Bitterness unit measuring device and bitterness unit measuring method

Abstract

Provided is a bitterness unit measuring device which is able to efficiently and highly precisely measure the absorbance of isooctane containing an extracted bitter component without requiring collection of an exact sample quantity, and with which it is possible to directly and accurately calculate a bitterness unit from the absorbance, as established in official methods.　The present invention comprises: a sampling unit 5 which performs sampling of a specimen containing a bitter component; a slug flow-forming unit 6 which mixes the specimen, isooctane, and an acid aqueous solution at a predetermined volumetric ratio to form a liquid-liquid slug flow; an extracting unit 7 into which the liquid-liquid slug flow is introduced from the slug flow-forming unit 6 and which extracts the bitter component contained in the specimen into the isooctane; and an absorbance measuring unit 9 which measures the absorbance of the isooctane containing the bitter component.

Description

Bitterness value measuring device and bitterness value measuring method

[0001] The present invention relates to a bitterness value measuring device and a bitterness value measuring method for measuring the bitterness value of a sample containing a bitter component.

[0002] Measurement of bitterness value, as defined by official methods such as the analytical method prescribed by the National Tax Agency in Japan, is performed by manual analysis using the following steps (1) to (5): (1) A sample containing bitter components (e.g., beer), an acidic aqueous solution, and isooctane are placed in a centrifuge tube in the volume ratio defined by the official method. (2) The centrifuge tube is shaken in a shaker to extract the bitter components in the sample into the isooctane. (3) The isooctane and the sample are separated using a centrifuge. (4) The absorbance of the separated isooctane is measured using a spectrophotometer. (5) The bitterness value is calculated from the absorbance measurement results.

[0003] Patent Document 1 discloses a flow injection beer bitterness value analyzer. This bitterness value analyzer is configured to combine a carrier liquid (aqueous solution) containing the beer to be analyzed (sample beer), an acid aqueous solution, and isooctane, transfer the bitter components contained in the sample beer to the isooctane, separate an aqueous phase containing the sample beer from which the bitter components have been extracted, the carrier liquid, and the acid aqueous solution, and an organic phase (oil phase) containing the bitter components and isooctane, and send the separated organic phase to a UV detector. The absorbance at a specific wavelength (275 nm) is then measured, and the bitterness value of the sample beer can be determined from the peak height according to a previously obtained calibration curve. Note that, since both the bitterness value and the bitterness value are calculated based on the absorbance measurement results, the bitterness value and the bitterness value are considered to be essentially equivalent.

[0004] Patent Literature 2 discloses an extraction apparatus in which an aqueous phase consisting of a first liquid, which is water or an aqueous solution, and an organic phase consisting of a second liquid, which is a hydrophobic organic liquid, are alternately flowed to form a liquid-liquid slug flow, and target components contained in the aqueous phase are transferred to the organic phase for extraction. In this extraction apparatus, internal circulation flows are generated in both the aqueous phase and the organic phase, so that the contact surface between the aqueous phase and the organic phase can be continuously renewed, thereby facilitating the transfer of target components contained in the aqueous phase to the organic phase.

[0005] Utility Model Publication No. 7-929 Patent No. 7062287

[0006] In the manual analysis method described above, the series of steps required for measurement are complicated, require a great deal of time and effort, and there is also the problem of measurement errors due to individual differences between measurers.

[0007] In the bitterness value analyzer disclosed in Patent Document 1, the sample volume is strictly specified, and when measuring the absorbance of isooctane containing extracted bitter components, calibration of the change during measurement (e.g., peak value or integral amount) with a reference solution is essential.Since the bitterness value is calculated from the correlation under specific liquid delivery conditions using a correlation method, the bitterness value cannot be calculated directly from the absorbance specified in the official method.

[0008] Patent Document 2 discloses a configuration for efficiently extracting target components contained in an aqueous phase into an organic phase, but does not specifically disclose other configurations required to specifically calculate the bitterness value.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a bitterness value measuring device and a bitterness value measuring method that can efficiently and accurately measure the absorbance of isooctane containing extracted bitter components without the need to collect a precise sample amount, and that can accurately calculate the bitterness value directly from the absorbance specified by the official method.

[0010] The bitterness value measuring device of the present invention, which solves the above-mentioned problems, has a characteristic configuration comprising: a sampling section for sampling a sample containing bitter components; a slug flow forming section for forming a liquid-liquid slug flow by combining the sample, isooctane, and an acid aqueous solution at a predetermined volume ratio; an extraction section into which the liquid-liquid slug flow is introduced from the slug flow forming section and which extracts the bitter components contained in the sample into the isooctane; and an absorbance measuring section for measuring the absorbance of the isooctane containing the bitter components.

[0011] According to the bitterness value measurement device of this configuration, a sample containing bitter components, isooctane, and an acid aqueous solution are joined in a slug flow forming section at a predetermined volume ratio to form a liquid-liquid slug flow. By setting the predetermined volume ratio to a volume ratio specified by an official method, a liquid-liquid slug flow can be formed by joining the sample, isooctane, and acid aqueous solution at the same volume ratio. When the sample and acid aqueous solution join, the bitter components (iso-α acids) in the sample are liberated and dissolved into the oil phase (isooctane). This liquid-liquid slug flow is then introduced into the extraction section, where the aqueous phase containing the sample and the acid aqueous solution and the oil phase containing isooctane alternately flow. The bitter components contained in the aqueous phase (sample) are transferred to the oil phase (isooctane) and extracted. In the extraction section, internal circulation flows are generated in both the aqueous and oil phases, continuously renewing the contact surface between the aqueous and oil phases and accelerating the transfer of the bitter components contained in the aqueous phase to the oil phase. The absorbance of the isooctane containing the extracted bitter components is then measured in the absorbance measurement unit. In this way, the absorbance of the isooctane containing the extracted bitter components can be measured efficiently and with high precision without the need to collect a precise sample amount, and the bitterness value can be accurately calculated directly from the absorbance specified by the official method.

[0012] The bitterness value measuring device according to the present invention preferably further comprises a temperature adjusting unit that adjusts the temperature of the isooctane containing the bitter component.

[0013] According to the bitterness value measuring device of this configuration, the temperature of isooctane containing bitter components can be easily maintained at the predetermined temperature (20°C) specified by the official method by the temperature control unit.

[0014] In the bitterness value measuring device according to the present invention, it is preferable that the slug flow forming section is configured so that the sample and the isooctane are joined together and then the aqueous acid solution is joined together.

[0015] The bitterness value measuring device of this configuration can prevent the bitter components (iso-alpha acids) in the sample from being liberated before being extracted into isooctane and adsorbed onto the inner walls of the pipe through which the sample flows, thereby allowing the bitter components to be sufficiently extracted into isooctane.

[0016] In the bitterness value measuring device of the present invention, the slug flow forming section includes a confluence section where at least the sample and the isooctane confluence, a liquid delivery flow path for delivering the combined liquid, and a slug flow path in which the liquid-liquid slug flow is formed, and it is preferable that the ratio (A / B) of the flow path diameter (A) of the liquid delivery flow path to the flow path diameter (B) of the slug flow path is 0.5 or more and 4.0 or less.

