JPH04190737A - Thawing of frozen meat - Google Patents

Abstract

PURPOSE:To enable the thawing of frozen meat without lowering the quality by closely packaging a dressed and frozen meat with a specific sheet, putting the packaged meat into a thawing chamber maintained at a specific temperature, thawing the meat while lowering the temperature of the chamber and taking the meat out of the chamber when the central temperature of the meat reaches a specific level. CONSTITUTION:A dressed and frozen meat (preferably meat cut in the form of block) is closely packaged with a water-absorbing polymer sheet, charged into a thawing chamber maintained at >=20 deg.C, left standing for a prescribed period, thawed by lowering the chamber temperature in steps until the central temperature of the dressed meat reaches 0-3 deg.C and taken out of the thawing chamber to obtain the objective thawed meat.

Description

[Detailed description of the invention] <Industrial application field> This invention relates to a high temperature thawing method for frozen meat.

<Conventional technology> The methods of defrosting frozen meat generally include heating and defrosting methods,
Are electronic thawing methods, high-frequency thawing methods, etc. known? First, they are not suitable for processing large quantities in a short period of time, and are there any conventional heating thawing methods that can process large quantities? In some cases, large amounts of drips are unavoidable, and secondly, electronic or high-frequency thawing methods, which reduce the amount of drips that flow out and cause quality deterioration, can only process extremely small amounts, but are expensive and require complicated thawing equipment. There are various restrictions such as being considered as

On the other hand, due to restrictions imposed by the thawing method, so-called chilled meat is generally preferred for general household consumption. However, in the case of chilled meat cuts, the storage limit is said to be a maximum of 60 days after slaughter, depending on the type of meat. However, from a distribution point of view, this product can only be distributed for about 60 days at most, and if it is distributed for general household use, various problems must be faced. For example, in the case of imported beef, it often takes about 30 days for it to be tilted in the country of production and for customs clearance procedures to be completed in Japan if transported by regular ship, which is the so-called best-before period. The period has been cut down to less than half, and it is extremely difficult to ship the products in a planned manner in accordance with the day-to-day fluctuations in demand and consumption.

<Invention or problem to be solved> In the case of frozen meat, it has been confirmed that there is no deterioration in quality when stored for at least 6 months, so it is easy to ship it in accordance with daily fluctuations in consumption. be. However, in this case, as mentioned above, the advantages of frozen meat cannot be fully utilized because there is no means to thaw the meat in large quantities and in a short period of time without sacrificing quality as much as possible.

In other words, the leakage of water-soluble proteins involved in flavor, myoglobin, which is responsible for the color of meat, and vitamins useful as nutrients, which naturally occur when defrosting, is suppressed to the lowest possible level, resulting in a meat quality similar to that of Habotilted meat. It is necessary to provide thawed meat, and in order to do so, (1) thawing frozen portions should be done in as short a time as possible while minimizing changes in meat quality; During thawing time, it is essential that the temperature applied to the surface of the meat part is quickly replaced by the cold temperature of the center.

As a result of various studies, the inventor of the present invention has developed a method for packaging frozen meat cuts using a water-absorbing polymer sheet and changing and maintaining the temperature inside the refrigerator at a predetermined temperature according to the thawing stage. Requirements (1) and (2) above can be achieved by using heating and cooling means to maintain a uniform internal temperature, means for moving air within the refrigerator to maintain a uniform internal temperature, and a thawing warehouse equipped with thawing shelves. The present invention has been completed based on the discovery that the present invention is possible.

That is, the present invention provides the following steps: (1) Wrapping the frozen meat part in a water-absorbing polymer sort, and then packaging the frozen meat part tightly with a vacuum packaging film to keep the polymer sheet in close contact; (2) Wrapping the frozen meat part wrapped in this way Place the meat in a thawing chamber that has been maintained at a temperature of at least 20°C in advance and leave it for a certain period of time, and ■ After leaving it for a certain period of time, continue the thawing operation while gradually lowering the temperature inside the chamber, and then remove the portions of meat. This method relates to a method for thawing frozen meat, characterized in that a portion of meat is taken out from a thawing chamber when the temperature of the meat at the center reaches approximately 0°C to 3°C.

Furthermore, in the present invention, a water-absorbing polymer sheet is attached again to the thawed meat taken out from the thawing chamber, and after vacuum packaging with a vacuum packaging film that exhibits virtually no air permeability, the meat is kept in a stable refrigerated state and stored in the refrigerator. This invention relates to a method for thawing frozen meat characterized by the following.

