JP2006061084A - Method for producing food by electric conductive processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy low-cost method for producing a food by electric conductive processing, capable of evenly and sufficiently raising the temperature of the surface part and the central part of a food material soaked in water or a dilute solution. <P>SOLUTION: This method for producing the food by electric conductive processing comprises holding an electrolyte-containing food material (A) together with water or the dilute electrolyte solution B in a container 3 oppositely set with a pair of electrodes 1 and 2 in the inside in a condition of being soaked in the water or the dilute electrolyte solution without contacting with the electrodes, and sterilizing the food material (A) through giving electric conductive action after an electrically conductive state becomes possible by the electrolyte eluted from the food material (A) in the water or the dilute electrolyte solution B. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing an electrically processed food by heating and heating a food material immersed in water or a dilute electrolyte solution.

  Conventionally, in the heat sterilization of foods such as ham and sausage, these food materials are boiled or steamed. In these heat sterilization methods, first, the temperature of the surface portion of the food material is raised, and the temperature is raised from the surface layer portion of the food material to the central portion by heat conduction. Therefore, in order to sufficiently heat sterilize the central portion of the food material, the surface layer portion is overheated, which may deteriorate the quality of the food such as color tone.

  As an alternative to boiled or steamed heating, a method has been developed in which current is applied to the food material using Joule heating (electric heating) using the inherent electrical resistance of the food material. Since food materials can be heated from the inside in a short time, application to heating of various foods has been advanced. As an aspect of heating the food material by such energization heating, the food material is housed in an insulating container together with an outer solution containing an electrolyte (for example, saline solution), and a pair of electrodes disposed in the container A method has been proposed in which a meat material is energized via an external solution by applying a voltage between them and the food material is heated by Joule heating (Patent Document 1 and Patent Document 2). However, if the meat material is heated until a sufficient bactericidal value is obtained by these methods, one of the surface layer portion or the central portion of the food material is overheated, and the quality of the food, such as the color tone, is deteriorated.

  Specifically, if the electrolyte concentration of the outer solution is too high, an excessive current flows in the outer solution due to the high conductivity of the outer solution, and only a relatively small current flows in the food material. Accordingly, the external solution is preferentially heated by the electric heating, and the temperature of the external solution rises faster than the food material. Therefore, a temperature difference between the outer solution and the food material occurs. As the temperature rises, the conductivity further increases, so that the current flowing in the outer solution further increases, and thus the temperature rise rate of the outer solution further increases. On the other hand, since the temperature rise rate of the food material remains relatively small, the temperature difference between the outer solution and the food material is further widened. As a result, the surface of the food material is overheated.

  On the other hand, if the electrolyte concentration of the outer solution is too low, the current flowing through the food material and the outer solution becomes small, so that the food material cannot be heated sufficiently or even if it can be heated, it takes a very long time. Furthermore, even when the food material can be sufficiently heated, the current is relatively easy to flow through the food material while the current is relatively difficult to flow through the external solution. There will be a difference in the heating rate. In this case, the conductivity increases with the temperature of the food material, whereas the temperature of the outer solution does not change so much, so the change in conductivity is small. Therefore, the temperature difference between the food material and the external solution is further widened by energization heating. As a result, the central portion of the food material is overheated. Moreover, in order to heat the surface layer part of meat material, the electricity heating method using the hot water heated at 70 to 80 degreeC is also proposed (patent document 3). However, since this method heats the surface layer portion of the food material first with hot water, the food material cannot be heated uniformly, and the quality such as the color tone of the food is deteriorated.

Therefore, in any case, a temperature difference is generated between the surface layer portion and the central portion of the food material, and the quality such as the color tone of the food is deteriorated.
JP 61-132137 A JP 63-296672 A Japanese Patent Laid-Open No. 10-229853

  An object of the present invention is to provide a simple and low-cost method for producing an electrically heated food that can uniformly and sufficiently raise the temperature of the surface layer portion and the central portion of the food material immersed in water or a dilute solution. It is.