[0017] According to the bitterness value measuring device of this configuration, a liquid-liquid slug flow suitable for extracting bitter components can be reliably formed.

[0018] In the bitterness value measuring device according to the present invention, it is preferable that the acid aqueous solution further joins the confluence of the sample and the isooctane.

[0019] According to the bitterness value measuring device of this configuration, there is no need to provide multiple confluences where the sample, isooctane, and aqueous acid solution are confluent, and the device configuration can be simplified.

[0020] In the bitterness value measuring device of the present invention, it is preferable that the sampling unit has a sample loop in which the sample is filled and a pump that delivers a carrier liquid to the sample loop, and is configured to use the carrier liquid delivered by the pump to push out the sample filled in the sample loop and deliver the sample.

[0021] According to the bitterness value measuring device of this configuration, the device can serve both as a sample delivery device and a sample loop cleaning device, thereby simplifying the device configuration.

[0022] In the bitterness value measuring device according to the present invention, it is preferable that the measurement of absorbance by the absorbance measuring unit and the sampling by the sampling unit are performed in parallel.

[0023] According to the bitterness value measuring device of this configuration, the bitterness value of a sample can be measured efficiently.

[0024] In the bitterness value measuring device according to the present invention, the absorbance measuring unit has an irradiation unit that irradiates ultraviolet light, and when measuring the absorbance of isooctane containing the bitter component by the absorbance measuring unit, the supply of isooctane containing the bitter component to the absorbance measuring unit is stopped, and the absorbance measuring unit is maintained at a predetermined temperature by the temperature control unit, while the isooctane containing the bitter component is irradiated with ultraviolet light from the irradiation unit, and when the measurement is not being performed, it is preferable to reduce the amount of ultraviolet light irradiated by the irradiation unit or stop irradiating ultraviolet light.

[0025] With the bitterness value measuring device of this configuration, absorbance measurements are performed while maintained at a predetermined temperature, thereby improving reproducibility, and by dimming or turning off the light when measurements are not being performed, the impact on the bitterness value measurement value caused by the decomposition of iso-alpha acids due to irradiation with ultraviolet light can be reduced.

[0026] In the bitterness value measuring device according to the present invention, the sample containing the bitter component is preferably beer, a beer-flavored beverage, or a semi-finished product thereof.

[0027] The bitterness value measuring device of this configuration can accurately calculate the bitterness value of beers, beer-flavored beverages, or semi-finished products thereof.

[0028] Next, the characteristic configuration of the bitterness value measurement method of the present invention for solving the above-mentioned problems is that it includes: a sampling step of sampling a sample containing bitter components; a slug flow formation step of forming a liquid-liquid slug flow by merging the sample, isooctane, and an acid aqueous solution at a predetermined volume ratio; an extraction step of extracting the bitter components contained in the sample into the isooctane while flowing the liquid-liquid slug flow formed in the slug flow formation step; and an absorbance measurement step of measuring the absorbance of the isooctane containing the bitter components.

[0029] According to this bitterness value measurement method, in the slug flow formation step, a sample containing bitter components, isooctane, and an acid aqueous solution are combined at a predetermined volume ratio to form a liquid-liquid slug flow. The bitter components contained in the sample are extracted into the isooctane by performing an extraction step on the liquid-liquid slug flow. Then, in the absorbance measurement step, the absorbance of the isooctane containing the extracted bitter components is measured. Thus, the absorbance of the isooctane containing the extracted bitter components can be measured efficiently and accurately without the need to collect a precise sample volume, and the bitterness value can be accurately calculated directly from the absorbance specified by the official method.

[0030] FIG. 1 is a block diagram showing the schematic configuration of a bitterness value measuring device according to a first embodiment of the present invention. FIG. 2 is a block diagram showing the schematic configuration of a control system of the bitterness value measuring device according to the first embodiment. FIG. 3 is a flowchart showing the procedure for bitterness value measurement. FIG. 4 is a graph showing an example of the change in absorbance over time during measurement. FIG. 5 is a block diagram showing the schematic configuration of a bitterness value measuring device according to a second embodiment of the present invention. FIG. 6 is a structural explanatory diagram of a slug flow forming section in the bitterness value measuring device according to the second embodiment. FIG. 7 is a flowchart showing the procedure for another example of bitterness value measurement.

[0031] The present invention will be described below with reference to the drawings. In the following embodiments, a bitterness value measuring device and a bitterness value measuring method are used to measure the bitterness value of a sample, such as a beer, a beer-taste beverage, or a semi-finished product thereof. However, the present invention is not intended to be limited to the configurations shown in the following embodiments or drawings.

[0032] [First Embodiment] <Overall Configuration> Fig. 1 is a block diagram showing the schematic configuration of a bitterness value measuring device 1A according to a first embodiment of the present invention. Fig. 1(a) shows a case where a switching valve 45 (described later) is in a first switching state, and Fig. 1(b) shows the main parts when the switching valve 45 is in a second switching state. As shown in Fig. 1(a), the bitterness value measuring device 1A includes a carrier liquid delivery mechanism 2, an isooctane delivery mechanism 3, an aqueous acid solution delivery mechanism 4, a sampling unit 5, a slug flow forming unit 6, an extraction unit 7, a phase separator 8, an absorbance measurement unit 9, and a temperature control unit 10.

[0033] The carrier liquid delivery mechanism 2 includes a carrier liquid container 11 containing a carrier liquid (pure water in this example), a syringe pump 12, and a three-way valve 13. The carrier liquid delivery mechanism 2 is configured such that, by switching the three-way valve 13, it can switch between two operations: aspirating the carrier liquid from the carrier liquid container 11 with the syringe pump 12 through a carrier liquid suction tube 14 connected to the three-way valve 13 so as to be able to suction the carrier liquid in the carrier liquid container 11; and pumping the carrier liquid with the syringe pump 12 through a carrier liquid pressure feed tube 15 connecting the three-way valve 13 to a seventh port of a switching valve 45 (described later). Note that the pump used for delivering the carrier liquid is not limited to the syringe pump 12, and may be, for example, a diaphragm pump, a piezoelectric micro pump, or the like (the same applies to syringe pumps 22, 32, and 82 (described later)).

[0034] <Isooctane Liquid Delivery Mechanism> The isooctane liquid delivery mechanism 3 includes an isooctane container 21 containing isooctane, a syringe pump 22, and a three-way valve 23. The isooctane liquid delivery mechanism 3 is configured to switch between an operation of sucking isooctane from the isooctane container 21 with the syringe pump 22 through an isooctane suction pipe 24 connected to the three-way valve 23 so as to be able to suck the isooctane in the isooctane container 21, and an operation of pressure-feeding isooctane with the syringe pump 22 through an isooctane pressure-feed pipe 25 connecting the three-way valve 23 to an upstream port of a first T-shaped pipe 61 described later, by switching the three-way valve 23.

