JP4520577B2 - Molecular membrane for taste inspection - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for increasing selective responsiveness to salty, sour and umami in a molecular film used for taste inspection.
[0002]
[Prior art]
In order to inspect the taste, a method of using a molecular film made of lipid or the like as a sensor has been conventionally proposed.
[0003]
Conventional taste-inspecting molecular films used for such purposes include polymer materials such as PVC (eg, polyvinyl chloride) and amphipathic or bitter substances such as lipids (eg, quaternary ammonium salts). And a plastic material mixed at a predetermined ratio to form a film, and when immersed in a liquid, the film potential changes according to the taste substance in the liquid.
[0004]
[Problems to be solved by the invention]
However, the response characteristics of conventional molecular membranes generally do not have significant selectivity for each taste substance, and only a specific taste substance for a liquid containing multiple taste substances. It is difficult to detect a single molecular film.
[0005]
For this reason, conventionally, it is extremely complicated to measure the same test object using a plurality of molecular films having different characteristics and analyze the amount of each taste substance contained in the test object from the obtained measurement results. Work was necessary.
[0006]
An object of the present invention is to solve this problem and provide a molecular film for taste inspection having selective responsiveness particularly to salty taste, sour taste and umami taste.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the molecular film of claim 1 of the present invention comprises:
In a molecular membrane for taste inspection, which is formed into a membrane by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
In addition to 800 mg of the polymer material PVC , only lipid DOP having a negative charge as the lipid is included in a ratio of 1000 mg or more , or in addition, lipid DOPP having no charge is included in a ratio of 200 mg or less. It is characterized by being responsive to salty substances.
[0008]
The molecular film according to claim 2 of the present invention is
In a molecular membrane for taste inspection, which is formed into a film by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
To the polymeric material PVC 800 mg, only lipids having a charge as the lipid is in a ratio of 10-150 mg, the lipid having the charge, lipid TOMA 40-60 percent with a positive charge, negative The lipid DOP having the following charge is contained at a ratio of 60 to 40 percent , or the lipid DOPP having no charge is further contained at a ratio of 150 mg or less, and the sour substance Remarkable responsiveness is shown.
[0009]
The molecular film according to claim 3 of the present invention is
In a molecular membrane for taste inspection, which is formed into a film by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
With respect to the polymer material PVC 800 mg, lipids having a charge as the lipid 2000～3000Mg, lipid DOPP with no charge is in a ratio of more than 4 200 mg, and, the lipid having the charge is positive It is characterized by containing 40 to 60 percent of lipid TOMA having a charge and 60 to 40 percent of lipid DOP having a negative charge, and exhibits a remarkable response to umami substances.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The inventors of the present application conducted experiments to examine the responsiveness to each taste substance by changing the polarity, amount, etc. of lipids and plasticizers constituting the conventional molecular membrane for taste inspection. It was possible to obtain a taste-inspecting molecular film showing remarkable responsiveness to the salty substance, sour substance and umami substance which were not obtained.
[0011]
Hereinafter, the method and experimental results of this experiment will be described.
FIG. 1 shows a system for performing this experiment.
[0012]
This system includes a container 11 for containing a reference solution, a sample solution, etc., a reference electrode 12, a molecular film sensor 15, a voltage detector 20 for detecting a potential difference, and an output of the voltage detector 20 as a digital value. An A / D converter 21 for converting to an A / D converter, a calculation device 22 for performing processing such as storage and calculation for the output of the A / D converter 21, and an output device 23 for outputting the processing result of the calculation device 22 Has been.
[0013]
The reference electrode 12 is for outputting a reference potential for measuring the potential of the molecular film. The surface of the reference electrode 12 is covered with a buffer layer 13 in which 100 mmol of KCl (potassium chloride) is fixed with agar. 12a is connected.
[0014]
In addition, the molecular film sensor 15 is fixed to the surface of a base material 16 such as acrylic with the molecular film 17 exposed on one side, and the buffer layer of the reference electrode 12 is disposed on the opposite surface of the molecular film 17. An electrode 19 is provided via a buffer layer 18 equivalent to 13, and a lead wire 15 a is connected to the electrode 19.
[0015]
As the molecular film 17, as described above in the preliminary experimental stage, a number of films having different lipids, plasticizer components, polarities, amounts and the like are used.
[0016]
For example, PVC (polyvinyl chloride) is used as the polymer material, DOP (dioctyl phosphate) having a negative charge and TOMA (trioctylmethylammonium chloride) having a positive charge are used as the charged lipid, As a fragile lipid (plasticizer), DOPP (dioctylphenyl phosphonate) is used.
