Method for determining residual chlorine concentration, method for evaluating water purifier, and device for evaluating water purifier

Abstract

To provide a technique related to the olfactory recognition of water purification effects.SOLUTION: A method for determining residual chlorine concentration includes the steps of: extracting herbal tea from herbal tea ingredients using sample water; conducting a sensory evaluation of the aroma of the herbal tea; determining whether an unpleasant odor is perceived; determining that the residual chlorine concentration in the sample water is below a prescribed value when no unpleasant odor is perceived.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a method for determining a residual chlorine concentration, a method for evaluating a water purifier, and an apparatus for evaluating a water purifier. [Background technology]

[0002] Patent Document 1 discloses a method for displaying a water purifier, which supplies raw water containing luminescent particles to a raw water storage tank, purifies the raw water with a water purification cartridge, and supplies the purified water to the purified water storage tank. It is described that the water purifier display method uses raw water with transparency close to that of drinking water, making it possible to more clearly present the water purification ability of the water purifier. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-124690 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, methods for demonstrating the effectiveness of purified water are known to be visually recognized, such as by decolorizing colored water or removing luminescent particles. However, there is no known method for demonstrating the effectiveness of purified water through the sense of smell using cooked foods.

[0005] The present disclosure is intended to solve at least a part of the above-mentioned problems, and aims to provide technology related to olfactory recognition of water purification effects and to utilize the technology. [Means for solving the problem]

[0006] The method for determining the residual chlorine concentration of the first aspect of the present disclosure involves using sample water to extract herbal tea from herbal tea ingredients, sensory evaluation of the odor of the herbal tea to determine whether or not an unpleasant odor is detected, and if no unpleasant odor is detected, determining that the residual chlorine concentration of the sample water is less than a predetermined value.

[0007] The method for evaluating a water purifier of the first aspect of the present disclosure includes preparing raw water having a residual chlorine concentration equal to or higher than a predetermined value, and purified water obtained by purifying the raw water using a water purifier, using the raw water to extract herbal tea from herbal tea ingredients under predetermined conditions, using the purified water to extract herbal tea from the herbal tea ingredients under the same conditions as the predetermined conditions, performing a sensory evaluation of the smell of the herbal tea extracted using the raw water and the smell of the herbal tea extracted using the purified water, and evaluating the purification performance of the water purifier based on the results of the sensory evaluation.

[0008] The water purifier evaluation device of the first aspect of the present disclosure comprises an adjustment unit that adjusts the residual chlorine concentration of raw water, a water purifier installation unit in which a water purifier that purifies the raw water is installed, and an extraction unit that uses the raw water to extract herbal tea from herbal tea ingredients under specified conditions, and uses the purified water purified by the water purifier to extract herbal tea from the herbal tea ingredients under the same conditions as the specified conditions.

[0009] A method for determining a residual chlorine concentration in a second aspect of the present disclosure involves using sample water to prepare a stock from stock ingredients, sensory evaluation of the odor of the stock to determine whether or not an unpleasant odor is detected, and if no unpleasant odor is detected, determining that the residual chlorine concentration of the sample water is less than a predetermined value.

[0010] The method for evaluating a water purifier of the second aspect of the present disclosure involves preparing raw water having a residual chlorine concentration equal to or higher than a predetermined value, and purified water obtained by purifying the raw water using a water purifier, using the raw water to make stock from stock ingredients under predetermined conditions, using the purified water to make stock from the stock ingredients under the same conditions as the predetermined conditions, sensory evaluating the smell of the stock made using the raw water and the smell of the stock made using the purified water, and evaluating the purification performance of the water purifier based on the results of the sensory evaluation.

[0011] The water purifier evaluation device of the second aspect of the present disclosure includes an adjustment unit that adjusts the residual chlorine concentration of raw water, a water purifier installation unit in which a water purifier that purifies the raw water is installed, and a preparation unit that uses the raw water to prepare dashi from dashi ingredients under specified conditions, and also uses the purified water purified by the water purifier to prepare dashi from the dashi ingredients under the same conditions as the specified conditions. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a schematic diagram of an evaluation device (part 1) for a water purifier according to an embodiment. [Diagram 2] FIG. 1 is a diagram showing an example of a process flow of the water purifier evaluation device (part 1). [Diagram 3] FIG. 1 is a diagram showing the results of gas chromatography analysis of chamomile herbal tea. [Figure 4] FIG. 1 shows the results of gas chromatography analysis of lemongrass herbal tea. [Diagram 5] FIG. 1 shows the results of gas chromatographic analysis of peppermint herbal tea. [Figure 6] FIG. 1 shows the results of gas chromatography analysis of lavender herbal tea. [Figure 7] FIG. 1 is a diagram showing the relationship between the residual chlorine concentration in water and each component in chamomile herbal tea. [Figure 8] FIG. 1 is a diagram showing the relationship between the residual chlorine concentration in water and each component in lemongrass herbal tea. [Figure 9] FIG. 1 is a diagram showing the relationship between the residual chlorine concentration in water and each component in peppermint herbal tea. [Figure 10] FIG. 1 is a diagram showing the relationship between the residual chlorine concentration in water and each component in lavender herbal tea. [Figure 11] FIG. 1 is a diagram showing a mass spectrum of a specific substance. [Figure 12] FIG. 1 is a diagram showing the results of gas chromatographic analysis of chamomile herbal tea at various pH levels. [Figure 13]FIG. 13 is a diagram showing an example of a process flow of the water purifier evaluation device (part 2). [Figure 14] FIG. 1 is a diagram showing the results of gas chromatographic analysis of chicken soup. [Figure 15] FIG. 1 is a diagram showing the results of gas chromatographic analysis of bonito stock. [Figure 16] FIG. 1 is a diagram showing the relationship between the residual chlorine concentration in water and each component in chicken soup. [Figure 17] FIG. 1 is a diagram showing the relationship between the residual chlorine concentration in water and each component in bonito stock. [Figure 18] FIG. 1 is a diagram showing a mass spectrum of a specific substance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1. How to determine residual chlorine concentration (part 1) The method for determining the residual chlorine concentration involves using sample water to extract herbal tea from herbal tea ingredients, sensory evaluation of the smell of the herbal tea to determine whether or not an unpleasant odor is detected, and if no unpleasant odor is detected, determining that the residual chlorine concentration of the sample water is less than a predetermined value.

[0014] The method for determining the residual chlorine concentration disclosed herein was developed based on the new finding that, when the odor of herbal tea is sensorily evaluated, if the residual chlorine concentration of the sample water is below a predetermined value, no unpleasant odor is felt. In other words, according to this method, if no unpleasant odor is felt, the residual chlorine concentration of the sample water is below a predetermined value, which can be sensed by the sense of smell.

[0015] The sample water is not particularly limited as long as it is suitable for drinking. For example, when tap water is used as the sample water, the residual chlorine concentration of the tap water can be evaluated. When raw water before purification by a water purifier and purified water obtained by purifying raw water by a water purifier are used as the sample water, the sample water can be used to evaluate the performance of the water purifier. The method of evaluating the water purifier will be described later.

[0016] Since the purpose of this method is to determine the residual chlorine concentration of the sample water, the residual chlorine concentration of the sample water is not particularly limited. In one or more water purification plants in Kochi Prefecture, Kagoshima Prefecture, Mie Prefecture, Yamaguchi Prefecture, Chiba Prefecture, Hiroshima Prefecture, and Kyoto Prefecture in 2019, the maximum residual chlorine concentration of tap water was reported to be 1.6 ppm to 2 ppm. Assuming the evaluation of the residual chlorine concentration of tap water or the evaluation of the residual chlorine concentration of purified water obtained by purifying tap water, the residual chlorine concentration of the sample water may be, for example, 0 ppm or more and 2 ppm or less.

