阅读说明：本技术 一种减菌前处理结合气调包装的鱼块非冻保鲜方法 (Non-freezing preservation method for fish blocks by combining bacteria-reducing pretreatment with modified atmosphere packaging ) 是由 孙黎明 王祥光 年益莹 李佳桐 于 2020-05-19 设计创作，主要内容包括：本发明公开了一种减菌前处理结合气调包装的鱼块非冻保鲜方法,属于水产品加工贮藏技术领域。包括以下步骤：S1、整鱼前处理、取鱼肉、切块；S2、鱼块放入减菌溶液中浸泡；S3、气调包装；S4、非冻贮藏。所述减菌前处理结合气调包装的鱼块非冻保鲜方法,减菌前处理能够显著降低贮藏初期鱼肉中腐败菌的数量,减菌处理后的鱼块品质不受影响；气调包装可在贮藏过程中进一步抑制腐败菌的生长,提升鱼块鲜度,从而延长鱼块货架期。本发明所述方法应用方便、操作安全、生产成本低,适合新鲜鱼块的保鲜贮藏。(The invention discloses a non-freezing preservation method for fish blocks by combining bacteria-reducing pretreatment with modified atmosphere packaging, and belongs to the technical field of processing and storage of aquatic products. The method comprises the following steps: s1, pre-treating the whole fish, taking fish and cutting into blocks; s2, soaking the fish blocks in the bacteria-reducing solution; s3, modified atmosphere packaging; s4, storing in a non-frozen manner. The pretreatment of bacteria reduction is combined with the non-freezing preservation method of the fish blocks packaged by the modified atmosphere, the number of putrefying bacteria in the fish meat at the initial storage stage can be obviously reduced by the pretreatment of bacteria reduction, and the quality of the fish blocks after the bacteria reduction treatment is not influenced; the modified atmosphere packaging can further inhibit the growth of putrefying bacteria in the storage process, and improve the freshness of the fish blocks, thereby prolonging the shelf life of the fish blocks. The method of the invention has convenient application, safe operation and low production cost, and is suitable for the fresh-keeping storage of the fresh fish blocks.)

1. A non-freezing preservation method for fish blocks by combining bacteria-reducing pretreatment with modified atmosphere packaging is characterized by comprising the following process steps:

s1, raw material pretreatment: removing viscera, head, scale and blood stain and body surface mucus of raw fish, washing with ice water, draining water, taking fish meat, and cutting into pieces;

s2, pretreatment for bacteria reduction: taking the fish blocks obtained in the step S1, soaking the fish blocks in a bacteria-reducing solution according to the material-to-liquid ratio of 1: 10-1: 20g/ml, soaking at the temperature of 0-10 ℃ for 1-10 min, draining for 2-6min, putting the fish blocks into a baking soda solution at the temperature of 0-10 ℃ and with the pH of 7-9, taking the fish blocks out after 10-60 seconds, and draining for 2-6min to obtain the bacteria-reducing fish blocks;

wherein the bacteria-reducing solution is any one of the following solutions a to c:

a: 0.1 to 1 mass percent of acetic acid solution;

b: citric acid solution with mass fraction of 0.1-2%;

c: lactic acid solution with mass fraction of 0.1-2%;

s3, modified atmosphere packaging: placing the bacteria-reduced fish blocks in the step S2 in an air-conditioned packaging box, mixing air by using an air proportional mixer, vacuumizing, inflating and sealing by using an air-conditioned packaging machine, and carrying out air-conditioned packaging to obtain finished fish block products; the gas filled in the modified atmosphere package comprises the following components in percentage by volume: CO 2₂60 to 90% of N₂10-40%;

s4, storage: non-freezing storage is carried out on the fish fillet finished product in the step S3; the non-freezing storage is refrigeration, ice storage or ice temperature storage, the refrigeration temperature is 2-6 ℃, the ice storage is placed on ice or in ice, and the ice temperature storage is placed at-1 to-3 ℃.

2. The non-freezing preservation method for fish fillets subjected to the pretreatment before the bacteria reduction and the modified atmosphere packaging according to claim 1, wherein the raw material fish in the step S1 is sturgeon.

3. The method for non-freezing preservation of fish blocks combined with modified atmosphere packaging before bacteria reduction according to claim 1, wherein step S3 is to place one reduced bacteria fish block in each box of the modified atmosphere packaging box for modified atmosphere packaging; the gas used by the modified atmosphere package is 70 percent CO by volume percentage₂And 30% N₂And (4) forming.

