JP2008002985A - System and method for evaluating quality of frozen food, and operation control method of freezing device utilizing quality evaluation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and method capable of performing objective and highly-reliable quality evaluation of the frozen food by quantitatively determining a surface color of the frozen food, and an operation control method of a freezing device capable of optimizing an operation condition of the freezing device by utilizing the evaluation method. <P>SOLUTION: The system for determining quality of the freezing state by the surface color of the frozen food 100 includes a color difference meter 101 for measuring the surface color of the frozen food 100, a color system conversion part 103 for converting color difference measured data 102 acquired by the color difference meter into RGB color system data 104, and a comparison/determination part 106 for determining the freezing state of the frozen food 100 based on the RGB color system data 104 acquired by the color system conversion part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a frozen food quality evaluation system and method for quantitatively evaluating the quality of frozen food based on its surface color, and further to optimize the operating conditions of the freezing apparatus using the evaluation method. The present invention relates to a method for controlling the operation of a freezing apparatus.

  In recent years, techniques for producing frozen foods by freezing foods such as scallops, seafood such as fish fillets, or livestock meat have become widespread. Frozen foods have the advantage that they can be stored for a long period of time by freezing in a raw state or processed state, so that foods can be supplied throughout the year, and products of a certain quality can be supplied. As a food freezing apparatus, for example, a brine type freezer using a liquid refrigerant (brine) described in Patent Document 1 (Japanese Patent Laid-Open No. 2003-322452) or the like, and Patent Document 2 (Japanese Patent Laid-Open No. 2004-169960). There is a collision jet freezer described in the above. The brine type freezer performs rapid freezing of food by spraying brine such as ethylene glycol and propylene glycol from above and below the object to be frozen, and enables relatively uniform freezing in a short time. On the other hand, the impinging jet freezer is a method of freezing by injecting cooling air, and has the advantage that it is safe and easy to handle.

The frozen state of frozen food is caused by the type and structure of the freezing device and the setting of various operating conditions such as the cooling temperature and the cooling time. Therefore, there is a problem that the quality of the frozen product is deteriorated unless the apparatus and operating conditions suitable for frozen food are selected.
Conventionally, the quality evaluation of frozen foods currently depends on visual inspection. For example, when evaluating the quality of frozen scallops, quality factors such as color, cracking, and flowering (with frost) can be cited. Among them, the factors that serve as an index to grasp the frozen state are the surface color of frozen foods. It is. As shown in FIG. 11A, the surface and cut surface of the frozen scallop in a uniform and good frozen state are uniformly whitened. If the frozen state is bad, the surface may become a dark color as shown in FIG. Accordingly, as the frozen scallops in circulation, those that are uniformly whitened as shown in FIG. 11 (a) have high quality and are in great demand.
However, in the visual inspection with the naked eye, there is a problem in that the determination result varies depending on the inspector, and the fairness cannot be ensured, or the subtle color difference cannot be determined, making it difficult to distinguish the quality.

Japanese Patent Laid-Open No. 2003-322452 JP 2004-169960 A

As described above, in the quality evaluation of frozen foods, the conventional visual inspection has individual differences, resulting in variations in measurement, and cannot be measured objectively and quantitatively. Accordingly, the conventional visual quality evaluation information has low reliability for a third party who wants to grasp the accurate quality.
When evaluating the quality of frozen foods, quality factors such as color, shape, and frost are listed. In the present invention, the surface color is the object of evaluation, and the surface color is quantitatively determined to make it objective and reliable. The purpose of the present invention is to provide a frozen food quality evaluation system and method capable of evaluating the quality of highly frozen foods, and further to optimize the operating conditions of the freezing apparatus using the evaluation method. An object of the present invention is to provide an operation control method for a freezing apparatus.

Therefore, in order to solve the above-described problems, the present invention provides
In the frozen food quality evaluation system that evaluates the frozen state based on the surface color of the frozen food,
The color difference meter for measuring the surface color of the frozen food, the color difference measurement data obtained by the color difference meter, the color system conversion means for converting to RGB color system data, and the color system conversion means. And determining means for determining a frozen state of the frozen food based on RGB color system data.
According to the present invention, the surface color of the frozen food is measured with a color difference meter, and the color difference measurement data is converted into RGB color system data. Therefore, the color difference measurement data such as L * a * b * color system is used. In addition, the quality of frozen food can be evaluated with an expression color closer to the color seen with the naked eye. Further, according to the present invention, the surface color of the frozen food can be quantitatively determined, and the objective and reliable quality evaluation of the frozen food can be performed.