[0017] The pH of the sample water is not particularly limited. The pH of the sample water may be 5.8 or more and 8.6 or less, for example, with reference to the standards for tap water. The pH of the sample water is preferably 6.5 or more, more preferably 7.0 or more, from the viewpoint of making it easier to perceive specific substances that cause chlorine odor and irritating odor, which are types of unpleasant odors. The specific substances will be described later.

[0018] Herbal tea is a beverage extracted from herbal tea ingredients. The herbal tea ingredients used in the present method are not particularly limited. It has been found that at least some components that produce a common unpleasant odor are detected in a plurality of herbal tea ingredients. Therefore, the present technology is considered to be a highly versatile technology that can be applied regardless of the type of herbal tea ingredient. The herbal tea ingredient is preferably one or more selected from the group consisting of chamomile, lemongrass, peppermint, and lavender. The extraction conditions for herbal tea are not particularly limited. For example, the extraction temperature for herbal tea is usually 60°C or higher and 100°C or lower, preferably 80°C or higher and 100°C or lower. The amount of herbal tea ingredients used, the extraction time for herbal tea, etc. can be appropriately set according to the herbal tea ingredients.

[0019] The smell of herbal tea is usually a mixture of multiple components with different odor qualities. In this method, the smell of herbal tea is evaluated sensorily to determine whether it is an unpleasant odor.

[0020] Sensory evaluation, also called sensory testing or sensory testing, is the evaluation of an object using human senses (sight, hearing, taste, smell, touch). In the present disclosure, sensory evaluation of odors is performed using the sense of smell in particular. The evaluator who performs the sensory evaluation may be a general consumer or a specialized panel. There is no particular limit to the number of responses (number of evaluation results) given by the evaluator.

[0021] The odor of the herbal tea may be evaluated by holding it in the mouth or not. The method of the sensory evaluation is not particularly limited. For example, the evaluator may be presented with herbal tea extracted using sample water and herbal tea not containing components that generate unpleasant odors, and their odors may be compared to determine whether or not the herbal tea extracted using the sample water has an unpleasant odor. The evaluator may be presented with only the herbal tea extracted using the sample water, and whether or not the unpleasant odor is detected. The evaluator may be presented with herbal tea extracted using sample water and components that generate unpleasant odors, and their odors may be compared to determine whether or not the herbal tea extracted using the sample water has an unpleasant odor.

[0022] An example of the evaluation results will be described in detail. Table 1 shows the results of a sensory evaluation of the odor of herbal tea extracted from chamomile using sample water with residual chlorine concentrations of 0.2 ppm, 0.3 ppm, 0.5 ppm, 1 ppm, and 2 ppm in Experiment 1 described below. [Table 1]

[0023] The detection limit of unpleasant odors in the sensory evaluation of the herbal tea odor in this experiment is a range of 0.3 ppm to 0.5 ppm of the residual chlorine concentration of the sample water. Therefore, if no unpleasant odor is detected, it can be determined that the residual chlorine concentration of the sample water is less than 0.5 ppm. In addition, by checking the detection limit of unpleasant odors for each evaluator in advance as in Table 1, it can also be determined that the residual chlorine concentration of the sample water is less than the detection limit of the unpleasant odor for each evaluator when each evaluator does not detect an unpleasant odor. Specifically, if Evaluator A in Table 1 does not detect an unpleasant odor, it can be determined that the residual chlorine concentration of the sample water is less than 0.3 ppm. If Evaluator B in Table 1 does not detect an unpleasant odor, it can be determined that the residual chlorine concentration of the sample water is less than 0.5 ppm. The predetermined value is not limited to 0.5 ppm or 0.3 ppm. The predetermined value can be appropriately determined by conducting a preliminary experiment such as Experiment 1 described below depending on the type of herbal tea raw material, the extraction method, the pH of the sample water, etc. Naturally, sample water having a "residual chlorine concentration below the detection limit" can also be determined to be sample water having a "residual chlorine concentration at or below the detection limit."

[0024] The components that produce unpleasant odors can be identified, for example, by comparing the components contained in herbal teas that do not have an unpleasant odor and herbal teas that have an unpleasant odor, obtained using the same herbal tea ingredients and the same extraction conditions.

[0025] Figures 3 to 6 show the results of comparing the components contained in herbal teas with and without an unpleasant odor, using GC-MS (gas chromatography-mass spectrometry) in Experiment 3 described below. The thick line shows the results for herbal teas with and without an unpleasant odor. The thin line shows the results for herbal teas with and without an unpleasant odor. The herbal tea ingredients used were chamomile, lemongrass, peppermint, and lavender, respectively. In each figure, (1) is the peak containing isobutyraldehyde. (2) is the peak containing 2-methylbutyraldehyde. (3) is the peak containing isovaleraldehyde. (4) is the peak containing a specific substance described below. In this way, it is possible to identify components that are more abundant in herbal teas with an unpleasant odor than in herbal teas with no unpleasant odor, and to identify the components that cause the unpleasant odor based on the odor qualities of the identified components and the odor qualities of the unpleasant odor of the herbal tea.

[0026] In the present disclosure, examples of components that generate unpleasant odors include one or more selected from the group consisting of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and specific substances described below. The odor qualities of each component are as follows. Isobutyraldehyde: Burnt odor 2-Methylbutyraldehyde: Burnt odor Isovaleraldehyde: stuffy odor, irritating odor Specific substances listed below: Chlorine odor, irritating odor

[0027] The above specific substances are substances that are identified by the following analytical method. (Analysis method) The specific substance is measured by GC-MS (gas chromatography mass spectrometry) under the following analytical conditions, and when the retention time of isobutyraldehyde is 6.4 min, the retention time of 2-methylbutyraldehyde is 8.5 min, and the retention time of isovaleraldehyde is 8.6 min, the specific substance appears as a peak at a retention time of 12.0 min, and peaks are detected at m / z values ​​of 69, 68, 42, 41 (base peak), 40, and 39. [GC-MS measurement conditions] Equipment name: Shimadzu Gas Chromatograph Mass Spectrometer GCMS-QP2020 Column: Agilent DB-WAX (60m x 0.25mm df=0.25μm) Carrier gas: Helium (linear velocity 25.5 cm / s) Split ratio: 5.0 Inlet temperature: 250℃ Column oven temperature: 40°C (hold for 3 min) - 3°C / min increase - 240°C (hold for 5 min) Ionization method: EI Ion source temperature: 230℃ Interface temperature: 250℃ Scan range m / z: 33-400

[0028] Figure 11 shows the mass spectra of the specific substances in the herbal teas of chamomile, lemongrass, peppermint, and lavender. The horizontal axis represents the m / z value, and the vertical axis represents the relative intensity. In the scan range of m / z 33 to 400, peaks were detected at m / z values ​​of 69, 68, 42, 41 (base peak), 40, and 39.

[0029] Although the above specific substances have not yet been identified, they are presumed to be components that produce unpleasant odors based on the quality of their odors. The above specific substances are also characterized by the following analysis results. Note that the specific substances are not limited to a single compound, and may be a mixture of two or more compounds.

[0030] Figure 12 shows the results of gas chromatography analysis of chamomile herbal tea using sample water of pH 6, pH 7, and pH 8 in Experiment 4 described below. Based on these results, it may be possible to confirm that the components that produce unpleasant odors include the specific substances mentioned above. In addition, if sample water with a high pH is used, the unpleasant odors produced by the specific substances mentioned above can be felt more prominently, and the effect of further enhancing the sensory effect of the residual chlorine concentration can be expected.

