Coffee beverage manufacturing method

Abstract

To suppress deposits in an industrially applicable manner. [Solution] The method for producing a coffee beverage according to the present invention is characterized by including a step of sterilizing a raw material liquid containing coffee bean extract and having a pH of 5.5 or less.

Description

Technical Field

[0001] The present invention relates to a method for producing a coffee beverage.

Background Art

[0002] Coffee is a popular beverage consumed worldwide, and the global production volume of coffee beans reaches approximately 1,000 tons. As one aspect of coffee that can be easily consumed, coffee beverages enclosed in containers such as resin, metal, and paper are commercially produced and sold.

[0003] In the commercial provision of coffee beverages, the maintenance and management of production equipment pose a problem. In particular, it is known that hardly soluble deposits are likely to occur in parts where coffee beverages come into contact with liquid. Since such deposits can cause pipe blockages and malfunctions of instruments, it is desirable to prevent them. For example, Japanese Patent Application Laid-Open No. 2022-7464 (Patent Document 1) discloses an invention that prevents the generation of deposits inside a coffee extractor by using permeated water of a nanofilter for coffee extraction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The invention described in Patent Document 1 is assumed to be applicable to a coffee extractor installed at the storefront of a retail store, etc., and it was difficult to apply it when a beverage manufacturer industrially produces coffee beverages. This is because, in the industrial-scale production of coffee beverages, the pressure loss of water due to the use of a nanofilter often cannot be ignored from the viewpoints of production technology and energy consumption.

[0006] Therefore, there is a need to realize a method for producing coffee beverages that can suppress deposits in an industrially applicable way. [Means for solving the problem]

[0007] The method for producing a coffee beverage according to the present invention is characterized by including a step of sterilizing a raw material liquid containing coffee bean extract and having a pH of 5.5 or less.

[0008] The inventors of this invention have discovered that phytic acid salts, which are deposits derived from phytic acid contained in coffee beverages, do not form under conditions of pH 5.5 or lower, and have completed this invention. With the above configuration, deposits can be suppressed in an industrially applicable manner during the production of coffee beverages.

[0009] Preferred embodiments of the present invention will be described below. However, the scope of the present invention is not limited by the examples of preferred embodiments described below.

[0010] In one embodiment, the method for producing a coffee beverage according to the present invention preferably further includes a step of adjusting the pH of the raw material liquid to 5.5 or less.

[0011] The pH of coffee bean extract can vary depending on various factors such as the variety and roasting level of the coffee beans, as well as the extraction conditions. With the above configuration, the pH of the raw material solution can be set to 5.5 regardless of the pH of the coffee bean extract itself, thereby suppressing deposits.

[0012] In one embodiment, the method for producing a coffee beverage according to the present invention preferably further includes the step of adding a basic pH adjuster to the sterilized raw material liquid.

[0013] The above configuration makes it easy to achieve both a pH that is desirable during sterilization and a pH that is desirable when consumed as a beverage.

[0014] In one embodiment, the method for producing a coffee beverage according to the present invention preferably further includes the step of filling a container with the sterilized raw material liquid.

[0015] According to this configuration, the present invention can be applied to the production of coffee beverages packed in resin containers with relatively high demand.

[0016] In one aspect, it is preferable that the raw material liquid does not contain dairy products in the method for producing a coffee beverage according to the present invention.

[0017] Since the generation of deposits is particularly likely to be a problem during the production of coffee beverages that do not contain dairy products, it is more preferable to apply the present invention when the raw material liquid does not contain dairy products.

[0018] Further features and advantages of the present invention will become more apparent from the following description of exemplary and non-limiting embodiments described with reference to the drawings.

Brief Description of the Drawings

[0019] [Figure 1] It is a diagram showing the configuration of manufacturing equipment used in the manufacturing method according to the embodiment. [Figure 2] It is a diagram showing the pH dependence of the generation behavior of deposits derived from phytate. [Figure 3] It is a diagram showing the configuration of a test apparatus according to an example. [Figure 4] It is a diagram showing the configuration of a test apparatus according to an example.

Modes for Carrying Out the Invention

[0020] An embodiment of the method for producing a coffee beverage according to the present invention will be described with reference to the drawings.

[0021] 〔Configuration of Manufacturing Equipment〕 First, the configuration of the manufacturing equipment 1 used in the manufacturing method according to this embodiment will be described. The manufacturing equipment 1 includes an extraction device 2, a dilution device 3, a blending liquid storage tank 4, a blending device 5, a sterilization device 6, and a filling device 7 (Fig. 1). Each device constituting the manufacturing equipment 1 is arranged in accordance with the process sequence of the manufacturing method of the coffee beverage. In the manufacturing equipment 1, a coffee beverage filled in a PET bottle (an example of a resin container) is manufactured.

[0022] The extraction device 2 is a device that extracts coffee from coffee beans to obtain an extract containing a coffee bean extract. The coffee extraction method in the extraction device 2 is not particularly limited and may be a known method such as an immersion method or a permeation method. The extraction device 2 may be a known device according to the extraction method, and for example, a drip extraction device or the like may be used. In addition, the semi-finished liquid obtained at each stage of the manufacturing equipment 1, including those mentioned hereinafter, is collectively referred to as a raw material liquid.

