Pretreatment and preservation method for duck fillet

Abstract

The invention discloses a duck fillet pretreatment and preservation method, belongs to the technical field of meat product treatment, aims to solve the preservation problem of prefabricated duck fillet products, and comprises the steps of duck breast meat pretreatment, plasma activated water preparation, duck fillet pickling and duck fillet storage. The total number of bacterial colonies of the duck fillet in the storage period can be reduced; meanwhile, TVB-N increase can be slowed down, lipid oxidation is improved, the storage quality of the duck willow is effectively maintained, and the storage period of the duck willow is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of meat product processing, in particular to a duck fillet pretreatment and fresh-keeping method. Background Art

[0002] Pre-prepared dishes are finished or semi-finished dishes that use one or more agricultural products as raw materials, supplemented with various seasonings, and are made through standardized and streamlined operations, pre-processed and (or pre-)cooked, and packaged for storage, transportation and sales. Among them, livestock and poultry meat pre-prepared dishes are pre-packaged dishes with livestock and poultry meat as the main raw materials. In recent years, under the background of lazy economy, the domestic pre-prepared food industry has developed rapidly. In the late 1990s, fast food chains led by KFC and McDonald's entered the Chinese market, and the model of clean vegetable distribution and processing plants gradually emerged in China. After the 21st century, the advancement of cold chain technology further promoted the development of the pre-prepared food industry, and some semi-finished food production companies were gradually established. In 2010, the rapid development of agricultural and sideline product processing industry promoted the emergence of industrial staple foods, convenient pre-prepared foods and pre-prepared meat products. In 2013, pre-prepared food retail stores opened one after another, providing consumers with a more convenient purchasing channel. In 2014, the booming takeout industry promoted the supply of cooking packages to the market, and the industrialization of food gradually expanded. From 2015 to 2019, the scale of the pre-prepared food market has slowly increased. In 2020, the scale of the pre-prepared food market will enter a period of rapid growth. It is expected that my country's pre-prepared food market will grow at a high rate of 20% in the future, and the scale of the pre-prepared food market may reach 831.67 billion yuan in 2025.

[0003] However, with the rapid development of the pre-prepared food market, some problems also exist. At present, there are no specific product regulations in the pre-prepared food industry. Enterprises produce and process pre-prepared food according to the product attributes and implement the standards of similar products of relevant countries or industries. The pre-prepared food industry lacks hygiene standards and processing specifications corresponding to specific products, and does not have an effective supervision system. At the same time, the pre-prepared food industry, which is in the early stages of the industry, is developing rapidly, but the lack of unified standards may cause chaos: the threshold of the pre-prepared food market is low, resulting in a mixed bag of production companies and prone to food safety incidents; product evaluation indicators and standard systems are the basis for measuring product quality. Since the pre-prepared food industry has not yet formed a complete and unified standard system, third-party testing agencies cannot evaluate products. The occurrence of related chaos has allowed some companies to take advantage of the situation. The irregular operations in the production, processing and transportation of pre-prepared food make the products susceptible to contamination, resulting in product corruption, shortened shelf life, and even complete loss of value. Among them, microbial contamination is one of the main problems in the production of pre-prepared meals. Due to the semi-processed nature of some pre-prepared products, conventional sterilization methods (pasteurization, 116°C sterilization and 121°C sterilization) are difficult to apply. Ultra-high pressure sterilization, ultraviolet sterilization, ozone sterilization and irradiation sterilization are not applicable due to certain negative impacts on product sensory, color and texture or for economic reasons.

[0004] Plasma is the fourth form of matter composed of positive ions, negative ions, electrons, excited and neutral atoms, free radicals, ground and excited molecules, and ultraviolet photons. It is divided into hot plasma (HP) and cold plasma (CP) based on thermodynamic temperature. The main ways to prepare plasma are plasma jet, dielectric barrier discharge and corona discharge. Except for a few plasma jets, the temperature of cold plasma never exceeds 60 °C. Plasma activated water (PAW) is a liquid prepared by ionizing plasma on the surface or under water. It usually has a low pH, high redox potential and high conductivity, and contains substances such as reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS can effectively destroy microbial cell membranes, proteins and nucleic acids, thereby inactivating microorganisms. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a novel method for prefabricated duck fillet preservation.

[0006] The above-mentioned object of the present invention is achieved through the following technical solutions: A method for pre-treating and preserving duck fillet comprises the following steps: (1) Duck breast pretreatment; (2) Preparation of plasma activated water; (3) Pickling of duck fillet; (4) Storage of duck fillet.

[0007] Preferably, in the duck fillet pretreatment and preservation method, the duck breast meat pretreatment step is: thawing the duck breast meat frozen at -20°C in running water for 30 min, cutting it into 5 cm×1 cm×0.5 cm, 5 g thin strips, taking 25 g and sealing it in a sterile sampling bag, and storing it at 4°C for later use.

[0008] Preferably, in the duck fillet pretreatment preservation method, the plasma activated water preparation conditions are: the carrier gas is air, the gas flow rate is 28-32 L / min, the power is 680-700 W, the distance between the spray gun and the liquid surface is 4 cm, and 50 mL of sterilized water is treated for 6 minutes.

