JPS5834777B2 - Taste measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring taste, more specifically, sweetness,
This invention relates to a method for electrochemically measuring four basic tastes: salty, savory, and bitter.

Traditionally, taste measuring devices have relied on the human tongue, and only recently have electric taste meters (Elg.
(ustometer) has appeared, and it has been reported that this device can induce a sharp taste with the character of sourness or metal licking by stimulating the + side electrode (anodic stimulation) of the DC voltage it generates. However, there is no way to distinguish between sweetness, saltiness, sourness, bitterness, etc., which should be distinguished as basic tastes. Ori,
It was thought to be impossible to measure mechanically.

Therefore, even in the field of food manufacturing, taste control relies solely on the tongue of an expert, and if this taste can be measured as an electrical quantity, taste management can be easily done using the measured electrical quantity. It can be expected to have great utility value in various industrial fields related to taste, including food production and agriculture. As a result of research on human taste function, the present inventor found that the structure of human taste is based on its anatomy. By analogy, the hair-like projections and supporting cells surrounding them are
It is considered to be a type of galvanic cell in which saliva, which is thought to be a dielectric solution, is inserted between the two electrodes of a so-called organic semiconductor. receptor (Taste-rec)
A galvanic cell is used as a galvanic cell (eptor) to produce salty, sweet,
We thought that it would be possible to distinguish between sour and bitter tastes, and published a detailed device for this purpose in Oita Institute of Technology Bulletin, Vol. 5, No. 1, July 1976.

In this device, the contact potential difference (Con-tact pot
We devised a way to maintain a certain stable state of the internal difference (difference), and under this state, the taste substance added from the outside dissolves in the dielectric solution, and in some cases becomes an ionizing solution and becomes an ion. It diffuses and generates a current, and sometimes it becomes a non-ionizing solution and diffuses, causing a change in the dielectric constant in the solution, resulting in a change in the contact potential mc, P, D) between the two electrodes, This change in contact potential difference is the taste response potential (Custatory).
), which takes advantage of the appearance of the taste characteristic curve.

However, in the above-mentioned apparatus, although the taste of the taste substance can be determined from the shape of the taste characteristic curve, the taste cannot be quantitatively indicated.

As a result of further elucidation of the above taste characteristic curve, the present invention found that the time constant of the rising or falling portion of this curve, and therefore the frequency corresponding to the time constant, differs depending on the type of taste, and that the strength of the taste varies depending on the peak value of the frequency component. It turns out that it is possible to show the extent.

The present invention has been made by taking advantage of this property.

A description will be given below based on specific examples.

As mentioned above, it is known that a galvanic cell is used in place of the human taste mechanism, but this cell is composed of semiconductor P-type Ge and N-type semiconductors as electrodes, or it is composed of P-type or N-type semiconductors. - type Ge is used as one electrode, the other electrode is made of platinum, and a mixed solution of distilled water and methanol at a mixing ratio of 1:1 is used between the two electrodes.

This galvanic cell contains four types of taste substances (sugar, salt, acetic acid, quinine) that are the basis of taste.
When a sample is injected, a change in the contact potential difference occurs depending on the type of taste.If this contact potential difference is taken out from both electrodes and the state of the change is measured, the aforementioned taste characteristic curve is obtained.

Figure 1 shows typical characteristic curves. 1 is salt (salty taste), 2 is acetic acid (salty taste), 3 is sugar (sweet taste),
4 is a characteristic curve showing quinine (bitter taste).

As a result of analysis of these characteristic curves, the facts of the method were found.

l) Among the above four tastes, salty and bitter are the basic tastes, and sweet and savory are obtained by synthesizing these tastes.

2) Salty taste is felt when the taste potential curve has a rising characteristic, and the time constant of the rising characteristic curve is 1.5931 to 0.7.
In the range of 965, the salty taste is especially strong.

In other words, if a characteristic curve with a rising part is simulated as a waveform as shown in Figure 2, the salty taste will be felt by ab and d.
It is felt in the e and gh parts, but not in the bC9ef and hi parts.

Furthermore, when this waveform is analyzed by a low-pass filter using a CR circuit, the 3 dB upper limit frequency (frequency at which the filter output gain is 3 dB or more) corresponding to a time constant of 1.5931 to 0.7965 is 0.09990 to 0.19981 Hz.
There is a particularly sensitive region around 0.1 Hz.

Also, although the sensitivity is low, a salty taste can be felt in the frequency range of 125 to Q, 002 Hz.

3) Contrary to salty taste, bitterness occurs when the taste potential curve has a falling characteristic, that is, the bitterness is felt at the crystal ', d7e', and i' portions of the waveform shown schematically in FIG.

The time constant of the falling part is 0.8333 to 0.4762,
Its 3dB upper limit frequency is 0.1909Hz ~ 0.334
2Hz, but the actual measurement results show that there is a region of high sensitivity around 0°35Hz, and as with salty and spicy tastes, the sensitivity ranges from 125Hz to 0.35Hz.
Over the entire frequency range of 0.002 Hz, a bitter taste is perceived at the falling edge of the % sensitivity curve.

4) Sweetness is at 0, which is the center of the region of high sensitivity for bitterness;
In the region close to the frequency of 35 Hz, salty and bitter tastes coexist, resulting in a mixed taste, and in the range (3 Hz to 0.15 Hz) where the bitter taste is slightly superior, the characteristic curve The sweetness hits you at the rise.

The synthesized time constant is 0.4547 to 1.0610, and the 3 dB upper limit frequency is 0.35 to 0.15 Hz.

