JP2008295435A - Method for high-quality freezing of bone-removed meat, freezer therefor and high-quality frozen meat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a high-quality freezing method that eliminates drip occurrence during thawing, removes meat cracks occurring on the surface of fat side during freezing and keeps the meat in a high-quality state for a long period of time. <P>SOLUTION: In the method for high-quality freezing of bone-free meat by rapidly passing bone-free meat through a maximum ice crystal formation temperature zone, the bone-free meat (m) precooled to 0 to 7°C is brought into contact with a cold energy at -45°C to -65°C so that the meat is rapidly passed through the maximum ice crystal formation temperature zone, the temperature distribution of the cold energy (r) in contact with the bone-free meat (m) during the passage of the maximum ice crystal formation temperature zone is differed and the formation of ice crystal in the bone-free meat (m) is directed at least in one coordinate direction. Therefore, the bone-free meat is frozen so that the most delayed point (t) of the ice crystal formation in the bone-free meat (m) is eccentrically-located from the position of the center of gravity of the bone-free meat (m) to the surface layer side and then the cold energy contact is continued until the core temperature of the bone-free meat (m) is dropped to ≤-20°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention is the occurrence of cell membrane destruction and cracking during freezing when freezing partial meat of meat, block meat, or cut meat from which bone has been removed from carcasses of livestock such as cattle, horses, pigs, and sheep. High quality freezing method for boneless meat that can be preserved in a high quality state for a long period of time. The present invention relates to an apparatus suitable for carrying out a quality freezing method, and high-quality frozen meat frozen by the high-quality freezing method.

  Conventionally, frozen meat that has been slowly frozen in the maximum ice crystal formation temperature range (0 to -several degrees Celsius), or frozen so that the cell membrane is destroyed even by intracellular freezing by rapid freezing has a large amount of drip when thawed Therefore, there is a problem that the yield decreases and the umami component flows out. This is because, even in the case of intracellular freezing, the cell membrane of the meat is destroyed by the ice crystals that are formed and enlarged when the meat is frozen. For this reason, chilled (unfrozen) meat is more valuable and is distributed as fresh meat. On the other hand, chilled meat imported from foreign countries is transported for a long period of time (about 3 weeks), causing netting and struggling with countermeasures.

  Since the latent heat temperature region (synonymous with the maximum ice crystal formation zone) for generating ice crystals is usually between -1 ° C and -5 ° C, the conventional quick freezing method shortens the maximum ice crystal generation temperature zone. By passing it through time, the ice crystal grains are kept small. In this case, since the surface of the meat is sensitive to the ambient temperature of the freezer compartment, the problem is the center of the meat where heat conduction is delayed.

  Patent Document 1 (Japanese Patent Laid-Open No. 51-142561) discloses a method for rapidly freezing pork carcasses. An object of the present invention is to eliminate the occurrence of cracks on the fat side surfaces of the thigh and shoulder which are the maximum thickness of pork carcasses. In the present invention, the fat side surface of the maximum thickness portion is embrittled at a critical temperature (specifically −40) while performing quick freezing in which the central portion of the maximum thickness portion passes through the maximum ice crystal formation temperature zone in a short time. The temperature of the freezer is controlled so as to be kept at a low temperature within a range not reaching (° C.).

  Patent Document 2 (Japanese Patent Application Laid-Open No. 57-65149) relates to a rapid cooling method for large-sized slaughtered meat such as cattle and pigs. The carcasses that have undergone a series of pretreatment steps after slaughtering are -20 to -15 ° C. Then, the surface lipid part is cooled to about 0 ° C with cold air, and then cooled with -5 ° C to 0 ° C for several hours until the core part becomes 15 ° C to 20 ° C (precooling), The cooled carcass is divided into partial meats at each part, and the partial meats are brought into contact with a cooling belt cooled to -25 ° C to -30 ° C to make a chilled state. By such a treatment, the carcass cooling time can be shortened to several hours.

  In addition, the invention of Patent Document 3 (Japanese Patent Laid-Open No. 58-20145) prevents whitening phenomenon in the freezing process of raw hamburger, raw meatballs, etc., maintains the quality and makes the flesh color bright red For the purpose of maintaining, the processed meat is frozen so that the time required for the surface layer portion of the processed meat to pass through the latent heat temperature zone is 30 minutes to 10 hours. That is, the reason for the whitening of the true meat is that fine ice crystals are formed on the surface of the processed meat, which causes the diffuse reflection of light, and the passage through the maximum ice crystal generation temperature range is compared. By performing the process slowly, the generation of fine ice crystals that cause diffuse reflection of light is reduced.

Japanese Patent Laid-Open No. 51-142561 JP 57-65149 A JP 58-20145 A

  When the to-be-frozen meat passes the maximum ice crystal generation temperature zone, the surface portion is first frozen, and the escape from the surface portion is concentrated on the central portion, and the expansion pressure at the central portion increases. Thereafter, the central portion expands further due to freezing, and a large internal stress is generated. The greater the wall thickness, the greater the internal stress. For this reason, the fat-side surface of the thick part cannot withstand this and causes cracks. The commercial value of the frozen meat decreases due to the occurrence of cracks.

  In Patent Document 1, the fat side surface of the maximum thickness portion is kept at a low temperature within a range not reaching the embrittlement critical temperature (specifically −40 ° C.), thereby preventing the occurrence of cracks. Since the freezing temperature is restricted by this, the cooling rate cannot be increased, and therefore the time required for freezing cannot be significantly shortened. For the above reason, the time for the central portion of the meat to be frozen to pass through the maximum ice crystal generation temperature zone cannot be shortened by a certain time or more, and therefore, the enlargement of ice crystals in the central portion cannot be avoided to some extent.

In the present invention, in view of the problems of the prior art, in the case of rapidly freezing a cut meat obtained by dividing a carcass of livestock and removing bones, or a cut meat obtained by cutting them according to purposes such as tonkatsu and steak Another object of the present invention is to eliminate the occurrence of drip during thawing by eliminating the destruction of the meat cell membrane. The objective is to reduce costs by optimal freezing.
Another object of the present invention is to realize a high-quality freezing method that can be stored in a high-quality state for a long period of time while eliminating cracks that occur on the fat-side surface during freezing.

More specifically, the target processed meat is roast after removing bones such as ribs, femurs, shank and humerus from carcasses of sheep, horses, cows, wild boars, bears and other animal meats in addition to pigs. (Sirloin), fillet (tenderloin), shoulder loin, three pieces of meat (Calbi), or any of the thighs (the meat is a lump of raw meat) and does not include bone-in meat, tail, or internal organs . However, beef tongue is included in the true meat because it is a cut meat, but it does not include chopped meat or minced meat.
The reason why the meat with no bone is not included is that the temperature distribution during freezing differs between the bone and the meat, and the reason why the visceral meat is not included is because the tissue of fat or meat is different.

  Further, the object to be processed is refrigerated raw meat precooled at 5 to 0 ° C. so that the freezing time and the freezing start point do not vary. The high-quality freezing referred to in the present invention refers to one that has been frozen in a state in which cell depletion is eliminated. Here, the sashimi is also referred to as a fat cross, and this marbling enters pork as well as marbled beef. In addition, the greater the fat cross, the softer the meat, the more the fat in the meat melts and feels better, but when there is a cell disruption, it becomes fat, stiff and hard. Therefore, it can be said that high-quality frozen meat is frozen in a state where the meat has a finely cut portion in the cross section. Furthermore, even when this state is stored at a low temperature, it is most preferable that the state can be maintained for one year or longer (high quality long-term storage), but in the present invention, the state can be maintained for one month or longer (high quality medium term). For storage).

In order to achieve such an object, the high-quality freezing method for boneless meat of the present invention comprises:
When thawing parts of animal meat (including block meat) from which bone has been removed from carcass, or cut meat (hereinafter referred to as boneless meat) that has been cut according to the purpose, by eliminating the occurrence of cell membrane destruction and cracking during freezing It is a high-quality freezing method for boneless meat that can prevent the spill of umami and can be frozen and stored in a high-quality state for a long period of time,
At least one surface layer of the boneless meat pre-cooled to 0 to 7 ° C. is brought into surface contact with cold energy of −20 ° C. or less to perform rapid cooling, and the other surface layer is slowly cooled by cold air,
The ice layer formation at the maximum ice crystal formation temperature zone is started from one side of the surface layer on the quick freezing side, and the most delayed point of ice crystal formation in the boneless meat is slowly cooling from the center of gravity position of the boneless meat The cold energy intensity applied to the surface layer side portion of the boneless meat so as to be unevenly distributed in the vicinity of the surface of the boneless meat is weaker than the cold energy intensity applied to the other surface layer located on the opposite side of the surface layer of the boneless meat In this state, the first freezing treatment is performed by passing through a maximum ice crystal generation temperature range of 0 to −several degrees Celsius.