[0035] <Aqueous Acid Solution Delivery Mechanism> The aqueous acid solution delivery mechanism 4 includes an aqueous acid solution container 31 containing an aqueous acid solution (e.g., hydrochloric acid (6N), hydrochloric acid (3N), phosphoric acid, etc.), a syringe pump 32, and a three-way valve 33. The aqueous acid solution delivery mechanism 4 is configured so that, by switching the three-way valve 33, it is possible to switch between an operation of using the syringe pump 32 to suck the aqueous acid solution from the aqueous acid solution container 31 through an aqueous acid solution suction pipe 34 connected to the three-way valve 33 so as to be able to suck the aqueous acid solution (in this example, hydrochloric acid (3N)) in the aqueous acid solution container 31, and an operation of using the syringe pump 32 to pressure-feed the aqueous acid solution through an aqueous acid solution pressure-feed pipe 35 connecting the three-way valve 33 to a branch port of a second T-shaped pipe 62 (described later).

[0036] <Sampling Unit> The sampling unit 5 samples a sample containing bitter components, and in this example is configured by a so-called autosampler.

[0037] The sampling section 5 includes a sample setting section 41 in which multiple sample containers 40 containing samples can be set, multiple needles 42 arranged so that samples can be collected from each of the multiple sample containers 40, a switching valve 45 having eight ports (first port to eighth port) and capable of switching the connection between adjacent ports, and multiple sample loops 51, 52 (first sample loop 51, second sample loop 52) for holding samples aspirated from the tips of the needles 42.

[0038] The switching valve 45 is configured to be switchable between a state in which the first port and the second port, the third port and the fourth port, the fifth port and the sixth port, and the seventh port and the eighth port are connected, respectively, as shown in FIG. 1( a) (this state will be referred to as the “first switching state”), and a state in which the second port and the third port, the fourth port and the fifth port, the sixth port and the seventh port, and the eighth port and the first port are connected, respectively, as shown in FIG. 1( b) (this state will be referred to as the “second switching state”), in response to a valve switching control signal from a valve control unit 102 (described later).

[0039] A sampling pipe 55 is arranged between the multiple needles 42 and the switching valve 45. The sampling pipe 55 has a main pipe 56 having one end connected to a first port of the switching valve 45, and multiple branch pipes 57 provided at the other end of the main pipe 56 in a form that branches into multiple pipes so as to be connected to each of the multiple needles 42. An on-off valve 58 is provided in each branch pipe 57. In this embodiment, the on-off valve 58 provided in the branch pipe 57 connected to the needle 42 corresponding to one or multiple sample containers 40 containing a sample to be collected (tested) is opened (if all of the multiple sample containers 40 are to be collected, all of the on-off valves 58 are opened), and the other on-off valves 58 are closed, thereby making it possible to collect the sample to be collected. A moving mechanism for moving the needle 42 in the horizontal plane (XY directions) and the vertical direction (Z direction) may be provided, and the needle 42 may be moved by the moving mechanism to bring the target sample into a state where it can be collected from a sample container 40 containing the target sample among the plurality of sample containers 40. Alternatively, a first mechanism for moving the needle 42 in the vertical direction (Z direction) and a second mechanism for moving the sample setting section 41 in the horizontal plane (XY directions) or rotating the sample setting section 41 about the vertical axis may be provided, and the first and second mechanisms may work together to bring the target sample into a state where it can be collected from a sample container 40 containing the target sample among the plurality of sample containers 40.

[0040] The first sample loop 51 is formed by winding a portion of the pipe into a coil to provide the pipe with a length that allows a predetermined amount of sample to be held within the pipe, and one end is connected to the second port of the switching valve 45, while the other end is connected to the sixth port of the switching valve 45. The second sample loop 52, like the first sample loop 51, is formed by winding a portion of the pipe into a coil, and one end is connected to the fourth port of the switching valve 45, while the other end is connected to the eighth port of the switching valve 45.

[0041] <Slug Flow Forming Section> The slug flow forming section 6 forms a liquid-liquid slug flow by joining the sample, isooctane, and aqueous acid solution at a predetermined volume ratio, and includes a joining section 60 and a slug flow pipe 65.

[0042] <Confluence> The confluence 60 includes a first confluence formed by a first T-shaped tube 61 and a second confluence formed by a second T-shaped tube 62. The first T-shaped tube 61 and the second T-shaped tube 62 are arranged in this order from upstream to downstream in the liquid flow direction. The upstream port of the first T-shaped tube 61 is connected to the three-way valve 23 of the isooctane liquid delivery mechanism 3 via an isooctane pressure delivery tube 25 for liquid delivery. The downstream port of the first T-shaped tube 61 is connected to the upstream port of the second T-shaped tube 62 for liquid delivery via a connecting tube 63 for liquid delivery. The branch port of the first T-shaped tube 61 is connected to the third port of the switching valve 45 for liquid delivery via a sample flow tube 64 for liquid delivery. The downstream port of the second T-shaped tube 62 is connected to the phase separator 8 for liquid delivery via a slug flow tube 65 for liquid delivery. The branch port of the second T-shaped pipe 62 and the three-way valve 33 in the acid aqueous solution delivery mechanism 4 are connected via an acid aqueous solution pressure delivery pipe 35 so as to be able to deliver the solution.

[0043] <Extraction Section> The slug flow tube 65 introduces a liquid-liquid slug flow, formed by converging the sample, isooctane, and aqueous acid solution at a predetermined volume ratio at the confluence section 60, into the tube, forming a slug flow path through which the liquid-liquid slug flow flows. The slug flow tube 65 includes an extraction section 7, also referred to as an extraction coil, wound in a coil shape along the length of the tube to allow time for the bitter components contained in the sample to be extracted into the isooctane while the liquid-liquid slug flow is passing through the tube. In this embodiment, the inner diameter of the extraction section 7 (slug flow tube 65) is set to 0.5 mm, and the coil length of the extraction section 7 is set to 5 m. In the slug flow tube 65, the liquid-liquid slug flow alternates between an aqueous phase containing the sample and aqueous acid solution and an oil phase containing isooctane, and is introduced into the extraction section 7. The bitter components contained in the aqueous phase (sample) are transferred to the oil phase (isooctane) and extracted. In the extraction section 7, an internal circulating flow occurs in each of the aqueous phase and the oil phase, so that the contact surface between the aqueous phase and the oil phase is continuously renewed, promoting the transfer of bitter components contained in the aqueous phase to the oil phase.

[0044] The inner wall surface of the slug flow tube 65 is preferably hydrophilic. The inner wall surface may be made of a hydrophilic material (e.g., glass or silica capillary) or may be made hydrophilic by surface treatment. In this case, the aqueous phase has better wettability (smaller contact angle) with respect to the inner wall surface of the slug flow tube 65, while the oil phase has poorer wettability (larger contact angle). Therefore, in the liquid-liquid slug flow, the aqueous phase flows as a continuous phase along the inner wall surface of the slug flow tube 65, while the oil phase flows as a slug of droplets. In other words, a thin film of the aqueous phase spreads along the inner wall surface of the slug flow tube 65, and the slug flows with this thin film of the aqueous phase interposed between the oil phase as slug droplets and the inner wall surface of the slug flow tube 65. This ensures a large interfacial area between the aqueous and oil phases during the liquid-liquid slug flow, further accelerating the migration of bitter components contained in the aqueous phase to the oil phase.