5) Sanmi (subasa) is a region close to the center frequency of 0.1 Hz or a region lower than 0.1 Hz, where the sensitivity of salty and spicy taste is high.
．． At 15 Hz to 0.04 Hz, salty taste and bitter taste coexist, and in the region where the salty taste slightly exceeds the bitter taste as a mixed taste, there is a harsh taste at the rise of the characteristic curve. come.

Its synthesized time constant is 1.0610~3.0725, and the 3dB upper limit frequency is 0.15 Hz~0.0518
It is Hz.

6) The boundary frequency between sweetness and savory taste is around 0.15Hz.

FIG. 4 shows a frequency spectrum related to the degree of contribution of the various frequency components included in the characteristic curves for each taste obtained as described above to the taste.

Using the above principles, it is possible to quantitatively measure the four types of tastes described above as follows.

l) A taste substance to be measured is introduced into the electrolyte of the galvanic cell prepared as described above, and a characteristic curve showing the temporal change in the potential difference generated between the two electrodes of the cell is determined.

2) Determine which of the four basic tastes the basic taste of the taste substance belongs to from the shape of the characteristic curve.

(If you already know what the basic taste of the substance is, this judgment can be omitted.

) 3) Find the amplitude (absolute value or relative value) of the specific frequency component included in the characteristic curve for a specific frequency corresponding to the determined basic taste, and quantitatively evaluate the taste from the amplitude. to ask.

FIG. 5 shows one end of an apparatus for carrying out the above measurement method.

For the measurement, first, 4 cc of a mixed solvent of distilled water and methanol with a volume ratio of 1:1 was inserted into a container, and then a suitable electrode support stand was placed so that the position and spacing of the electrodes could be adjusted. (not shown) to maintain the distance between the electrodes in the range of (0,1 to 0.5) L and the electrodes at an appropriate depth of 1 cfrL in the solution, the corresponding galvanic cell A contact potential difference (C, P, D) appears at both electrodes.

This is further amplified by a high-power amplifier 4 and a high-sensitivity DC amplifier 5, and the output voltage is displayed on the paper of a recorder 6 for waveform observation or on the tube of a cathode ray tube oscilloscope 7.

Further, the output voltage of the galvanic cell at this time is measured using a precision potentiometer 2.

This value typically ranges from approximately 400 mV to 600 mV.

This value serves as a reference for the change in contact potential difference after the taste substance is added, and it is important that this value be very stable. It is necessary to operate it for some time and make repeated adjustments to ensure sufficient stability.

Once the above preparations have been completed, a fixed amount of a pre-prepared aqueous solution of a taste substance with an arbitrary concentration is dropped using a burette, and the taste shows a change in the contact potential difference, that is, a change in the taste-corresponding potential. Recorder 6 for waveform observation of characteristic curves
At that time, we observe whether the change tendency of the taste-corresponding potential is a rising characteristic or a falling characteristic to determine whether it tastes salty or bitter, and if it is a rising characteristic, in light of the previous experimental facts, The type of taste (salty, sweet, savory) can be determined by comparing and contrasting the trend of the time constant with the standard characteristic curve plotted on transparent 5-ection paper placed on a cathode ray tube. .

In addition, since the voltage value changing from the reference value of the contact potential difference at that time can be measured with a potentiometer, Ga1
It was possible to identify the types of taste substances (salt, sugar, acetic acid, quinine) put into the vanic cell, and the degree of taste due to the difference in the amount of taste substances was drawn on a precision potentiometer and recording paper. This device is designed to enable measurements to be made based on the magnitude of the amplitude of the taste potential characteristic curve.

The low frequency function wave generator is (0,0008 to 12,000
) Hz, and while displaying a static image of the characteristic curve of the taste substance to be measured on a cathode ray tube, the generated waveform from the generator is superimposed on it, and the frequency of the generated waveform is determined. Find the frequency when both change and match.

As described above, the basic taste of the taste substance is determined from the overall shape of the characteristic curve, and the intensity of the taste is quantified from the frequency components and peak values of the rising or falling parts. It can be found exactly.

7

[Brief explanation of the drawing]

Figure 1 is a diagram showing the taste characteristic curves of various basic tastes, Figure 2 is a diagram simulating the part related to salty taste in the characteristic curve, and Figure 3 is a diagram showing the part related to bitterness in the characteristic curve. FIG. 4 is a diagram showing frequency spectra of characteristic curves for various basic tastes, and FIG. 5 is a block diagram showing a circuit of an apparatus for measuring taste according to the present invention.

Claims (1)

[Claims] 1. A taste substance to be measured is introduced into the electrolyte of a galvanic cell, and a characteristic curve showing the temporal change in the potential appearing at both electrodes of the cell is obtained, and the characteristic curve is The basic taste of the taste substance is measured based on the shape of the taste substance, and the degree of taste of the taste substance is quantitatively measured from the peak value of a specific frequency component corresponding to the determined basic taste. Measuring method. 2. Claim 1 is characterized in that a reference characteristic curve is determined in advance for a predetermined basic taste, and the basic taste of the taste substance is determined from a comparison between the measured characteristic curve and the reference characteristic curve. Taste measurement method. 3% Allowance In claim 1 or 2, when the basic taste is salty, the specific frequency is approximately 0 or 1 Hz.
, approximately 0.35Hz for bitterness and 0.35Hz for sweetness.
~0.15Hz1 0.15~0.5 for San taste
A taste measurement method characterized in that the frequency is 18Hz.