[0031] According to the method for determining the residual chlorine concentration disclosed herein, for example, the residual chlorine concentration of the sample water can be sensed by the sense of smell that it is less than a predetermined value. When the sample water itself, such as tap water or purified water, is evaluated by sensory evaluation using the sense of smell or taste, it is difficult for general consumers to obtain knowledge regarding the residual chlorine concentration. On the other hand, the present method determines the residual chlorine concentration based on whether or not an unpleasant odor is felt in the sensory evaluation of the smell of herbal tea, so that it is easy for general consumers to make a judgment. In addition, since no analytical equipment is required, the present method can be easily performed in various situations such as exhibitions. Herbal tea itself is generally a beverage that is preferred regardless of age or gender. The present method is novel in that it focuses on the relationship between the residual chlorine concentration of the sample water and the unpleasant odor of herbal tea, which was not known until now, and uses it to evaluate the sample water, and it is easy to make the evaluator feel like experiencing it. The unpleasant odor of herbal tea is suitable for the detection sensitivity of human olfactory sense, and is unlikely to cause the evaluator to feel excessively unpleasant. The present method is groundbreaking as a method for displaying sample water.

[0032] When the components that produce unpleasant odors contain one or more selected from the group consisting of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and the above-mentioned specific substances, the sense of smell can effectively tell that the residual chlorine concentration in the sample water is below a predetermined value.

[0033] When the herbal tea ingredients are one or more selected from the group consisting of chamomile, lemongrass, peppermint, and lavender, the residual chlorine concentration of the sample water can be determined to be, for example, less than 0.5 ppm. Therefore, it is suitable for evaluating the quality of tap water and the performance of water purifiers.

[0034] 2. Water purifier evaluation method (part 1) The method of evaluating water purifiers involves preparing raw water with a residual chlorine concentration above a predetermined value, and purified water obtained by purifying the raw water using a water purifier, using the raw water to extract herbal tea from herbal tea ingredients under predetermined conditions, and using the purified water to extract herbal tea from the herbal tea ingredients under the same predetermined conditions, performing a sensory evaluation of the smell of the herbal tea extracted using the raw water and the smell of the herbal tea extracted using the purified water, and evaluating the purification performance of the water purifier based on the results of the sensory evaluation.

[0035] Since the purpose of this method is to evaluate the purification performance of the water purifier, the residual chlorine concentration of the raw water is set to a predetermined value or more. The predetermined value can be appropriately determined by conducting a preliminary experiment such as Experiment 2 described later depending on the type of herbal tea raw material, the extraction method, the pH of the sample water, etc. The residual chlorine concentration of the raw water can be set to, for example, 0.3 ppm or more, and may be set to 0.5 ppm or more, or 0.6 ppm or more. The upper limit of the residual chlorine concentration of the raw water is not particularly limited and can be set to, for example, 2 ppm or less. For example, if the residual chlorine concentration of tap water used in this method is a predetermined value or more, tap water can be used as it is as raw water. The residual chlorine concentration of the raw water may be set to 1 ppm or less, which is the water quality management target value. The residual chlorine concentration of tap water may be appropriately adjusted depending on the purification performance of the water purifier, the type of herbal tea raw material, etc. The residual chlorine concentration of tap water can be increased, for example, by adding sodium hypochlorite for food additives. The residual chlorine concentration of tap water can be decreased, for example, by adding purified water with a lower residual chlorine concentration than tap water.

[0036] The pH and other properties of the raw water can be the same as those of the sample water. The explanation for the pH and other properties of the raw water is the same as for the sample water, and the explanation is omitted here.

[0037] Purified water is prepared by purifying raw water with a water purifier. The water purifier is not particularly limited. It is sufficient that the water purifier has a structure capable of purifying raw water. For example, a commercially available water purifier may be used as is, or only parts such as a water purification cartridge related to the purification of raw water may be used as appropriate.

[0038] The conditions for extracting herbal tea using raw water and purified water, and the ingredients for herbal tea can be the same as those for the method for determining the residual chlorine concentration of sample water described above. The conditions for extracting herbal tea and the ingredients for herbal tea are the same as those for the method for determining the residual chlorine concentration of sample water described above, and the explanation will be omitted.

[0039] The water purifier is evaluated by sensory evaluation of the smell of herbal tea extracted using raw water and the smell of herbal tea extracted using purified water. The smell of the herbal tea may be evaluated by holding it in the mouth or not.

[0040] An example of the evaluation results will be used to provide a specific explanation. Table 2 shows the results of a sensory evaluation of the odor of herbal tea obtained in Experiment 2, which will be described later, in which raw water with residual chlorine concentrations of 0.2 ppm, 0.3 ppm, 0.5 ppm, 1 ppm, and 2 ppm was purified using a water purifier, and herbal tea was extracted from chamomile using the raw water and purified water. In Table 2, the herbal tea extracted using raw water is referred to as raw water herbal tea, and the herbal tea extracted using purified water is referred to as purified water herbal tea. The difference in odor between the herbal tea extracted using raw water and the herbal tea extracted using purified water was evaluated using the following evaluation criteria. "A": The difference in smell is clearly noticeable. "B": A difference in smell is detected. "C": There is a slight difference in smell. "D": No difference in smell is detected.

[0041] [Table 2]

[0042] If a sensory evaluation of the smell of herbal tea reveals a difference in smell between herbal tea extracted using raw water and herbal tea extracted using purified water, it is understood that residual chlorine and the like have been removed by the water purifier. The more significant the difference in smell, the higher the purification performance of the water purifier is considered to be. In the present disclosure, the purification performance of the water purifier may, for example, relate to the residual chlorine removal performance, and may relate to the removal performance of various components that are removed by the same action as residual chlorine.

[0043] The difference in smell between herbal tea extracted using raw water and herbal tea extracted using purified water is believed to be mainly due to the components that produce the unpleasant odors described above. The explanation of the components that produce the unpleasant odors is the same as that of the method for determining the residual chlorine concentration of sample water, and will not be repeated here.

[0044] According to the evaluation method of the water purifier disclosed herein, the purification performance of the water purifier can be experienced by the sense of smell. When raw water and purified water are directly compared in a sensory evaluation by smell or taste, it is difficult for general consumers to sense the difference between raw water and purified water. On the other hand, in the present method, by sensing the difference in smell between herbal tea extracted using raw water and herbal tea extracted using purified water through a sensory evaluation of the smell of herbal tea, general consumers can easily sense the difference between raw water and purified water. In addition, since no analytical equipment is required, the present method can be easily performed in various situations such as exhibitions. Herbal tea itself is generally a beverage that is enjoyed by people of all ages and genders. The present method is novel in that it focuses on the difference in smell between herbal tea extracted using raw water and purified water, which was not known until now, and uses it to evaluate water purifiers, and it is easy to make the evaluator feel like experiencing it. The smell of herbal tea is suitable for the detection sensitivity of human olfactory sense, and is unlikely to cause excessive unpleasant feelings in the evaluator. The present method is groundbreaking as a method for displaying water purifiers.

[0045] 3. Water purifier evaluation device (part 1) 1, the water purifier evaluation device 10 includes an adjustment unit 20, a water purifier installation unit 30, and an extraction unit 40. The water purifier evaluation device 10 further includes a water supply unit 11 such as tap water, a measurement unit 12 that measures the residual chlorine concentration, a heating unit 13, various sensors 14, 15, and 16, and a flow path 50 that connects the various units.