  As a result, the meat can be frozen in a state in which a large portion of the meat is included in the cross section of the meat, which can be referred to as high-quality frozen meat. In this case, cold energy of −45 ° C. to −65 ° C. is applied from one side of the surface layer that is rapidly frozen following the first freezing process, and the core temperature of the boneless meat falls to −20 ° C. or lower. By continuing the contact of the cold energy until it is done, in the present invention, the state can be stored for more than a month (high quality medium-term storage).

Further, after the first freezing treatment is completed, the boneless meat is moved into a static space, and is −45 to −60 ° C. from one side or both sides of the surface layer until the core temperature of the boneless meat drops to −20 ° C. or lower. By continuing the application of cold energy, homogeneous frozen meat can be produced.
Further, after completion of the first freezing treatment, the boneless meat is moved into a static space, and the temperature of the boneless meat is less than the above temperature from one side or both sides until the core temperature of the boneless meat drops to -45 ° C to -65 ° C. By continuing the application of cold energy, it can be stored for more than a year (high quality long-term storage).

  In the method of the present invention, the bone-free meat can be rapidly frozen by bringing the to-be-frozen meat pre-cooled to 0 to 7 ° C. into one side with low-temperature cold energy of −45 ° C. to −65 ° C., and the maximum ice crystal formation temperature You can pass the belt in a short time. That is, in the case of partial meat or block meat in the present invention, after the frozen meat pre-cooled to 0 to 7 ° C. passes through the maximum ice crystal formation temperature zone, the bone temperature of the boneless meat drops to −20 ° C. or less. Within minutes, in the case of cut meat, let it pass within 45 minutes. Thereby, it is possible to prevent the growth or enlargement of ice crystals when passing through the maximum ice crystal generation temperature zone, and it is possible to prevent destruction of the meat cell membrane by the grown ice crystals. The maximum ice crystal generation temperature zone is, for example, −1.5 ° C. to −3 ° C. for the pork loin partial meat.

  When the periphery of the meat is cooled with a uniform temperature distribution, the surface layer of the meat is first frozen, and ice crystals are formed on the surface layer. The escape from the expansion of the ice crystals concentrates on the center, and the expansion pressure at the center increases. Thereafter, the central portion expands due to freezing, and a large internal stress is generated. The greater the wall thickness, the greater the internal stress.

In the present invention, at least one surface layer of the boneless meat pre-cooled to 0 to 7 ° C. is brought into surface contact with cold energy of −45 ° C. to −65 ° C. or less to perform rapid cooling, and the other surface layer is slowly cooled by cold air. By cooling, it cools with a different temperature distribution depending on the part of the boneless meat, and forms a temperature gradient toward the slow cooling side. Thereby, the generation temperature distribution of the ice crystals in the boneless meat when passing through the maximum ice crystal generation temperature zone is oriented in the slow cooling coordinate direction. For this reason, the expansion pressure generated by the expansion of the ice crystals on the surface portion does not concentrate on the central portion, and can be released to a part of the surface layer side. In this way, by directing the generation of ice crystals in the coordinate direction on the slow cooling side, the most delayed point that freezes at the end is located not in the center of the meat but in the vicinity of the surface side of the slow cooling side of the meat. For this reason, a big internal stress does not generate | occur | produce in the center part of meat.
As a result, cracks due to the internal stress are not generated in the surface layer portion of the frozen meat, particularly the fat side surface. However, if a bump-like unique bump occurs, this is taken as a high-quality indicator.

  In the method of the present invention, if the freezing temperature is higher than −45 ° C. (warm), high-quality freezing cannot be performed. On the other hand, when cooling at a temperature lower than -65 ° C, the temperature of the boneless meat becomes too steeply decreasing, and ice crystals are rapidly generated in each part of the boneless meat. It becomes impossible to give directionality to the formation of crystals. Therefore, the cold energy temperature to be brought into contact with one side of the present invention is set to -45 ° C to -65 ° C. Further, in the present invention, since it is frozen at an extremely low temperature of −45 ° C. or less, “freezing burn” on the meat surface can be prevented.

  In the method of the present invention, the generation distribution of ice crystals in the boneless meat may be directed from the two-coordinate side. In short, it is only necessary to ensure at least one direction of escape that allows the inflation pressure generated by the expansion of ice crystals to escape to the surface layer side.

  Preferably, the freezing energy of the method of the present invention is such that cold energy of −45 ° C. to −65 ° C. is applied from one side of the surface layer, which is rapidly frozen following the first freezing treatment, The contact with the cold energy may be continued until the core temperature falls below −20 ° C. (using a normal spiral conveyor), or after the first freezing process, the boneless meat is placed in a static space. Until the core temperature of the boneless meat drops below -20 ° C, the application of cold energy of -45 to -60 ° C from one side or both sides of the surface layer may be continued (in the form of a normal tunnel) A formed freezer (using a steel belt or mesh belt) and a batch refrigerator).

  In such a configuration, the moving body is cooled by cold energy, and the cooling action on the boneless meat is performed mainly through the contact surface with the moving body. Therefore, since a temperature gradient is formed in which the cooling temperature rises from the contact surface toward the opposite surface, and ice crystals are generated from the contact surface toward the opposite surface. It can be unevenly distributed in the vicinity of the opposite surface. Therefore, the bulging pressure generated by the ice crystals can escape to the opposite surface side, so that no large internal stress is generated at the center of the boneless meat.

  In addition, in the freezer or spiral freezer method formed in a tunnel shape using such a belt freezer, the boneless meat can be continuously frozen while being placed on a moving body, so that the freezing process can be performed quickly. And can be performed efficiently. Furthermore, the freezing time can be adjusted by adjusting the moving speed of the moving body.

With such a belt freezer, as a means for cooling at different temperature distributions depending on the part of the boneless meat, the surface one-side freezing treatment is performed on the moving body whose surface is a mesh belt (perforated metal plate) or a steel belt. The bottom surface of the meat is placed, and a collision jet of cold energy of −45 ° C. to −65 ° C. is ejected from the lower part of the belt through the belt toward the boneless meat, and the upper part is open space, and the slow cold air is There is no slow cooling space in contact, or the surface one side freezing treatment is performed by placing a boneless meat bottom surface on the moving body with a heat insulating material on the belt and −45 ° C. from above the boneless meat. You may eject the collision jet by the cold energy of -65 degreeC.
In addition, both the upper and lower surfaces of boneless meat consisting of block meat and partial meat are supported on the moving body consisting of a mesh belt (perforated metal plate) or steel belt so that the boneless meat is sandwiched and supported by the boneless meat. It is possible to eject a collision jet of cold energy of −45 ° C. to −65 ° C. from below the belt through both sides of the boneless meat, and open both sides of the boneless meat.
When boneless meat is put in a container (box) and frozen, the boneless meat can be transported to the freezer compartment after freezing and stored in a freezer, facilitating work.

  In addition, when using a mesh belt, in addition to the cooling effect caused by the contact between the boneless meat and the mesh belt, the cooling effect by the cooling energy passing through the pores of the mesh belt is added, so the lower limit value of the cooling energy temperature May be set to −50 ° C.

  In the method of the present invention, as another embodiment, the cooling liquid is showered from above on boneless meat placed on a resin or heat insulating conveyor, and the upper surface side of the boneless meat is rapidly cooled and the lower surface side is cooled slowly, The generation of ice crystals in the boneless meat when passing through the maximum ice crystal generation temperature zone may be directed from the upper surface side to the lower surface side. If it does in this way, the freezing process of this invention can be implemented with a comparatively simple apparatus structure. In addition, since the freezing process can be performed while transferring the boneless meat on the conveyor, the freezing process can be performed continuously and systematically.

  As still another embodiment of the method of the present invention, the coolant liquid is showered from above on boneless meat placed on a conveyor so that the temperature distribution of the cold energy contacting the boneless meat differs between the upper and lower surfaces of the boneless meat. Thus, the generation of ice crystals in the boneless meat when passing through the maximum ice crystal generation temperature zone may be directed in at least one coordinate direction. Even in such a configuration, the freezing process of the present invention can be performed with a simple apparatus configuration, and the freezing process can be performed while transferring boneless meat on a conveyor, so that the freezing process can be performed continuously and systematically.

  Moreover, if the to-be-frozen meat is degassed and subjected to a freezing treatment, the to-be-frozen meat can be prevented from being dried, and adhesion of germs can be avoided. In addition, after freezing storage, it can be distributed as it is.

In the method of the present invention, after the boneless meat is subjected to the freezing treatment and passed through the maximum ice crystal formation temperature zone, the boneless meat is kept in contact with the cold energy until the core temperature of the boneless meat drops below -20 ° C. To do. Thereafter, if the boneless meat is stored in a static space of -20 ° C. or lower, it can be stored in a high quality state for a period of one month or longer.
In the method of the present invention, preferably, after the boneless meat is subjected to the freezing treatment and passed through the maximum ice crystal formation temperature zone, the boneless meat has a core temperature that falls to -45 ° C to -65 ° C. If boneless meat is kept in contact with cold energy and then stored in a static space of -45 ° C to -65 ° C, it can be stored in a high quality state for a long period of more than one year. become.