Further, the storage unit stores a reference range of RGB total values of the RGB color system data, which is good for each frozen food, and is obtained by the color system conversion unit in the frozen food determination unit. Comparing the RGB total value of the RGB color system data and the reference range, and determining that the frozen state of the frozen food is good when the RGB total value exists within the reference range. Features.
Thereby, selection of frozen food based on quality evaluation can be easily performed.

In addition, a method for evaluating the quality of a frozen food by evaluating the frozen state based on the surface color of the frozen food,
After measuring the surface color of the frozen food with a color difference meter, the color difference measurement data obtained with the color difference meter is converted into RGB color system data to obtain RGB color system data serving as an evaluation index for the frozen food. It is characterized by that.
Further, according to the frozen food to be evaluated, a reference range of the RGB total value of the RGB color system data in which the frozen state is good is set in advance, and the total of the obtained RGB color system data is set When the value is within the reference range, it is determined that the frozen state of the frozen food is good.

Furthermore, the operation control method of the freezing device using the quality evaluation method,
Based on the RGB color system data obtained by the conversion, an operation control method for the freezing apparatus is proposed, which controls the operation of the control items of the freezing apparatus.
Furthermore, the freezing apparatus includes a conveyor belt that conveys food into the cooling space, a fan that stirs the cold air in the cooling space, and a means for setting the temperature in the cooling space,
The control item is at least one of fan rotation speed, capacity control of the freezing device, conveyor belt feed speed, and set temperature of the cooling space.
As a result, the operating conditions of the freezing apparatus can be optimized, and a frozen food in a good frozen state can be produced.

As described above, according to the present invention, the surface color of frozen food is measured with a color difference meter, and the color difference measurement data is converted into RGB color system data, so that the expression color is closer to the color seen with the naked eye. The quality of frozen food can be evaluated. In this way, by treating the surface color of frozen food as RGB numerical information, it is possible to evaluate and evaluate the performance of frozen foods as objective food quality information that can be easily judged by a third party. Can be used.
In addition, by controlling the operation of the freezing apparatus using the evaluation method of the present invention, it is possible to optimize the operating conditions of the freezing apparatus, and it is possible to produce a frozen food in a good frozen state.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.
In this embodiment, the present invention can be applied to foods typified by meat such as scallops, fish fillets, crab meat, and other meat such as beef and pork internal organs. It can be suitably applied to quality evaluation).

FIG. 1 is a block diagram showing a basic configuration of a quality evaluation system according to the present embodiment.
In this embodiment, as shown in FIG. 1, the surface color of the frozen food 100 is measured with a color difference meter 101, and the color difference measurement data 102 obtained with the color difference meter 101 is converted into an RGB table by a color system conversion unit 103. The color system data 104 is converted. Then, the RGB color system data 104 obtained by the color system conversion unit 103 is output from the output unit 107. Thereby, the quality evaluation of the frozen food can be output with an expression color closer to the color seen with the naked eye, and the quality evaluation can be easily performed.

For each frozen food, a reference range of the RGB total value of the RGB color system data that is in an optimal frozen state is set, and the reference range is stored in the reference range storage unit 105. Then, a reference range corresponding to the frozen food 100 to be measured is extracted from the reference range storage unit 105, and the comparison / determination unit 107 extracts the reference range and the RGB color system obtained by the color system conversion unit 103. The RGB total value of the data 104 is compared, and an evaluation that the frozen state is good is given when the RGB color system data is within the reference range. Thereby, the selection according to the quality of frozen food can be performed easily.
At this time, the reference range may be set for each numerical value of RGB without being set as the RGB total value, and may be determined by comparing each numerical value of the RGB color system data obtained by measurement.

The color difference meter 101 is a well-known device that measures a reflective object color in a color system such as L * a * b *, XYZ, and L * C * H °. The “L * a * b * color system” that displays colors numerically represents lightness as “L *” and chromaticity as “a *” and “b *”. “+ A *” indicates the red direction, “−a *” indicates the green direction, “+ b *” indicates the yellow direction, and “−b *” indicates the blue direction. In this embodiment, the color system used for obtaining the color difference is described using the L * a ^* b ^* color system. However, the present embodiment is applied to other color systems. Can do.