[0046] FIG. 2 is an example of a process flow performed by the water purifier evaluation device 10. The raw water adjustment water supplied to the water purifier evaluation device 10 has its residual chlorine concentration adjusted by the adjustment unit 20. For example, tap water, purified water, RO water, etc. can be used as appropriate for the raw water adjustment water. The adjusted water, which is water with an adjusted residual chlorine concentration, corresponds to raw water. A part of the raw water is purified by a water purifier installed in the water purifier installation unit 30, and the residual chlorine is removed. The water purified by the water purifier is called purified water. The raw water and purified water are each heated and used to extract herbal tea. The extracted herbal tea is provided to an evaluator, and a sensory evaluation of the smell is performed.

[0047] The adjusting unit 20 adjusts the residual chlorine concentration of the raw water. The adjusting unit 20 has, for example, a storage unit 21 that stores an adjusting liquid, and a pump 22 that sends the adjusting liquid from the storage unit 21. The adjusting liquid is a liquid for adjusting the residual chlorine concentration of the water sent from the supply unit 11. The adjusting liquid is, for example, a sodium hypochlorite aqueous solution. The adjusting unit 20 adds a predetermined amount of the adjusting liquid to the water sent from the supply unit 11 according to the set value of the residual chlorine concentration of the raw water. In this manner, raw water with an adjusted residual chlorine concentration is obtained.

[0048] The properties of the raw water can be the same as those of the raw water in the evaluation method for water purifiers described above. The residual chlorine concentration and pH of the raw water are the same as those described in the evaluation method for water purifiers, and the explanation is omitted here.

[0049] The water purifier installation unit 30 is installed with a water purifier that purifies raw water. The installation manner of the water purifier is not particularly limited. For example, the water purifier installation unit 30 may be installed with a commercially available water purifier as is, or only parts such as a water purification cartridge may be appropriately installed.

[0050] The extraction unit 40 uses raw water to extract herbal tea from herbal tea ingredients under predetermined conditions, and also uses purified water purified by a water purifier to extract herbal tea from herbal tea ingredients under the same predetermined conditions. In this embodiment, one extraction unit 40 is used to obtain herbal tea extracted using raw water and herbal tea extracted using purified water. That is, in this embodiment, one extraction unit 40 is shared by dividing the time. The flow path 50 of the water purifier evaluation device 10 has a first flow path 51 that flows raw water to the extraction unit 40, and a second flow path 52 that purifies the raw water with a water purifier and flows the purified water to the extraction unit 40. The first flow path 51 and the second flow path 52 are switched between open and closed by a switching valve 53. The water purifier installation unit 30 is provided in the second flow path 52.

[0051] The conditions for extracting herbal tea using raw water and the ingredients for herbal tea can be the same as those for the method for determining the residual chlorine concentration of sample water described above. The conditions for extracting herbal tea and the ingredients for herbal tea are the same as those for the method for determining the residual chlorine concentration of sample water, and the explanation will be omitted. Specifically, the water purifier evaluation device 10 is provided with a heating unit 13 upstream of the extraction unit 40 in the flow path 50. The heating unit 13 heats the water flowing through the flow path 50 to a temperature of 60°C or higher and 100°C or lower, preferably 80°C or higher and 100°C or lower.

[0052] In addition, the water purifier evaluation device 10 is not limited to the above embodiment, and the extraction unit may have a first extraction unit that extracts herbal tea using raw water and a second extraction unit that extracts herbal tea using purified water.

[0053] According to the water purifier evaluation device 10 of the present disclosure, it is possible to provide herbal tea suitable for carrying out the above-mentioned water purifier evaluation method. Then, by carrying out the water purifier evaluation method, the residual chlorine concentration removal performance of the water purifier can be experienced by the sense of smell. According to the water purifier evaluation device 10, it is possible to achieve the same effect as the above-mentioned water purifier evaluation method.

[0054] 4. How to determine residual chlorine concentration (part 2) The method for determining the residual chlorine concentration involves using sample water to prepare stock from stock ingredients, and then performing a sensory evaluation of the smell of the stock to determine whether or not an unpleasant odor is detected. If no unpleasant odor is detected, it is determined that the residual chlorine concentration of the sample water is less than a predetermined value.

[0055] The method of determining the residual chlorine concentration disclosed herein was developed based on the new finding that, when the odor of soup stock is sensorily evaluated, if the residual chlorine concentration of sample water is less than a predetermined value, no unpleasant odor is felt. In other words, according to this method, if no unpleasant odor is felt, the sense of smell can be sensed that the residual chlorine concentration of the sample water is less than a predetermined value. As for the sample water, the explanation given in the section "1. Method of determining residual chlorine concentration (part 1)" applies as is, and the explanation will be omitted.

[0056] Stock is a liquid in which stock ingredients are boiled or soaked in water to extract flavor. The stock ingredients used in the present method are not particularly limited. It has been found that at least some of the components that produce a common unpleasant odor are detected in a plurality of stock ingredients. Therefore, the present technology is considered to be a highly versatile technology that can be applied regardless of the type of stock ingredient. The stock ingredients are preferably one or more selected from the group consisting of seafood, cut fish, seaweed, meat, and vegetables. The seafood is, for example, bonito, mackerel, sardine, horse mackerel, clam, mussel, crab, and shrimp. The cut fish is, for example, bonito flakes, mackerel flakes, sardine flakes, mullet flakes, dried sardines, dried flying fish, dried scallops, and dried shrimp. The seaweed is, for example, kelp. The meat is chicken, beef, or pork. The parts of these meats used are, for example, meat and bones. The vegetables are, for example, green onions, onions, carrots, celery, and cabbage. The stock raw material may be one type, or a mixture of two or more types. The stock raw material may be used as it is, or may be used as a shredded product, paste, dried product, or frozen product, or may be an extract or hydrolyzate obtained from these starting raw materials. From the viewpoint of convenience, the stock raw material is preferably a solid stock containing an extract obtained from the starting raw material. The shape of the solid stock is not particularly limited, and may be, for example, granular, powdered, or cube-shaped. Specific examples of solid stock are chicken soup base and bonito soup base. The stock may contain components other than the components derived from the stock raw material as long as the effects of the present disclosure are not impaired. The components other than the components derived from the stock raw material are, for example, seasonings. The conditions for preparing the stock are not particularly limited. The stock may be prepared by extracting the starting raw material, or by dissolving the extract obtained from the starting raw material in hot water. The temperature for making the dashi is usually from 60° C. to 100° C., and preferably from 80° C. to 100° C. The amount of dashi raw materials used, the time for making the dashi, etc. can be appropriately set depending on the dashi raw materials.

[0057] The smell of soup stock is usually a mixture of several components with different odor qualities. This method involves sensory evaluation of the smell of soup stock to determine whether it is perceived as an unpleasant odor. For the sensory evaluation, replace "herbal tea" in the explanation in the section "1. Method for determining residual chlorine concentration (part 1)" with "soup stock" and the explanation will be omitted.

[0058] An example of the evaluation results will be described in detail. Table 3 shows the results of sensory evaluation of the odor of soup stock made with chicken stock powder using sample water with residual chlorine concentrations of 0.2 ppm, 0.3 ppm, 0.5 ppm, 1 ppm, and 2 ppm in Experiment 5 described later. [Table 3]

[0059] The detection limit of unpleasant odors in the sensory evaluation of the odor of the soup stock in this experiment is a range of 0.3 ppm to 1 ppm of the residual chlorine concentration of the sample water. Therefore, if no unpleasant odor is detected, it can be determined that the residual chlorine concentration of the sample water is less than 1 ppm. In addition, by checking the detection limit of unpleasant odors for each evaluator in advance as in Table 3, it can be determined that the residual chlorine concentration of the sample water is less than the detection limit of the unpleasant odor for each evaluator when each evaluator does not detect an unpleasant odor. Specifically, if Evaluator A in Table 3 does not detect an unpleasant odor, it can be determined that the residual chlorine concentration of the sample water is less than 0.3 ppm. If Evaluator B in Table 3 does not detect an unpleasant odor, it can be determined that the residual chlorine concentration of the sample water is less than 1 ppm. The predetermined value is not limited to 0.3 ppm or 1 ppm. The predetermined value can be appropriately determined by conducting a preliminary experiment such as Experiment 5 described below depending on the type of soup stock raw material, the preparation method, the pH of the sample water, etc. Naturally, sample water having a "residual chlorine concentration below the detection limit" can also be determined to be sample water having a "residual chlorine concentration at or below the detection limit."