Next, as a device suitable for carrying out the method of the present invention, the device of the present invention is:
When thawing parts of meat (including block meat) from which the bone has been removed from the carcass, or cut meat (hereinafter referred to as boneless meat) that has been cut according to the purpose, it eliminates cell membrane destruction and cracking during freezing. It is a high-quality freezing device for boneless meat that prevents spillage of umami and can be frozen and stored in a high-quality state for a long period of time,
A closed space for freezing the boneless meat pre-cooled to 0 to 7 ° C., a quick freezing means for bringing one surface of the boneless meat in the space into surface contact with cold energy of −20 ° C. or less, and an open space on the other surface Or it has a slow cooling means that slowly cools the cold air and slowly cools the other surface side of the boneless meat,
The maximum ice crystal generation temperature zone ice crystal generation is started from one surface layer side of the quick freezing means side, and the latest delay point of ice crystal generation in the boneless meat is slower cooling than the center of gravity position of the boneless meat Cold energy to be applied to the other side of the surface of the boneless meat that is applied to the surface of the boneless meat so as to be unevenly distributed in the vicinity of the surface on the other side of the surface layer. The first freezing process is performed by passing the maximum ice crystal generation temperature range of 0 to −several degrees Celsius in a state weaker than the strength.

  In this case, the quick freezing means can apply a cooling energy of −45 ° C. to −65 ° C. from one side of the surface layer, and the contact of the cooling energy can be continued until the core temperature of the boneless meat falls to −20 ° C. or lower. The first freezing treatment means is a freezer formed in a tunnel shape through which a steel belt or a mesh belt is inserted, and the bone-free meat conveyed from the freezer is used. The freezer that moves into a static space and continues to apply cold energy from -45 ° C to -65 ° C from one or both sides of the surface layer until the core temperature of the boneless meat drops to -20 ° C or lower in the static space And a batch type freezer.

  More preferably, the contact body is formed with a recess for storing the workpiece, and the contact body and the workpiece are in contact with each other on the bottom surface and the side surface of the contact body and are processed in the recess. The open space may be formed so as to face the upper surface of the workpiece. The concave portion may be configured to extend in the longitudinal direction of the moving body, or may be a plurality of independent concave portions arranged in parallel in the longitudinal direction of the moving body.

  According to the apparatus of the present invention, ice crystals from the contact surface with the contact body to the opposite surface facing the open space can be formed while conveying boneless meat on the moving body, so that it passes through the maximum ice crystal generation temperature zone. The most delayed point of time can be formed in the vicinity of the opposite surface. Therefore, since the expansion pressure generated by the expansion of the ice crystals escapes from the opposite surface, no internal stress is generated in the boneless meat. Therefore, no crack is generated in the surface portion of the boneless meat.

  In addition, the high-quality frozen meat of the present invention is generated in such a manner that the generation direction of the maximum ice crystal generation temperature zone of the boneless meat is generated from one surface side to the other side, By directing the formation of ice crystals in at least one coordinate direction, the most delayed point of ice crystal formation in the boneless meat is unevenly distributed on the surface layer side from the center of gravity of the boneless meat, and the core temperature of the boneless meat is Is maintained at −20 ° C. or lower, and there is no cell membrane destruction in the cross-section of the frozen meat, and a high-quality frozen meat characterized in that there is no time change in the “seed” state can be obtained.

The high-quality frozen meat of the present invention rapidly passes through the maximum ice crystal formation temperature zone by bringing boneless meat pre-cooled to 0 to 7 ° C. with cold energy of −45 ° C. to −65 ° C. Sometimes no ice crystal enlargement occurs. Therefore, there is no destruction of meat cells and no drip is generated during thawing.
In addition, cooling at different temperature distributions depending on the boneless meat part, and by directing the formation of ice crystals in the boneless meat in at least one coordinate direction when passing through the maximum ice crystal generation temperature zone, Since the most delayed point of ice crystal generation is unevenly distributed on the surface side of the center of gravity of the boneless meat, no internal stress is generated in the boneless meat. For this reason, cracks due to internal stress do not occur on the surface portion.
Accordingly, it is possible to realize a boneless meat in a “seed” state in which there is no cracking, no yield reduction during thawing, and no umami component flows out.

  The high-quality frozen meat of the present invention can be produced by the apparatus of the present invention, for example, a combination of the spiral freezer or the freezer formed in a tunnel shape and a batch freezer. In this case, the high-quality frozen meat of the present invention is placed in a cooling space and the surface is placed on a moving body made of a mesh belt (perforated metal plate) or a steel belt, and is placed on the placing surface of the moving body. A collision jet is formed from above and below by cold energy of −45 ° C. to −65 ° C., and is frozen by surrounding the moving body with cold energy of −45 ° C. to −65 ° C. Is located in the vicinity of the open surface on the opposite side facing the mounting surface of the moving body.

The high-quality frozen meat of the present invention is obtained by subjecting the boneless meat to the cold temperature until the core temperature of the boneless meat drops below −20 ° C. after the bone free meat is subjected to the freezing treatment and passed through the maximum ice crystal formation temperature zone. The energy contact is continued to obtain frozen meat in a “seed” state without cell membrane destruction.
Thereafter, if the frozen meat is stored in a static space of −20 ° C. or lower, it can be stored in a high quality state for a period of one month or longer.
In the high-quality frozen meat of the present invention, preferably, after the bone-free meat is subjected to the freezing treatment and passed through the maximum ice crystal formation temperature zone, the core temperature of the bone-free meat is -45 ° C to -65 ° C. If the boneless meat is kept in contact with the cold energy until it is lowered to obtain frozen meat, and then the frozen meat is stored in a static space of -45 ° C to -65 ° C, it is of high quality for a long period of more than one year. It can be saved in the same state.

Furthermore, in the high quality frozen meat of the present invention, the generation direction of the maximum ice crystal generation temperature zone of the boneless meat is generated from the both sides of the boneless meat toward the center, and the latest delay of ice crystal formation in the boneless meat is generated. When the points are unevenly distributed on the left and right circumferential surfaces from the center of gravity of the boneless meat and the core temperature of the boneless meat is maintained at -20 ° C. or lower, there is no cell membrane destruction in the cross section of the frozen meat. It is also possible to obtain high-quality frozen meat characterized by the fact that there is no temporal change in the “sauce” state.
More preferably, the generation direction of the maximum ice crystal formation temperature zone of the boneless meat is generated from the both sides of the boneless meat toward the center, and the latest delay point of the ice crystal formation in the boneless meat is the boneless meat. By storing the boneless meat on the left and right peripheral surfaces from the center of gravity and maintaining the core temperature of the boneless meat at −45 ° C. to −65 ° C., there is no cell membrane destruction in the cross section of the frozen meat. It is also possible to obtain high-quality frozen meat characterized by no change in state over time.

  The present invention is applicable to livestock, for example, processed block meat such as cows, horses, pigs and sheep, partial meats, or cut meats thereof. Sites include loin (sirloin), fillet (tenderloin), shoulder loin, triple meat (kalbi), thigh and the like.

  According to the method of the present invention, at least one surface layer of boneless meat precooled to 0 to 7 ° C. is brought into surface contact with cold energy of −20 ° C. or less to perform rapid cooling, and the other surface layer is slowly cooled by cold air. Thus, the maximum ice crystal generation temperature zone ice crystal generation is started from the surface layer side of the quick freezing side, and the latest delay point of ice crystal generation in the boneless meat is slower cooling than the center of gravity position of the boneless meat The cold energy intensity applied to the surface layer side portion of the boneless meat so as to be unevenly distributed in the vicinity of the surface on the other surface side of the surface layer, than the cold energy intensity applied to the other surface layer located on the opposite side of the surface layer side of the boneless meat In the weakened state, the first freezing treatment is performed by passing through the maximum ice crystal formation temperature range of 0 to −several degrees Celsius, thereby preventing the ice crystals from becoming enlarged and causing no cell destruction or cracking. Frozen storage in high quality state Possible to become. Further, since no drip is generated at the time of thawing, a high value-added boneless meat can be realized in which the yield does not decrease and the umami component does not flow out. Furthermore, since it is frozen at an extremely low temperature, “freezing burns” can be prevented.

  Further, according to the apparatus of the present invention, the closed space for freezing the boneless meat pre-cooled to 0 to 7 ° C, and the quick freezing means for bringing the boneless meat surface layer in the space into surface contact with cold energy of -20 ° C or less. And a slow cooling means that slowly cools the other surface side of the boneless meat by slowly circulating open space or cold air on the other surface layer, and a maximum ice crystal formation temperature zone from one surface layer side of the quick freezing means side When the ice crystal formation is started, the latest delay point of ice crystal formation in the boneless meat is unevenly distributed in the vicinity of the surface on the other side of the surface layer where the cooling is slower than the center of gravity of the boneless meat. The maximum ice crystal of 0 to −several degrees Celsius in a state in which the cold energy intensity applied to the surface layer side of the boneless meat is weaker than the cold energy intensity applied to the other surface layer located on the opposite side of the one surface layer of the boneless meat The first freezing process is performed through the generation temperature zone. And allows the internal stresses due to expansion of ice crystals in the maximum ice crystals forming temperature zone during the passage to obtain a high-quality frozen meat does not occur.

