JPH06317528A - Method and device for judging freshness of egg - Google Patents

Abstract

PURPOSE:To nondestructively judge the freshness of eggs without giving chemical and physical influence to their contents by applying an ultraviolet ray to an egg with shell and measuring the intensity of red fluorescence generating on the surface of the egg. CONSTITUTION:When an ultraviolet ray is applied to an egg placed in a sample fixing part 3 by using a light source 1 consisting of a long wavelength type ultraviolet lamp with a blue filter, a small amount of protoporphyrin which is included in a cuticular layer made of amorphous covering film and an egg- shell is excited, and a red fluorescence is generated. The intensity of the fluorescence becomes weak as the freshness of the egg is degraded. It is because the cuticular layer which existed on the surface of the egg-shell during oviposition is peeled off gradually with time elapse and the protoporphyrin amount included therein is reduced as well. Then, the generated fluorescence is received by a light receiving part 2, the output that the obtained minute current is amplified by an amplifier 4 is displayed on a display part 5 and it is also inputted to a judgement processing part 6 such as a computer, etc. Therefore, the result is compared with an optionally preset reference value to judge the freshness of the egg.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the determination of freshness of chicken eggs, and more particularly to a non-destructive method of determining freshness of eggs with shells.

[0002]

2. Description of the Related Art Conventionally, as a method for determining the freshness of chicken eggs, visual inspection such as specific gravity measurement, visual inspection of the egg surface, and light transmission inspection (for example, JP-A-62-21154, JP-A-03-
No. 103129 and Japanese Patent Laid-Open No. 04-194650.

[0003]

Among those described in the prior art, in the specific gravity measurement method, determination is made based on the size of the air chamber inside the egg, so except when the freshness is extremely low,
A clear judgment is impossible.

[0004] Further, the visual inspection is for cracks in the shape of an egg or an eggshell,
It is a method of inspecting the surface condition such as gloss and contamination, and it is an inspection method necessary for quality control such as selecting abnormal eggs, but it is often not directly related to freshness judgment.

Further, in the light-transmitting test, abnormalities in the egg such as the spread of the air chambers, the swelling of the yolk, blood spots, and the proliferation of microorganisms can be judged to some extent, but the judgment accuracy is not as high as that of the breaking test. There were problems such as the need for empirical intuition and the inability to process a large number of eggs in a short time.

Of the various tests performed after breaking eggs,
In particular, the measurement of the Howe unit and the egg yolk coefficient are currently used as a highly reliable method for determining the freshness of chicken eggs. However, since it is an inspection after breaking eggs, it does not judge the freshness as a shell egg, and thus has a fundamental problem that it is not evaluated as a commercial value.

The present invention has been made in view of the above problems, and an object of the present invention is to apply a completely different principle to freshness of eggs with a shell from various conventional methods. By doing so, it is an object of the present invention to provide a nondestructive determination method and its apparatus.

[0008]

In order to achieve the above-mentioned object, in the freshness judging method and the apparatus therefor of the present invention, a light source which emits ultraviolet rays is used, and the eggs on the shell are irradiated with ultraviolet rays so that the outermost portion of the eggshell is exposed. Exciting a small amount of protoporphyrin existing in the cuticle and egg shell, which is an amorphous film with a thickness of about 10 μm covering the eye, and observing the red fluorescence generated by the observer with the naked eye or receiving light with various light receiving elements, To be able to measure.

The positional relationship between the light source in the above-mentioned measuring system, the shell egg serving as the subject, and the observer or the light receiving element may be arbitrary, but the ultraviolet irradiation area to the subject should be as wide as possible. It is advisable to make adjustments so that fluorescence is most efficiently generated and photometry can be performed by preventing the photometric unit from facing each other and the light emitting surface of the subject and the photometric position facing each other as much as possible.

Further, it is desirable to perform measurement in a dark field as much as possible in order to reduce noise as much as possible.

[0011]

In the measurement system configured as described above, when a shell egg as a sample is irradiated with ultraviolet rays, a small amount of protoporphyrin on the surface of the eggshell is excited and emits red fluorescence.
Since the eggshell itself is white, when viewed with the naked eye, the eggshell surface actually looks like a red-purple color that is a mixture of the red color and the purple or blue light from the light source.

Further, when the chicken egg is very fresh, the fluorescence intensity is strong, and it appears as a red-red magenta color. When the egg becomes old and less fresh, the fluorescence intensity weakens, and the red-red magenta color becomes even older. It looks pale on the egg.

The cause of the above-mentioned change in color tone is that the cuticle layer on the surface of the eggshell, which was present at the time of spawning, gradually drops off with time, and the amount of protoporphyrin present therein also decreases accordingly. Conceivable. Moreover, this phenomenon depends on the environmental temperature in which the egg is placed.

Therefore, eggs stored at low temperature retain their freshness even after a considerable number of days, but at high temperatures, they will deteriorate in a short period of time, similar to the conventionally known changes in freshness. Since it has a tendency, if this is used, freshness can be judged.

If the amount of ultraviolet rays radiated to the egg is always constant, the amount of ultraviolet rays reflected on the egg shell surface is also always constant, so this change in color tone is simply due to the fluctuation of only the red fluorescence intensity. Can be said.

From the above, when the above method is used, the hue changes depending on the difference in the freshness of chicken eggs, so that the rough freshness can be judged only by the visual inspection.