  The present inventor has found that the food material can be sufficiently heated by using water or a dilute electrolyte solution as the outer solution by elution of a small amount of electrolyte from the food material into the outer solution. When applying an energizing action to an outer solution containing a small amount of electrolyte, the present inventor determines that the heating rate of the food material varies depending on the distance between the electrode and the food material, and the heating rate of the food material and the outer solution It has been found that it can be adjusted by the applied voltage when applying the action. Based on these findings, the present invention adjusts the distance between the food material and the electrode and the applied voltage to conduct heating, so that the surface layer portion and the central portion of the food material immersed in water or a dilute electrolyte solution are uniformly distributed. As a result of finding out that the temperature can be sufficiently increased and further eagerly researching to solve the above-mentioned problems, the present invention has been completed.

  That is, the present invention provides a container in which a pair of electrodes are provided inside, together with water or a dilute electrolyte solution, and without bringing the food material containing the electrolyte into contact with the electrodes and in the water or the dilute electrolyte solution. The energized processed food is characterized in that the food material is stored in a state immersed in water and becomes energizable by the electrolyte eluted from the food material into water or a dilute electrolyte solution, and then the food material is sterilized by applying an energizing action. Provides a manufacturing method.

  Hereinafter, the method of the present invention will be described in detail.

  FIG. 1 shows a schematic view of an electric heating apparatus of the present invention. Here, 1 and 2 are electrodes, and 3 is a container for facing these electrodes. A is a food material containing an electrolyte, and B is water or a dilute electrolyte solution.

  The food material containing an electrolyte in the present invention includes an animal food material. Examples of the animal food material in the present invention include livestock meat materials such as ham, press ham, and sausage, and fish meat product materials such as fish ham, fish sausage, kamaboko, rice bran, and fish paste. In the present invention, ham, sausage, fish ham, fish sausage, kamaboko and the like are preferable, and ham and sausage are particularly preferable. The shape of the food material is usually a lump with a certain thickness, and is preferably a cylinder with a central axis (cylinder, square cylinder, elliptic cylinder, etc.). The electrolyte concentration of the food material of the present invention before energization is usually about 0.5 to 5% by weight, and preferably about 1 to 3% by weight.

  In the present invention, the food material used as the material may be packaged in a breathable or moisture permeable packaging material or unpackaged, but is preferably packaged in a breathable package. Here, the air-permeable or moisture-permeable packaging material may be any material that can permeate the electrolyte and can maintain the shape of the food material.

  Examples of the electrolyte in the solution used in the present invention include, but are not limited to, inorganic salts such as sodium salt, potassium salt, and magnesium salt. As an electrolyte in the solution in the present invention, sodium chloride (salt) is preferable.

  Sodium chloride is preferable as the electrolyte in the food material used in the present invention.

  In the present specification, the dilute electrolyte solution refers to an aqueous solution of the above-mentioned salts of about 0.02 M or less.

  The pH of the electrolyte solution may be in a range where the food material is not acid-denatured or alkali-denatured.

  In this specification, water includes not only tap water but also distilled water and ultrapure water.

  In the method of the present invention, first, a food material containing an electrolyte is immersed in water or a dilute electrolyte solution, together with an outer solution that is water or a dilute electrolyte solution, in a container having a pair of electrodes disposed inside. Accommodate. The food material is stored at an interval so as not to contact the electrode. Further, the side and lower surfaces of the food material are accommodated at intervals so as not to contact the wall surface and bottom of the container. The distance between the upper surface and the water surface of the food material and the distance between the side surface and the lower surface of the food material and the wall surface and the bottom surface of the container are all preferably about 0.1 cm to 10 cm, more preferably about 1 cm to 2 cm. preferable.

  Here, in order to uniformly heat the food material, the temperature of the outer solution before energization is usually about 0 to 50 ° C., preferably about 5 to 20 ° C. The temperature is usually about 0 to 40 ° C., preferably about 5 to 20 ° C.