  In addition, according to the high-quality frozen meat of the present invention, since the freezing treatment is performed by the method of the present invention, there is no cell membrane destruction, so that no drip occurs at the time of thawing and the surface portion is cracked due to internal stress. It is possible to realize a high-quality frozen body in the “seed” state without any.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.
(Embodiment 1)

  FIG. 1 shows a steel belt type freezer (a freezer formed in a tunnel shape) for carrying out the freezing step of the present embodiment, and the entire configuration of this freezer is well known. Is a perspective view showing a freezer and the like. In FIG. 1, this freezer is composed of a horizontally long casing 10 composed of a plurality of modules 11, and is provided with a conveyor 12 consisting of a conveyor belt 12 a that penetrates the bottom of the casing from the inlet toward the outlet. The conveyor belt 12a mounts a workpiece m, which is a member to be processed, to form a conveyance space, and an upper jet portion 14 and a lower jet portion 15 are provided on both upper and lower surfaces.

  The turbulent cooling energy generated by the impinging jet is brought into contact with the conveyor belt 12a and the meat m to be frozen through the upper and lower jet portions 14 and 15 each having a large number of jet slits 14a and 15a, thereby cooling efficiency. A high cooling space is formed. Such a high-efficiency heat transfer allows the meat m to be frozen to be cooled or frozen. That is, the cold air cooled by an air cooler (not shown) and ejected from the blower 17 is branched into the upper and lower bifurcated cold air recirculation passages 21a and 21b and introduced into the blowing ports of the upper jet portion 14 and the lower jet portion 15 in the cooling space. ing. Further, a gull wing door 13 for internal inspection is provided.

  The conveyor belt 12a is made of a steel belt made of a good heat conductor made of a thin stainless steel material, cooled by cold air, and the meat m to be frozen placed on the steel belt is transferred to the steel belt and the frozen meat. Cool from the contact surface with m. A mesh belt in which the steel belt is formed in a mesh shape having a large number of pores may be used. In this case, the to-be-frozen meat m placed on the mesh belt is cooled in contact with the mesh belt cooled by the cold air ejected from the lower jet section 15, and is ejected from the lower jet section 15 and the finely-squeezed meat m. It is cooled by the cold air coming in contact through the holes (for details, see JP-A-11-63777).

A first embodiment of the present invention will be described with reference to FIG.
FIG. 2 is a schematic view showing a state in which the meat m to be frozen is placed on the steel belt 12a shown in FIG. In FIG. 2, a cold collision jet r ₁ is formed from a large number of jet slits 15 a of the lower jet part 15 toward the steel belt 12 a at the lower part of the steel belt 12 a. The temperature of the impinging jet r ₁ is −45 ° C. to −65 ° C., and the flow velocity is 15 to 20 m / s. In the upper steel belt 12a, the cold air ejected from the upper jet unit 14 are stopped, the cool air r ₂ for stirring the following velocity 2m / s is formed by the cold air agitation fan 16 instead (one slow Freezing).

  In such a configuration, the to-be-frozen meat m pre-cooled to 5 to 7 ° C. is placed on the steel belt 12a and transmitted from the contact surface with the steel belt 12a while being conveyed in the direction of arrow a in the freezer. It is rapidly cooled from one side (bottom side) by cold air at a temperature of from -C to -65C. The to-be-frozen meat m is a partial meat obtained by dividing the carcass or a cut meat (for example, a cut meat for tonkatsu) obtained by cutting them for different purposes. For example, it is a cut meat for pork cutlet obtained by further cutting a partial meat of a boneless loin after cutting a pork carcass to remove bone.

  In the case of pork loin, the maximum ice crystal formation temperature range is -1.5 ° C to -3 ° C, and the cold air is an extremely low temperature of -45 ° C to -65 ° C. After that, it passes through the maximum ice crystal formation temperature zone in a short time. The time to drop below 20 ° C after passing through the maximum ice crystal formation temperature zone is within 60 minutes, preferably within 45 minutes for pork loin partial meat, and when pork loin is cut meat for tonkatsu, Within 10 minutes. In the present embodiment, the frozen meat m is mainly cooled on one side from the contact surface side with the steel belt 12a, so that the generation of ice crystals is directed from the contact surface to the opposite surface (upper surface, stirring fan 16 side). Proceed in the b direction. Accordingly, the solidification line c connecting the points at which ice crystals are generated at the same time is as shown in FIG. 2, and the most delayed point t at which ice crystals are finally generated is unevenly distributed near the top surface of the meat m to be frozen. (Hereinafter referred to as freezing treatment).

After the freezing treatment by the steel belt freezer, the to-be-frozen meat m is transferred into the batch-type freezer 18 that forms a stationary space s ₁ having the same temperature as the freezer atmosphere temperature and frozen. The batch-type freezer 18 is provided with a transfer belt conveyor 18a that can move up and down at the entrance, and a moving carriage 19 having a plurality of belt conveyors 19a arranged in multiple stages in the horizontal direction and wheels 19b at the bottom. ing. In the batch type freezer 18, the to-be-frozen meat m is received from the steel belt type freezer by the delivery belt conveyor 18a, and further distributed from the delivery belt conveyor 18a to the belt conveyor 19a of each stage. In the belt conveyor 19a, the to-be-frozen meat m can be mounted in the whole conveyance surface by moving a conveyance surface ahead whenever it receives the to-be-frozen meat m. Here, the meat m to be frozen is cooled until the core temperature reaches -45 ° C to -65 ° C.

  Thereafter, the to-be-frozen meat m is moved to the storage 20 adjacent to the batch type freezer 18 together with the moving carriage and stored in the storage 20 set to a temperature of -45 ° C to -65 ° C. Or it is distributed (sold) in a degassed packaging (packaging with some air left inside, not as much as vacuum packaging) and stored in a storage set at a temperature of -45 ° C to -65 ° C. It is offered to stores and traders. Thus, after freezing, the frozen meat m is cooled until the core temperature becomes −45 ° C. to −65 ° C., and then stored in a static space at a temperature of −45 ° C. to −65 ° C. for one year or more. The frozen meat m can be stored with high quality for a long period of time.

  In addition, you may freeze in the batch-type freezer 18 after deaeration-packaging the to-be-frozen meat m. If it does in this way, drying of the to-be-frozen meat m can be prevented during a freezing process, and a favorable sanitary state can be maintained.

According to the present embodiment, the meat m to be frozen is rapidly frozen from -one side at -45 ° C to -65 ° C with a steel belt type freezer, so that the maximum ice crystal generation temperature zone can be passed in a very short time, thereby Since the enlargement of ice crystals can be prevented, the meat cell membrane is not destroyed. Accordingly, no drip is generated at the time of thawing, so that the yield does not decrease and the umami component does not flow out. In addition, when passing through the maximum ice crystal generation temperature zone, by transmitting mainly cold air from the contact surface side of the steel belt 12a, ice crystals can be generated in order from the contact surface toward the opposite surface, Therefore, the bulging pressure generated by the formation of ice crystals can be released toward the opposite surface. Thereby, it is possible to prevent the internal stress from remaining in the meat m to be frozen, to prevent the occurrence of cracks due to the internal stress, and to maintain the meat m to be frozen in high quality.
(Embodiment 2)

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of the conveyor belt of the present embodiment. In FIG. 3, a recess 21 a that can store the meat m to be frozen is formed in the conveyor belt 21 made of a steel belt disposed in the freezer shown in FIG. 1 along the conveying direction. The recess 21 a may extend in a long shape in the axial direction of the conveyor belt 21. The to-be-frozen meat m is accommodated in the concave portion 21a and is conveyed in contact with the bottom surface of the concave portion 21a and the three left and right side surfaces. The upper surface of the to-be-frozen meat m becomes an open surface m ₁ that does not come into contact with the recess 21a. An open space s ₂ is formed above the open surface m ₁ and is slowly frozen.

Other configurations are the same as those of the first embodiment. That is, cold air r _{1 of} −45 ° C. to −65 ° C. is jetted from the lower jet portion (not shown) disposed below the conveyor belt 21 toward the lower surface of the conveyor belt 21, and the conveyor belt 21 collides with the cold jet r ₁ is cooled. And the to-be-frozen meat m accommodated in the recess 21a is rapidly cooled by direct contact with the bottom surface and the three sides of the recess 21a.

