JP2009008292A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator capable of suppressing oxidation by properly adjusting vacuum in storing food in a raw state by vacuuming at a refrigerating temperature zone to prevent degradation, that is, capable of retaining color and freshness by suppressing oxidation of food. <P>SOLUTION: In this refrigerator having a pressure reducing chamber defined in a refrigerating compartment, a vacuum pump for reducing a pressure in the pressure reducing chamber, and a control means for controlling the vacuum pump, the pressure inside of the pressure reducing chamber is controlled to be 0.4 atmosphere or more and less than atmospheric pressure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigerator.

  In recent years, due to changes in the social environment, the number of days for storing food is increasing, and it is important to store food freshly without waste and improve the quality of fresh food during storage.

  In general, during food storage, quality deterioration occurs due to changes due to enzyme action, changes due to microorganisms, physical changes, chemical changes, and the like. It is important to delay these changes and maintain food quality.

  For example, the change by enzyme action includes browning by oxidoreductase, protein degradation by hydrolase, lipid hydrolysis, and the like.

  Microorganisms such as bacteria, yeast and fungi are influenced by the water activity of food, pH, ingredients and the environment surrounding the food. Among them, the largest factor is the storage temperature.

  Moreover, drying is mentioned as a physical change. In general, in drying, the difference between the vapor pressure on the surface of the food and the vapor pressure of the air in contact with the food is large, and the drying proceeds as the flow rate of the air in contact with the food increases. Drying of food not only reduces eye weight, but also promotes metrification (reaction to turn meat color brown metmyoglobin) in tuna and the like. These changes that occur during the storage of foods become less the lower the temperature, and this is the principle of cold storage.

  Chemical changes include food oxidation. Oxygen in the air causes oxidation and pigmentation of fats and oils, resulting in an unpleasant flavor. Oxidation of fats and oils in foods is generally referred to as fat and oil rancidity or oil burning, and depends on temperature, moisture, light, and oxygen partial pressure.

  However, discoloration of foods due to oxidation particularly among quality degradations significantly lowers consumers' willingness to purchase, and also occurs at a relatively earlier time than other quality degradations. Therefore, suppression of oxidation is an important issue for maintaining quality.

  As a conventional example of a refrigerator having a decompression device, for example, as shown in Patent Document 1, a decompression pump is controlled so that an oxygen concentration in a chilled room or a freezing room becomes an oxygen concentration of 2.5% to 5%. Refrigerator that suppresses discoloration is mentioned.

  In this device, since the degree of vacuum is high, oxidation of meat and fish is suppressed and long-term storage becomes possible.

JP 2000-337758 A

  However, in freezing, the water contained in the muscle tissue freezes as it passes through the maximum ice crystal formation zone, and the volume increases, resulting in the destruction of the muscle tissue. The problem is that the free water that did not become a drip results in a runoff and loss of taste.

  In addition, there is a problem that a free texture is changed to a soft texture due to the formation of many ice crystals in the muscle tissue due to free water freezing and the strength of the muscle tissue after thawing is reduced.

  And since it is frozen, there is also a problem that it takes time and effort to defrost when eating.

  In addition, the lower the atmospheric pressure, such as the oxygen concentration of 2.5% to 5%, the easier it is to evaporate.

  An object of the present invention is to provide a refrigerator that suppresses deterioration and suppresses deterioration by adjusting an appropriate degree of vacuum when food is stored in a raw state with respect to the above-described problems.

  The present invention is a refrigerator having a decompression chamber in a refrigerator compartment, a vacuum pump for decompressing the decompression chamber, and a control means for controlling the vacuum pump, wherein the pressure in the decompression chamber is at least 0.4 atm and less than atmospheric pressure. It is controlled.

  The present invention is also a refrigerator having a decompression chamber in a refrigeration chamber, a vacuum pump for decompressing the decompression chamber, and a control means for controlling the vacuum pump, wherein the decompression chamber is changed from 0.5 atm to 0.8 atm. It is characterized by controlling the pressure.

  Further, the present invention is a refrigerator having a decompression chamber, a vacuum pump for decompressing the decompression chamber, and a control means for controlling the vacuum pump, wherein the pressure in the decompression chamber is controlled to 0.7 atm. It is characterized by.

  Further, the present invention is characterized in that the decompression chamber is in a refrigeration temperature zone of 0 ° C. or higher.

  According to the present invention, when the food is stored in a raw state, the refrigerator can be suppressed by suppressing oxidation by adjusting an appropriate degree of vacuum to suppress deterioration.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an explanatory cross-sectional view of a main part of a refrigerator.