  Further, by using the outer solution having a volume of about 0.5 to 3 times the volume of the food material, the loss of the electrolyte concentration of the food material due to the elution of the electrolyte concentration of the meat material into the outer solution is almost eliminated. .

  Next, a voltage is applied to the opposing electrode to heat and heat the food material. The voltage may be applied using a direct current power supply or an alternating current power supply, but is usually applied using an alternating current power supply. At that time, the frequency may be about 50 to 60 Hz, which is a commercial frequency, or a high frequency of about 20 kHz. Here, the applied voltage and the distance between the electrode and the food material are set so that the ratio of the applied voltage to the distance between the electrode and the meat material is usually about 20 V / cm, preferably about 40 V / cm.

  In the method of the present invention, the distance between the electrode and the food material is a distance that can be formed between the two electrodes and both ends of the food material (when the end of the food material facing the electrode is a curved surface or the electrode surface is a curved surface). Is the average value of the distance at the closest position.

  The applied voltage is usually about 50 to 1000V, preferably about 100 to 500V.

  The final temperature in the electric heating of the present invention is usually about 60 ° C to 100 ° C, preferably about 70 ° C to 90 ° C.

  This process heats the food material through a small amount of electrolyte eluted from the food material to the outer solution. Therefore, the surface layer and the center of the food material immersed in a dilute electrolyte solution or water are evenly distributed. The temperature can be increased.

  In addition, the food material and water or a dilute electrolyte solution can be heated more uniformly by changing the applied voltage during the electrical processing.

  According to the method of the present invention, the temperature of the surface layer portion and the central portion of the food material can be uniformly raised during the electric current processing. Therefore, the method of the present invention can produce a food excellent in quality such as color tone as compared with a food processed by a conventional method in which a temperature difference occurs between the surface layer portion and the central portion of the food material during the electric current processing. . In addition, the method of the present invention can heat sterilize food by energization heating without adding extra manufacturing cost and running cost due to adjustment of the electrolyte solution. Moreover, the bactericidal effect of the method of the present invention is equivalent to processing by boiling water.

  Further, in the method of the present invention, since the food material (not the packaging container) is energized and heated in the state of being immersed in the external solution without being brought into contact with the electrode, the food material having unevenness on the surface can be energized and heated. .

  The following examples describe specific embodiments of the present invention, but these examples are not intended to limit the invention.

Relationship between electrolyte concentration of external solution and temperature rise Fill the container (width 80mm x length 150mm x depth 80mm) with ultrapure water, tap water or 800ml of 1.7mM, 8.6mM saline, variable frequency power supply (maximum current) Value: 3A) was used to conduct current at a current frequency of 60 Hz or 20 kHz, 250V. FIG. 2 shows the rising pattern of the water temperature. By applying an energizing action, the water temperature rapidly rises with 8.6 mM saline, but gradually rises with tap water or 1.7 mM saline, and does not rise with ultrapure water. Next, 350 g of minced salted meat was filled into a breathable non-edible casing to produce a food material (70 mmφ × 130 mm). After the food material is stored in a container (width 80 mm × length 150 mm × depth 80 mm) together with the external solution (ultra pure water or 1.7 mM to 17 mM saline 450 ml) without contacting the electrode, a 20 kHz high frequency power supply An energization action was applied at 200 V using (maximum current value: 5 A). The distance between the electrode and the meat material is 1 cm. A temperature sensor was embedded in the surface layer (upper and lower) and center of the meat material, and the temperature was measured over time. At the same time, the temperature of the outer solution at the top and bottom of the meat material was measured using a temperature sensor. FIG. 3 shows the temperature rise pattern of the meat material and the outer solution immersed in the outer solution of each electrolyte concentration. Even when ultrapure water is used as the outer solution (FIG. 3 (a)), the energizing action is applied in the same manner as when the saline is used as the outer solution (FIGS. 3 (b) to 3 (d)). The meat material and the outer solution are heated.