Agitating cold air r ₂ having a flow rate of 2 m / s or less is formed above the conveyor belt 21 from the cool air agitating fan, as in the first embodiment. The to-be-frozen meat m that has been pre-cooled to 0 to 7 ° C. is put into the freezer and brought into contact with the conveyor belt 21 to be rapidly cooled from the bottom surface and the three sides of the both sides. It passes the maximum ice crystal formation temperature zone in a short time until the end of the process. After the transfer by the freezer is completed, the internal atmosphere is stored in a storage room in which a stationary space having a temperature of −45 ° C. to −65 ° C. is formed as in the first embodiment. And it cools until the core temperature of the to-be-frozen meat m reaches -20 degrees C or less, and completes freezing.

In this embodiment, the frozen meat m is a top is slow cooling is rapidly cooled by direct contact from the three sides of the bottom surface and both side surfaces of the cooled recess 21a by impinging jet r ₁ of the cool air. Therefore, in the meat to be frozen m, ice crystals are formed from the vicinity of the bottom surface and both side surfaces of the recess 21a when passing through the maximum ice crystal generation temperature zone. That is, as shown in FIG. 3, a solidification line c is formed, and ice crystals grow in the direction of arrow b. Therefore, the most delayed point t when passing through the maximum ice crystal generation temperature zone is formed in the vicinity of the open surface m1.

Therefore, in this embodiment as well, as in the first embodiment, the frozen m is rapidly cooled from one side at an extremely low temperature of −45 ° C. to −65 ° C., so that the maximum ice crystal generation temperature zone is set to be extremely short. And thereby prevent the ice crystals from growing, so that the cell destruction of the meat does not occur. Accordingly, no drip is generated at the time of thawing, so that the yield does not decrease and the umami component does not flow out.
In addition, since it is quick freezing from the three surfaces of the bottom surface and both side surfaces, and the top surface is slowly cooled, the maximum delay point t when passing through the maximum ice crystal generation temperature zone is formed in the vicinity of the open surface m1. In addition, no internal stress is generated in the meat m to be frozen during the freezing process, and the occurrence of cracks due to the internal stress can be prevented.

In addition, you may make it the recessed part 21a form the volume of a cube or a rectangular parallelepiped independently for each to-be-frozen meat m. In this case, the to-be-frozen meat m comes into contact with the bottom surface of the recess and the left and right front and back side surfaces of the four sides, so that the transfer of cold air from the conveyor belt 21 to the to-be-frozen meat m can be improved.
(Embodiment 3)

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of the conveyor unit of the present embodiment. In FIG. 4, the conveyor belt uses a mesh belt 31 in which a large number of fine holes 31 a are provided in a mesh shape on a steel belt. In the freezer, cool air is ejected from the upper jet part 14 and the lower jet part 15, but in the case of the present embodiment, the heat insulation cover having heat insulation from the upper side on the meat m to be frozen placed on the mesh belt 31. 32, and the cold collision jet r ₁ ejected from the upper jet section 14 (not shown) is blocked. The heat insulating cover 32 is made of a heat insulating material such as polystyrene foam. Other configurations are the same as those of the first embodiment.

A collision jet stream r ₁ of cold air of −45 ° C. to −65 ° C. is jetted from a lower jet section 15 (not shown) disposed below the mesh belt 31 toward the mesh belt 31. The atmosphere in the freezer is maintained at -45 ° C to -65 ° C. A part of the impinging jet stream r ₁ injected from below enters the inside of the heat insulating cover 32 through the pores 31a of the mesh belt 31, enters the upper surface of the meat m to be frozen, and slowly cools the upper surface.

In the present embodiment, when the frozen meat m passes through the maximum ice crystal generation temperature zone, the collision jet r _{1 of} −45 ° C. to −65 ° C. that collides with the lower surface of the frozen meat m through the fine holes 31a, and the collision by the contact of the mesh belt 31, which is cooled by jets r _1, to be frozen meat m is gradually being rapidly cooled primarily from the bottom surface. And ice crystals are formed from the lower surface vicinity of the to-be-frozen meat m. Therefore, the solidification line c of the meat m to be frozen proceeds in the direction of arrow b. Thus, since ice crystals are formed from the lower surface to the upper surface of the frozen meat m, the most delayed point t of the frozen meat m is formed in the vicinity of the upper surface.

Therefore, also in this embodiment, the to-be-frozen meat m is rapidly cooled from the bottom side by the cryogenic impinging jet r ₁ , so that it passes through the maximum ice crystal generation temperature zone in a short time, and therefore the ice crystals are enlarged. Does not happen. In addition, the generation of ice crystals from the bottom surface to the top surface allows the expansion pressure generated by cell freezing to escape to the most delayed point t on the top surface, so that no internal stress is formed on the frozen meat m. Therefore, no crack is generated in the surface layer portion (upper surface side). Therefore, the same high quality frozen meat as in the first and second embodiments can be obtained.
(Embodiment 4)

Next, a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 5, in the present embodiment, cold air is ejected from the upper jet portion 14 and the lower jet portion 15, but when the meat m to be frozen is conveyed on the mesh belt 31, heat insulation is provided on the mesh belt 31. A styrofoam tray 41 is placed and conveyed with the meat m to be frozen placed thereon. The frozen meat m is formed with a collision jet r ₁ by cold air of −45 ° C. to −65 ° C. from upper and lower jet portions 14 and 15 (not shown).

With this configuration, the cold collision jet r ₁ injected from the lower jet section (not shown) to the mesh belt 31 is blocked by the heat insulating tray 41 and does not serve to cool the meat m to be frozen. Meanwhile, since the impinging jet r ₁ of the cool air which is injected toward the upper jet unit 14 (not shown) to be frozen meat m collides with the upper surface of the frozen meat m, to be frozen meat m is cooled from the upper side. Therefore, when the to-be-frozen meat m passes through the maximum ice crystal generation temperature zone, ice crystals start to be formed near the upper surface of the to-be-frozen meat m, and the solidification line c descends from above in the direction of arrow b. The most delayed point t is located near the lower surface of the meat m to be frozen.

Therefore, also in this embodiment, since no internal stress is generated in the meat m to be frozen, no cracks are generated in the surface layer portion.
(Embodiment 5)

Next, a fifth embodiment of the present invention will be described with reference to FIG. In FIG. 6A, a steel belt 51 is wound around a drive sprocket 53 and a driven sprocket 52 so as to move in the direction of arrow a. On the other hand, above the steel belt 51, the steel belt 54 is wound around the drive sprocket 56 and the driven sprocket 55 so as to move in the direction of arrow a. Lower jet unit 57 is provided on the inner side of the steel belt 51, towards the back of the steel belt 51 which is arranged above to form a collision jet r ₁ of the cool air.

Further, an upper jet portion 58 that forms a cold collision jet r ₁ downward is provided inside the steel belt 54, and a cold collision jet r ₁ is formed toward the steel belt 54. The to-be-frozen meat m is placed on the steel belt 51 and conveyed in the direction of arrow a. On the back side of the steel belt 51, a plurality of freezing rolls 59 for supporting the steel belt 51 are provided. The surface portion of the refrigeration roll 59 is made of a metal having good heat conductivity that is cooled by the cold air r, and the steel belt 51 is supported by the refrigeration roll 59 and the back surface of the steel belt 51 is cooled.

In such a configuration, the to-be-frozen meat m is inserted into the gap between the steel belt 51 and the steel belt 54 in a deaerated state, and conveyed in the direction of arrow a while being sandwiched between the steel belts 51 and 54. . Since the steel belts 51 and 54 are cooled by the cold collision jet r ₁ ejected from the upper and lower jet portions 57 and 58, the meat m to be frozen is mainly cooled from both the upper and lower surfaces. Therefore, when passing through the maximum ice crystal generation temperature zone, the generation of ice crystals starts from the vicinity of the upper surface and the lower surface, and as shown in FIG. 6B, the solidification line c is in the direction of the arrow b, that is, the direction toward both sides. proceed. The most delayed points are located at t ₁ and t ₂ near the left and right side surfaces.

Accordingly, in the present embodiment, the generation of ice crystals proceeds in the direction of the arrow b, so that the inflation pressure due to the expansion of the ice crystals can escape to the left and right side surfaces along the direction of the arrow b. Therefore, since the internal stress due to the expansion pressure is not generated in the meat to be frozen m, the surface layer portion is not cracked.
(Embodiment 6)

Next, a sixth embodiment of the present invention will be described with reference to FIG. In FIG. 7, a refrigerant liquid tank 61 in which the refrigerant liquid n is stored is provided, and a chain conveyor 62 is disposed above the refrigerant liquid tank 61. A plurality of boxes 63 are attached to the chain conveyor 62 in a row, and the meat 63 to be frozen is stored in the boxes 63. The chain conveyor 62 is disposed at such a height that the meat m to be frozen in the box 63 is immersed in the refrigerant liquid n. Top m1 of the frozen meat m in the box 63 is opened, the open space s ₂ is formed thereabove.