[0045] <Phase Separator> The phase separator 8 includes a permeable membrane 70 made of a porous membrane of a hydrophobic material such as PTFE (polytetrafluoroethylene), and a primary cell 71 and a secondary cell 72 formed on the primary and secondary sides of the permeable membrane 70, respectively. The primary cell 71 is made of a hydrophilic material such as glass and has a liquid-liquid slug flow inlet port 71a formed on the upstream side in the flow direction and an aqueous phase outlet port 71b formed on the downstream side in the flow direction. The secondary cell 72 is made of a hydrophobic material such as PTFE and has an oil phase outlet port 72a. The downstream end of the slug flow pipe 65 is connected to the liquid-liquid slug flow inlet port 71a of the primary cell 71.

[0046] In the phase separator 8 configured as described above, when a liquid-liquid slug flow is introduced from the slug flow pipe 65 through the liquid-liquid slug flow inlet port 71a into the primary cell 71, the aqueous phase in the liquid-liquid slug flow cannot pass through the hydrophobic permeable membrane 70 and flows along the wall of the primary cell 71 to be discharged through the aqueous phase outlet port 71b. On the other hand, the oil phase in the liquid-liquid slug flow passes through the permeable membrane 70, flows along the wall of the secondary cell 72, and is discharged through the oil phase outlet port 72a. In this way, the phase separator 8 is configured to perform phase separation by utilizing the difference in wettability between the aqueous and oil phases of the liquid-liquid slug flow.

[0047] <Absorbance measurement unit> The absorbance measurement unit 9 measures the absorbance of the oil phase separated in the phase separator 8, i.e., the absorbance of isooctane containing bitter components extracted in the extraction unit 7, and is equipped with a flow cell 75, an irradiation unit 76, and a light receiving unit 77.

[0048] The flow cell 75 has an oil phase inlet port 75a. The oil phase inlet port 75a and the oil phase outlet port 72a are connected by a first oil phase suction pipe 73. The flow cell 75 also has an oil phase outlet port 75b that is paired with the oil phase inlet port 75a. The flow cell 75 further has a cell portion 75c that is formed to have a known optical path length (10 mm in this example) midway through the flow path along which isooctane introduced from the secondary cell 72 via the oil phase outlet port 72a, the first oil phase suction pipe 73, and the oil phase inlet port 75a flows to the oil phase outlet port 75b.

[0049] The irradiating unit 76 is configured to irradiate ultraviolet light of a specific wavelength (275 nm in this example) using, for example, a mercury lamp or a deuterium lamp as a light source. The light-receiving unit 77 includes a light-receiving element such as a photodiode or a phototransistor, and is configured to convert the received light into an electrical signal proportional to the intensity of the light. The irradiating unit 76 and the light-receiving unit 77 are arranged so that the ultraviolet light irradiated from the irradiating unit 76 passes through a cell portion 75 c of the flow cell 75 in the optical path length direction, and the light that has passed through the cell portion 75 c is received by the light-receiving unit 77.

[0050] The absorbance measurement unit 9 is provided with a suction mechanism 81 that suctions the oil phase flowing through the flow cell 75. The suction mechanism 81 includes a syringe pump 82 and a three-way valve 83. The suction mechanism 81 is configured to switch between two operations by switching the three-way valve 83: suctioning the oil phase from the flow cell 75 with the syringe pump 82 through a second oil phase suction pipe 84 connected to the three-way valve 83 so as to be able to suction the oil phase that flows through the flow cell 75 and is discharged through the oil phase discharge port 75b; and pressure-feeding the sucked oil phase with the syringe pump 82 through a third drain pipe 93 (described later) that connects the three-way valve 83 to a waste liquid tank 90 (described later) and discharging it into the waste liquid tank 90.

[0051] <Temperature Control Unit> The temperature control unit 10 includes a first temperature control mechanism 10a that controls the temperature of the extraction unit 7 and a second temperature control mechanism 10b that controls the temperature of the absorbance measurement unit 9. Both the first temperature control mechanism 10a and the second temperature control mechanism 10b may be configured to maintain the isooctane containing the bitter components extracted by the extraction unit 7 at a predetermined temperature (20°C) specified by the official method. While not particularly limited, for example, a temperature control unit including a casing that houses the temperature control target (extraction unit 7, absorbance measurement unit 9) and an air conditioner that circulates air while heating or cooling the temperature control target within the casing can be used. The temperature control unit 10 configured in this manner can easily maintain the temperature of the isooctane containing the bitter components at the predetermined temperature (20°C) specified by the official method. Furthermore, the first temperature control mechanism 10a enables the bitter components contained in the sample to be extracted with a partition coefficient similar to that of the official method, regardless of the ambient temperature. In this embodiment, the temperature of both the extraction unit 7 and the absorbance measurement unit 9 is adjusted, i.e., the temperature adjustment unit 10 is constituted by both the first temperature adjustment mechanism 10a and the second temperature adjustment mechanism 10b. However, this is not limited to this, and there may also be an embodiment in which the temperature of only one of the extraction unit 7 and the absorbance measurement unit 9 is adjusted, i.e., the temperature adjustment unit 10 is constituted by only the first temperature adjustment mechanism 10a or the second temperature adjustment mechanism 10b.

[0052] The bitterness value measuring device 1A further includes a waste liquid tank 90 that stores the liquid discharged from the sampling unit 5, the phase separator 8, and the absorbance measuring unit 9. The waste liquid tank 90 and the fifth port of the switching valve 45 are connected by a first drain pipe 91. The waste liquid tank 90 and the aqueous phase outlet port 71b of the phase separator 8 are connected by a second drain pipe 92. The waste liquid tank 90 and the three-way valve 83 in the suction mechanism 81 are connected by a third drain pipe 93. A tube pump 95 is provided in the middle of the first drain pipe 91.

[0053] Fig. 2 is a block diagram showing a schematic configuration of a control system of the bitterness value measuring device 1A of the first embodiment. In Fig. 2, a controller 100 equipped in the bitterness value measuring device 1A is mainly composed of a computer, and includes an overall control unit 101 that controls the bitterness value measuring device 1A. The controller 100 further includes a valve control unit 102 that controls the three-way valves 13, 23, 33, and 83 and the switching valve 45, a pump control unit 103 that controls the syringe pumps 12, 22, 32, and 82 and the tube pump 95, an irradiation control unit 104 that controls the irradiation unit 76, a temperature adjustment control unit 105 that controls the temperature adjustment unit 10 (first temperature adjustment mechanism 10a, second temperature adjustment mechanism 10b) based on detection signals from temperature sensors 96 and 97 (see FIG. 1( a)) that detect the temperature inside a casing containing the temperature adjustment targets (extraction unit 7, absorbance measurement unit 9), a data processing unit 106 that acquires and processes electrical signals from the light receiving unit 77 to measure absorbance, a judgment unit 107 that makes various judgments, and a bitterness value calculation unit 108 that calculates a bitterness value based on the measurement results of the data processing unit 106. In the controller 100, the functions of the various functional units are exerted by executing a predetermined program. Input and output of signals, information, etc. to and from the various functional units is performed via an input / output port 110 .