The thawing method of the present invention can be applied to all kinds of meat, ie, chicken, mutton, pork, beef, and large fish such as tuna, and can be particularly preferably applied to beef.

The frozen meat to be thawed according to the present invention is preferably one that is normally butchered and further cut into blocks as partial meat.

As the water-absorbing polymer sheet used during thawing in the present invention, a sheet made by wrapping an absorbent material made by adding valves and the like to a water-absorbing polymer in a suitable polymer film can be used. Examples of water-absorbing polymers include polyacrylate, starch, isobutylene/maleic anhydride copolymer, polyhinyl alcohol/maleic anhydride copolymer, etc., which have a water absorption capacity of about 50 to 1000 times.
A carboxymethyl cellulose (CMC) crosslinked product or the like is used.

In particular, a water-absorbing polymer sheet commercially available from Nippon Vilene ■ under the trade name Drip Keeper for Thawing is preferably used.

In order to improve heat exchange efficiency, the water-absorbing polymer sheet needs to be kept in close contact with the surface of the frozen meat part for a long time, so the water-absorbing polymer sheet is tightly wrapped around the meat part and then vacuum-packed on top of it. Is it necessary to tightly package the product with protective film? As a film used for tight packaging, it is sufficient to maintain airtightness, so there is no need to select a film with a particularly low oxygen permeability.
Any film that can be used as a vacuum packaging film for packaging can be used without any problems.

Frozen meat cuts are usually backed up, so when using this thawing method, it is necessary to remove the bag. Of course, if the food is packaged with the above-mentioned water-absorbing polymer sheet and vacuum-packaged with a vacuum packaging film during freezing, it can be used as is for the thawing method according to the present method without the need to remove the pack. That is, in that case, the above-mentioned step (2) can be omitted.

The amount that can be thawed with this invention is about 5 kg to about 1 to
up to n, preferably 5 considering operating costs etc.
From 0 kg to 1 ton.

The thawing chamber used in the present invention must at least (1) have a structure that is not affected by outside temperature, (2) have means for heating and cooling to a specific temperature, and (3) (4) have a means to maintain a uniform temperature inside the refrigerator; and (5) have a means to change the temperature in stages according to the thawing situation. It is necessary to have a thawing rack designed to ensure that all cuts of meat are evenly exposed to the same temperature.

As a structure that is not affected by the outside temperature, a typical example is an insulating wall, or the material is not particularly important as long as it exhibits an insulating effect and does not adversely affect the food.

A heating device may be used as a means for heating to a specific temperature, but its heat generation source and structure are not limited. It is sufficient to have the ability to quickly raise the temperature inside the refrigerator to the set temperature within a predetermined time.

The means for lowering the temperature to a specific temperature may include a cooling device, and the type of refrigerant does not matter.

However, it is necessary to have the ability to quickly cool the inside of a refrigerator of a certain size to a specific temperature within a predetermined time. However, since the cooling capacity also depends on the type of meat to be thawed, it is necessary to have a capacity that can be changed as appropriate depending on the type of meat.

As a means of changing the temperature in stages according to the thawing situation, there is a program that can change the temperature in stages according to the amount and type of meat to be thawed, solid weight differences depending on the type of meat part, and combinations thereof. An example of such a device is a digital program controller manufactured by Rika Kogaku Co., Ltd. Of course, it is also possible to manually change the internal temperature based on the display on the thermometer. Particularly in the case of small quantities, a device that can be changed manually may be sufficient. However, since it requires strict temperature control over a long period of time, it automatically sets pre-programmed temperature conditions to ensure air volume regardless of the type of hanging, and can change the air speed as appropriate depending on the situation. It is necessary to have the ability to maintain a constant internal temperature at all times. Such means include, for example, an air curtain with an inoter function.

As a defrosting shelf, firstly it must have good thermal conductivity, secondly it must be able to withstand a considerable amount of weight, and thirdly it must not significantly disturb the uniformity of temperature inside the refrigerator, so heat conduction is required. Made of high-quality metal, the shelves on which the cuts are placed are made of slats, grids, or mesh to withstand the weight of frozen meat, and to ensure good air circulation without significantly interfering with the uniformity of temperature inside the refrigerator. It is preferable that the structure has sufficient voids. It is also preferable to attach casters to the legs of the shelf so that they can be moved.