  In this configuration, the chain conveyor 62 moves in the direction of arrow a, and the box 63 attached to the chain conveyor 62 is immersed in the refrigerant liquid n in the refrigerant liquid tank 61 while moving in the direction of arrow a. The box 63 moves while being immersed in the refrigerant liquid n, while the meat m to be frozen is cooled by the refrigerant liquid n. For example, liquid nitrogen or polypropylene glycol is used as the refrigerant liquid n. The box 63 may be a mesh having fine holes. The refrigerant liquid n is sent to the cooling device 64, cooled, and returned to the refrigerant liquid tank 61, whereby the refrigerant liquid n in the refrigerant liquid tank 61 is kept at a constant low temperature.

For example, when PG (polyethylene glycol) is used as the refrigerant liquid, the refrigerant liquid n is maintained at a temperature of −23 ° C. to −26 ° C. And the box 63 is immersed in the refrigerant | coolant liquid n for 20 to 30 minutes, and it cools until the to-be-frozen meat m passes the maximum ice-crystal production | generation temperature range. Thereafter, the box 63 is transferred as it is to the storage 65 adjacent to the refrigerant liquid tank 61. The inside of the storage 65 is held in a static space s ₁ having a temperature of −45 ° C. to −65 ° C., where it is frozen until the core temperature of the meat m to be frozen reaches −45 ° C. to −65 ° C.

According to this embodiment, the lower surface and side surfaces of the meat m to be frozen are cooled by being in surface contact with the refrigerant liquid n directly or via the box 63. On the other hand, since the upper surface m1 of the meat m to be frozen is released from the refrigerant liquid n, ice crystals are gradually formed from the vicinity of the lower surface and the vicinity of the side surface toward the upper surface when passing through the maximum ice crystal generation temperature zone. Therefore, the most delayed point of the meat m to be frozen is located in the vicinity of the upper surface. Thus, since the ice crystal is formed in the direction from the lower surface and the side surface toward the upper surface, the bulging pressure accompanying the generation of the ice crystal can escape to the upper surface side. Therefore, no internal stress due to the bulging pressure is generated, so that no crack occurs in the surface layer portion.
(Embodiment 7)

  Next, a seventh embodiment of the present invention will be described with reference to FIG. In FIG. 8, a resin belt conveyor 71 (heat insulating belt conveyor) wound around the drive sprocket 73 and the driven sprocket 72 is disposed. The meat m to be frozen is put on the belt conveyor 71 and conveyed in the direction of arrow a. The upper side of the belt conveyor 71 is covered with a glass case 74, and a showering device 75 is provided inside the glass case 74. From the showering device 75, for example, a refrigerant liquid n made of brine such as saline is sprayed downward.

In such a configuration, the meat m to be frozen is conveyed on the belt conveyor 71 in a deaerated state, and the refrigerant liquid n is sprayed from above toward the meat m to be frozen on the belt conveyor 71, thereby The meat m is cooled from its upper surface. Accordingly, when the meat m to be frozen passes through the maximum ice crystal generation temperature zone, ice crystals are formed from the upper surface, so that the most delayed point is located near the lower surface. Therefore, in the present embodiment, the expansion pressure generated with the generation of ice crystals can escape to the lower surface side of the meat m to be frozen. Therefore, since no internal stress is generated in the frozen meat m, no crack is generated in the surface layer portion. In this embodiment, similarly to the sixth embodiment, the to-be-frozen meat m is cooled by the belt conveyor 71 until it passes through the maximum ice crystal generation temperature zone, and then the core temperature of the to-be-frozen meat m is stored in an adjacent storage. May be cooled to −45 ° C. to −65 ° C.
(Embodiment 8)

Next, an eighth embodiment of the present invention will be described with reference to FIGS. The embodiments so far have been suitable for freezing processing of thin frozen meat such as cut meat, but this embodiment is suitable for freezing processing of thick frozen meat such as partial meat. it is (still space by blown to be frozen meat m the collision jet r ₁ of cold air -45 ℃ ~-65 ℃ from the slit nozzle 94a is placed below the spiral-shaped transport path 81a, especially in this embodiment Cooling is not necessary.) 9 is an elevation view of the present embodiment, FIG. 10 is a plan view of the present embodiment, and FIG. 11 is a transverse side view taken along the line AA in FIG.

  9-11, the spiral conveyor 81 by which the conveyance path was comprised helically is arrange | positioned inside the building 80 which has a structure which can be sealed inside. The spiral conveyor 81 includes a spiral conveyance path 81a that moves from below to above, a vertical section 81b in which the spiral conveyance path 81a that has reached the upper end descends vertically through a guide roll 82, and a lower end of the vertical section 81b. And a horizontal portion 81c positioned on the guide rolls 83 and 84 outside the building 80 and in contact with the entrance conveyor 85.

  A cooling unit 90 is installed at the center of the spiral conveyor 81. The cooling unit 90 takes in the atmosphere in the building 80 from the direction of the arrow d, and heat exchanger 91 that cools the atmosphere, and two blowers that circulate the atmosphere cooled by the heat exchanger 91 to the high-pressure cool air casing 93. 92. The high-pressure cool air casing 93 is hollow inside and forms a cooling passage, and is provided along the spiral conveyance path 81a of the spiral conveyor 81, and has a slit nozzle portion 94 protruding to the outer peripheral side.

As shown in FIG. 11, the slit nozzle portion 94 includes a plurality of slit nozzles 94 a that are disposed between the spiral conveyance paths 81 a that are disposed in a plurality of strips at intervals in the vertical direction and that are directed downward. . Collision jet r ₁ of the cool air is injected at high pressure toward the slit nozzle 94a to arranged spiral transport path 81a thereunder.

In such a configuration, the to-be-frozen meat m transferred by the entrance conveyor 85 is delivered to the horizontal portion 81 c of the spiral conveyor 81. The horizontal portion 81c moves in the direction of arrow a to reach the spiral conveyance path 81a. Be frozen meat m on a spiral-shaped transport path 81a is granted the collision jet r ₁ of the high pressure cold air from the slit nozzle 94a, it is cooled. The to-be-frozen meat m conveyed on the spiral conveyance path 81a and reaching the upper end of the spiral conveyance path 81a goes out of the building 80 and is delivered to the outlet conveyor 86.

When the impinging jet r ₁ of cold air of −45 ° C. to −65 ° C. is blown from the slit nozzle 94a to the meat m to be frozen placed on the lower spiral conveying path 81a, the meat m to be frozen is cooled from its upper surface. Is done. Therefore, ice crystals start to form from the upper surface when passing through the maximum ice crystal generation temperature zone, and the ice crystals grow gradually downward. Therefore, the most delayed point of the to-be-frozen meat m is located near the lower surface.
Thus, in this embodiment, since ice crystals are formed from the upper surface to the lower surface of the meat m to be frozen, the bulging pressure generated by the formation of the ice crystals faces the lower surface and can escape through the most delayed point. Therefore, it is not trapped inside the meat m to be frozen. Therefore, no internal stress is generated in the meat m to be frozen, and no cracks are generated in the surface layer portion.
Example 1

  Next, a first embodiment of the present invention based on experiments will be described. As meat to be frozen, cut meat (length 150 mm x width 60 mm x height 25 mm) cut from a partial meat (length 600 mm x width 150 mm x height 60 mm) of the loin portion divided into carcasses with a width of 25 mm is used. The experimental data at the time of freezing in 1st Embodiment shown by 2 are shown. In this case, the deaerated package of the cut meat is frozen.

  FIG. 12 shows the experimental results. (A) relates to the first embodiment of the present invention, and is the one subjected to the freezing process according to the first embodiment. That is, the cut meat pre-cooled to 5 to 7 ° C. is put into a freezer shown in FIG. 1 and subjected to a freezing treatment by injecting cold air at −50 ° C. (B) is a comparative example, in which the cut meat pre-cooled to 5 to 7 ° C. is put into a thermostatic bath forming a static space of −20 ° C. and subjected to a freezing treatment. (C) shows a conventional chilled (unfrozen) cooling.

  FIG. 13 shows the meat structure immediately after the core temperature of (a) according to the first embodiment of the present invention reaches −50 ° C. In the figure, the maximum ice crystal generation temperature zone transit time during the freezing treatment is as short as about 6 minutes, suppresses the growth of ice crystals and does not show much destruction of the structure. In the figure, the white part is the ice crystal part, and the pink part (dark part) is the meat cell. FIG. 14 also shows the meat tissue after freezing at −50 ° C. and subsequently stored in a static space at a temperature of −50 ° C. for 30 days in the freezing treatment of (a). In the figure, the growth of ice crystals during storage is suppressed, and the destruction of the meat tissue is hardly observed.