  Here, using the method described above, an experiment was conducted to evaluate the surface color of a frozen scallop column produced by rapidly freezing scallop columns and a raw scallop column as an example. Fig. 2 Table showing each color system data of raw scallops and frozen scallops and converted RGB color system data. Fig. 3 is a table showing RGB color system data of frozen scallops obtained by an experimental apparatus. It is.

First, the surface color of frozen scallops and raw scallops is measured using a color difference meter 101 and digitized as color difference measurement data 102 composed of L * a * b *. The color difference measurement data 102 is converted into a color system conversion unit 103. Thus, the RGB color system data 104 is converted. In this experiment, the surface color was digitized using a Munsell color sample as a comparative example, and converted to RGB color system data in the same manner.
In this surface color evaluation method, in the case of slow freezing, transparent ice is formed on the surface, so when measuring with a color difference meter, the light for measurement emitted from the color difference meter is absorbed or scattered by the ice layer, and in fact, It is measured as a darker color than the color data. On the other hand, in the case of rapid cooling, since the ice crystals on the surface are small, the measurement light is reflected and detected as a white color. Therefore, it can be used as an effective objective evaluation because it can be an indicator of the quality of a frozen product, in particular, whether quick freezing is good or bad.

As shown in FIG. 2, RGB color system data converted from color difference measurement data and RGB color system data converted from Munsell color system data are compared in raw scallops and frozen scallops. The RGB color system data obtained from Munsell color system data has a large variation because the base Munsell color system data is obtained by collation with a sample by visual observation, and it is difficult to judge with high accuracy. I know that there is.
On the other hand, it can be seen that the RGB color system data converted from the color difference measurement data is darkly expressed in the raw scallop. This is presumably because, as in the case of slow freezing, the measurement light emitted from the color difference meter is significantly absorbed or scattered and is measured as a darker color than the actual color data. In the frozen scallop, the RGB color system data was detected as a white color, and the result was almost the same as the visual surface color.

Therefore, in this example, as a method for quantitatively grasping the surface color of frozen food, it has been clarified that an appropriate evaluation result can be obtained by converting color difference measurement data into RGB color system data.
In addition, after the RGB conversion of the color difference measurement data, the frozen scallop that was uniformly whitened in a good frozen state was found to express the RGB value brightly, so the RGB values (230, 205, 185), the RGB total value 620 is set as the target value of the surface color. From this point, it is preferable that the reference range of the total value of the RGB color system data indicating a frozen scallop in a frozen state is 600 or more.

Furthermore, as shown in FIG. 3, the graph which evaluated the surface color of the scallop pillar frozen using different freezing apparatuses (experimental apparatuses 1-5) is shown.
Experimental apparatuses 1 and 4 are cases where a brine type freezer is used in which brine is brought into direct or indirect contact with scallops to cool and freeze the scallops. Experimental apparatuses 2, 3 and 5 are cooled. This is a case where an impinging jet freezer is used in which air is brought into direct or indirect contact with a scallop column to cool and freeze the scallop column.
As shown in FIG. 3, the RGB color system data obtained by the apparatus is different. This represents a difference in freezing capacity. That is, in the brine type freezer (experimental apparatuses 1 and 4) having a relatively high freezing capacity, the total RGB value exceeds 600, which is in the reference range, indicating that the freezing state is good. On the other hand, in the impinging jet freezer (experimental devices 2 and 3), the RGB total value is 600 or less, and the quality is low because it does not exist in the reference range.
Although the experimental apparatus 5 uses a collision jet type freezer, an experiment is performed using a transfer type freezing apparatus 1 (see FIGS. 6 to 7) described later, and the RGB total value is within a reference range of 603, which is favorable. It became frozen.
As described above, according to the evaluation method according to the present embodiment, the frozen state is good or bad by the RGB total value, and the freezing ability of the freezing apparatus can be quantitatively and accurately evaluated.

  In FIG. 4, the result of having evaluated the frozen pig heart (heart) using the evaluation method for this example is shown. The measurement sites in FIG. 4 correspond to the measurement sites in FIG. The surface color of each porcine heart was measured with a color difference meter in the same manner as the frozen scallop at each disassembled measurement site. The color difference measurement data obtained by the color difference meter was converted to the RGB color system to obtain RGB color system data. Even in the frozen pig heart, the RGB color system data can output the quality evaluation of frozen foods in an expression color closer to the color seen with the naked eye, and the quality evaluation can be easily performed. When setting a reference range and selecting according to quality, of course, a reference range different from the frozen scallop is set.