When thawing approximately 1 ton of meat, a thawing chamber with a floor area of approximately 13 m is sufficient. Of course, the size of the thawing chamber can be selected as appropriate depending on the throughput, but it is not economical to have thawing chambers of various sizes from the standpoint of incidental equipment. The height should be about 3 m for workability.

That is, according to the method of the present invention, l to
A thawing warehouse with a floor space of about 13 square meters can be appropriately used for thawing until 1 ton.
By installing a plurality of warehouses as a unit, there is an advantage that the thawing operation can be performed quickly and continuously, and a larger amount can be thawed by defrosting at different times in each thawing warehouse.

Next, the defrosting conditions will be explained.

In order to thaw within a short time, it is necessary to perform rapid heat exchange under high temperatures, so the first step is to keep the temperature inside the thawing chamber at least 20℃ or above, but usually between 20℃ and above.
The thawing temperature of frozen meat is maintained at a relatively high temperature of 60°C, preferably about 40°C, wrapped in a water-absorbing polymer sheet, and further frozen meat portions tightly wrapped with vacuum packaging film are added. Leave at the above temperature for a specified period of time. The leaving time is selected depending on the type of meat, the size of the meat part, and the amount to be processed, but is usually about 2 to 5 hours.

Next, the temperature inside the refrigerator is lowered in stages. First of all 1
The temperature is rapidly lowered to 5°C to 35°C and maintained at this temperature for about 1 hour.

Further, the temperature is lowered again to 0° to 20°C and this temperature is maintained for about 1 hour. With this operation, the surface temperature of the portion of meat is approximately 5 to 100 liters.
The 0°C1 center temperature becomes approximately 0 to 3°C, and the thawing operation is completed.

Usually, the temperature is automatically controlled using a device that can be programmed for the above-mentioned temperature and time.

The selection of the temperature in each of the above-mentioned thawing processing steps and the selection of the time in the first step may be carried out in consideration of the purpose of thawing, the quantity, and the individual differences in the frozen meat portions.

The thawed portions of meat serve the purpose of cooling stabilization,
- Remove the packaging from thawing, apply a new water-absorbing polymer sheet, and then apply non-porous vacuum packaging film to absorb drips during refrigerated storage and maintain the original color and flavor of the meat. Vacuum packaging.

In terms of material, it may be the same as the water-absorbing polymer sheet used for thawing, or it may be one that absorbs drips during refrigerated storage.It is not necessary to wrap the entire portion of meat, but rather wrap it around the surface of the portion of meat. It is sufficient to attach a water-absorbing polymer sheet of an appropriate size. An example of such a water-absorbing polymer sheet is Trip Keeper manufactured by Nippon Vilene Co., Ltd.

The product vacuum-packed in this way can be stored in a regular commercial refrigerator. The cooling time in the refrigerator is preferably at least 5 to 7 hours depending on the individual differences in the meat part. Also, the internal temperature of the refrigerator is preferably 0 to 5°C. On the other hand, since the thawing chamber according to the present invention has a cooling device, after thawing is completed, the temperature inside the chamber is set to a predetermined 0 to 5°C, and the portion meat that has been thawed and re-vacuum-packed is re-packed. It can also be used for refrigerated storage by placing it on a thawing shelf and keeping it in a stable refrigerated state in the thawing chamber.

In this way, in terms of meat quality, thawed meat can be obtained that is comparable to chilled meat.

Hereinafter, the present invention will be explained using an example of the operation of this method when approximately 1000 kg of frozen beef portion is thawed, but the present invention is of course not limited to the following operation example.

Pre-processing of Frozen Meat Frozen meat is wrapped in a water-absorbing polymer sheet and trip keeper for thawing (manufactured by Nippon Hi-Lean Co., Ltd.), and the meat in that state is further vacuum-packed with a vacuum packaging film.

Frozen meat that has been vacuum packaged is placed on thawing shelves assembled with metal pipes.

Place the above frozen meat in a thawing chamber equipped with the following equipment.

The storage room is designed with insulated walls to block outside air.

The refrigerator has a heating function, a cooling function, and an air movement function to maintain the entire interior at a specified temperature.

It has the function of maintaining the inside of the refrigerator at a specified temperature for a specified period of time according to the desired quantity of thawed meat and individual differences in frozen meat, and then continuously lowering the specified temperature in stages.

How to unzip: Keep the above storage room stable at +40°C.

