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of okra extract, 15 parts of honeysuckle extract, 4 parts of juglans regia extract, and 900 parts of distilled water.

[0039] Experimental group 12: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 15 parts of okra extract, 15 parts of honeysuckle extract, 4 parts of coptis chinensis extract, and 900 parts of distilled water.

[0040] Experimental group 13: Do not add the coating agent or any preservatives, and cancel step (3).

[0041] Experimental group 14: Do not add the coating agent, and add 1.5 g / kg of potassium sorbate.

[0042] Experimental group 15: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 30 parts of okra extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0043] Experimental group 16: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 30 parts of honeysuckle extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0044] Experimental group 17: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 17 parts of okra extract, 17 parts of honeysuckle extract, and 900 parts of distilled water.

[0045] Experimental group 18: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 30 parts of aloe vera extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0046] Experimental group 19: The weight ratio of each component of the coating agent is: 20 parts of gelatin powder, 30 parts of feverfew extract, 4 parts of artemisia annua extract, and 900 parts of distilled water.

[0047] The above experimental groups were respectively subjected to the total colony count and peroxide value tests, and the test results are shown in Table 1.

[0048] Table 1 Comparison of the characteristics of the cured meat products (the coating agent was added at 4% of the meat weight and measured after 70 days of addition)

[0049] Table 1

[0050]

[0051] Total colony count determination: Refer to GB 4789.2—2016 "National Food Safety Standard Food Microbiology Examination Total Colony Count Determination".

[0052] Peroxide value determination: Refer to GB 5009.227—2016 "National Food Safety Standard Determination of Peroxide Value in Foods".

[0053] Table 2 Sensory Scoring Criteria

[0054]

[0055]

[0056] As can be seen from Table 1, using natural composite coating agents (Group 1 - Group 3) as preservatives, their fresh-keeping effect is significantly better than that of Group 13 without coating agents or any preservatives, and exceeds the effect of sodium sorbate (Group 14). When replacing the okra extract (Group 4, 5, 6) with aloe extract, konjac extract or tremella extract, replacing the honeysuckle extract (Group 7, 8, 9) with feverfew extract, bitter orange flower extract or hyacinth bean flower extract, and replacing the artemisia annua extract (Group 10, 11, 12) with fritillaria thunbergii extract, walnut septum extract or coptis chinensis extract, the antibacterial and antioxidant effects of the fresh-keeping film decrease significantly. The main reason is that the okra extract, honeysuckle extract and artemisia annua extract in the original formula of the composite coating agent have a synergistic effect in antibacterial and antioxidant aspects, which enhances the antibacterial and antioxidant effects. When replacing the okra extract, honeysuckle extract or artemisia annua extract with other extracts, the synergistic effect no longer exists, and the antibacterial and antioxidant effects of the fresh-keeping film decrease accordingly. The synergistic effect of the composite coating agent will be further explained below.

[0057] Comparing Group 2 with Group 15, 16, 17, for the composite coating agent in Group 2, 15 parts of okra extract + 15 parts of honeysuckle extract + 4 parts of artemisia annua extract = 34 parts. The coating agents of Group 15, 16, 17 respectively use 30 parts of okra extract + 4 parts of artemisia annua extract = 34 parts, 30 parts of honeysuckle extract + 4 parts of artemisia annua extract = 34 parts, 17 parts of okra extract + 17 parts of honeysuckle extract = 34 parts, and the other components of the coating agent remain unchanged. Comparative analysis shows that the total number of colonies and peroxide value measured using the composite coating agent in Group 2 are significantly lower than those of the coating agents using any two of the extracts in Group 15, 16, 17, indicating that the okra extract, honeysuckle extract and artemisia annua extract in the composite coating agent in Group 2 have a synergistic effect in antibacterial and antioxidant aspects.

[0058] Group 4 was compared with Groups 16 and 18. In the composite coating agent of Group 4, 15 parts of aloe extract + 15 parts of honeysuckle extract + 4 parts of artemisia annua extract = 34 parts. The coating agents of Groups 16 and 18 used 30 parts of honeysuckle extract + 4 parts of artemisia annua extract = 34 parts and 30 parts of aloe extract + 4 parts of artemisia annua extract = 34 parts respectively. Comparative analysis showed that the total number of colonies and peroxide value measured using the composite coating agent of Group 4 were higher than those of the coating agent of Group 18 using aloe extract and artemisia annua extract (with other components of the coating agent unchanged). This indicates that the composite coating agent of Group 4 does not have a synergistic effect, that is, after replacing okra extract with aloe extract, the aloe extract, honeysuckle extract and artemisia annua extract in the composite coating agent no longer have a synergistic effect in terms of antibacterial and antioxidant properties.