When the determination is made by using various light receiving elements other than the visual inspection, the sum of the reflection amount of the ultraviolet ray and the red fluorescence amount or the intensity of the fluorescence only may be measured due to the above factors. Good.

In this case, because of light reflection and fluorescence, the sampling time required for one sample can be almost ignored, and high-speed processing can be performed in a state close to real time.

[0019]

EXAMPLES Examples will be described with reference to the drawings.
In FIG. 1, a long-wavelength type ultraviolet lamp with a blue filter is used as a light source 1, a photodiode is used as a light receiving section 2, and an ultraviolet ray is applied to a chicken egg placed in a specimen setting section 3 located at a distance of about 25 cm from the light source. Irradiate. The red fluorescent light excited by the ultraviolet rays reflected from the egg shell surface by the ultraviolet ray irradiation is generated by the light receiving section 2 set at a position about 5 cm away from the chicken egg, and the obtained minute current is amplified by the amplifier 4. The output is what you have done.

The output may be expressed as an absolute value,
It may be expressed as a relative value with respect to a certain reference value, and the output form may be current as it is, but it may be extracted in the form of voltage or frequency conversion or logarithmic conversion.

While displaying or recording the obtained output on the display panel, level meter, recorder or the like on the display unit 5, the output is directly read or sequentially input to the determination processing unit 6 such as a computer, and the output is preset in advance. You may judge freshness by comparing with the reference value set to.

In this case, the yolk coefficient and the Howe unit value have a correlation with the value obtained by measuring the egg with this measuring system, and therefore the reference value may be set based on this.

The positional relationship between the light source, the light receiving portion, the subject, and the like shown in the embodiments are merely examples, and may be arbitrarily changed according to the purpose of use and scale.

For example, regarding the light source shown in the embodiment,
Although an ultraviolet lamp may be used, other than this, a low-pressure mercury lamp having a large wattage, a medium-pressure or high-pressure mercury lamp may be used, and any deuterium lamp or a xenon tube that emits ultraviolet rays may be used. It is okay, but at this time,
When the wavelength of visible light is also generated, it is desirable to apply an appropriate filter such as high-cut or band-pass so that only the wavelength in the ultraviolet region is possible.

Further, in the power source section of the light source, a constant voltage,
It is advisable to maintain a constant amount of light by using a constant current circuit or the like, or by feeding back with a light receiving element that monitors the amount of light, or by using a double beam system.

As the light receiving element, a photodiode or a phototransistor may be used in the embodiment. In this case, however, since there are various wavelength ranges of the sensitivity characteristic, the central sensitivity in the vicinity of 600 nm is set for the measurement. Things are suitable.

A solar cell panel or a photomultiplier may be used as an element that can expect the same effect.

Further, by mounting a bandpass filter centering around 600 nm or various filters in combination on the light receiving portion of various light receiving element parts such as the above-mentioned photodiode, background noise can be reduced. Since only fluorescence is measured, the measurement sensitivity and accuracy can be further improved.

Alternatively, the color may be expressed numerically or symbolically by using a colorimetric method or a color difference measuring method, and in this case, the egg yolk coefficient or the correlation coefficient with the how unit value is also obtained. By using this as a reference value, freshness can be determined.

Further, if a diode array, an image eye, a CCD camera, etc. are used, several or several tens of them are used.
It is also possible to carry out simultaneous determination of a large number of eggs with one block as a block.

In this case, the captured image data is
-After D conversion, if it is processed by a fuzzy control type computer or a neuro computer as well as an image diagnostic processing device or a normal computer, or if it is processed by a neural network logic circuit program or the like, the response speed is fast and highly accurate. It is also possible to create a device for determining freshness.

At this time, the data can be evaluated by using either the light quantity or the color.

In addition, the above-mentioned various systems are incorporated into, for example, an automatic sorter line at an egg yard, or as one item of an egg test before breaking eggs at a liquid egg manufacturing factory, a mayonnaise factory, or the like. You can

Further, the measuring device itself can be made small, for example, a battery-driven type and a handy type can be used.

[0035]

Since the present invention is configured as described above, it has the following effects.

Since it is only irradiated with ultraviolet rays, no chemical or physical change is required to the appearance and the egg contents after the inspection.

Since a destructive test such as the conventional egg breaking test is not performed, not only is the commercial value of the shell egg not impaired even after the freshness of the chicken egg is judged,
More precise quality control is possible.

Since the inspection takes up no space and the measuring time ends instantly, it can be said that it is directly incorporated into the conventional line as one of the inspection items before the selection and processing steps in various factories handling eggs. However, this does not cause actual damage such as a decrease in the overall processing speed.

This test method is not limited to white eggs, but colored eggs,
It is also applicable to so-called red balls, eggs that have been oil-coated for the purpose of long-term storage, or avian eggs other than chicken.

The battery-operated and handy type can be used, for example, as a device for determining the freshness of chicken eggs in small and medium-sized confectionery manufacturers and their homes.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of an embodiment of the present invention.

[Explanation of symbols]

 1 Light Source 2 Light Receiving Section 3 Sample Setting Section 4 Amplifier 5 Display Section 6 Judgment Processing Section

Claims (1)

[Claims] 1. A method and apparatus for determining freshness by irradiating an egg with ultraviolet rays and measuring the intensity of fluorescence generated on the surface of the egg shell.