[0060] The components that produce unpleasant odors can be identified, for example, by comparing the components contained in a stock that does not have an unpleasant odor and a stock that has an unpleasant odor, which are obtained using the same stock ingredients and the same preparation conditions.

[0061] Figures 14 and 15 show the results of a comparison of the components contained in broths that do not have an unpleasant odor and broths that do have an unpleasant odor, using GC-MS (gas chromatography-mass spectrometry) in Experiment 7, which will be described later. The thick line is the result for broths that do not have an unpleasant odor. The thin line is the result for broths that have an unpleasant odor. The broth ingredients used were chicken stock and bonito stock, respectively. In each figure, (1) is the peak containing isobutyraldehyde. (2) is the peak containing 2-methylbutyraldehyde. (3) is the peak containing isovaleraldehyde. (4) is the peak containing a specific substance, which will be described later. In this way, it is possible to identify components that are more abundant in broths that have an unpleasant odor than in broths that do not have an unpleasant odor, and to identify the components that cause the unpleasant odor based on the odor qualities of the identified components and the odor quality of the unpleasant odor of the broth.

[0062] In the present disclosure, examples of components that generate unpleasant odors include one or more selected from the group consisting of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and specific substances described below. The four components that generate unpleasant odors are the same as the components that generate unpleasant odors described in the section "1. Method for determining residual chlorine concentration (part 1)", so the description will be applied as is and omitted. In addition, the analytical method for identifying the above specific substances is also the analytical method described in the section "1. Method for determining residual chlorine concentration (part 1)", so the description will be omitted.

[0063] Figure 18 shows the mass spectra of the above-mentioned specific substances in chicken soup and bonito stock. The horizontal axis represents the m / z value, and the vertical axis represents the relative intensity. In the scan range of m / z 33 to 400, peaks were detected at m / z values ​​of 69, 68, 42, 41 (base peak), 40, and 39.

[0064] Although the specific substance has not yet been identified as a compound, it is presumed to be a component that generates an unpleasant odor based on the quality of the odor. The specific substance may be presumed to be 1-vinylaziridine. The present disclosure is not limited to these presumptions. The specific substance is not limited to one type of compound, and may be a mixture of two or more types of compounds.

[0065] According to the method for determining the residual chlorine concentration disclosed herein, for example, the residual chlorine concentration of the sample water can be sensed by the sense of smell that it is less than a predetermined value. When the sample water itself, such as tap water or purified water, is evaluated by sensory evaluation using the sense of smell or taste, it is difficult for general consumers to obtain knowledge regarding the residual chlorine concentration. On the other hand, the present method determines the residual chlorine concentration based on whether or not an unpleasant odor is felt in the sensory evaluation of the smell of the soup stock, so that it is easy for general consumers to make a judgment. In addition, the present method can be easily performed in various situations such as exhibitions because no analytical equipment is required. The soup stock itself is generally a beverage consumed regardless of age or gender. The present method is novel in that it focuses on the relationship between the residual chlorine concentration of the sample water and the unpleasant odor of the soup stock, which was not known until now, and is used to evaluate the sample water, and it is easy to make the evaluator feel like experiencing it. The unpleasant odor of the soup stock is suitable for the detection sensitivity of the human sense of smell, and is unlikely to cause the evaluator to feel excessively unpleasant. The present method is groundbreaking as a method for displaying sample water.

[0066] When the components that produce unpleasant odors contain one or more selected from the group consisting of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and the above-mentioned specific substances, the sense of smell can effectively tell that the residual chlorine concentration in the sample water is below a predetermined value.

[0067] 5. How to evaluate water purifiers (part 2) The method of evaluating a water purifier involves preparing raw water with a residual chlorine concentration above a predetermined value, and purified water obtained by purifying the raw water using a water purifier, using the raw water to make stock from stock ingredients under predetermined conditions, and using the purified water to make stock from the stock ingredients under the same predetermined conditions, and performing a sensory evaluation of the smell of the stock made using the raw water and the smell of the stock made using the purified water, and evaluating the purification performance of the water purifier based on the results of the sensory evaluation.

[0068] Since the purpose of this method is to evaluate the purification performance of the water purifier, the residual chlorine concentration of the raw water is set to a predetermined value or more. The predetermined value can be appropriately determined by conducting a preliminary experiment such as Experiment 6 described later depending on the type of soup stock raw material, the preparation method, the pH of the sample water, etc. The residual chlorine concentration of the raw water can be set to, for example, 0.3 ppm or more, and may be set to 0.5 ppm or more, 1 ppm or more, or 1.5 ppm or more. The upper limit of the residual chlorine concentration of the raw water is not particularly limited and can be set to, for example, 2 ppm or less. For example, if the residual chlorine concentration of tap water used in this method is a predetermined value or more, tap water can be used as it is as raw water. The residual chlorine concentration of the raw water may be set to 1 ppm or less, which is the water quality management target value. The residual chlorine concentration of tap water may be appropriately adjusted depending on the purification performance of the water purifier, the type of soup stock raw material, etc. The residual chlorine concentration of tap water can be increased, for example, by adding sodium hypochlorite for food additives. The residual chlorine concentration of tap water can be decreased, for example, by adding purified water with a lower residual chlorine concentration than tap water.

[0069] The pH and other properties of the raw water can be the same as those of the sample water. The explanation for the sample water applies as is to the raw water and will be omitted. The explanation for the purified water applies as is to the "2. Evaluation method for water purifiers (part 1)" column and will be omitted.

[0070] The conditions for making soup stock using raw water and purified water, and the ingredients for soup stock can be the same as those for the method for determining the residual chlorine concentration of sample water described above. The conditions for making soup stock and the ingredients for soup stock are the same as those for the method for determining the residual chlorine concentration of sample water, and the explanation is omitted here.

[0071] The water purifier is evaluated by sensory evaluation of the odor of soup stock made from raw water and the odor of soup stock made from purified water. The odor of the soup stock may be evaluated by holding it in the mouth or not.

[0072] An example of the evaluation results will be used to provide a specific explanation. Table 4 shows the results of sensory evaluation of the odor of the soup stock produced in Experiment 6, which will be described later, in which raw water with residual chlorine concentrations of 0.2 ppm, 0.3 ppm, 0.5 ppm, 1 ppm, and 2 ppm was purified using a water purifier, and the raw water and purified water were used to produce soup stock using chicken stock powder. In Table 4, the soup stock produced using raw water is referred to as soup stock made from raw water, and the soup stock produced using purified water is referred to as soup stock made from purified water. The difference in odor between the soup stock produced using raw water and the soup stock produced using purified water was evaluated using the following evaluation criteria. "A": The difference in smell is clearly noticeable. "B": A difference in smell is detected. "C": There is a slight difference in smell. "D": No difference in smell is detected.

[0073] [Table 4]

[0074] If a sensory evaluation of the odor of the soup stock reveals a difference in odor between the soup stock made using raw water and the soup stock made using purified water, it is understood that residual chlorine and the like have been removed by the water purifier. The more significant the difference in odor, the higher the purification performance of the water purifier is considered to be. In the present disclosure, the purification performance of the water purifier may, for example, relate to the residual chlorine removal performance, and may relate to the removal performance of various components that are removed by the same action as residual chlorine.