  FIG. 15 is a case of (b) as a comparative example, and shows the meat tissue immediately after freezing until the core temperature of the cut meat reaches −20 ° C. In this case, the passage time of the maximum ice crystal generation temperature zone at the time of the freezing process is as long as 2 hours, and ice crystals grow, and the destruction of the structure is confirmed in some places. In the figure, the white part is the ice crystal part, and the pink part (dark part) is the meat cell. Also, FIG. 16 is the same (b) freezing treatment, and after the freezing treatment until the core temperature of the cut meat reaches −20 ° C., the meat after being stored for 30 days in a static space at a temperature of −20 ° C. Indicates the organization. In the figure, ice crystals grow during storage, and the destruction of the structure can be confirmed in several places.

  FIG. 17 shows a meat structure of cut meat that has been chilled (unfrozen) cooled at 0 to −1 ° C., and is frozen and stored in a static space at a temperature of −20 ° C. after chilled cooling. In the figure, during storage, ice crystals grow and the destruction of the structure is in progress. Compared to FIG. 16, it can be seen that the flesh cells are scattered.

  The experimental result which measured the drip amount of the sample of these Examples 1 and a comparative example is shown. In the measurement method, the package was opened, and the frozen meat was completely thawed under normal pressure. After complete thawing, the drip generated from the meat was collected in a package, and the collected drip was collected with a pipette and weighed. The total amount of drip and meat weight was taken as the total weight, and the drip amount was calculated by weight ratio. The results are shown in FIGS. FIG. 18 shows the case of the comparative example of FIG. That is, a comparative example is shown in which pre-cooled cut meat is frozen at −20 ° C. in a thermostatic bath, and the core temperature of the cut meat reaches −20 ° C. and then stored at −20 ° C. In this case, it can be seen that the amount of drip after 30 days of storage has increased to twice the amount of drip after 20 days of storage.

FIGS. 19-21 is the experimental result of Example 1 of this invention, FIG. 19 is the case of FIG. 12 (a) of the said 1st Example, and cut meat is rapidly frozen at -50 degreeC, After the core temperature of the partial meat reaches −50 ° C., the meat is stored in a static space at a temperature of −50 ° C. In this case, even when stored for 30 days, the amount of drip is as low as that of stored for 20 days.
(Example 2)

FIG. 20 relates to a second embodiment of the present invention, and uses the partial meat of the loin before cutting into cut meat, and the wind speed from above and below is applied to the partial meat placed on the steel belt 12a by the freezer shown in FIG. It was rapidly frozen from one side by applying a collision jet of 15 m / s at −50 ° C. and stored in a static space at −20 ° C. after the core temperature of the partial meat reached −50 ° C. In this case, the drip amount is small even after 30 days of storage. The meat tissue after 30 days storage is shown in FIG. In the figure, the growth of ice crystals during storage is suppressed, and the destruction of the meat tissue is hardly observed.
(Example 3)

FIG. 22 shows a third embodiment of the present invention. That is, using the same method as in the second embodiment, the partial meat of the loin before cutting into cut meat is rapidly frozen from one side by applying a collision jet of −50 ° C., and the core temperature of the partial meat is − After reaching 20 ° C., the meat tissue after storage for 30 days in a static space at −20 ° C. is shown. Similarly to FIG. 22, it can be seen that the growth of ice crystals during storage is suppressed, and the destruction of the meat tissue is hardly observed.
Example 4

  FIG. 23 relates to a fourth embodiment of the present invention. In this case, using the partial meat of the loin portion from one side, rapidly freezing from one side at −50 ° C. with the freezer shown in FIG. 2, and after the core temperature of the partial meat reached −50 ° C., the temperature of −50 ° C. Stored in static space. In this case, the drip amount is small even after 30 days of storage.

  According to the present invention, a portion of animal meat (including block meat) from which bone has been removed from carcass, or cut meat that has been cut according to the purpose, is eliminated at the time of thawing by eliminating the occurrence of cell membrane destruction and cracking during freezing. It is possible to prevent outflow of savory meat, freeze and store it in a high quality state for a long period of time, and provide frozen meat with high added value to the market.

It is a perspective view which shows the whole structure of the steel belt type freezer to which this invention is applied. It is longitudinal section explanatory drawing of the belt longitudinal direction which shows 1st Embodiment of this invention. It is a cross-sectional explanatory drawing of the belt crossing direction which shows 2nd Embodiment of this invention. It is longitudinal cross-sectional explanatory drawing of the belt longitudinal direction which shows 3rd Embodiment of this invention. It is a longitudinal section explanatory view of the belt longitudinal direction showing a 4th embodiment of the present invention. (A) is longitudinal explanatory drawing of the belt longitudinal direction which shows 5th Embodiment of this invention, (b) is explanatory drawing which shows the ice crystal production | generation state of to-be-frozen meat. It is a vertical elevation view which shows 6th Embodiment of this invention. It is a vertical elevation view which shows 7th Embodiment of this invention. It is an elevational view showing an eighth embodiment of the present invention. It is a top view which shows 8th Embodiment of this invention. It is a cross-sectional side view which follows the AA line in FIG. It is a diagram which shows the freezing treatment method of 1st Example of this invention and a comparative example. It is a meat structure figure by the said 1st Example (just after -50 degreeC freezing). FIG. 2 is a meat organization chart according to the first embodiment (30 days after freezing at −50 ° C.). It is a meat structure figure by the said comparative example (just after -20 degreeC freezing). It is a meat | texture structure chart by the said comparative example (-30 degreeC storage after -20 degreeC freezing). It is a meat tissue by the conventional freezing process. It is a graph which shows the drip amount of the said comparative example. It is a graph which shows the drip amount of the said 1st Example. It is a graph which shows the drip amount of 2nd Example of this invention. It is a meat organization chart of the second embodiment. It is a meat organization chart of the 3rd example of the present invention. It is a graph which shows the drip amount of 4th Example of this invention.

Explanation of symbols

10 Housing 12a, 21 Conveyor belt (moving body)
21a Concave part 31 Mesh belt (moving body)
32 Insulation cover 41 Insulation tray 51, 54 Steel belt (moving body)
61 Refrigerant liquid tank 62 Chain conveyor (conveyor)
75 Showering device c Coagulation line m Meat to be frozen (boneless meat)
r ₁ impinging jet of cold air r ₂ cold air for stirring s ₁ static space s ₂ open space t, t ₁ , t ₂

Claims (27)