4. The method for non-freezing preservation of fish fillet combined with modified atmosphere packaging according to the pretreatment of bacteria reduction as claimed in claim 1, characterized by comprising the steps of:

s1, pretreating raw materials, namely removing viscera, heads and body surface mucus of sturgeons, washing bloodstains, washing with ice water, draining, taking fish, and cutting into blocks of 15cm, × 6cm, × 5cm and sturgeon blocks to obtain sturgeon blocks;

s2, pretreatment for bacteria reduction: taking the sturgeon blocks obtained in the step S1, soaking the sturgeon blocks in an acetic acid solution with the mass fraction of 0.2% according to the material-to-liquid ratio of 1:10g/ml, soaking at the temperature of 4 ℃ for 2min, draining for 4min, then placing the sturgeon blocks in a baking soda solution with the pH of 8 at the temperature of 4 ℃ for soaking for 0.5min, and fishing out and draining for 4min to obtain the antibacterial fish blocks;

s3, modified atmosphere packaging: placing the bacteria-reduced fish blocks in the step S2 into controlled atmosphere packaging boxes, placing one bacteria-reduced fish block in each box, packaging the sturgeon blocks by adopting mixed gas, mixing the gas by using a gas proportion mixer, vacuumizing, inflating and sealing by using a controlled atmosphere packaging machine, and performing controlled atmosphere packaging to obtain sturgeon block finished products; the mixed gas is composed of 75% CO by volume percentage₂And 25% N₂Composition is carried out;

s4, storage: and (4) performing non-freezing storage on the sturgeon block finished product obtained in the step S3, performing cold storage at 4 ℃ in the first 4 days, and then storing at 0.5 +/-0.3 ℃.

Technical Field

The invention belongs to the technical field of processing and storage of aquatic products, and particularly relates to a non-freezing preservation method for fish blocks by combining bacteria-reducing pretreatment with modified atmosphere packaging.

Background

Fish meat is one of the main sources of animal protein for humans. Compared with livestock meat, the fish meat has high water content, abundant endogenous enzyme content and loose texture, so the fish meat is deteriorated and decayed quickly, and the shelf life of the fish meat stored under non-freezing condition is much shorter than that of the livestock meat. China is a large country for aquatic product production, and the fish yield accounts for almost more than half of the total aquatic product production. Consumers in China always prefer fresh fish, freshwater fish in the market of China is mainly sold in the form of fresh and live whole fish, seawater fish mainly comprises frozen and iced fresh whole fish, and few fresh raw fish blocks are sold. Compared with the whole fish and the boned fish fillet, the raw fish fillet product brings convenience to the consumers for removing the head, the viscera, the meat, the fillet, the fish bone and other troubles of the whole fish to the maximum extent compared with the current work and life rhythm which is increasingly accelerated. Not only saves time and labor for consumers, but also can meet the diversified and personalized processing/cooking requirements of people to the maximum extent. Therefore, the raw fish block is a product form which can simultaneously meet multiple requirements of consumers in China on freshness, convenience and larger processing freedom degree of fish meat. But why are the fresh fish block products very rare in our country's market? The reason is that the fish flesh is high in deterioration and decay speed, particularly, the fish blocks are infected with more or less spoilage bacteria in the processing and packaging processes of the raw fish blocks, the muscle tissues damaged in the cutting process are cut, endogenous enzymes are released at the cutting parts, and the speed of infecting the fish flesh by the spoilage bacteria is accelerated. The storage temperature of the fresh fish blocks is generally-3-4 ℃, and the reproduction of microorganisms and the activity of endogenous enzymes cannot be completely inhibited within the temperature range. Therefore, the processing and storage links of the raw fish blocks are great challenges for the production of the raw fish blocks, so that the freshness of the product form is reduced quickly, the shelf life is short, and a large amount of the product cannot enter the market. Therefore, there is an urgent need for continuous exploration and improvement of methods and techniques for controlling freshness of raw fish blocks and prolonging shelf life. The putrefying bacteria are the core reason for causing the quick putrefaction of the fresh fish blocks, so the control of the growth of the putrefactive bacteria is the key of the control of the processing and storage processes of the fresh fish blocks.

Disclosure of Invention

The invention provides a convenient, safe and effective pretreatment and storage method aiming at the problem that the fish meat quality is reduced rapidly in the non-freezing (cold storage, ice storage and ice temperature) fresh-keeping process of fish blocks. The quality of the fresh fish blocks is kept and the shelf life of the fish blocks is prolonged by adopting the means of combining the bacteria-reducing pretreatment with the modified atmosphere packaging.

The invention establishes an effective putrefying bacteria control technology starting from the whole process of processing and storage from the viewpoint of putrefying bacteria control. Mainly comprises two aspects of (1) pretreatment of the fish blocks after processing and before storage, namely reducing the number of putrefying bacteria in the fish blocks, and (2) inhibition of growth of the putrefying bacteria in the storage process, namely modified atmosphere packaging. The combination of the two aspects can obviously improve the freshness of the fish blocks in the storage process and prolong the shelf life of the fish blocks.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a non-freezing preservation method for fish blocks by combining bacteria-reducing pretreatment with modified atmosphere packaging comprises the following process steps:

s1, raw material pretreatment: removing viscera and head of raw material fish, removing scales, bloodstain and body surface mucus, washing with ice water, draining water, taking fish meat, and cutting into pieces; wherein the raw material fish is fresh whole fish;

s2, pretreatment for bacteria reduction: taking the fish blocks obtained in the step S1, soaking the fish blocks in the bacteria-reducing solution according to the material-liquid ratio of 1: 10-1: 20g/ml, soaking for 1-10 min at the temperature of 0-10 ℃, and then draining for 2-6 min; after the bacteria reduction treatment, putting the fish blocks into baking soda solution with the temperature of 0-10 ℃ and the pH value of 7-9, fishing out after 10-60 seconds, and draining for 2-6min to obtain the bacteria-reduced fish blocks;