Next, the operation control method of the freezing apparatus using the evaluation method according to the present embodiment will be described below. As an example, a conveying type freezing apparatus using the collision jet type freezer shown in FIGS. 6 to 8 will be described. In the transport-type freezing apparatus 1, a conveyor belt 15 that transports the food to be frozen 20 is extended in a casing 2 that forms a cooling space. The conveyor belt 15 is formed of a material having a high heat transfer rate, and for example, a steel belt is preferably used. The frozen food 20 is quickly frozen when placed on the conveyor belt 15 and passes through the freezing device 1, and is discharged from the freezing device 1 as frozen food 20 '.
A cold air generator 3 is provided at the upper part of the casing 2, and a feed duct 4 extends from the cold air generator 3 downward. A fan 5 is installed in the feed duct 4 to send the cool air generated by the cool air generator 3 downward.

An end of the feed duct 4 is connected to a lower cooling space 6 installed below the conveyor belt 15. The lower cooling space 6 is provided with a slit nozzle 7 for vertically ejecting cold air toward the lower surface of the conveyor belt 15. A plurality of the slit nozzles 7 are arranged at predetermined intervals in the transport direction of the transport conveyor 15.
An agitator fan 10 is installed above the conveyor belt 15 to agitate the upper cooling space 11 of the conveyor belt 15.
In addition, a return duct 13 is disposed on the side of the casing 2, and cool air blown to the conveyor belt 15 from the upper cooling space 11 and / or the slit nozzle 7 of the conveyor belt 15 is circulated to the cold air generator 3. It is supposed to let you.

The frozen food 20 conveyed by the conveyor belt 15 is cooled and collided (contacted) with the cold air on the lower surface of the conveyor belt 15 by the slit nozzle 7, and the belt 15 is cooled. On the other hand, the upper cooling space 11 is agitated by the agitator fan 10, and cool air is supplied to the upper surface of the food to be frozen 20 to cool the whole food to be frozen.
Further, in this embodiment, the air volume supplied to the lower surface side of the conveyor belt 15 is set to be larger than the air volume supplied to the upper surface side.
At this time, the air volume balance of the cold air supplied to each is preferably 9: 1 to 7: 3 on the belt lower surface side: belt upper surface side, and more preferably about 9: 1 on the belt lower surface side: belt upper surface side. And Moreover, it is preferable that the temperature in the casing 2 is −38 ° C. or lower.

As the air volume adjusting means, as shown in FIG. 8, a bypass path leading to the upper cooling space 11 of the feed belt 4, that is, the conveyor belt 15, may be provided. This can be achieved, for example, by forming a feed duct wall facing the upper cooling space 11 with a material having a hole such as a punching metal 14.
Thereby, since a part of cold air branches through the punching metal 14 and flows into the upper cooling space 11, the air volume of the upper surface of the food to be frozen 20 can be secured.

As a characteristic configuration of the transport-type freezing apparatus 1 in the present embodiment, quality evaluation is performed from the surface color of the frozen food 20 ′ on the rear stage side of the freezing apparatus 1, and the evaluation results are fed back to various types of the freezing apparatus 1. A configuration for controlling the operation of control items is provided.
As shown in FIG. 1, a measurement zone comprising a heat insulating space 30 is formed on the rear side of the freezing device 1 as shown in FIG. 1, and a non-contact type color difference meter 31 is installed in the measurement zone. The above evaluation is performed based on the measurement data. Based on the evaluation result, various control items are controlled by the control device 32 so as to obtain a high-quality frozen food 20 ′. Examples of the control items include fan speed, refrigerator capacity control, belt feed rate, and adjustment of temperature setting in the cabinet, and at least one of these control items is controlled.
As a result, the freezing capacity of the freezing apparatus 1 can be optimized, and a high-quality frozen food 20 ′ can be produced.
Further, a defective frozen product removing means (not shown) is provided on the rear end side of the conveyor belt 15, and the frozen food 20 ′ determined to be defective due to the evaluation is excluded from the conveyor belt 15, so that the high quality frozen food 20 ′ is removed. Only products may be shipped as products.