Relationship between frequency of energization current and temperature rise 350 g of minced salted meat was filled into a breathable non-edible casing to produce a food material (70 mmφ × 130 mm). After the food material is housed in a container (width 80 mm × length 150 mm × depth 80 mm) together with the outer solution (1.7 mM saline 450 ml) without contacting the electrodes, the frequency variable power source (maximum current value: 3A) ) Was applied at a current frequency of 60 Hz or 20 kHz, 70 V. The distance between the electrode and the food material is 1 cm. Similarly to Example 1, the temperature of the food material and the external solution was measured over time. FIG. 4 shows the temperature rise pattern of the food material and the external solution subjected to the energization treatment at each frequency. There is no difference in the temperature rise pattern of the food material and the external solution between the commercial frequency of 60 Hz (FIG. 4 (a)) and the high frequency of 20kHz (FIG. 4 (b)). Not affected by.

Relationship between energizing voltage and temperature rise 350 g of minced salted meat was filled into a breathable non-edible casing to produce a food material (70 mmφ × 130 mm). A container (80 mm wide x 150 mm long x 80 mm deep), together with the outer solution (450 ml of ultrapure water) and the food material without being brought into contact with the electrode, a 20 kHz high frequency power supply (maximum current value: 5 A) was placed. The energizing action was applied at 100V, 200V, and 300V. The distance between the electrode and the meat material is 1 cm. Similarly to Example 1, the temperature of the food material and the external solution was measured over time. FIG. 5 shows the temperature rise pattern of the food material and the external solution at each energized voltage (FIGS. 5A and 100V; FIG. 5B and 200V; FIG. 5C and 300V). The heating rate increases as the energization voltage increases.

Relationship between electrode and food material distance and temperature rise Filled non-edible casing with minced salted meat and various sizes of food material (Food material large: 70mmφ × 490mm, medium: 70mmφ × 400 mm, food material small: 70 mmφ × 300 mm). After the food material is accommodated in the container (width 80 mm × length 500 mm × depth 80 mm) together with the outer solution (ultra pure water) without contacting the electrode, a variable frequency power supply (maximum current value: 3 A) is used. The current was applied at 200V. The distance between the electrode and the food material is 0.5 cm, 5 cm, and 10 cm for the large food material, medium food material, and small food material, respectively. Similarly to Example 1, the temperature of the food material and the external solution was measured over time. FIG. 6 shows the temperature rise pattern of the food material and the external solution at the distance between each electrode and the food material and the applied voltage (FIG. 6 (a), 0.5 cm, 200 V; FIG. 6 (b), 5 cm, 200 V; FIG. 6 (c), 10 cm, 200 V; FIG. 6 (d), 10 cm, 400 V). The distance between the electrode and the food material affects the heating rate, and the shorter the distance, the faster the heating rate. Further, when the rate of temperature rise is slow, the temperature can be quickly raised by increasing the energization voltage.

Adjustment of energization voltage for uniform temperature increase 350 g of minced salted meat was filled into a breathable non-edible casing to prepare a food material (70 mmφ × 130 mm). A container (width 80 mm x length 150 mm x depth 80 mm) and a food material together with an external solution (ultra pure water 450 ml) are accommodated without contacting the electrodes, and then a variable frequency power supply (maximum current value: 3 A) is installed. The current was applied at a current frequency of 60 Hz or 20 kHz and 200 V. The distance between the electrode and the meat material is 1 cm. When the current value reached the maximum current value of 3A, the voltage was lowered to 100V, and when the current value reached the maximum current value, the voltage was set to 50V and an energization operation was performed. Similarly to Example 1, the temperature of the food material and the external solution was measured over time. FIG. 7 shows the temperature rise pattern of the food material and the external solution when the energization voltage is changed (FIG. 7 (a), 60Hz; FIG. 7 (b), 20kHz). From the comparison with FIG. 5B in which the energization heating is performed under the same conditions as in FIG. 7B except that the energization voltage is constant, by changing the energization voltage when applying the energization action, the food material and It can be seen that the temperature of the outer solution can be increased more uniformly.