  In FIG. 1, reference numeral 40 denotes a refrigerator main body, and a plurality of compartments are provided in the refrigerator main body 40, and the refrigerators are disposed in order from the top in the order of frequency of use. It is configured to improve usability.

  For example, a refrigerator room 44, a freezing temperature room 43, and a vegetable room 45 are provided in order from the top, and the freezing temperature room 43 is, for example, an ice making room that is maintained at a freezing temperature of about minus 6 ° C to minus 30 ° C. 41 and the freezer compartment 42 are divided and configured such that the refrigerator compartment 44 can be used as a refrigerator compartment 46 having a temperature of about 0 ° C. to 10 ° C., for example.

  And the vegetable compartment 45 is comprised so that temperature may be hold | maintained at about 0 to 5 degreeC and humidity, for example, about 70 to 95% so that it may be advantageous for long-term preservation | save of vegetables etc.

  A plurality of vegetable containers, for example, a vegetable container 61 having a relatively shallow container depth, a vegetable container 63 having a relatively deep container depth, and a vegetable container 62 having an intermediate depth between the containers 61 and 63 are used. The vegetables according to the container depth can be stored.

  51 is a blower configured to blow and circulate cold air generated in the cooling chamber 50 provided with the cooler 49, and in order to reduce the manufacturing cost of the refrigerator, the above-described freezing temperature chamber 43 and refrigeration temperature chamber 46 can be cooled by one blower 51.

  Reference numeral 48 denotes defrosting means configured to be able to remove frost attached to the cooler 49, and reference numeral 47 denotes a compressor constituting a refrigeration cycle by the cooler 49, a condenser (not shown), or the like. , 67 is a control device that controls the operation of the refrigerator, as will be described later.

  Reference numeral 58 denotes an internal temperature sensor configured to detect the internal temperature of the freezing temperature chamber 43 so that the operation of the compressor 47 and the blower 51 can be controlled by the detection value of the internal temperature sensor 58. It is configured.

  Reference numeral 57 denotes an internal temperature sensor configured to detect the temperature in the refrigerator compartment 44, and 59 denotes an internal temperature sensor configured to detect the temperature in the vegetable compartment 45. The opening / closing of the electric damper 54 can be controlled by the detection values of the internal temperature sensors 57 and 59.

  Here, the cooling operation in the above configuration will be described with reference to FIG.

  First, the cold air generated by the cooler 49 is blown from the cooling chamber 50 into the freezing cold air duct 52 by the operation of the blower 51. A part of the cold air blown into the freezing cold air duct 52 is discharged into the freezing temperature chamber 43 from the plurality of discharge ports 42d, and after cooling the freezing temperature chamber 43 to a predetermined temperature, it is not illustrated. Return to the cooling chamber 50 from the return port.

  Then, a part of the cold air blown into the refrigeration cold air duct 52 is diverted to the refrigeration cold air duct 53 and controlled by the electric damper 54 configured to control the cold air passage amount, The air is blown into the cold air passage 44c for refrigeration.

  A part of the cool air blown into the refrigeration cool air passage 44c is discharged into the refrigerating chamber 44 from the plurality of discharge ports 44d, and after cooling the refrigerating chamber 44 to a predetermined temperature, the freezing temperature chamber 43 Return to the cooling chamber 50 through a suction port 44e provided in a partition member 55 that divides the storage chamber 44 and the refrigerator compartment 44, and a return port (not shown).

  A part of the cold air blown into the chilling cold passage 44c is diverted to the vegetable cold passage 45c and discharged into the vegetable chamber 45 from the plurality of discharge ports 45d. After cooling to temperature, it returns to the cooling chamber 50 through the suction port 45f and the return port 45g provided in the partition member 56 which divides the freezing temperature chamber 43 and the vegetable chamber 45.

  As an example of controlling the cooling operation, for example, the control device 67 uses the detection value of the internal temperature sensor 58 configured to detect the temperature in the freezing temperature chamber 43 so that the compressor 47 and the blower 51 are controlled. By controlling the operation, the temperature in the freezing temperature chamber 43 is cooled to a predetermined temperature.

  Further, for example, the control device 67 controls the opening and closing of the electric damper 54 based on the detection values of the internal temperature sensors 57 and 59 configured to detect the temperature in the refrigeration temperature chamber 46, and the amount of cool air passing therethrough is controlled. By controlling the above, the temperature in the refrigeration temperature chamber 46 is cooled to a predetermined temperature.