Frozen meat wrapped in a water-absorbing polymer sheet, vacuum-packed with vacuum packaging film, and arranged on a thawing shelf is placed in a thawing chamber at a constant temperature, and the interior of the warehouse is sealed. Approximately 5
Leave it for a while.

Using a digital program controller made by Rika Kogyo Co., Ltd., which was input with the program that had been assembled based on the original purpose, the temperature inside the refrigerator, which was initially set at +40℃, was then rapidly lowered to +30℃ to maintain this condition for about 1 hour. Leave it for a while. Furthermore, the temperature inside the refrigerator was rapidly lowered to +15° C. and the chamber was further left under this condition. As a result of this series of digital program adjustments, the food is allowed to stand at a temperature that is automatically thawed approximately 7 hours after the start of thawing. At the same time, the surface temperature of the partial meat is approximately +7°C1, and the temperature at the center of the partial meat varies between approximately 0°C and +3°C.

Post-thawing treatment: After thawing the meat, immediately remove the water-absorbing polymer sheet and vacuum packaging film used for thawing, and place a new water-absorbing polymer sheet on the muscle side of the meat (behind the surface fat side), such as a commercially available refrigerated product. Place a drip keeper for storage (manufactured by Nippon Vilene Co., Ltd.) on top of the drip keeper, and then place a non-breathable shrink film for vacuum packaging (for example, Bailiano, manufactured by Brace Co., Ltd.) on top of it.
The meat is vacuum packaged in a vacuum-packed container (Nog 0) and placed in a regular commercial refrigerator for at least 5 to 7 hours depending on individual differences, to cool down the temperature of the meat that has risen during thawing, and to bring the thawed meat into a stable refrigerated state.

Thus, according to the present invention, A. Heat exchange occurs at the film interface, and due to the heat conduction effect of the polymer sheet, the heat conduction within the frozen meat during thawing can be made uniform, eliminating uneven thawing of the thawed meat, and at the same time improving the consistency of the meat chunks. There is no brown discoloration band on the inside.

Also, since the meat is vacuum packed, the surface of the meat does not dry out at all.

B. Due to the high temperature thawing, the leakage water in the meat is quickly melted and absorbed into the polymer sheet, which prevents excessive leakage and prevents the leakage of frozen meat juices, which have a lower melting point than frozen water, after thawing. It has the effect of keeping the color of thawed meat at its original red color, and as a result, preserves the original flavor of the meat.

By absorbing the C0 leakage moisture into the water-absorbing polymer sheet, the leakage moisture is prevented from being reabsorbed into the meat mass, and as a result, deterioration and discoloration of the meat surface are prevented.

D. Despite high-temperature thawing, water-absorbing polymer sheets are used to maintain the inner and outer surface temperatures at the heat exchange temperature, which prevents boiling of the meat surface and always maintains the appropriate thawing temperature to prevent protein denaturation. It does not occur.

E1 Several types of frozen meat with significantly different individual differences and weight differences can be thawed at the same time. For example, you can thaw pork fillet and beef thigh at the same time.

In addition, by sequentially exposing thawed meat to a pre-programmed thawing temperature, it has the advantage that a large amount of thawed meat can be processed in a short period of time while maintaining the quality of the thawed meat at approximately the same level as chilled meat.

In this way, the portion meat itself is thick (and heavy, which causes uneven thawing and a large amount of dripping. By thawing the island, it is possible to supply chilled portion meat, and various portions can be divided into small pieces according to demand, and commercial It can be used for various purposes in all fields of general household use.

Claims (2)

[Claims] (1) [1] Wrapping the frozen meat part with a water-absorbing polymer sheet and then tightly packaging it; [2] Pre-maintaining the frozen meat part wrapped in this way at a temperature of at least 20°C or higher. Place the meat in the thawing chamber and leave it for a certain period of time, and [3] After leaving it for a certain period of time, continue to thaw while gradually lowering the temperature inside the chamber until the temperature of the center part of the meat is approximately 0℃ to 3℃. A method for thawing frozen meat, which is characterized by taking out a portion of meat from a thawing chamber when the meat is frozen. (2) In the method of claim 1, further, the packaging of the thawed meat taken out from the thawing chamber is removed, a water-absorbing polymer sheet is affixed to the thawed meat again, and a substantially non-permeable vacuum packaging film is further applied. After vacuum packaging, it is stored in a stable state under refrigeration.