[0017]
These various molecular membranes are prepared by dissolving 800 mg of the polymer material PVC, which is the base of the molecular membrane, and a lipid and a plasticizer, dissolved in THF, and transferred to a flat-bottomed container. A film having a predetermined thickness (about 200 μm) is used by volatilizing THF by keeping it at about 30 ° C. for 2 hours.
[0018]
The voltage detector 20 detects the membrane potential of the molecular film 17 on the basis of the potential of the reference electrode 12 and outputs it to the A / D converter 21. The A / D converter 21 converts the membrane potential into a digital value and outputs the digital value to the arithmetic device 22. The arithmetic device 22 performs storage, arithmetic processing, etc. on the input value, and outputs the processing result to the output device 23. .
[0019]
Next, a procedure for measuring the response characteristics of the molecular film 17 with respect to each taste substance using this system will be described.
[0020]
Prior to measurement, the following reference solution, sample solution and cleaning solution were prepared.
Standard solution: KCl (30 mM) + tartaric acid (0.3 mM)
Salty sample solution: KCl (300 mM) + tartaric acid (0.3 mM)
Sour sample solution: KCl (30 mM) + tartaric acid (3.0 mM)
Umami sample solution: KCl (30 mM) + tartaric acid (0.3 mM) + MSG (10 mM)
Bitter sample solution 1: KCl (30 mM) + tartaric acid (0.3 mM) + quinine hydrochloride (0.1 mM)
Bitter sample solution 2: KCl (30 mM) + tartaric acid (0.3 mM) + isoalpha acid (0.01%)
Astringency sample solution: KCl (30 mM) + tartaric acid (0.3 mM) + tannic acid (0.05%)
Washing solution 1: ethanol (30%) + HCl (100 mM)
Washing solution 2: Ethanol (30%)
[0021]
Here, each sample solution is set so as to have an intermediate concentration in a region felt by a person. The cleaning liquid 1 and the cleaning liquid 2 are used for different types of molecular films. The cleaning liquid 1 is used for a molecular film containing only DOP lipid, and the molecular film containing DOP and TOMA for lipid. In this case, the cleaning liquid 2 is used.
[0022]
As shown in FIG. 2, the measurement for each sample solution is performed by first immersing the molecular membrane sensor 15 in the reference solution together with the reference electrode 12, and measuring and storing the membrane potential Va at that time (S1). Then, the molecular membrane sensor 15 is immersed in the sample solution together with the reference electrode 12, the membrane potential Vb at that time is measured and stored (S2), and the potential difference ΔV = Vb−Va is obtained and stored (S3). The process of washing the sensor 15 and the reference electrode 12 (S4) is repeated a plurality of times (here, 5 times) for the same sample solution (S5) (S5), and the average value of the potential difference ΔV is obtained (S6). The same process is performed on the sample liquid (S7).
[0023]
As described above, the following was found from the results of preliminary experiments in which the treatment described above was performed by varying the type and amount of lipid in the molecular film 17 and the amount of plasticizer.
[0024]
(1) When the amount of charged lipid (DOP) is 1000 mg or more and the amount of non-charged lipid (plasticizer DOPP) is 0 to 200 mg with respect to 800 mg of the polymer material, the response to salty taste is Much higher than other flavors.
[0025]
(2) With respect to 800 mg of the polymer material, the amount of lipid having a charge containing almost the same amount of positively charged lipid (TOMA) and negatively charged lipid (DOP) is changed to 10 to 150 mg, and lipid having no charge ( When the amount of the plasticizer DOPP) is 0 to 150 mg, the responsiveness to sourness is remarkably higher than other tastes.
[0026]
(3) With respect to 800 mg of the polymer material, the amount of lipid having a charge containing almost the same amount of positively charged lipid (TOMA) and negatively charged lipid (DOP) is set to 2000 to 3000 mg, and the lipid having no charge ( When the amount of the plasticizer DOPP) is 400 mg or more, the responsiveness to umami is significantly higher than other tastes.
[0027]
A typical example will be described below.
FIG. 3 shows a conventional molecular film formed by mixing 800 mg of a polymer material with 100 mg of negatively charged lipid (DOP) and 1000 μl of non-charged lipid (plasticizer DOPP) (hereinafter referred to as conventional film 1). The responsiveness with respect to each said sample liquid is shown. As is apparent from FIG. 3, this conventional membrane 1 has effective sensitivity to salty, sour, umami and bitterness 1 and does not have selective responsiveness to specific taste substances.
[0028]
FIG. 4 shows that the amount of negatively charged lipid (DOP) is increased to 2000 mg and the amount of uncharged lipid (plasticizer DOPP) is decreased to zero with respect to the conventional membrane 1 having the characteristics shown in FIG. In addition, the responsiveness of the molecular film according to the embodiment of the present invention (hereinafter referred to as a salty taste film) to each sample solution is shown.