[0075] The difference in smell between soup stock made from raw water and soup stock made from purified water is believed to be mainly due to the components that generate the unpleasant odors described above. The explanation of the components that generate the unpleasant odors is the same as that of the method for determining the residual chlorine concentration of sample water, and will not be repeated here.

[0076] According to the evaluation method of the water purifier disclosed herein, the purification performance of the water purifier can be experienced by the sense of smell. When raw water and purified water are directly compared in a sensory evaluation by smell or taste, it is difficult for general consumers to sense the difference between raw water and purified water. On the other hand, in the present method, by sensory evaluation of the smell of the soup stock, general consumers can easily sense the difference between raw water and purified water by sensing the difference in smell between soup stock made using raw water and soup stock made using purified water. In addition, since no analytical equipment is required, the present method can be easily performed in various situations such as exhibitions. Soup stock itself is generally a beverage consumed regardless of age or gender. The present method is novel in that it focuses on the difference in smell between soup stock made using raw water and purified water, which was not known until now, and is used to evaluate water purifiers, and it is easy to make the evaluator feel like experiencing it. The smell of soup stock is suitable for the detection sensitivity of human olfactory sense, and is unlikely to cause excessive unpleasant feelings in the evaluator. The present method is groundbreaking as a method for displaying water purifiers.

[0077] 6. Water purifier evaluation device (part 2) The water purifier evaluation device (part 2) includes an adjustment unit 20, a water purifier installation unit 30, and a production unit. The water purifier evaluation device (part 2) can be configured similarly to the water purifier evaluation device 10 described in "3. Water purifier evaluation device (part 1)". The water purifier evaluation device 10 will be described below with reference to FIG. 1.

[0078] FIG. 13 is an example of a process flow performed by the water purifier evaluation device 10. The raw water adjustment water supplied to the water purifier evaluation device 10 has its residual chlorine concentration adjusted by the adjustment unit 20. For example, tap water, purified water, RO water, etc. can be used as appropriate for the raw water adjustment water. The adjusted water, which is water with an adjusted residual chlorine concentration, corresponds to raw water. A part of the raw water is purified by a water purifier installed in the water purifier installation unit 30, and the residual chlorine is removed. The water purified by the water purifier is called purified water. The raw water and purified water are each heated and used to prepare soup stock. The prepared soup stock is provided to an evaluator, and a sensory evaluation of the smell is performed.

[0079] The adjustment unit 20 and the water purifier installation unit 30 are the same as those described in the section "3. Water purifier evaluation device (part 1)" and will not be described here. The properties of the raw water can be the same as those of the raw water in the water purifier evaluation method described above. The residual chlorine concentration and pH of the raw water, etc., are the same as those of the raw water in the water purifier evaluation method and will not be described here.

[0080] The preparation unit may prepare stock by extracting starting materials as long as stock can be prepared, or may prepare stock by dissolving an extract obtained from the starting materials in hot water. In this embodiment, the extraction unit 40 in the water purifier evaluation device 10 corresponds to the preparation unit. The preparation unit prepares stock from stock raw materials under specified conditions using raw water, and prepares stock from stock raw materials under the same specified conditions using purified water purified by a water purifier. Other configurations of the preparation unit, i.e., the extraction unit 40, are applied by replacing "herbal tea" with "stock" in the explanation given in the section "3. Water purifier evaluation device (part 1)" and will not be explained further.

[0081] The conditions for making soup stock using raw water and the soup stock ingredients can be the same as those in the method for determining the residual chlorine concentration of sample water described above. The conditions for making soup stock and the soup stock ingredients are the same as those in the method for determining the residual chlorine concentration of sample water, and the explanation is omitted. Specifically, the water purifier evaluation device 10 is provided with a heating unit 13 upstream of the preparation unit in the flow path 50. The heating unit 13 heats the water flowing through the flow path 50 to 60°C or higher and 100°C or lower, preferably 80°C or higher and 100°C or lower.

[0082] According to the water purifier evaluation device 10 of the present disclosure, soup stock for carrying out the above-mentioned water purifier evaluation method can be suitably provided. Then, by carrying out the water purifier evaluation method, the residual chlorine concentration removal performance of the water purifier can be experienced by the sense of smell. According to the water purifier evaluation device 10, the same effect as the above-mentioned water purifier evaluation method can be achieved. EXAMPLES

[0083] The present invention will be explained in more detail below with reference to Example (Part 1).

[0084] 1. Experiment 1: Relationship between residual chlorine concentration in sample water and the odor of herbal tea Sample water with residual chlorine concentrations of 0.2 ppm, 0.3 ppm, 0.5 ppm, 1 ppm, and 2 ppm was prepared. 1.0 g of chamomile (TWINIGS, Kataoka Bussan Co., Ltd.) was added with 140 mL of sample water at 90°C to 100°C, and left to stand for 4 minutes to extract herbal tea. Solid matter was removed from the obtained herbal tea, which was then provided to evaluators A and B, who conducted a sensory evaluation of the smell. Evaluators A and B were presented with herbal tea extracted using the sample water and herbal tea extracted using water with a residual chlorine concentration of 0 ppm. The sensory evaluation of the smell involved sniffing each herbal tea with the nose or holding it in the mouth, comparing the smells, and judging whether the herbal tea extracted using the sample water had an unpleasant smell. The evaluation results are shown in Table 1 above.

[0085] From the results of Experiment 1, it was found that if Evaluator A and Evaluator B did not detect any unpleasant odor, it was possible to determine that the residual chlorine concentration of the sample water was less than 0.5 ppm. It was also found that if Evaluator A did not detect any unpleasant odor, it was possible to determine that the residual chlorine concentration of the sample water was less than 0.3 ppm.

[0086] 2. Experiment 2: Comparison of the odor of herbal tea extracted using raw water and herbal tea extracted using purified water Tap water from Tokoname City, Aichi Prefecture was prepared. The prepared tap water had a pH of 7.3 and a residual chlorine concentration of 0.4 mg / L. The residual chlorine concentration of the tap water was adjusted to 1 mg / L using food additive grade sodium hypochlorite manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., and used as raw water. The raw water was passed through a water purifier to remove free residual chlorine and obtain purified water. The raw water and purified water were each heated to 90°C to 100°C. Herbal tea was extracted using the following herbal tea ingredients under the extraction conditions in Table 5.

[0087] Herbal Tea Ingredients Details Chamomile: TWINIGS, manufactured by Kataoka Bussan Co., Ltd. Lemongrass: Venus, manufactured by Sandra Co., Ltd. Peppermint: TWINIGS, manufactured by Kataoka Bussan Co., Ltd. Lavender: Venus, Sandra Co., Ltd.

[0088] [Table 5]

[0089] The solid matter was removed from the obtained herbal tea and provided to the evaluators for a sensory evaluation of the smell. The evaluators were presented with the herbal tea extracted using the raw water and the herbal tea extracted using the purified water. The sensory evaluation of the smell was carried out by sniffing each herbal tea with the nose or holding it in the mouth, comparing the smells, and judging whether or not there was a difference in the smell. The evaluation results are shown in Table 2 above.

[0090] The results of Experiment 2 showed that when the residual chlorine concentration of the raw water was 0.3 ppm or higher, the purification performance of the water purifier could be experienced through the sense of smell.

[0091] 3. Experiment 3: Analysis of the components that cause unpleasant odors in herbal tea The components contained in the herbal tea were analyzed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GCMS).