[0009] Preferably, the duck fillet pretreatment and preservation method, wherein the duck fillet pickling comprises the following steps: S1, marinade water is prepared by adding 4% of the weight of plasma activated water, and duck fillet is prepared by adding 50% of the weight of marinade water; S2. Seal the marinade and duck fillet in a sterile bag, marinate in a 4 ℃ refrigerator for 24 h, and finally pour out the marinade.

[0010] S3. Seal the duck fillets in sterile bags and store in a 4 ℃ refrigerator.

[0011] The above technical solution addresses the problem that existing semi-processed prefabricated duck fillets are difficult to sterilize. By using PAW for pickling, it provides a new idea for preservation without damaging the quality of the duck fillets. The number of microorganisms in the duck fillets is significantly reduced during storage; the increase of TVB-N and lipid oxidation are slowed down to effectively maintain the storage quality of the duck fillets and extend the storage period of the duck fillets. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the plasma activated water preparation equipment of the present invention; Figure 2 The change of live bacteria count in duck fillet during storage period; Figure 3 Changes of TVB-N in duck fillet during storage; Figure 4 Changes of TBARS in duck fillet during storage. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solution and advantages of the implementation mode of the present application clearer, the technical solution in the implementation mode of the present application will be clearly and completely described in combination with the drawings in the implementation mode of the present application. Obviously, the described implementation mode is a part of the implementation mode of the present application, not all the implementation modes. Based on the implementation mode in the present application, all other implementation modes obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application. The specific implementation modes of the present invention are described in detail in combination with the drawings in the specification.

[0014] The implementation steps of this embodiment are: using plasma jet to treat sterilized water for 6 minutes to prepare plasma activated water, then pickling duck fillets with plasma activated water for 24 hours, and then storing the duck fillets at 4°C. Embodiment 1

[0015] Reference Figure 1 , is the total number of colonies on days 0, 3 and 6 of duck fillet infected with Escherichia coli pickled with plasma activated water disclosed in the present invention.

[0016] The implementation principle of the above embodiment is: plasma activated water is prepared by treating sterilized water with plasma jet for 2 min, 4 min and 6 min, and then duck fillets are pickled with plasma activated water for 24 h, and then stored at 4°C. Duck fillets pickled with sterilized water and acidic water (acetic acid is used to adjust the pH of sterilized water to 3.1, which is consistent with PAW with a preparation time of 6 min) are added as controls and named as sterilized water group and acidic water group. The total number of colonies is determined on days 0, 3 and 6 with reference to GB 4789.2-2016 "Determination of the total number of colonies in food microbiology examination".

[0017] To analyze the effect of PAW on the colony count of duck fillet during storage, the colony count of E. coli was measured on day 0, day 3, and day 6. Figure 2 It can be seen that on the 0th day of storage, the initial colony count in the sterile water group was the highest at 3.49 lg CFU / g, followed by the acidic water group at 3.05 lg CFU / g. The colony counts of the three groups treated with PAW were 2.92 lg CFU / g, 2.83 lg CFU / g and 2.67 lg CFU / g, respectively, indicating that PAW treatment inhibited the proliferation of Escherichia coli during pickling. With the increase of storage time, the colony counts of all treatment groups showed an upward trend. On the 3rd day, the colony count of the PAW-6 min group decreased by 1.33 lgCFU / g compared with the colony count of the sterile water group. On the 6th day, the colony counts of the duck fillets treated with PAW in the three groups were basically the same, but still lower than those of the sterile water group and the acidic water group. Substances such as nitrite, ozone and hydrogen peroxide contained in PAW are cytotoxic, which leads to the oxidation of bacterial proteins and nucleic acids, damage to membrane structures and leakage of intracellular substances, resulting in bacterial death, thus achieving a preservation effect. On the other hand, since the active substances of PAW decompose over time, the colony count of the PAW-treated group in the late storage period still grows normally. The inhibitory effect of PAW on the surface mainly acts on the early growth of bacteria in storage, thereby delaying the time of rapid bacterial growth. In summary, PAW treatment effectively delays the growth of microorganisms and prolongs the shelf life of duck fillet. Embodiment 2

[0018] Reference Figure 1 , which is a graph disclosed by the present invention showing the changes in the volatile basic total nitrogen content of duck fillets infected with Escherichia coli pickled with plasma activated water at 0, 3 and 6 days.

