JPS6385430A - Food evaluating device - Google Patents

Abstract

PURPOSE:To digitize and evaluate the degree of freshness of food by sticking a probe which is made constant in optical path length into the food and measuring the absorption spectrum of specific wavelength corresponding to the optical path length. CONSTITUTION:When samples 10 flow on a line, a holder 28 slides to stick probes 24 and 26 into the samples 10. An optical fiber is run in the probe 24 as a light guide and led to a light source unit through a lead part 30. An optical fiber as a light guide is provided in the probe 26 as well and this optical fiber is connected to a detector unit through the other lead part 32. Then, light projected from the tip of the probe 24 is photodetected by the tip of the probe 26 and light absorption at the tip distance L between the probes 24 and 26 is measured by the detector unit. Thus, the absorption spectrum is measured to digitize and evaluate the degree of freshness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a food evaluation device that measures the freshness of food using light.

(Conventional technology) In the food industry, freshness is evaluated based on dates such as the shipping date at the place of origin, but even if the food has the same date, freshness can vary due to differences in conditions such as the place of origin, transportation route, and storage conditions. It is not possible to quantitatively evaluate the difference.

It is a common experience in daily life that as food loses its freshness, its color changes due to oxidation and other factors. Therefore, visual freshness evaluation is also performed using color changes.

(Problems to be Solved by the Invention) Even if freshness is evaluated visually based on color changes, it is not possible to quantify how much the freshness has deteriorated, and visual evaluation only evaluates the surface condition. It is not possible to evaluate the freshness of the internal state.

Furthermore, even if spectroscopic measurements are used for quantitative measurements, it is extremely difficult to measure because the optical path length is not constant for objects of variable size, such as lumps of meat.

An object of the present invention is to provide an apparatus that can quantify and measure the freshness of food using a spectroscopic method.

(Means for Solving the Problems) In the food evaluation device of the present invention, two probes that are pierced into food are fixed so that the distance between the tips of both probes is constant, and one probe is attached to the probe. The other probe is provided with a light irradiation means for emitting light from the tips of the probe, and the other probe is provided with a light receiving means for receiving light at the tip of the probe. Evaluate food.

(Function) Figure 2 shows the absorption spectrum curves of pork as an example of food, measured by the transmission method and the reflection method. A is a spectrum obtained by the transmission method, and B is a spectrum obtained by the reflection method.

A weak absorption band (indicated by an arrow) of metmyoglobin due to oxidation is detected near 650 mμ in both open lines A and B. This absorption band is not found in fresh pork, so pork freshness can be tested by measuring absorption at 650 mμ.

(Example) FIG. 1 shows a block diagram of one embodiment of the invention.

Reference numeral 2 denotes a light source that generates light in the visible region and near-infrared region. The light from the light source 2 is made monochromatic by a spectroscope 4 or a filter 6, and then is passed through an optical fiber 8, which is a light guide in the probe, to the sample 1 into which the probe is pierced.
It leads to 0. The light transmitted through the sample 10 is received by the optical fiber 12, which is a light guide of the other probe inserted into the sample 10. 14 is a detector, for example a photomultiplier tube is used. The light detected by the detector 14 is photoelectrically converted and then amplified.

Reference numeral 16 denotes a microcomputer, which is equipped with a function of processing signals from the detector and a data analysis function of evaluating freshness etc. by data analysis. The output of the microcomputer 16 is recorded on a recorder 18 or displayed on a monitor 20.

In the embodiment shown in FIG. 1, instead of the light source 2 and spectrometer 4 or filter 6, a laser diode 22 is directly attached to the tip of one of the prongs pierced into the sample 10, or the light from the laser diode 22 is connected to an optical fiber 8. Alternatively, the light may be emitted from the tip of the probe.

When using a light-receiving element such as a photodiode as the detector 14, it can be attached directly to the tip of the other probe inserted into the sample 10, or it can be used to receive light guided by the optical fiber 12. You can also do it.

FIG. 3 shows an embodiment in which the present invention is applied to a meat processing line.

24, 26 are probes, and the probes 24-. 2
The proximal end of 6 is fixed to the holder 28. Holder 28
can be slid up and down by a controller (path shown).