Bactericidal value and product quality by energization treatment and boiled treatment 350g of minced salted meat containing a certain amount of heat-resistant lactic acid bacteria (Enterococcus faecalis, IFO 12968) is filled in a breathable non-edible casing to produce a food material (70 mmφ × 130 mm). A container (width 80 mm x length 150 mm x depth 80 mm) and a food material together with an external solution (ultra pure water 450 ml) are accommodated without contacting the electrodes, and then a variable frequency power supply (maximum current value: 3 A) is installed. The current was applied at a current frequency of 60 Hz or 20 kHz and 200 V. The distance between the electrode and the food material is 1 cm. In addition, the meat material was boiled at 80 ° C. to prepare a control plot. When both the test group and the control group reached 70 ° C., the heating was stopped and the food material was ice-cooled. The temperature rising pattern at the center of each test group and control group is shown (FIG. 8). The time required for the central temperature of the food material to reach 70 ° C. was 43 minutes in the control group, 15 minutes in the test group subjected to current treatment at a frequency of 60 Hz, and 12 minutes at a frequency of 20 kHz. When the heating time corresponding to 63 ° C. when the Z value of the heat-resistant lactic acid bacteria is 4.7 is calculated, 139.9 minutes for boiled 80 ° C., 58.1 minutes for 60 Hz energization treatment, and 54. 2 minutes. In both the test group and the control group, heat sterilization at 63 ° C. for 30 minutes or more is performed, but in the control group, the food material is excessively heated in terms of 63 ° C. In each test group and control group, the meat material was ice-cooled when the temperature in the center reached 30, 50, and 70 ° C., and the number of surviving bacteria was measured. The survival rate of the heat-resistant lactic acid bacteria at each temperature during the temperature rise is shown in FIG. The heat-resistant lactic acid bacteria decreased by 1 order when the temperature reached 50 ° C. and decreased by about 6 orders when the temperature reached 70 ° C., and no difference in bactericidal value depending on the energization frequency was observed. Table 1 below shows the sodium, salt, nitrite, and vitamin B ₁ content of the sterilized food.

There is no significant difference in the contents of sodium, salt, nitrite, and vitamin B ₁ between the electric current processed food and the heated food by boiling. This result shows that the electrically processed food of the present invention is a food that is produced in a shorter time than the heated food by boiling and maintains the same safety and quality.

Color of product by energization treatment and boiled treatment 350 g of minced salted meat was filled into a breathable non-edible casing to produce a food material (70 mmφ × 130 mm). As a test plot, the food material was heated by energization according to the method of the present invention until it reached a temperature of 75 ° C., and then immediately cooled with ice water. At that time, the energization heating was carried out with an applied voltage of 200 V and an alternating current of 60 Hz. As a control, the same food material was heated in boiling water until the center temperature reached 65 ° C., 70 ° C., 75 ° C., 80 ° C., 85 ° C., 90 ° C., and then immediately cooled in ice water. Further, the cured meat similarly cut into pieces and filled in a breathable non-edible casing was heated by steaming until the central part reached a temperature of 75 ° C., and immediately cooled rapidly with ice water. The boiling temperature and steaming temperature were set 5 ° C. higher than the reaching temperature. The color tone (L, a, b) of the food material after each treatment was measured with a color difference meter. The measurement results are shown in Table 2 below.

  In boiled salted meat, the L value and b value increased as the center temperature increased. In the case of energization processing, since the processing time is short, the food material is less damaged and the increase in the b value is suppressed. This result shows that the food processed by the method of the present invention has a lower b value than boiled and steamed, that is, yellow color is suppressed and has a good color tone.