[0092] Water with residual chlorine concentrations of 0 ppm, 0.5 ppm, 1 ppm, and 2 ppm was prepared. Herbal teas were extracted using herbal tea ingredients of chamomile, lemongrass, peppermint, and lavender in the same manner as in Experiment 2. 10 mL of each of the obtained herbal teas was dispensed into a 20 mL vial containing 3 g of sodium chloride. For each herbal tea, odor components were analyzed under the above [Gas Chromatography Analysis Conditions: GC-MS Measurement Conditions] described in the embodiment and the following [SPME Conditions]. [SPME conditions] Fiber: SUPELCO 50 / 30um DVB / Carboxen / PDMS Sample volume: 10mL Extraction temperature: 60℃ Extraction time: 20 min Desorption time: 1min

[0093] The gas chromatographic analysis results of each herbal tea are shown in Figures 3 to 6. The horizontal axis is retention time (min) and the vertical axis is detection intensity (-). In each figure, the thick line is the result for the herbal tea extracted using water with a residual chlorine concentration of 0 ppm. The thin line is the result for the herbal tea extracted using water with a residual chlorine concentration of 1 ppm. In each figure, (1) is a peak containing isobutyraldehyde. (2) is a peak containing 2-methylbutyraldehyde. (3) is a peak containing isovaleraldehyde. (4) is a peak containing the specific substance described in the embodiment.

[0094] At least one of the peak intensities of (1), (2), (3), and (4) above was significantly greater in the herbal tea with a residual chlorine concentration of 1 ppm than in the herbal tea with a residual chlorine concentration of 0 ppm. As a result of the odor sensory evaluation, none of the herbal teas extracted using water with a residual chlorine concentration of 0 ppm had an unpleasant odor. All of the herbal teas extracted using water with a residual chlorine concentration of 1 ppm had an unpleasant odor. Based on these results, the odor quality of each component, and the odor quality of the unpleasant odor of the herbal tea, it was suggested that isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and at least one of the specific substances described in the embodiment are components that generate unpleasant odors.

[0095] The relationship between the residual chlorine concentration in water and isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and the specific substances described in the embodiment are shown in Figures 7 to 10. The horizontal axis is the residual chlorine concentration in water (ppm), and the vertical axis is the detection intensity (-) of each component. In each figure, column A is a graph of isobutyraldehyde. Column B is a graph of 2-methylbutyraldehyde. Column C is a graph of isovaleraldehyde. Column D is a graph of the specific substances described in the embodiment. The specific substances are indicated as Unknown1. For lavender, the peak intensities of (1), (2), and (3) above are not significantly large, so only the graph of the specific substance described in the embodiment in column D is shown.

[0096] The detection intensity of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and the specific substances described in the embodiment increased as the residual chlorine concentration of the water increased. As a result of the odor sensory evaluation, the higher the residual chlorine concentration of the water, the stronger the unpleasant odor of the herbal tea felt. These results suggest that at least one of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and the specific substances described in the embodiment is a component that generates an unpleasant odor.

[0097] 11 shows the mass spectra of the specific substances in the herbal teas of chamomile, lemongrass, peppermint, and lavender. The horizontal axis represents the m / z value, and the vertical axis represents the relative intensity. The m / z values ​​of the peaks are as described in the embodiment.

[0098] 4. Experiment 4: Effect of water pH Water with pH 6, pH 7, and pH 8 was prepared. The residual chlorine concentration of the water was set to 1 ppm. In the same manner as in Experiment 3, herbal tea was extracted using chamomile herbal tea raw material, and the components contained in the herbal tea were analyzed by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GCMS method).

[0099] The gas chromatographic analysis results of each herbal tea are shown in Figure 12. The horizontal axis is retention time (min) and the vertical axis is detection intensity (-). In Figure 12, the thick line is the result for the herbal tea extracted using water of pH 6. The thin line is the result for the herbal tea extracted using water of pH 7. The thick grey line is the result for the herbal tea extracted using water of pH 8. (4) is a peak containing the specific substance described in the embodiment.

[0100] The peak intensity of (4) above was stronger as the pH increased. This result suggests that if water with a high pH is used, the difference in odor can be more clearly sensed by sensory evaluation. In addition, the difference in detection intensity due to pH may be utilized to identify a specific substance as information indicating the properties of the specific substance described in the embodiment.

[0101] 5. Effects of Example (Part 1) This embodiment can provide a technique related to olfactory recognition of the effect of purified water.

[0102] The present invention will be explained more specifically below with reference to Example (Part 2).

[0103] 6. Experiment 5: Relationship between the residual chlorine concentration of sample water and the odor of soup stock Sample water with residual chlorine concentrations of 0.2 ppm, 0.3 ppm, 0.5 ppm, 1 ppm, and 2 ppm was prepared. Chicken stock base: Chicken stock, Heiwa Foods Co., Ltd. 3.0 g was added to 200 mL of sample water at 90°C to 100°C to prepare soup stock. The resulting soup stock was provided to evaluators A and B, and a sensory evaluation of the smell was performed. Evaluators A and B were presented with soup stock made using the sample water and soup stock made using water with a residual chlorine concentration of 0 ppm. The sensory evaluation of the smell was performed by sniffing each soup stock with the nose or holding it in the mouth, comparing the smells, and judging whether or not the soup stock made using the sample water had an unpleasant smell. The evaluation results are shown in Table 3 above.

[0104] From the results of experiment 5, it was found that if evaluator A and evaluator B did not detect any unpleasant odor, it was possible to determine that the residual chlorine concentration of the sample water was less than 1 ppm. It was also found that if evaluator A did not detect any unpleasant odor, it was possible to determine that the residual chlorine concentration of the sample water was less than 0.3 ppm.

[0105] 7. Experiment 6: Comparison of the odor of soup stock made with raw water and purified water Tap water from Tokoname City, Aichi Prefecture was prepared. The prepared tap water had a pH of 7.3 and a residual chlorine concentration of 0.5 mg / L. The residual chlorine concentration of the tap water was adjusted to 1 mg / L using sodium hypochlorite, food additive grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., and used as raw water. The raw water was passed through a water purifier to remove free residual chlorine and obtain purified water. The raw water and purified water were heated to 90°C to 100°C. The following soup stock ingredients were used to prepare soup stock under the preparation conditions in Table 6. The soup stock ingredients quickly dissolved in hot water, so the time required for preparation is not listed.

[0106] Details of dashi ingredients Chicken stock: Chicken stock, made by Heiwa Foods Co., Ltd. Bonito stock: Hon Dashi, manufactured by Ajinomoto Co., Inc.

[0107] [Table 6]

[0108] The resulting soup stock was provided to evaluators, and a sensory evaluation of the smell was conducted. The evaluators were presented with soup stock made using raw water and soup stock made using purified water. The sensory evaluation of the smell was conducted by sniffing each soup stock with the nose or holding it in the mouth, comparing the smells, and evaluating whether or not there was a difference in the smell. The evaluation results are shown in Table 4 above.

[0109] The results of Experiment 6 showed that when the residual chlorine concentration of the raw water was 0.3 ppm or higher, the purification performance of the water purifier could be experienced through the sense of smell.

[0110] 8. Experiment 7: Analysis of the components that cause unpleasant odors in soup stock The components contained in the soup stock were analyzed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GCMS).

[0111] Water with residual chlorine concentrations of 0 ppm, 0.5 ppm, 1 ppm, and 2 ppm was prepared. In the same manner as in Experiment 6, chicken stock and bonito stock were used as stock ingredients to prepare stock. 10 mL of each of the resulting stocks was dispensed into a 20 mL vial containing 3 g of sodium chloride. Each stock was analyzed for odor components under the above [Gas Chromatography Analysis Conditions: GC-MS Measurement Conditions] described in the embodiment and the above [SPME Conditions] described in Experiment 3.