  In addition, the vegetable room 45 is advantageous for long-term storage of vegetables and the like, so that the inside humidity can be maintained in a high humidity state of, for example, about 70 to 95%, for example, the cold air is used for vegetable containers 61, 62, 63, etc. The inside of the vegetable containers 61, 62, 63 can be adjusted by the partition members 64, 65, 66 and the like so as to forcibly circulate outside.

  Next, the decompression chamber 70 will be described. The decompression chamber 70 is composed of a hermetically sealed container, and is configured to be opened and closed by a door of a vegetable container 71 capable of taking in and out food. Further, the decompression chamber can be decompressed by a vacuum pump (not shown). And it is controlled by the control means (not shown) of the refrigerator so that it can be reduced to a predetermined pressure by the pressure sensor.

  Next, FIGS. 2 to 4 will be described. FIG. 2 shows changes in myoglobin and discoloration of fresh meat that are seen in tuna and beef as typical examples of color degradation. The color of fresh meat is derived from the muscle pigment myoglobin. Oxygen is bound to the Mb heme iron, and the iron changes to bivalent or trivalent, so that induced forms exhibiting various colors are recognized. It is done.

  The main eating form of tuna is raw, such as sashimi, and its freshness depends largely on color, texture and drip. In order to satisfy these requirements, it is necessary to prevent the formation of meth- ods without freezing and store them raw and delicious.

  Therefore, it was decided to evaluate tuna stored in a vacuum using a freshness index K value that is generally used for evaluation of freshness, together with methodization.

  As the fish freshness index, the post-mortem sclerotia count, K value, and the like are known. Among them, the fish freshness constant K value shows a good correlation with the initial freshness (goodness of life).

  Freshness, which is important for the quality of fresh fish, decreases at the stage of autolysis before the start of bacterial growth. The K value is an index of freshness, that is, enzymatic chemistry.

  After death, adenosine triphosphate (ATP) in the muscle is enzymatically degraded and adenosine diphosphate (ADP) → adenosine monophosphate (AMP) → inosinic acid (IMP) → inosine (HxR), hiboxanthin (Hx) It will change in the order.

  When ATP to IMP is the main component in fish meat, the freshness is good, but HxR (nucleotide) and Hx (purine derivatives) increase as the freshness decreases. In addition, the ATP content is maintained for a while after death, but when the ATP content is significantly reduced, the muscle becomes stiff. Depending on the fish species, HxR is generated, Hx is generated, or both are generated, but in any case, the percentage of HxR and Hx in the ATP-related substance component is freshness. It becomes an index.

  FIG. 3 shows the relationship between the degree of vacuum of beef preserved for 12 days in frozen storage and the production rate of metmyoglobin. The abscissa indicates the atmospheric pressure, and the ordinate indicates the metation rate (ratio of metmyoglobin in the pigment). As shown in FIG. 3, it is known that the mettolation is promoted when the degree of vacuum is in the range of 0 to 0.2 atm. However, in the case of this figure, since the storage temperature is lower than the freezing temperature, and the methation is highly temperature-dependent, it is considered that the methanolysis is likely to proceed at a refrigerated temperature that can be eaten raw.

  The results of evaluating the freshness of tuna stored in a vacuum for 3 days at a temperature of 3.8 ° C. and a humidity of 40% are shown in FIGS. In addition, the same evaluation result will be obtained if it is a refrigeration temperature range (0 degreeC or more). The evaluation items were measured using a K value for measuring freshness and a redness (a *) that well indicates the freshness of meat during storage with a spectroanalyzer as an index when tuna was stored.

  The determination of the K value had to be quantified for ATP-related substances by high-performance liquid chromatography, etc., which had the inconvenience that it could only be measured by an established laboratory, but recently biosensors, test papers, etc. have been developed. Quantification of ATP-related substances is simple. Therefore, the determination of the K value was carried out using a test paper that can measure the freshness of seafood using an enzyme reaction test paper. This test paper measures the degree of degradation (K value) of ATP present in the muscles of animals with time by using two types of enzyme color reaction (HxR + Hx) and (AMP + IMP) and comparing them with a color chart. can do.

  In addition, the measurement of color is a measure of methanation, and there is variation in the sensory evaluation by visual observation. Therefore, the color of the tuna surface was measured using a colorimeter to quantitatively evaluate the degree of methanization. What was actually used was a colorimeter called CR-13 manufactured by Konica Minolta.

  As the color system, the L * a * b * color system widely used for expressing the color of an object was used. In this color system, a * indicates the color in the red direction, and the higher the value, the brighter the color. Therefore, the redness a * before storage and the redness a * after vacuum storage were measured, and the change rate was measured as the red residual rate.