[0054] An input unit 111 that inputs various control commands and the like to the controller 100, and a display unit 112 that displays absorbance measurement results calculated by the controller 100, are connected to the overall control unit 101 via an input / output port 110. The operator operates the input unit 111 while looking at the display unit 112 to set measurement conditions, issue a measurement start command, and other various instructions. The overall control unit 101 then automatically measures the absorbance of the sample under the measurement conditions set by the operator, and automatically displays the measurement results on the display unit 112.

[0055] FIG. 3 is a flowchart showing the bitterness value measurement procedure executed by the bitterness value measurement device 1A. In FIG. 3, the symbol "S" represents a step. By repeatedly executing a series of processes S1 to S12 shown in FIG. 3 at a predetermined cycle time, multiple pieces of data related to bitterness values ​​can be obtained. In the bitterness value measurement shown in the flowchart of FIG. 3, the temperature adjustment control unit 105 controls the air conditioner unit to maintain the temperature inside the casing at a predetermined temperature (20°C in this example) based on a detection signal from a temperature sensor 96 that detects the temperature inside the casing in the first temperature adjustment mechanism 10a. Similarly, the temperature adjustment control unit 105 controls the air conditioner unit to maintain the temperature inside the casing at a predetermined temperature (20°C in this example) based on a detection signal from a temperature sensor 97 that detects the temperature inside the casing in the second temperature adjustment mechanism 10b. This allows the isooctane containing bitter components extracted in the extraction unit 7 to be maintained at the predetermined temperature (20°C) specified by the official method in both the extraction unit 7 and the absorbance measurement unit 9. In the following, an example will be described in which bitterness value measurement is started when the switching valve 45 is in the first switching state shown in FIG. 1(a).

[0056] <S1> The valve control unit 102 sends a valve open / close signal to the on-off valve 58 to open the on-off valve 58 disposed in the branch pipe 57 connected to the needle 42 corresponding to one or more sample containers 40 containing the sample to be collected and to close the other on-off valves 58. This allows the sample container 40 containing the sample to be collected, ready for collection. Next, the pump control unit 103 sends a pump drive signal to the tube pump 95 to perform a suction operation. This drives the tube pump 95 to aspirate the sample to be collected. The sample to be collected aspirated by the tube pump 95 flows into the waste tank 90 via the needle 42, the sampling pipe 55, the first and second ports of the switching valve 45, the first sample loop 51, the sixth and fifth ports of the switching valve 45, and the first drain pipe 91. By driving the tube pump 95 for a predetermined time (e.g., approximately 180 seconds), the first sample loop 51 is washed with the sample to be collected.

[0057] (Sampling step) <S2> When the co-washing is completed, the pump control unit 103 sends a pump stop signal to the tube pump 95. This stops the tube pump 95, leaving a predetermined amount of sample held in the conduit of the first sample loop 51, and completing sampling by the first sample loop 51.

[0058] <S3> The valve control unit 102 transmits a valve switching signal to switch the switching valve 45 from the first switching state shown in Fig. 1(a) to the second switching state shown in Fig. 1(b). As a result, the switching valve 45 is switched to the second switching state.

[0059] <S4> Next, the valve control unit 102 transmits valve switching signals to the three-way valves 13, 23, 33 to enable the syringe pump 12 to suck the carrier liquid from the carrier liquid container 11 via the carrier liquid suction tube 14, enable the syringe pump 22 to suck the isooctane from the isooctane container 21 via the isooctane suction tube 24, and enable the syringe pump 32 to suck the acid aqueous solution from the acid aqueous solution container 31 via the acid aqueous solution suction tube 34. The pump control unit 103 also transmits pump drive signals to the syringe pumps 12, 22, 32 to perform suction. As a result, syringe pumps 12, 22, and 32 are driven, and carrier liquid is sucked into syringe pump 12 from carrier liquid container 11 via carrier liquid suction tube 14, isooctane is sucked into syringe pump 22 from isooctane container 21 via isooctane suction tube 24, and the acid aqueous solution is sucked into syringe pump 32 from acid aqueous solution container 31 via acid aqueous solution suction tube 34. Valve control unit 102 then transmits valve switching signals to three-way valves 13, 23, and 33 to enable syringe pump 12 to pump the carrier liquid via carrier liquid pressure feed tube 15, enable syringe pump 22 to pump isooctane via isooctane pressure feed tube 25, and enable syringe pump 32 to pump the acid aqueous solution via acid aqueous solution pressure feed tube 35. In this way, carrier liquid delivery mechanism 2, isooctane delivery mechanism 3, and acid aqueous solution delivery mechanism 4 are all ready to deliver liquid, completing preparations for liquid delivery.

[0060] (Slug flow formation process) <S5> Pump control unit 103 sends pump control signals to syringe pumps 12, 22, 32 to control the timing and discharge volume of the discharge operations of syringe pumps 12, 22, 32 so that after the sample and isooctane are merged in first T-shaped tube 61 at junction 60, the acid aqueous solution is merged in second T-shaped tube 62, the sample, isooctane, and acid aqueous solution have a predetermined volume ratio (sample:isooctane:acid aqueous solution=10:20:1), and the sample, isooctane, and acid aqueous solution flow in this order in the liquid flow direction in slug flow tube 65.

[0061] In the carrier liquid delivery mechanism 2, the syringe pump 12 performs a discharge operation to pressure-feed the carrier liquid to the first sample loop 51 via the carrier liquid pressure-feed pipe 15 and the seventh and sixth ports of the switching valve 45, which has been switched to the second switching state shown in FIG. 1B. Accordingly, the sample held in the first sample loop 51 is forced out by the pressure-feed carrier liquid and pressure-feed from the first sample loop 51 to the first T-tube 61 via the second and third ports of the switching valve 45 and the sample flow pipe 64. In the isooctane delivery mechanism 3, the syringe pump 22 performs a discharge operation to pressure-feed isooctane to the first T-tube 61 via the isooctane pressure-feed pipe 25. In the acid solution delivery mechanism 4, the syringe pump 32 performs a discharge operation to pressure-feed the acid solution to the second T-tube 62 via the acid solution pressure-feed pipe 35. In this embodiment, pure water is used as the carrier liquid, which can serve both to deliver the sample and to clean the first sample loop 51, eliminating the need for a separate cleaning mechanism and simplifying the device configuration.

[0062] In this way, the sample, isooctane, and aqueous acid solution are combined at a predetermined volume ratio, and the sample, isooctane, and aqueous acid solution flow in this order in the direction of liquid flow. If the sample, isooctane, and aqueous acid solution are treated as a set of liquid flows, multiple sets of these liquid flows will flow in series, and a liquid-liquid slug flow is formed in slug flow tube 65 in slug flow forming section 6, in which an aqueous phase containing the sample and aqueous acid solution and an oil phase containing isooctane flow alternately.