[0112] The gas chromatographic analysis results of each stock are shown in Figures 14 and 15. The horizontal axis is retention time (min) and the vertical axis is detection intensity (-). In each figure, the thick line is the result for stock made using water with a residual chlorine concentration of 0 ppm. The thin line is the result for stock made using water with a residual chlorine concentration of 1 ppm. In each figure, (1) is a peak containing isobutyraldehyde. (2) is a peak containing 2-methylbutyraldehyde. (3) is a peak containing isovaleraldehyde. (4) is a peak containing the specific substance described in the embodiment.

[0113] The peak intensities of (1), (2), (3), and (4) above were significantly greater in the soup stock with a residual chlorine concentration of 1 ppm than in the soup stock with a residual chlorine concentration of 0 ppm. As a result of the odor sensory evaluation, none of the soup stocks made using water with a residual chlorine concentration of 0 ppm had an unpleasant odor. All of the soup stocks made using water with a residual chlorine concentration of 1 ppm had an unpleasant odor. Based on these results, the odor quality of each component, and the odor quality of the unpleasant odor of the soup stock, it was suggested that isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and at least one of the specific substances described in the embodiment are components that generate unpleasant odors.

[0114] The relationship between the residual chlorine concentration in water and isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and the specific substances described in the embodiments are shown in Figures 16 and 17. The horizontal axis is the residual chlorine concentration in water (ppm), and the vertical axis is the detection intensity (-) of each component. In each figure, column A is a graph of isobutyraldehyde. Column B is a graph of 2-methylbutyraldehyde. Column C is a graph of isovaleraldehyde. Column D is a graph of the specific substances described in the embodiments. The specific substances are indicated as Unknown1.

[0115] The detection intensity of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and the specific substances described in the embodiment increased as the residual chlorine concentration of the water increased. As a result of the odor sensory evaluation, the higher the residual chlorine concentration of the water, the stronger the unpleasant odor of the soup stock felt. These results suggest that at least one of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and the specific substances described in the embodiment is a component that generates an unpleasant odor.

[0116] 18 shows mass spectra of the specific substances in chicken soup and bonito stock. The horizontal axis shows the m / z value, and the vertical axis shows the relative intensity. The m / z values ​​of the peaks are as described in the embodiment.

[0117] 9. Effects of Example (Part 2) This embodiment can provide a technique related to olfactory recognition of the effect of purified water. [Explanation of symbols]

[0118] 10...water purifier evaluation device, 11...supply section, 12...measuring section, 13...heating section, 14, 15, 16: sensors, 20...adjustment section, 21...storage section, 22...pump, 30...water purifier installation section, 40...extraction section, 50...flow path, 51...first flow path, 52...second flow path, 53...switching valve

Claims

1. Using the sample water, extract herbal tea from the herbal tea ingredients, The odor of the herbal tea is subjected to a sensory evaluation to determine whether or not the odor is unpleasant. A method for determining a residual chlorine concentration, which determines that the residual chlorine concentration of the sample water is less than a predetermined value if the unpleasant odor is not detected.

2. The method for determining a residual chlorine concentration according to claim 1, wherein the component that generates the unpleasant odor includes one or more selected from the group consisting of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and specific substances identified by the following analytical method. (Analysis method) The specific substance is a substance that appears as a peak at a retention time of 12.0 min when measured by GC-MS under the following analytical conditions, where the retention time of isobutyraldehyde is 6.4 min, the retention time of 2-methylbutyraldehyde is 8.5 min, and the retention time of isovaleraldehyde is 8.6 min, and peaks are detected at m / z values ​​of 69, 68, 42, 41 (base peak), 40, and 39. [GC-MS measurement conditions] Equipment name: Shimadzu Gas Chromatograph Mass Spectrometer GCMS-QP2020 Column: Agilent DB-WAX (60 m x 0.25 mm df = 0.25 μm) Carrier gas: Helium (linear velocity 25.5 cm / s) Split ratio: 5.0 Inlet temperature: 250℃ Column oven temperature: 40°C (hold for 3 min) - heating at 3°C / min - 240°C (hold for 5 min) Ionization method: EI Ion source temperature: 230° C. Interface temperature: 250°C Scan range m / z: 33-400

3. 3. The method for determining a residual chlorine concentration according to claim 1, wherein the herbal tea ingredient is one or more selected from the group consisting of chamomile, lemongrass, peppermint, and lavender.

4. Prepare raw water having a residual chlorine concentration equal to or higher than a predetermined value and purified water obtained by purifying the raw water with a water purifier; Using the raw water, extract herbal tea from herbal tea ingredients under specified conditions; Extracting herbal tea from the herbal tea ingredients using the purified water under the same conditions as the specified conditions; The odor of the herbal tea extracted using the raw water and the odor of the herbal tea extracted using the purified water are subjected to a sensory evaluation; A method for evaluating a water purifier, comprising evaluating the purification performance of the water purifier based on the results of a sensory evaluation.

5. An adjustment unit for adjusting the residual chlorine concentration of the raw water; A water purifier installation unit in which a water purifier for purifying the raw water is installed; The water purifier evaluation device is provided with an extraction unit that uses the raw water to extract herbal tea from herbal tea ingredients under specified conditions, and also uses purified water purified by the water purifier to extract herbal tea from the herbal tea ingredients under the same conditions as the specified conditions.

6. Using the sample water, broth is made from broth ingredients, The odor of the soup stock is subjected to a sensory evaluation to determine whether or not an unpleasant odor is felt; A method for determining a residual chlorine concentration, which determines that the residual chlorine concentration of the sample water is less than a predetermined value if the unpleasant odor is not detected.

7. The method for determining a residual chlorine concentration according to claim 6, wherein the component that generates the unpleasant odor includes one or more selected from the group consisting of isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, and specific substances identified by the following analytical method. (Analysis method) The specific substance is a substance that appears as a peak at a retention time of 12.0 min when measured by GC-MS under the following analytical conditions, where the retention time of isobutyraldehyde is 6.4 min, the retention time of 2-methylbutyraldehyde is 8.5 min, and the retention time of isovaleraldehyde is 8.6 min, and peaks are detected at m / z values ​​of 69, 68, 42, 41 (base peak), 40, and 39. [GC-MS measurement conditions] Equipment name: Shimadzu Gas Chromatograph Mass Spectrometer GCMS-QP2020 Column: Agilent DB-WAX (60 m x 0.25 mm df = 0.25 μm) Carrier gas: Helium (linear velocity 25.5 cm / s) Split ratio: 5.0 Inlet temperature: 250℃ Column oven temperature: 40°C (hold for 3 min) - heating at 3°C / min - 240°C (hold for 5 min) Ionization method: EI Ion source temperature: 230° C. Interface temperature: 250°C Scan range m / z: 33-400

8. Prepare raw water having a residual chlorine concentration equal to or higher than a predetermined value and purified water obtained by purifying the raw water with a water purifier; Using the raw water, a stock is produced from a stock ingredient under predetermined conditions; Using the purified water, a stock is produced from the stock raw material under the same conditions as the specified conditions, The odor of the soup stock made using the raw water and the odor of the soup stock made using the purified water are subjected to a sensory evaluation; A method for evaluating a water purifier, comprising evaluating the purification performance of the water purifier based on the results of a sensory evaluation.

9. An adjustment unit for adjusting the residual chlorine concentration of the raw water; A water purifier installation unit in which a water purifier for purifying the raw water is installed; A water purifier evaluation device comprising: a preparation unit that uses the raw water to prepare stock from stock ingredients under specified conditions, and a preparation unit that uses purified water purified by the water purifier to prepare stock from the stock ingredients under the same conditions as the specified conditions.

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