An optical fiber is passed through one of the probes 24 as a light guide, and this optical fiber is guided through a lead portion 30 to a light source unit (the path shown in the figure) equipped with a light source and a spectrometer. An optical fiber is provided as a light guide, and this optical fiber is connected via the other lead portion 32 to a detector unit (path shown) provided with a detector.

Sample 10 is a lump of pork or beef, and is placed on conveyor belt 3.
4 and is carried away in the direction of arrow 36.

In this embodiment, when the sample 10 is placed on the line and flows, the holder 28 slides downward, the probes 24 and 26 are stuck into the part of the sample 10 to be measured, and light is emitted from the tip of one probe 24. Then, the light is received at the tip of the other probe 26, and the light absorption is measured as a distance between the tips of the probes 24 and 26. After this, the holder 28 is slid upward and the detected signals are processed and monitored.

At this time, since sample 10 is meat, a light absorption spectrum of 650 m·μ is measured.

One step of measurement for one sample 10 is completed, and the next sample 10
When the sample 10 flows, the probes 24 and 26 are similarly inserted into the sample 10 on the line and the absorption spectrum at 650 mμ is measured, thereby making it possible to continuously and quickly measure the freshness inside the sample. .

It is convenient to make the tips of the probes 24 and 26 sharp so that they can be easily pierced into the sample).

Further, the direction of light irradiation from the tip of the probe 24 does not need to be particularly limited. That is, inside a piece of meat or other food, the light irradiated from the tip of the probe 24 is scattered and spread spatially, and reaches the tip of the other probe 26.

Also probe 24. ．． 26 need not be arranged in parallel. That is, even if the two are not parallel, it is sufficient that the distance between the tips is constant and that the tips can be pierced into the food.

The holder 28 is not limited to being movable in the vertical direction as in the embodiment. For example, the tip of the probe may be pierced into the sample by moving it in the left-right direction, or conversely, the holder 28 may be fixed and the table on which the sample is placed may be moved in the direction of the holder 28 to pierce the probe 28. It is also possible to stick a .26 into the sample 10.

The above example illustrates measuring the absorption spectrum of metmyoglobin at 650 mμ.

Foods whose freshness can be measured by metmyoglobin include frozen foods other than ordinary pork and beef, such as beef, tuna sashimi, and shrimp. Furthermore, the measurement wavelength is not limited to the 650 mμ of metmyoglobin, but it is sufficient to measure the absorption spectrum of a substance unique to each food that serves as an index of freshness.

Furthermore, by focusing on the wavelength that is the optical absorption peak of fat, it is possible to evaluate the internal fat content of meat using the apparatus of the present invention.

(Effects of the Invention) According to the present invention, a probe with a constant interval between tips, that is, a constant optical path length, is pierced into meat or other food, and the absorption spectrum of a specific wavelength at that optical path length is measured. Since the freshness and other aspects of the food are evaluated, the freshness inside the food can be quickly measured.

Since freshness and other factors can be quantified, the freshness or degree of corrosion can be clearly indicated at a glance.

Since visible light or near-infrared light can be used as a light source, there is no effect on the human body or the sample.

In addition, since the structure of the device of the present invention is simple, it can be manufactured at low cost, can be made small, and does not require a large installation space, and when a light guide is used, the length of the light guide can be reduced. By extending =8- it becomes possible to easily measure samples located far away.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the absorption spectrum of pork, and FIG. 3 is a perspective view showing an example in which the present invention is applied to a meat processing line. 2... Light source, 4... Spectrometer, 6... Filter, 8.12... Optical fiber, 10... Sample, 14 ...Detector, 16...Microcomputer, 22...
...Laser diode, 24.26...Probe, 28...Holder.

Claims (4)

[Claims] (1) Two probes that are pierced into food are fixed so that the distance between the tips of both probes is constant, one probe is provided with a light irradiation means that irradiates light from the tip of the probe, and the other probe is The food evaluation device includes a light receiving means for receiving light at the tip of the probe, and evaluates the food based on the absorption of light of a specific wavelength between the tips of the two probes in the food. (2) Optical fibers are provided as light guides in the two probes, and one optical fiber is connected to the light source side and the other optical fiber is connected to the detector side. The food evaluation device described in . (3) The food evaluation device according to claim 1, wherein a light emitting element is provided at the tip of one of the two probes, and a light receiving element is provided at the tip of the other probe. (4) The food evaluation device according to claim 1, 2, or 3, which uses 650 mμ as the specific wavelength.