FIG. 1 shows a schematic view of an electric heating apparatus of the present invention. FIG. 2 shows the temperature rising pattern by various heating of various solutions. Here, in FIG. 2, ♦ indicates a temperature rise pattern of a system in which ultrapure water is energized at a frequency of 20 kHz. (2) shows a temperature rise pattern of a system in which tap water is energized at a frequency of 20 kHz. □ indicates a temperature rise pattern of a system in which tap water is energized at a frequency of 60 Hz. ● indicates a temperature rise pattern of a system in which 1.7 mM saline is energized at a frequency of 20 kHz. A triangle indicates a temperature rising pattern of a system in which 8.6 mM saline is energized at a frequency of 20 kHz. Δ indicates a temperature rise pattern of a system in which 8.6 mM saline is energized at a frequency of 60 Hz. FIG. 3 shows the temperature rise pattern of the meat material and the outer solution immersed in the outer solution having various electrolyte concentrations. Here, ● indicates the temperature rising pattern on the upper part of the food material. ▲ indicates the temperature rise pattern at the center of the food material. (2) indicates the temperature rising pattern below the food material. A circle indicates a temperature rising pattern on the upper part of the outer solution. □ shows the temperature rising pattern at the bottom of the outer solution. FIG. 4 shows the temperature rise pattern of the meat material and the external solution subjected to the energization treatment at frequencies of 20 kHz and 60 Hz. Here, ● indicates the temperature rising pattern on the upper part of the food material. ▲ indicates the temperature rise pattern at the center of the food material. (2) indicates the temperature rising pattern below the food material. A circle indicates a temperature rising pattern on the upper part of the outer solution. □ shows the temperature rising pattern at the bottom of the outer solution. FIG. 5 shows the temperature rise pattern of the meat material and the outer solution at various energization voltages. Here, ● indicates the temperature rising pattern on the upper part of the food material. ▲ indicates the temperature rise pattern at the center of the food material. (2) indicates the temperature rising pattern below the food material. A circle indicates a temperature rising pattern on the upper part of the outer solution. □ shows the temperature rising pattern at the bottom of the outer solution. FIG. 6 shows temperature rising patterns of the meat material and the outer solution at various distances between the electrode and the meat material. Here, ● indicates the temperature rising pattern on the upper part of the food material. ▲ indicates the temperature rise pattern at the center of the food material. (2) indicates the temperature rising pattern below the food material. □ shows the temperature rising pattern at the bottom of the outer solution. FIG. 7 shows the temperature rise pattern of the meat material and the outer solution when the energization voltage is changed. Here, ● indicates the temperature rising pattern on the upper part of the food material. ▲ indicates the temperature rise pattern at the center of the food material. (2) indicates the temperature rising pattern below the food material. A circle indicates a temperature rising pattern on the upper part of the outer solution. □ shows the temperature rising pattern at the bottom of the outer solution. FIG. 8 shows a temperature rising pattern at the center of the meat material in the energization process at 20 kHz and 60 Hz and the boil process. FIG. 9 shows the E.D. in the energization process at 20 kHz and 60 Hz and the boiling process. The survival curve of Faecalis is shown. Here, ● represents E.D. in energization processing at 20 kHz. The survival curve of Faecalis is shown. ○ is E. in the energization process at 60 Hz. The survival curve of Faecalis is shown. ▲ indicates E. coli in 80 ° C. boiled treatment. The survival curve of Faecalis is shown.

Explanation of symbols

1 Electrode 2 Electrode 3 Container A Food material containing electrolyte B Water or dilute electrolyte solution

Claims (4)

  In a container with a pair of electrodes inside, together with water or a dilute electrolyte solution, a food material containing the electrolyte is accommodated without being in contact with the electrode and immersed in the water or dilute electrolyte solution. A method for producing an electrically processed food, characterized in that the food material is energized by an electrolyte eluted from the food material into the water or a dilute electrolyte solution, and then the food material is energized to be sterilized. .   2. The method according to claim 1, wherein an energizing action is performed under a condition that a ratio of an applied voltage to a distance between the electrode and the food material is 20 V / cm or more.   The method according to claim 1 or 2, wherein the food material has an electrolyte concentration in the range of 0.5 to 5 wt%. The method according to any one of claims 1 to 3, wherein the food material is selected from the group consisting of ham, sausage, fish ham, fish sausage, and kamaboko.

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