wherein the bacteria-reducing solution is any one of the following solutions a to c:

a: 0.1-1% by mass of acetic acid solution;

b: 0.1-2% by mass of citric acid solution;

c: lactic acid solution with mass fraction of 0.1-2%;

s3, modified atmosphere packaging: placing the bacteria-reduced fish blocks in the step S2 into a modified atmosphere packaging box, mixing gas with a gas proportional mixer, and performing modified atmosphere packaging by vacuumizing, inflating and sealing with a gas-regulated packaging machine to obtain the bacteria-reduced fish blocksFish block finished products; the gas filled in the modified atmosphere package comprises the following components in percentage by volume: CO 2₂60 to 90% of N₂10-40%;

s4, storage: and performing non-freezing storage on the finished fish fillet products subjected to modified atmosphere packaging, wherein the non-freezing storage is cold storage, ice storage or ice-temperature storage, the cold storage temperature is 0-6 ℃, the ice storage is placed on or in ice, and the ice-temperature storage is placed at the temperature of-1 to-3 ℃.

Preferably, the raw fish in step S1 is freshwater fish or marine fish, preferably sturgeon.

Preferably, in the step S3, each box of the modified atmosphere packaging box is filled with one piece of bacteria-reducing fish blocks for modified atmosphere packaging; the gas used by the modified atmosphere package is 70 percent CO by volume percentage₂And 30% N₂And (4) forming.

In a preferred mode, the non-freezing preservation method of the fish blocks by combining the bacteria-reducing pretreatment with the modified atmosphere packaging comprises the following steps:

s1, pretreating raw materials, namely removing viscera, heads and body surface mucus of sturgeons, washing bloodstain, washing with ice water, draining, taking fish, and cutting into sturgeon blocks with the size of about 15cm, × 6cm, × 5cm and the like;

s2, pretreatment for bacteria reduction: taking the sturgeon blocks obtained in the step S1, soaking the sturgeon blocks in an acetic acid solution with the mass fraction of 0.2% according to the material-to-liquid ratio of 1:10g/ml, soaking at the temperature of 4 ℃ for 2min, draining for 4min, then placing the sturgeon blocks in a baking soda solution with the pH of 8 at the temperature of 4 ℃ for soaking for 0.5min, fishing out and draining for 4min to obtain the bacteria-reduced sturgeon blocks;

s3, modified atmosphere packaging: placing the bacteria-reducing fish blocks in the step S2 into modified atmosphere packaging boxes, wherein each box is provided with one bacteria-reducing fish block, and 75% CO is adopted according to volume percentage₂And 25% N₂Packaging the sturgeon blocks by the formed mixed gas, mixing the gas by a gas proportional mixer, and performing controlled atmosphere packaging by a gas-regulated packaging machine through vacuumizing, inflating and sealing to obtain sturgeon block finished products;

s4, storage: and (3) performing non-freezing storage on the sturgeon block finished product packaged in a modified atmosphere, performing cold storage at 4 ℃ for the first 4 days, and then storing at 0.5 +/-0.3 ℃.

The invention has the beneficial effects that: the method can effectively delay the deterioration of the quality of the fresh fish blocks in the non-freezing preservation process, improve the freshness of the fish blocks and prolong the shelf life of the fish blocks. Compared with the traditional method for refrigerating and preserving the fish fillets, the method can effectively reduce the quality reduction speed of the fresh fish fillets in the refrigerating process, and can effectively delay the increase of the total number of bacterial colonies, the pH value, the TVB-N value, the TBARS value and the K value in the fish fillets. The shelf life of the non-frozen fresh-keeping fish blocks can be obviously prolonged, and an important theoretical basis is provided for the non-frozen storage and fresh keeping of the fish.

Drawings

FIG. 1 shows the measurement results of K values of sturgeon fillets prepared in each example of the invention during storage;

FIG. 2 shows the TVB-N values of sturgeon blocks prepared according to various examples of the present invention during storage;

FIG. 3 shows the results of measuring the TBARS values of sturgeon blocks prepared according to various examples of the present invention during storage;

FIG. 4 shows the results of the determination of the total number of colonies of the sturgeon fillets prepared according to the invention during storage;

FIG. 5 shows the pH value of the sturgeon blocks prepared according to the examples of the present invention during storage.

Detailed Description

In order to make the advantages and purposes of the present invention more apparent, the technical solutions of the present invention are described in detail below with reference to specific examples, but the scope of the present invention is not limited to the examples. The invention takes sturgeon as raw material, adopts acetic acid bacteria reduction pretreatment combined with modified atmosphere packaging to slow down the oxidation speed of fish meat, inhibit the growth and reproduction of internal microorganisms and reduce the enzymatic reaction rate, thereby achieving the purpose of keeping the freshness of the sturgeon meat for a long time and prolonging the shelf life of the sturgeon meat and providing a new method for refrigerating and refreshing sturgeon blocks.