[0029]
Comparing FIG. 3 and FIG. 4, this salty membrane has a sensitivity that is 1.4 times higher than that of the conventional membrane 1 with respect to saltiness, and is about 1/3 that of the conventional membrane 1 with respect to acidity, and the conventional membrane with respect to umami. The sensitivity is reduced to about 1/4 of the conventional film 1 with respect to the bitter taste 1, about 1/7 of the conventional film 1, and about 1/3 of the conventional film 1 with respect to the bitter taste 2 and astringency. It can be seen that the absolute value is much larger than the absolute values of the other taste measurements, indicating a very high selective response to salty taste.
[0030]
The selective responsiveness of the salty taste membrane is maintained even when the amount of charged lipid (DOP) is in the range of 1000 mg or more. When the amount is less than 1000 mg, the sensitivity to acidity increases, and the lipid (DOPP without charge) ) Above 200 mg, the sensitivity to bitterness is increased and the selectivity to salty taste is confirmed in the preliminary experiment.
[0031]
Therefore, as described above, a mixture of charged lipid DOP of 1000 mg or more and non-charged lipid DOPP at a ratio of 0 to 200 mg with respect to 800 mg of the polymer material PVC is suitable as a molecular film for salty taste. is there.
[0032]
FIG. 5 shows a conventional molecule formed by mixing 800 mg of a polymer material with 100 mg of negatively charged lipid (DOP), 80 mg of positively charged lipid (TOMA), and 1000 μl of lipid without charge (plasticizer DOPP). The responsiveness of the membrane (hereinafter referred to as the conventional membrane 2) to each sample solution is shown. This conventional membrane 2 has effective sensitivity to sourness, umami, bitterness 2 and astringency, and does not have selective response to a specific taste substance.
[0033]
FIG. 6 shows that the amount of the negatively charged lipid (DOP) and the positively charged lipid (TOMA) are both reduced to 50 mg with respect to the conventional membrane 2 having the characteristics shown in FIG. The responsiveness with respect to each said sample liquid of the molecular film (henceforth an acidity film | membrane) of embodiment of this invention which made the quantity of DOPP) 100 mg is shown.
[0034]
Comparing FIG. 5 and FIG. 6, the sourness film is slightly less sensitive to sourness than the conventional film 2, but has little sensitivity to salty taste, and the sourness film has no sensitivity to the umami. Sensitivity is reduced to about 1/10, bitterness 1 to about 1/2 of conventional membrane 2, bitterness 2 to about 1/4 of conventional membrane 2, and astringency to about 1/30 of conventional membrane 2. Thus, it can be seen that the absolute value of the measurement value of sourness is much larger than the absolute value of the measurement value of other tastes, indicating very high selective response to sourness.
[0035]
The selective responsiveness of the sour film is such that positively charged lipid (TOMA) and negatively charged lipid (DOP) are contained in an amount of 40 to 60 percent of the total charged lipid, and the charged lipid. In the preliminary experiment, the total amount is maintained in the range of 10 to 150 mg, and the selective responsiveness decreases when the ratio of the positively charged and negatively charged lipids is out of the above range or the total amount of lipids exceeds 150 mg. It has been confirmed.
[0036]
Therefore, as described above, with respect to the polymer material PVC 800 mg, the charged lipid contains 10 to 150 mg of lipid and the non- charged lipid DOPP of 0 to 150 mg, and the charged lipid includes A membrane containing 40 to 60 percent of lipid TOMA having a positive charge and 60 to 40 percent of lipid DOP having a negative charge is suitable as a molecular membrane for acidity.
[0037]
FIG. 7 shows a molecular film (hereinafter referred to as an umami film) in which the amount of negatively charged lipid (DOP) is increased to 1000 mg and the amount of positively charged lipid (TOMA) is increased to 800 mg with respect to the conventional membrane 2. The responsiveness with respect to each said sample liquid is shown.
[0038]
Comparing FIG. 5 and FIG. 7, the umami film is slightly more sensitive to umami than the conventional film 2, has little sensitivity to salty taste, and the conventional film 2 to acidity and bitterness 1. The sensitivity is almost the same, about 1/5 of the conventional film 2 for bitterness 2 and about 1/30 of the conventional film 2 for astringency, and the absolute value of the measured value of umami is the other taste. It can be seen that it is much larger than the absolute value of the measured value and shows a very high selective response to umami.