[0019] The implementation principle of the above embodiment is: use plasma jet to treat sterilized water for 2 min, 4 min and 6 min to prepare plasma activated water, then use plasma activated water to pickle duck fillets for 24 h, and then store the duck fillets at 4°C. Add duck fillets pickled with sterilized water and acidic water (use acetic acid to adjust the pH of sterilized water to 3.1, consistent with the PAW of preparation time 6 min) as controls and named sterile water group and acidic water group. The volatile basic total nitrogen was determined according to the automatic Kjeldahl nitrogen analyzer method in the national standard GB 5009.228-2016 "Determination of Volatile Basic Nitrogen in Food". The oxidative decomposition of nitrogen-containing compounds will generate organic amines, which are toxic and will cause changes in product color and taste. By Figure 3 It can be seen that on the 0th day, the acidic water group performed best, with a TVB-N content of only 16.3 mg / 100g, followed by the PAW-2 min group, which was 17.5 mg / 100g, and the sterile water group had a maximum content of 25.4 mg / 100g. As the storage period prolonged, the TVB-N value continued to increase. On the 6th day, the sterile water group had a maximum TVB-N of 29.88 mg / 100g, followed by the PAW-6 min group, which was 24.37 mg / 100g. The increase in TVB-N levels may be related to the metabolism of Escherichia coli, which decomposes protein nitrogen nutrients to produce organic amines; the TVB-N content of the PAW treatment group was higher at the beginning, but it increased slowly during the storage period because the number of Escherichia coli was small, the decomposition effect was low, and the accumulation of organic amines was slow. The results showed that PAW treatment delayed the increase of TVB-N during storage. Embodiment 3

[0020] Reference Figure 4 , which is disclosed in the present invention, the changes in thiobarbituric acid content in duck fillets infected with Escherichia coli pickled with plasma-activated water at 0, 3 and 6 days.

[0021] The implementation principle of the above embodiment is: plasma activated water is prepared by treating sterilized water with plasma jet for 2 min, 4 min and 6 min, and then duck fillets are pickled with plasma activated water for 24 h, and then stored at 4°C. Duck fillets pickled with sterilized water and acidic water (acetic acid is used to adjust the pH of sterilized water to 3.1, which is consistent with PAW with a preparation time of 6 min) are added as controls and named as sterilized water group and acidic water group. The malondialdehyde content is determined by spectrophotometry according to GB 5009.181-2016 "Determination of malondialdehyde in food".

[0022] Oxidative decomposition by microorganisms is an important reason for the decline in meat quality. The main cause of oxidative deterioration of meat is the oxidation of proteins and lipids or the mutual oxidation of the two. Oxygen free radicals act on lipids to generate oxidized lipids. Oxidized lipids are unstable and easily decomposed into a series of complex compounds, including malondialdehyde (MDA). Under acidic and high temperature conditions, MDA will condense with TBARS to generate brown-red trimethoate (3,5,5-trimethyloxazole-2,4-dione), with a maximum absorption wavelength of 532 nm. The MDA content can be estimated after colorimetry, and the degree of fat oxidation can be indirectly characterized by the MDA content. At the beginning of the storage period, the MDA content in the sterile water group reached the highest level of 0.31 mg / kg, followed by the three PAW treatment groups, and the lowest level in the acidic water group. As the storage period prolonged, the TBARS value showed an overall upward trend. On the 6th day, the TBARS value in the sterile water group reached 0.52 mg / kg, an increase of 0.21 mg / kg compared with the 0th day, while the TBARS value in the PAW-6 min group only increased by 0.12 mg / kg during the 6-day storage. The TBARS value in the acidic water group was still the lowest on the 6th day, at 0.31 mg / kg, but its growth rate during the storage period was second only to the sterile water group, with an increase of 0.16 mg / kg. The sterile water group had the highest TBARS value, which may be due to the largest number of live Escherichia coli, the strongest microbial decomposition, and the deepest degree of fat spoilage. The TBARS value in the PAW treatment group was higher than that in the acidic water group, which may be due to the high content of active substances in the initial PAW, which showed strong oxidation, and some fat was oxidized during the pickling process. Fat oxidation during the storage period was mainly caused by microbial decomposition. After PAW treatment, the number of viable Escherichia coli was reduced and the oxidation was weakened, resulting in a slower increase in TBARS in the three PAW treatment groups.

Claims

1. A method for pre-treating and preserving duck fillet, It is characterized in that The following steps are involved: (1) Duck breast pretreatment; (2) Preparation of plasma activated water; (3) Pickling of duck fillet; (4) Storage of duck fillet.

2. The method for pre-treating and preserving duck fillet according to claim 1, Features: The duck breast meat pretreatment steps are as follows: thawing the duck breast meat frozen at -20°C in running water for 30 min, cutting it into 5 cm×1 cm×0.5 cm, 5 g thin strips, taking 25 g and sealing it in a sterile sampling bag, and storing it at 4°C for later use.

3. The method for pre-treatment and preservation of duck fillet according to claim 1, Features: The preparation conditions of the plasma activated water are as follows: the carrier gas is air, the gas flow rate is 28-32 L / min, the power is 680-700 W, the distance between the spray gun and the liquid surface is 4 cm, and 50 mL of sterile water is treated for 6 minutes.

4. The method for pre-treatment and preservation of duck fillet according to claim 1, Features: The pickling of duck fillet comprises the following steps: S1, marinade water is prepared by adding 4% of the weight of plasma activated water, and duck fillet is prepared by adding 50% of the weight of marinade water; S2. Seal the marinade and duck fillet in a sterile bag and marinate in a refrigerator at 4°C for 24 hours. Finally, pour out the marinade. S3. Seal the duck fillets in sterile bags and store in a 4 ℃ refrigerator.

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