[0063] (Extraction Unit Cleaning Step) <S6> While syringe pumps 12, 22, and 32 are driven, a liquid-liquid slug flow flows through slug flow pipe 65, in which extraction unit 7 is formed. By driving syringe pumps 12, 22, and 32 for a predetermined time (e.g., about 120 seconds), extraction unit 7 is washed with the liquid-liquid slug flow.

[0064] (Extraction Step) <S7> The extraction unit 7 introduces the liquid-liquid slug flow formed in the slug flow forming unit 6. The liquid-liquid slug flow introduced into the extraction unit 7 flows through the slug flow pipe 65, with an aqueous phase containing the sample and an acid aqueous solution and an oil phase containing isooctane flowing alternately. The bitter components contained in the aqueous phase (sample) are transferred to the oil phase (isooctane) and extracted. In the extraction unit 7, internal circulation flows are generated in both the aqueous and oil phases, continuously renewing the contact surface between the aqueous and oil phases and accelerating the transfer of the bitter components contained in the aqueous phase to the oil phase. Furthermore, the extraction unit 7 is maintained at a predetermined temperature (20°C) by the first temperature control mechanism 10a, allowing the bitter components contained in the sample to be extracted with a partition coefficient similar to that of the official method, regardless of the ambient temperature.

[0065] (Phase Separation Step) <S8> Phase separator 8 introduces the liquid-liquid slug flow from slug flow pipe 65 through liquid-liquid slug flow inlet port 71a into primary cell 71. The aqueous phase in the liquid-liquid slug flow is then discharged to waste tank 90 via aqueous phase outlet port 71b and second drain pipe 92. Meanwhile, the oil phase in the liquid-liquid slug flow passes through permeable membrane 70, flows along the wall of secondary cell 72, and is discharged through oil phase outlet port 72a.

[0066] (Flow Cell Cleaning Step) <S9> Pump control unit 103 sends a pump drive signal to syringe pump 82 to perform a suction operation. This drives syringe pump 82, and the oil phase discharged through oil phase discharge port 72a and introduced into flow cell 75 via first oil phase suction tube 73 is sucked through second oil phase suction tube 84. Driving syringe pump 82 for a predetermined time (e.g., approximately 300 seconds) washes flow cell 75 with the oil phase. In suction mechanism 81, by switching three-way valve 83 and discharging the oil phase by syringe pump 82, the oil phase sucked into syringe pump 82 is pumped through third drain tube 93 and discharged into waste tank 90.

[0067] (Absorbance stability determination process) <S10> Once the co-washing of the flow cell 75 is completed, the determination unit 107 determines whether the oil phase is flowing stably through the flow cell 75 without generating bubbles, etc., based on, for example, an image from a camera (not shown) arranged to be able to capture the flow cell 75.

[0068] (Absorbance measurement process) <S11> When the oil phase flow in the flow cell 75 is stable ("YES" in S10), the data processing unit 106 acquires and processes an electrical signal from the light receiving unit 77 that receives ultraviolet light that has been irradiated from the irradiation unit 76 at a predetermined irradiation amount under the control of the irradiation control unit 104, passed through the cell portion 75c of the flow cell 75, and passed through the cell portion 75c, and measures the absorbance of a specific wavelength (275 nm).

[0069] 4 is a graph showing an example of the change in absorbance over time during measurement. In the example shown in FIG. 4, the measurement result obtained by data processing by the data processing unit 106 is an absorbance of 0.245.

[0070] (Bitterness Value Calculation Step) <S12> The bitterness value calculation unit calculates the bitterness value based on the following formula (1): Bitterness value = 50 × A ２７５ ... (1) A ２７５ : Absorbance measured by absorbance measuring unit 9 In the example shown in FIG. 4, the calculated result is that the bitterness value is 12.3.

[0071] In the bitterness value measurement device 1A of this embodiment, a sample containing bitter components, isooctane, and an acid aqueous solution are joined in the slug flow forming unit 6 at a predetermined volume ratio specified by the official method to form a liquid-liquid slug flow. When the sample and the acid aqueous solution join, the bitter components (iso-α acids) in the sample are liberated and dissolved into the oil phase (isooctane). This liquid-liquid slug flow is then introduced into the extraction unit 7, with the aqueous phase containing the sample and the acid aqueous solution and the oil phase containing isooctane flowing alternately. The bitter components contained in the aqueous phase (sample) are transferred to the oil phase (isooctane) and extracted. In the extraction unit 7, internal circulation flows are generated in both the aqueous and oil phases, continuously renewing the contact surface between the aqueous and oil phases and accelerating the transfer of the bitter components contained in the aqueous phase to the oil phase. The absorbance of the isooctane containing the extracted bitter components is then measured in the absorbance measurement unit 9. In this way, the absorbance of isooctane containing the extracted bitter components can be measured efficiently and with high precision without the need to collect a precise sample amount, and the bitterness value can be accurately calculated directly from the absorbance specified by the official method.

[0072] In the bitterness value measuring device 1A of this embodiment, the slug flow forming section 6 is configured so that the sample and isooctane are joined in a first T-shaped pipe 61, and then an aqueous acid solution is joined in a second T-shaped pipe 62. This configuration prevents bitter components (iso-α acids) in the sample from being liberated and adsorbed onto the inner wall of the pipe (slug flow pipe 65) through which the sample flows before being extracted into the isooctane, thereby enabling the bitter components to be sufficiently extracted into the isooctane.

[0073] In the bitterness value measurement device 1A of this embodiment, sampling is performed by the second sample loop 52 in parallel with absorbance measurement by the absorbance measurement unit 9. That is, when the switching valve 45 is in the second switching state shown in FIG. 1( b), the valve control unit 102 sends a valve opening / closing signal to the switching valve 58 to open the on-off valve 58 disposed in the branch pipe 57 connected to the needle 42 corresponding to one or more sample containers 40 containing the sample to be collected and to close the other on-off valves 58. This enables the sample containers 40 containing the sample to be collected to be ready for collection. Next, the pump control unit 103 sends a pump drive signal to the tube pump 95 to perform a suction operation. This drives the tube pump 95 to aspirate the sample to be collected. The sample to be collected aspirated by the tube pump 95 flows to the waste tank 90 via the needle 42, the sampling pipe 55, the first and eighth ports of the switching valve 45, the second sample loop 52, the fourth and fifth ports of the switching valve 45, and the first drain pipe 91. The tube pump 95 is driven for a predetermined time (e.g., about 180 seconds) to wash the second sample loop 52 with the sample to be collected. When the washing is complete, the pump control unit 103 sends a pump stop signal to the tube pump 95. This stops the tube pump 95, leaving a predetermined amount of sample held in the conduit of the second sample loop 52, completing sampling by the second sample loop 52. The absorbance measurement using the sample held in the second sample loop 52 is performed in the same manner as the absorbance measurement using the sample held in the first sample loop 51 described above.