[0059] Group 7 was compared with Groups 15 and 19. In the composite coating agent of Group 7, 15 parts of okra extract + 15 parts of feverfew extract + 4 parts of artemisia annua extract = 34 parts. The coating agents of Groups 15 and 19 used 30 parts of okra extract + 4 parts of artemisia annua extract = 34 parts and 30 parts of feverfew extract + 4 parts of artemisia annua extract = 34 parts respectively. Comparative analysis showed that the total number of colonies and peroxide value measured using the composite coating agent of Group 7 were higher than those of the coating agent of Group 19 using feverfew extract and artemisia annua extract (with other components of the coating agent unchanged). This indicates that the composite coating agent of Group 7 does not have a synergistic effect, that is, after replacing honeysuckle extract with feverfew extract, the okra extract, feverfew extract and artemisia annua extract in the composite coating agent no longer have a synergistic effect in terms of antibacterial and antioxidant properties.

[0060] Comparing Group 10 with Group 2, it can be seen that after replacing artemisia annua extract with fritillaria thunbergii extract, the total number of colonies and peroxide value measured for the composite coating agent increased significantly, indicating that using artemisia annua extract is superior to using fritillaria thunbergii extract.

[0061] In summary, when the formula of the composite coating agent is 20 - 22 parts of gelatin powder, 15 - 20 parts of okra extract, 15 - 20 parts of honeysuckle extract, 4 - 5 parts of artemisia annua extract, and 900 - 1000 parts of distilled water, the okra extract, honeysuckle extract and artemisia annua extract in the composite coating agent have a synergistic effect in terms of antibacterial and antioxidant properties. After replacing any one of the extracts in the formula with other extracts, the composite coating agent no longer has a synergistic effect, and its antibacterial and antioxidant effects decrease accordingly.

[0062] It has been proven by experiments that without using any additives (such as Group 7), the total number of colonies of Product 1 will exceed 4.699 lg (CFU / g), the total number of colonies allowed by the hygiene standard for cooked meat products within 14 - 24 days; when sodium sorbate is added (such as Group 8), the total number of colonies will exceed 4.699 lg (CFU / g), the total number of colonies allowed by the hygiene standard for cooked meat products in about 28 days; while for the products coated with this natural composite coating agent (such as Group 1, 2, 3), the total number of colonies still does not exceed 4.699 lg (CFU / g) within 70 days.

[0063] It can be seen from the sensory evaluation scores in Table 2 that the sensory evaluation scores of Groups 1, 2, and 3 with good sterilization and antioxidant effects are 27, 29, and 26 respectively, and the sensory effects can be accepted by the public.

[0064] Considering the product shelf life and sensory evaluation scores comprehensively, Group 2 in this embodiment is the best formula.

Claims

1. A method for extending the shelf life of cured meat products using a natural edible coating, characterized in that On: after curing the livestock and poultry meat and hanging it to dry, the pre-prepared coating agent is evenly applied to the surface of the meat pieces, and then air-dried and dehydrated. During the air-drying and dehydration process, the coating agent adheres tightly to the surface of the meat pieces to form a dense antioxidant and antibacterial coating; the coating agent is made by mixing, homogenizing okra extract, honeysuckle extract, artemisia annua extract, gelatin powder and distilled water. The weight ratio of each component is: 20-22 parts of gelatin powder, 15-20 parts of okra extract, 15-20 parts of honeysuckle extract, 4-5 parts of artemisia annua extract, and 900-1000 parts of distilled water; the preparation method of the okra extract is: wash the okra, cut it into pieces, homogenize it with a grinding machine after adding water, filter it and refrigerate it for 18-24 hours, then remove the water-insoluble substances and centrifuge at a high speed of 1000-12000 r / min. The clear liquid is concentrated to obtain the okra extract, which is stored at -18°C before use; the preparation method of the honeysuckle extract is: wash the honeysuckle with distilled water, dry it at 45-55°C and grind it into fine powder. After passing the fine powder through a 20-mesh sieve, it is ultrasonically extracted with edible alcohol in a ratio of (45-55):(750-850) for 1-1.5 h. After removing the insoluble substances, the solution is rotary dried by a rotary evaporator to obtain the honeysuckle extract. The preparation method of the artemisia annua extract is the same as that of the honeysuckle extract. The honeysuckle extract and the artemisia annua extract are stored at -18°C before use.

2. The method for prolonging the shelf life of cured meat products by using natural edible coatings according to claim 1, characterized in that: the preparation method of the coating agent is: first completely dissolve the gelatin powder with distilled water, then add the okra extract, honeysuckle extract and artemisia annua extract and dissolve them, then add an appropriate amount of water to adjust the viscosity of the coating agent, and finally homogenize it with a homogenizer to obtain the coating agent.

3. The method for prolonging the shelf life of cured meat products by using a natural edible film according to claim 2, characterized in that: the gelatin powder and distilled water are completely dissolved by the microwave method.

4. The method for prolonging the shelf life of cured meat products by using natural edible coatings according to claim 1 or 2, characterized in that: The number of homogenization times is 2 times.

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