  FIG. 4 shows the freshness measured using a K value after tuna is stored in a vacuum. The horizontal axis indicates the atmospheric pressure, and the vertical axis indicates the K value. From the measurement results, the range of atmospheric pressure showing a lower value than the raw edible limit K value of 20% was 0.4 atmospheric pressure to less than atmospheric pressure. From this result, it can be seen that the freshness is affected by a small difference in the degree of vacuum. Therefore, the degree of vacuum effective from the viewpoint of freshness is set to about 0.4 to less than atmospheric pressure.

  FIG. 5 shows the degree of methalation measured from the change in red surface of the tuna before and after vacuum storage. The horizontal axis indicates the atmospheric pressure, and the vertical axis indicates the red remaining rate. The red color remaining ratio, which is apparently fresh, is 0.8 or more.

  Judging from the red residual rate, since the temperature is higher than that of the mettolation shown in FIG. 3, the metotization proceeds at 0.2 to 0.4 atm and the discoloration is promoted. There was a trend.

  From this, it can be said that 0.5 atmosphere to 1.0 atmosphere is effective for suppressing discoloration when preserving fish without freezing.

  It turned out that it is possible to keep red as much as atmospheric pressure from 0.5 atmospheric pressure. Therefore, the degree of vacuum is controlled from 0.5 atm to less than atmospheric pressure from the effective range of K value (0.4 atm to less than atmospheric pressure) and the effective range of color (0.5 to 1.0 atm). And can satisfy both freshness and color. More preferably, the K value should be in the vicinity of 15 to 0.5 to 0.8 atm, and discoloration is small. Furthermore, the K value is maximized and discoloration can be reduced by setting the pressure to 0.7 atm.

  At this time, since the storage is not a freezing temperature zone but a refrigeration temperature zone, the labor of thawing can be saved and drip generated during thawing can be suppressed.

  Since the K value is a biochemical reaction and has high temperature dependence, freshness can be maintained by controlling the temperature low.

In recent years, an increasing number of people store cosmetics and the like in refrigerators, but the effects of bacteria and the like are less affected by low temperatures, but the effects of oxidation cannot be avoided. In the vacuum container of the present invention, by suppressing oxidation, it can be used for long-term storage of cosmetics and the like that do not contain preservatives and antioxidant components.

It is side surface sectional drawing of the refrigerator provided with the decompression chamber in the refrigerator compartment. It is a characteristic view showing the relationship between the change of myoglobin and discoloration of fresh meat. It is a characteristic view showing the relationship between the degree of vacuum and the methaization reaction in frozen food. It is a characteristic view showing the relationship between the vacuum degree and K value in refrigerated food. It is a characteristic view showing the relationship between the degree of vacuum and color change in refrigerated food.

Explanation of symbols

40 Refrigerator body 41 Ice making room
42 Freezer compartment 42d Discharge port
43 Freezing temperature chamber 44 Refrigerated chamber
44c Cooling air passages 44d, 45d Discharge port 44e Suction port 45 Vegetable room 45a Vegetable room door 45c Cold air passage for vegetables 45f Suction port 45g Return port 46 Refrigeration temperature chamber 47 Compressor 48 Defrosting means 49 Cooler
50 Cooling chamber 51 Blower
52 Cold air duct for refrigeration 53 Cold air duct for refrigeration 54 Electric dampers 55, 56, 64, 65, 66 Partition members 57, 58, 59 Internal temperature sensors 61, 62, 63, 71, 72 Vegetable containers

Claims (4)

A refrigerator having a decompression chamber in a refrigerator compartment, a vacuum pump for decompressing the decompression chamber, and a control means for controlling the vacuum pump,
The refrigerator characterized by controlling the pressure in the decompression chamber to 0.4 atmospheric pressure or more and less than atmospheric pressure. A refrigerator having a decompression chamber in a refrigerator compartment, a vacuum pump for decompressing the decompression chamber, and a control means for controlling the vacuum pump,
The refrigerator characterized by controlling the pressure in the decompression chamber from 0.5 atm to 0.8 atm. A refrigerator having a decompression chamber in a refrigerator compartment, a vacuum pump for decompressing the decompression chamber, and a control means for controlling the vacuum pump,
A refrigerator characterized in that the pressure in the decompression chamber is controlled to 0.7 atm.   The refrigerator according to any one of claims 1 to 3, wherein the decompression chamber is a refrigerated temperature zone of 0 ° C or higher.

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