For reference, FIGS. 9 and 10 show the state of the surface color of the frozen scallop column with respect to the operating conditions (upper wind speed, lower wind speed, cold air temperature) of the freezing apparatus.
FIG. 9 is a diagram showing the relationship of the surface color of the frozen scallop column to the lower wind speed and the cold air temperature. According to this, when the reference range in which the ball color (surface color) is the best is set to RGB = (223 <, 201 <, 177 <), the lower wind speed is 17 m / sec or less, preferably 18 m / sec. In the following, it is preferable that the cold air temperature is −36 ° C. or lower, and preferably −38 ° C. or lower. Similarly, when the range in which the bead color is good is set to RGB = (213 <, 190 <, 162 <), the range in which the bead color cannot be set is RGB = (201 <, 176 <, 151 <). When set, the corresponding operating conditions are determined as shown in the figure.
FIG. 10 is a diagram showing the relationship of the surface color of the frozen scallop shell to the upper wind speed and the cold air temperature. According to this, when the reference range in which the bead color (surface color) is the best is set to RGB = (223 <, 201 <, 177 <), the range in which the bead color is good is RGB = (212 < , 188 <, 161 <), the corresponding operating conditions are determined as shown in the figure.

It is a block diagram which shows the basic composition of the quality evaluation system which concerns on a present Example. It is a table | surface which shows each color system data of a raw scallop column and a frozen scallop column, and RGB color system data after conversion. It is a table | surface which shows the RGB color system data of the frozen scallop column obtained with the experimental apparatus. It is a table | surface which shows the RGB color system data of the frozen pig heart obtained with the experimental apparatus. It is a figure which shows the measurement site | part of a frozen pig heart. It is a side view of the conveyance type freezing apparatus using the evaluation method of a present Example. It is a top view of the conveyance type freezing apparatus of FIG. It is XX sectional drawing of the conveyance type freezing apparatus of FIG. It is a figure which shows the state of the surface color of the frozen scallop pillar with respect to a lower wind speed and cold air temperature. It is a figure which shows the state of the surface color of the frozen scallop pillar with respect to an upwind speed and cold wind temperature. A photograph of a frozen scallop is shown, where (a) shows a good frozen state, and (b) shows the surface color of the scallop.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conveyance type freezing device 3 Cold wind production | generation part 4 Feed duct 5 Fan 6 Lower cooling space 7 Slit nozzle 10 Agitator fan 11 Upper cooling space 14 Punching metal 15 Conveyor belt 20 Scallop pillar 20 'Frozen scallop pillar 100 Frozen food 101 Color difference meter 102 Color difference Measurement data 103 Remainder between colorimetric systems 104 RGB color system data 105 Reference range storage unit 106 Comparison / determination unit 107 Output unit

Claims (6)

In the frozen food quality evaluation system that evaluates the frozen state based on the surface color of the frozen food,
The color difference meter for measuring the surface color of the frozen food, the color difference measurement data obtained by the color difference meter, the color system conversion means for converting to RGB color system data, and the color system conversion means. A quality evaluation system for frozen food, comprising: determination means for determining a frozen state of the frozen food based on RGB color system data.   A storage unit storing a reference range of RGB total values of RGB color system data that is good for each frozen food, and the RGB obtained by the color system conversion unit in the frozen food determination unit; Comparing the RGB total value of the color system data with the reference range, and determining that the frozen state of the frozen food is good when the RGB total value exists within the reference range The quality evaluation system for frozen food according to claim 1. A method for evaluating the quality of a frozen food by evaluating the frozen state based on the surface color of the frozen food,
After measuring the surface color of the frozen food with a color difference meter, the color difference measurement data obtained with the color difference meter is converted into RGB color system data to obtain RGB color system data serving as an evaluation index for the frozen food. A method for evaluating the quality of frozen foods.   In accordance with the frozen food to be evaluated, a reference range of RGB total values of RGB color system data in which the frozen state is good is set in advance, and the total value of the obtained RGB color system data is 4. The method for evaluating the quality of frozen food according to claim 3, wherein the frozen food is judged to be in a good frozen state when it is within the reference range. An operation control method of a freezing apparatus using the quality evaluation method according to claim 3,
An operation control method for a freezing apparatus, wherein operation control of the control items of the freezing apparatus is performed based on RGB color system data obtained by the conversion. The freezing device includes a conveyor belt that conveys food into the cooling space, a fan that stirs the cold air in the cooling space, and a means for setting the temperature in the cooling space,
6. The operation control of the freezing apparatus according to claim 5, wherein the control item is at least one of a fan rotation speed, a capacity control of the freezing apparatus, a conveyor belt feed speed, and a set temperature of the cooling space. Method.

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