When thawing parts of meat (including block meat) from which the bone has been removed from the carcass, or cut meat (hereinafter referred to as boneless meat) that has been cut according to the purpose, it eliminates cell membrane destruction and cracking during freezing. It is a high-quality freezing method for boneless meat that can prevent the spill of umami and can be frozen and stored in a high-quality state for a long period of time,
At least one surface layer of the boneless meat pre-cooled to 0 to 7 ° C. is brought into surface contact with cold energy of −20 ° C. or less to perform rapid cooling, and the other surface layer is slowly cooled by cold air,
The ice layer formation at the maximum ice crystal formation temperature zone is started from one side of the surface layer on the quick freezing side, and the most delayed point of ice crystal formation in the boneless meat is slowly cooling from the center of gravity position of the boneless meat The cold energy intensity applied to the surface layer side portion of the boneless meat is weaker than the cold energy intensity applied to the other surface layer located on the opposite side of the surface layer of the boneless meat so that it is unevenly distributed in the vicinity of the surface of the bone. A bone-removed animal meat high-quality freezing method characterized by performing a first freezing treatment by passing a maximum ice crystal generation temperature range of 0 to -several degrees Celsius in a state.   Applying cold energy of −45 ° C. to −65 ° C. from one side of the surface layer that is rapidly frozen following the first freezing treatment, until the core temperature of the boneless meat falls to −20 ° C. or lower. The high quality freezing method for bone meat from which bone has been removed according to claim 1, wherein the contact with cold energy is continued.   After the completion of the first freezing treatment, the boneless meat is moved into a static space, and is kept at −45 ° C. to −60 ° C. from one side or both sides of the surface layer until the core temperature of the boneless meat falls to −20 ° C. or lower. The high-quality freezing method for animal meat from which bone has been removed according to claim 1, wherein the application of cold energy is continued.   After completion of the first freezing treatment, the object to be frozen is moved into a static space, and the cold temperature below the above temperature from one side or both sides of the surface layer until the core temperature of the boneless meat falls to -45 ° C to -65 ° C. The high-quality freezing method for animal meat from which bone has been removed according to claim 1, wherein the application of energy is continued.   The surface side freezing treatment is performed by placing a boneless meat bottom on a moving body whose surface is a mesh belt (perforated metal plate) or a steel belt, and below the belt through the belt toward the boneless meat. The bone according to claim 1, wherein a collision jet flow by cold energy of −45 ° C. to −65 ° C. is ejected, an upper space is an open space, and a slow cooling space in contact with slow cool air is removed. High-quality freezing method for fresh meat.   The surface side freezing treatment is performed by placing a boneless meat bottom on the moving body with a heat insulating material on the belt on the surface, and colliding with cold energy of −45 ° C. to −65 ° C from above the boneless meat. The high quality freezing method for animal meat from which bones have been removed according to claim 1, wherein a jet is ejected.   Boneless meat made of block or partial meat is supported on both sides of the boneless meat by placing both boneless meat on a moving body made of mesh belt (perforated metal plate) or steel belt to support the boneless meat. And a collision jet of cold energy of −45 ° C. to −65 ° C. is ejected from below the belt toward both surfaces of the boneless meat through the belt, and both the left and right sides of the boneless meat are open spaces. The high quality freezing method of the animal meat from which the bone of Claim 1 was removed.   A storage tank in which refrigerant liquid is stored is prepared, boneless meat stored in a box is immersed in the refrigerant liquid while being moved by a conveyor, and the upper surface of the boneless meat stored in the box is an open space that does not contact the refrigerant liquid. The bone-removed animal meat according to claim 1, wherein the formation of ice crystals in the boneless meat when passing through the maximum ice crystal generation temperature zone is directed from the immersion side to the open space side. Quality freezing method.   The boneless meat placed on a resin or heat-insulating conveyor is showered with coolant from above to make the upper surface of the boneless meat cool quickly and slowly cool the lower surface. The method for freezing bone-free animal meat according to claim 1, wherein the formation of ice crystals in the meat is directed from the upper surface side to the lower surface side.   The high-quality freezing method for animal meat from which bones have been removed according to any one of claims 1 to 9, wherein the boneless meat is degassed and packaged and frozen.   The boneless meat is applied to one side of the boneless meat until the boneless meat has a core temperature of -20 ° C or lower. After the cold energy contact of -45 ° C to -65 ° C is continued, the boneless meat is stored in a static space of -20 ° C or lower. The high-quality freezing method for animal meat from which bones have been removed according to claim 1 or 2.   After the boneless meat is subjected to the freezing treatment and passed through the maximum ice crystal generation temperature zone, the cold energy contact is continued until the core temperature of the boneless meat drops to -45 ° C to -65 ° C, and then the boneless The method for freezing bone-free animal meat according to claim 1 or 2, wherein the meat is stored in a static space of -45 ° C to -65 ° C. When thawing parts of animal meat (including block meat) from which bone has been removed from carcass, or cut meat (hereinafter referred to as boneless meat) that has been cut according to the purpose, by eliminating the occurrence of cell membrane destruction and cracking during freezing It is a high-quality freezing device for boneless meat that prevents spillage of umami and can be frozen and stored in a high-quality state for a long period of time,
A closed space for freezing the boneless meat pre-cooled to 0 to 7 ° C., a quick freezing means for bringing one surface of the boneless meat in the space into surface contact with cold energy of −20 ° C. or less, and an open space on the other surface Or, it has a slow cooling means that slowly cools the air and slowly cools the other side of the surface layer of the boneless meat,
The maximum ice crystal generation temperature zone ice crystal generation is started from one surface layer side of the quick freezing means side, and the latest delay point of ice crystal generation in the boneless meat is slower cooling than the center of gravity position of the boneless meat Cold energy to be applied to the other side of the surface of the boneless meat that is applied to the surface of the boneless meat so as to be unevenly distributed in the vicinity of the surface on the other side of the surface layer. A high-quality freezing apparatus for animal meat from which bone has been removed, wherein the first freezing treatment is performed by passing through a maximum ice crystal generation temperature range of 0 to -several degrees Celsius in a state where the strength is lower than the strength.   The quick freezing means applies a cooling energy of −45 ° C. to −65 ° C. from one side of the surface layer, and can convey the cooling energy until the core temperature of the boneless meat drops to −20 ° C. or lower. The high-quality freezing apparatus for animal meat from which bones have been removed according to claim 13.   The first freezing treatment means is a freezer formed in a tunnel shape through which a steel belt or a mesh belt is inserted, and the boneless meat conveyed from the freezer is moved into the stationary space, 14. The bone according to claim 13, wherein the application of cold energy of −45 ° C. to −65 ° C. is continued from one side or both sides of the surface layer until the core temperature of the boneless meat falls to −20 ° C. or less. High quality freezing equipment for dried meat.   On the bottom side of the boneless meat, there is provided mounting means for placing the boneless meat bottom surface on a movable body whose surface is a mesh belt (perforated metal plate) or a steel belt, and the belt is directed toward the boneless meat. It is configured so that a collision jet with cold energy of −45 ° C. to −65 ° C. is ejected from below the belt, and an open space is provided above the boneless meat on the opposite side, and the slow cool air is in slow contact with the boneless meat. The high-quality freezing apparatus for animal meat from which bones have been removed according to claim 13, wherein the apparatus is a cooling space.   A heat insulating material is interposed on the surface of the carrier on which the boneless meat is placed, and the boneless meat bottom surface is placed on the moving body in an adiabatic manner to carry it, from above the boneless meat, −45 ° C. to −65 ° C. 14. The high-quality freezing apparatus for animal meat from which bones have been removed according to claim 13, further comprising jetting means for jetting an impinging jet of cold energy.   Nipping and conveying means for sandwiching and conveying boneless meat by placing the upper and lower surfaces of boneless meat made of block meat or partial meat on a movable body made of mesh belt (perforated metal plate) or steel belt, and the boneless Means for ejecting a collision jet of cold energy of −45 ° C. to −65 ° C. from below the belt through the belt toward the meat, and both left and right sides of the boneless meat sandwiched and conveyed by the nipping and conveying means as an open space The high-quality freezing apparatus for animal meat from which bones have been removed according to claim 13.   A heat storage box for storing boneless meat; and a heat conductive box for storing boneless meat; and a conveyor for moving the heat conductive box while being immersed in the refrigerant liquid. The ice box is immersed in the refrigerant liquid while being moved by the conveyor, and the upper surface of the boneless meat stored in the heat conductive box is made an open space. 14. The apparatus for freezing bone-free animal meat according to claim 13, wherein the generation of ice crystals in the boneless meat at the time of passage is directed in at least one coordinate direction.   The boneless meat placed on the conveyor is provided with means for rapidly cooling the upper surface side of the boneless meat by showering the refrigerant liquid from above, and the conveyor is constituted by a resin or a heat insulating conveyor, and the boneless meat via the conveyor The bone is removed according to claim 13, wherein cooling from the lower surface side is slow cooling, and ice crystal formation in the boneless meat is directed to the lower surface side when passing through the maximum ice crystal generation temperature zone. High quality freezing equipment for dried meat.   The generation direction of the maximum ice crystal generation temperature zone of boneless meat is generated from one side of the boneless meat surface layer to the other side, and the generation of ice crystals in the boneless meat when passing through the maximum ice crystal generation temperature zone is at least in one coordinate direction The most delayed point of ice crystal formation in the boneless meat is unevenly distributed on the surface layer side from the center of gravity of the boneless meat and the core temperature of the boneless meat is maintained at -20 ° C. or lower. A high-quality frozen meat characterized in that there is no cell membrane destruction in the cross-section of the frozen meat and there is no time change in the “sashimi” state.   The generation direction of the maximum ice crystal generation temperature zone of boneless meat is generated from the both sides of the boneless meat toward the center, and the most delayed point of ice crystal formation in the boneless meat is left and right of the center of gravity position of the boneless meat. When the boneless meat is unevenly distributed on both peripheral surfaces and the core temperature of the boneless meat is maintained at -20 ° C. or lower, the frozen meat has no cell membrane destruction, and there is no time change in the “seed” state. The high-quality frozen meat according to claim 21, wherein:   A high-quality frozen meat characterized in that the time change of the "meat" state of the frozen meat obtained in claim 21 or 22 is one month or more.   The generation direction of the maximum ice crystal generation temperature zone of boneless meat is generated from one side of the boneless meat surface layer to the other side, and the generation of ice crystals in the boneless meat when passing through the maximum ice crystal generation temperature zone is at least in one coordinate direction The most delayed point of ice crystal formation in the boneless meat is unevenly distributed on the surface layer side from the center of gravity of the boneless meat, and the core temperature of the boneless meat is maintained at -45 ° C to -65 ° C. A high-quality frozen meat characterized in that there is no cell membrane destruction in the cross-section of the frozen meat and there is no time change in the “seed” state.   The generation direction of the maximum ice crystal generation temperature zone of boneless meat is generated from the both sides of the boneless meat toward the center, and the most delayed point of ice crystal formation in the boneless meat is left and right of the center of gravity position of the boneless meat. Temporal change in the state of the “seed” state with no cell membrane destruction in the cross-section of the frozen meat by storing the boneless meat core unevenly distributed on both peripheral surfaces and maintaining the core temperature of the boneless meat at −45 ° C. to −65 ° C. High quality frozen meat characterized by the absence of   A high-quality frozen meat characterized in that the time variation of the "meat" state of the frozen meat obtained in claim 24 or 25 is one year or more.   27. The boneless meat according to any one of claims 21 to 26, wherein the boneless meat is a partial meat (including block meat) of animal meat from which bone has been removed from a carcass of livestock, or a cut meat obtained by cutting them for different purposes. High quality frozen meat as described.

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