[0074] In this way, the bitterness value measuring device 1A is configured to perform, in parallel, absorbance measurement by the absorbance measuring unit 9 using a sample held in either the first sample loop 51 or the second sample loop 52, and sampling of the sample in the other of the first sample loop 51 and the second sample loop 52. With this configuration, the bitterness value of the sample can be measured efficiently.

[0075] [Second embodiment] Figure 5 is a block diagram showing a schematic configuration of a bitterness value measuring device 1B according to a second embodiment of the present invention. Figure 5(a) shows a case where the switching valve 45 is in a first switching state, and Figure 5(b) shows a case where the switching valve 45 is in a second switching state. In the bitterness value measuring device 1B of the second embodiment, components that are the same as or similar to those in the bitterness value measuring device 1A of the first embodiment are simply given the same reference numerals in the drawings, and detailed description thereof will be omitted. The following description will focus on the components unique to the bitterness value measuring device 1B of the second embodiment.

[0076] In the bitterness value measurement device 1A of the first embodiment shown in Fig. 1, the junction 60 is composed of a first junction made up of a first T-pipe 61 and a second junction made up of a second T-pipe 62. In contrast, in the bitterness value measurement device 1B of the second embodiment shown in Fig. 5, the junction 60 is composed of a joint block 200. Other than that, the bitterness value measurement device 1A of the first embodiment and the bitterness value measurement device 1B of the second embodiment have basically the same configuration.

[0077] 6 is a structural explanatory diagram of the slug flow forming unit 6 in the bitterness value measuring device 1B of the second embodiment. As shown in FIG. 6, a joint block 200 including a confluence 60 has a sample introduction port 201, an isooctane introduction port 202, an acid aqueous solution introduction port 203, and a liquid delivery port 204. In the joint block 200, a sample introduction flow path 205 is formed from the sample introduction port 201 toward the center of the joint block 200, an isooctane introduction flow path 206 is formed from the isooctane introduction port 202 toward the center of the joint block 200, an acid aqueous solution introduction flow path 207 is formed from the acid aqueous solution introduction port 203 toward the center of the joint block 200, and a liquid delivery flow path 208 is formed from the center of the joint block 200 toward the liquid delivery port 204.

[0078] In the joint block 200, the downstream end of the sample flow pipe 64 is connected to the sample introduction port 201. The downstream end of the isooctane pressure pipe 25 is connected to the isooctane introduction port 202. The downstream end of the acid aqueous solution pressure pipe 35 is connected to the acid aqueous solution introduction port 203. The upstream end of the slug flow pipe 65 is connected to the liquid delivery port 204.

[0079] In the bitterness value measurement device 1B of the second embodiment, a sample is introduced into the center of the joint block 200 via the sample flow pipe 64, the sample introduction port 201, and the sample introduction flow path 205. Isooctane is introduced into the center of the joint block 200 via the isooctane pressure pipe 25, the isooctane introduction port 202, and the isooctane introduction flow path 206. An acid solution is introduced into the center of the joint block 200 via the acid solution pressure pipe 35, the acid solution introduction port 203, and the acid solution introduction flow path 207. The sample, isooctane, and the acid solution are then joined at the center of the joint block 200, and the joined liquid is sent to the slug flow pipe 65 via the liquid sending flow path 208 and the liquid sending port 204. The center of the joint block 200 is the joining section 60 where the sample and isooctane join, and where the acid solution also joins. In this embodiment, the slug flow forming section 6 includes a confluence section 60, a liquid sending flow path 208 for sending the liquid joined at the confluence section 60, and a slug flow pipe 65 through which the liquid-liquid slug flow flows.

[0080] In the bitterness value measurement device 1B of the second embodiment, the timing and discharge amount of the syringe pumps 12, 22, and 32 are controlled by the pump control unit so that the sample, isooctane, and aqueous acid solution are mixed in a predetermined volume ratio (sample:isooctane:acid solution=10:20:1) and so that the sample, isooctane, and aqueous acid solution flow in this order in the liquid flow direction in the slug flow tube 65. As a result, the sample, isooctane, and aqueous acid solution are joined in a predetermined volume ratio, and the sample, isooctane, and aqueous acid solution flow in this order in the liquid flow direction. If the sample, isooctane, and aqueous acid solution are considered to be one set of liquid flows, multiple sets of these liquid flows will flow together, and a liquid-liquid slug flow is formed in the slug flow forming unit 6 in the slug flow tube 65, in which an aqueous phase containing the sample and aqueous acid solution and an oil phase containing isooctane flow alternately.

[0081] In the bitterness value measuring device 1B of the second embodiment, the results of the extraction rate in the extraction section 7 when the ratio (A / B) of the flow path diameter (A) of the liquid supply flow path 208 in the joint block 200 shown in Figure 6 to the flow path diameter (B) of the slug flow path in the slug flow tube 65 is changed are shown in Table 1.

[0082]

[0083] As shown in Table 1, when the ratio (A / B) is 0.5 or more and 4.0 or less, a liquid-liquid slug flow suitable for extracting bitter components can be reliably formed, and the extraction rate can be maintained at a high level. If the ratio (A / B) is less than 0.5, the droplet slug becomes finer and the particulate oil phase increases, preventing the generation of a circulating flow and resulting in a significant decrease in the extraction rate. If the ratio (A / B) exceeds 4.0, the oil phase becomes too long in the liquid flow direction, reducing the interfacial area and resulting in a significant decrease in the extraction rate. Furthermore, it becomes structurally difficult to connect the liquid supply channel 208 of the joint block 200 to the slug channel of the slug flow pipe 65.

[0084] In the bitterness value measurement device 1B of the second embodiment, the confluence 60 is configured so that the acid aqueous solution also confluences at the center of the joint block 200 where the sample and isooctane confluence. With this configuration, it is not necessary to provide multiple confluences for the sample, isooctane, and acid aqueous solution in the confluence 60, as in the bitterness value measurement device 1A of the first embodiment, and the device configuration can be simplified compared to the bitterness value measurement device 1A of the first embodiment.

[0085] Although the bitterness value measuring device and bitterness value measuring method of the present invention have been described above based on several embodiments, the present invention is not limited to the configurations described in the above embodiments, and the configurations can be appropriately changed within the scope of the gist of the present invention. Specific other embodiments are as follows.

[0086] (Another embodiment 1) In the above embodiment, an example was shown in which ultraviolet light was irradiated from the irradiation unit 76 onto the cell portion 75c of the flow cell 75, and absorbance was measured while the oil phase was being delivered to the cell portion 75c of the flow cell 75, but the present invention is not limited to this. Fig. 7 is a flowchart showing the procedure of another example of bitterness value measurement performed in the bitterness value measuring devices 1A and 1B. Note that the process contents of S1 to S9 in the flowchart shown in Fig. 7 are the same as the process contents of S1 to S9 in the flowchart shown in Fig. 3, so a description thereof will be omitted here. Below, the process contents of S10 to S14 in the flowchart shown in Fig. 7 will be described.