[0039]
The selective responsiveness of this umami membrane is that positively charged lipid (TOMA) and negatively charged lipid (DOP) are contained in an amount of 40 to 60 percent of the total charged lipid, and the charge is reduced. Maintained when the total amount of lipids is in the range of 2000 to 3000 mg (3000 mg or more cannot be formed into membranes yet unconfirmed), and the amount of lipid without charge (plasticizer DOPP) is 400 mg or more. As described above, the ratio of the positively charged lipid to the negatively charged lipid is out of the above range, the total amount of lipid is less than 2000 mg, or the amount of lipid without charge (plasticizer DOPP) is less than 400 mg. It has been confirmed in the preliminary experiment that the selective responsiveness is lowered.
[0040]
Therefore, as described above, with respect to the polymer material PVC 800 mg, the charged lipid contains 2000 to 3000 mg, and the non-charged lipid DOPP contains 400 mg or more, and the charged lipid includes What contains 40 to 60 percent of lipid TOMA having a positive charge and 60 to 40 percent of lipid DOP having a negative charge is suitable as a molecular membrane for umami.
[0042]
【The invention's effect】
As explained above, the molecular film for taste inspection according to claim 1 of the present invention is
In a molecular membrane for taste inspection, which is formed into a membrane by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
In addition to 800 mg of the polymer material PVC , only lipid DOP having a negative charge as the lipid is included in a ratio of 1000 mg or more , or in addition, lipid DOPP having no charge is included in a ratio of 200 mg or less. Therefore, the salty substance can be detected without being influenced by other taste substances.
[0043]
Moreover, the molecular film for taste inspection according to claim 2 of the present invention is:
In a molecular membrane for taste inspection, which is formed into a film by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
To the polymeric material PVC 800 mg, only lipids having a charge as the lipid is in a ratio of 10-150 mg, the lipid having the charge, lipid TOMA 40-60 percent with a positive charge, negative The lipid DOP with the following charge is contained in a ratio of 60 to 40 percent , or in addition, the lipid DOPP having no charge is contained in a ratio of 150 mg or less and has a remarkable responsiveness to a salty substance. As shown, the sour substance can be detected without being affected by other taste substances.
[0044]
Moreover, the molecular film for taste inspection according to claim 3 of the present invention is:
In a molecular membrane for taste inspection, which is formed into a film by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
With respect to the polymer material PVC 800 mg, lipids having a charge as the lipid 2000～3000Mg, lipid DOPP with no charge is in a ratio of more than 4 200 mg, and, the lipid having the charge is positive Since the charged lipid TOMA is contained in a proportion of 40 to 60 percent and the negatively charged lipid DOP is contained in a proportion of 60 to 40 percent and exhibits a remarkable response to the umami substance, It can be detected without being affected.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a system used in an experiment. FIG. 2 is a flowchart showing a procedure of the experiment. FIG. 3 is a diagram showing characteristics of a conventional molecular film. FIG. 5 is a diagram showing characteristics of a conventional molecular film. FIG. 6 is a diagram showing characteristics of the molecular film of the embodiment. FIG. 7 is a diagram showing characteristics of the molecular film of the embodiment.
DESCRIPTION OF SYMBOLS 11 Container 12 Reference electrode 13 Buffer layer 15 Molecular film sensor 16 Base material 17 Taste inspection molecular film 18 Buffer layer 19 Electrode 20 Voltage detector 21 A / D converter 22 Arithmetic device 23 Output device

Claims (3)

In a molecular membrane for taste inspection, which is formed into a film by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
In addition to 800 mg of the polymer material PVC , only lipid DOP having a negative charge as the lipid is included in a ratio of 1000 mg or more , or in addition, lipid DOPP having no charge is included in a ratio of 200 mg or less. A molecular film for taste inspection characterized by In a molecular membrane for taste inspection, which is formed into a membrane by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
To the polymeric material PVC 800 mg, only lipids having a charge as the lipid is in a ratio of 10-150 mg, the lipid having the charge, lipid TOMA 40-60 percent with a positive charge, negative The lipid DOP having the electric charge of 60 to 40% is contained , or in addition, the lipid DOPP having no electric charge is contained in the proportion of 150 mg or less . Molecular film. In a molecular membrane for taste inspection, which is formed into a membrane by mixing a polymer material and lipid, and the membrane potential changes depending on the taste substance in the liquid,
With respect to 800 mg of the polymer material PVC , the lipid contains 2000 to 3000 mg of charged lipid and 400 mg or more of uncharged lipid DOPP , and the charged lipid contains plus A molecular membrane for taste testing, comprising 40 to 60 percent of lipid TOMA having a negative charge and 60 to 40 percent of lipid DOP having a negative charge.

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