[0087] In the steps (S1 to S11) prior to S13 in the flowchart of Figure 7, in which the absorbance measurement unit 9 measures the absorbance of the oil phase, the irradiation unit 76 reduces the amount of ultraviolet light irradiated by the irradiation unit 76 or stops irradiating.

[0088] <S10> The pump control unit 103 transmits a pump drive stop signal to stop the suction operation by the syringe pump 82. This stops the drive of the syringe pump 82, and stops the delivery of the oil phase to the cell portion 75c of the flow cell 75.

[0089] (Oil phase temperature stability determination process) <S11> The determination unit 107 determines whether the temperature of the oil phase in the flow cell 75 is maintained stable at a predetermined temperature (20°C) based on, for example, a detection signal from a temperature sensor (not shown) attached to the flow cell 75.

[0090] (UV irradiation step) <S12> When the temperature of the oil phase in the flow cell is stably maintained at a predetermined temperature (20°C) ("YES" in S11), the irradiation control unit 104 controls the irradiation unit 76 so that ultraviolet light is irradiated from the irradiation unit 76 at a predetermined irradiation amount.

[0091] (Absorbance measurement process) <S13> The data processing unit 106 acquires and processes an electrical signal from the light receiving unit 77 that receives the ultraviolet light that has been irradiated from the irradiation unit 76 at a predetermined irradiation amount under the control of the irradiation control unit 104 and passed through the cell unit 75c of the flow cell 75, and measures the absorbance of a specific wavelength (275 nm).

[0092] (Bitterness Value Calculation Step) <S14> The bitterness value calculation unit calculates the bitterness value based on the above formula (1).

[0093] Thus, when measuring the absorbance of the oil phase (iso-octane containing bitter components) using the absorbance measurement unit 9, the delivery of the oil phase to the flow cell 75 of the absorbance measurement unit 9 is stopped, and the absorbance measurement unit 9 is maintained at a predetermined temperature (20 ° C.) using the second temperature control mechanism 10b, while irradiating the oil phase with ultraviolet light from the irradiation unit 76. When absorbance measurement is not being performed, the amount of ultraviolet light irradiated by the irradiation unit 76 is reduced or irradiation is stopped. In this way, by measuring absorbance while maintaining a predetermined temperature (20 ° C.), reproducibility can be improved, and by dimming or turning off the light when not measuring, the impact on the bitterness value measurement value caused by the decomposition of iso-α acids due to irradiation with ultraviolet light can be suppressed.

[0094] Alternative Embodiment 2 In the above embodiment, the phase separator 8 separates the liquid-liquid slug flow into an aqueous phase and an oil phase, introduces the oil phase into the flow cell 75, and measures the absorbance by irradiating the introduced oil phase with ultraviolet light from the irradiation unit 76 in the cell 75c. However, the present invention is not limited to this. For example, the irradiation timing of the irradiation unit 76 may be controlled by the irradiation control unit 104, and the ultraviolet light may be irradiated from the irradiation unit 76 only onto the oil phase, of the aqueous phase and the oil phase flowing alternately within the slug flow tube 65, thereby measuring the absorbance. In this case, the phase separator 8 can be omitted, thereby simplifying the device configuration.

[0095] (Alternative Embodiment 3) When the sample contains carbon dioxide, it is preferable to remove the carbon dioxide from the sample in advance by stirring the sample using, for example, a stirrer.

[0096] (Alternative Embodiment 4) When a sample contains solid matter, it is preferable to remove the solid matter from the sample in advance using, for example, a solid-liquid separator (for example, a filter made of nonwoven fabric).

[0097] The bitterness value measuring device and bitterness value measuring method of the present invention can be suitably used in applications where the bitterness value of a sample containing a bitter component, such as beer, beer-flavored beverages, or semi-finished products thereof, is measured.

[0098] 1A, 1B Bitterness value measuring device 5 Sampling section 6 Slug flow forming section 7 Extraction section 9 Absorbance measuring section 10 Temperature control section 51 First sample loop 52 Second sample loop 60 Junction section 65 Slug flow tube (slug flow path) 76 Irradiation section

Claims

1. A bitterness value measuring device comprising: a sampling unit that samples a sample containing bitter components; a slug flow forming unit that combines the sample, isooctane, and an acid aqueous solution at a predetermined volume ratio to form a liquid-liquid slug flow; an extraction unit that receives the liquid-liquid slug flow from the slug flow forming unit and extracts the bitter components contained in the sample into the isooctane; and an absorbance measuring unit that measures the absorbance of the isooctane containing the bitter components.

2. The bitterness value measuring device according to claim 1, further comprising a temperature control unit for controlling the temperature of the isooctane containing the bitter component.

3. A bitterness value measuring device according to claim 1 or 2, wherein the slug flow forming section is configured so that the sample and the isooctane are joined together and then the aqueous acid solution is joined together.

4. The bitterness value measuring device of claim 1 or 2, wherein the slug flow forming section includes a confluence section where at least the sample and the isooctane confluence, a liquid delivery flow path for delivering the combined liquid, and a slug flow path in which the liquid-liquid slug flow is formed, and the ratio (A / B) of the flow path diameter (A) of the liquid delivery flow path to the flow path diameter (B) of the slug flow path is 0.5 or more and 4.0 or less.

5. The bitterness value measuring device according to claim 4, wherein the acid aqueous solution is further joined at the joining point of the sample and the isooctane.

6. The bitterness value measuring device according to claim 1 or 2, wherein the sampling unit has a sample loop in which the sample is filled and a pump that delivers a carrier liquid to the sample loop, and is configured to use the carrier liquid delivered by the pump to push out the sample filled in the sample loop and deliver the sample.

7. The bitterness value measuring device according to claim 6, wherein the measurement of absorbance by said absorbance measuring unit and the sampling by said sampling unit are carried out in parallel.

8. The bitterness value measuring device according to claim 2, wherein the absorbance measuring unit has an irradiation unit that irradiates ultraviolet light, and when measuring the absorbance of isooctane containing the bitter component by the absorbance measuring unit, the supply of isooctane containing the bitter component to the absorbance measuring unit is stopped, and the absorbance measuring unit is maintained at a predetermined temperature by the temperature control unit, while the irradiation unit irradiates ultraviolet light onto the isooctane containing the bitter component, and when the measurement is not being performed, the amount of ultraviolet light irradiated by the irradiation unit is reduced or the irradiation of ultraviolet light is stopped.

9. A bitterness value measuring device according to claim 1 or 2, wherein the sample containing the bitter component is beer, a beer-flavored beverage, or a semi-finished product thereof.

10. A bitterness value measurement method comprising: a sampling step of sampling a sample containing bitter components; a slug flow formation step of forming a liquid-liquid slug flow by combining the sample, isooctane, and an acid aqueous solution at a predetermined volume ratio; an extraction step of extracting the bitter components contained in the sample into the isooctane while flowing the liquid-liquid slug flow formed in the slug flow formation step; and an absorbance measurement step of measuring the absorbance of the isooctane containing the bitter components.

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