[0023] The dilution device 3 is a device that adds a diluent to the extract obtained by the extraction device 2 to obtain a diluted liquid. As the dilution device 3, for example, devices such as an in-line mixer or a dilution tank can be used, but it is not limited thereto. In the dilution device 3, in addition to the diluent, coffee extract or the like may be added.

[0024] The blending liquid storage tank 4 is a tank that stores the blending liquid to be mixed in the blending device 5. The blending liquid storage tank 4 may be a tank made of a material such as stainless steel or resin, but is not limited to these materials. The blending liquid may contain substances such as a pH adjuster such as sodium hydrogen carbonate, and auxiliary raw materials such as sugar, liquid sugar, dairy products, flavors, and extracts.

[0025] The blending device 5 is a device that mixes the diluted liquid obtained in the dilution device 3 and the blending liquid stored in the blending liquid storage tank 4 to obtain a conditioning liquid. As the blending device 5, for example, devices such as an in-line mixer or a dilution tank can be used, but it is not limited thereto.

[0026] The sterilization device 6 is a device that sterilizes the prepared liquid obtained in the mixing device 5 to obtain the product liquid. The product liquid is a liquid that has been sterilized after auxiliary ingredients have been added to the coffee bean extract, and can be used for distribution, sale, storage, and consumption as a coffee beverage. The sterilization method in the sterilization device 6 may be a known method that utilizes heating, for example. The sterilization device 6 may be a known device depending on the sterilization method, and devices such as plate heat exchangers and shell-and-tube heat exchangers may be used.

[0027] The filling device 7 is a device that fills PET bottles with the product liquid obtained in the sterilization device 6 to obtain coffee beverages. Any known filling device can be used as the filling device 7.

[0028] [Method of manufacturing coffee beverages] Next, the method for manufacturing a coffee beverage according to this embodiment will be described. The method for manufacturing a coffee beverage will be described below by explaining the processes performed in each of the devices constituting the manufacturing equipment 1.

[0029] Extraction apparatus 2 extracts coffee from coffee beans. For example, it extracts coffee by immersing the coffee beans in water at approximately 80-95°C, or by allowing the water to permeate the coffee beans, thereby obtaining an extract containing coffee bean extract. The coffee bean extract contains substances such as sugars, lipids, proteins, polyphenols, caffeine, and organic acids. In the following explanation, we will use the example of a case where the concentration of coffee bean extract in the extract obtained in extraction apparatus 2 is higher than the concentration suitable for drinking, but the concentration of coffee bean extract in the extract is arbitrary. The pH of the extract may vary depending on various conditions such as the variety of coffee beans, the degree of roasting, and the extraction conditions, but it is often between 4 and 6, and particularly often between 4 and 5.

[0030] In the dilution apparatus 3, the extract is diluted to obtain a diluted solution. The diluent used to dilute the extract is, for example, water. In addition to or instead of the diluent, coffee extract or the like may be added to the extract. The diluted solution obtained here has a concentration of coffee bean extract suitable for drinking.

[0031] In the mixing apparatus 5, a preparation solution is added to the diluent to obtain a refined solution. The addition of the preparation solution is for making various adjustments to the diluent, taking into consideration the subsequent processes and the quality of the coffee beverage. The preparation solution contains a pH adjuster, and by adding it to the diluent, the pH of the refined solution is adjusted to 5.5 or less. If the pH of the diluent is 5.5 or less, the pH adjuster may or may not be added to the diluent. When adding a pH adjuster to the diluent, it is preferable to use a basic pH adjuster. Sodium bicarbonate, mentioned above, is an example of a basic pH adjuster. If the pH of the diluent exceeds 5.5, it is preferable to add a refined solution containing an acidic pH adjuster to the diluent. Examples of acidic pH adjusters include aqueous citric acid solution and aqueous malic acid solution. In addition, liquid properties such as Brix, acidity, hardness, liquid color, viscosity, and milk solids are also adjusted in the mixing apparatus 5, and the preparation solution contains components corresponding to the liquid properties adjusted here.

[0032] In the sterilization device 6, the prepared liquid is sterilized to obtain the product liquid. The prepared liquid used for sterilization here is the one whose pH has been adjusted to 5.5 or less in the mixing device 5. Therefore, in the sterilization process, the prepared liquid (raw material liquid) with a pH of 5.5 or less is sterilized. For example, if the sterilization device 6 sterilizes by heating the prepared liquid, the heating temperature may be, for example, around 120 to 140°C.

[0033] In the filling device 7, the product liquid is filled into PET bottles to obtain coffee beverages. The coffee beverages obtained here are bottled products that undergo processes such as product inspection, labeling, and boxing before being put into distribution. The pH of the product liquid (sterilized raw material liquid) before filling may be adjusted. For example, a sterilized pH adjusting agent is added to the product liquid sterilized in the sterilization device 6 to adjust it to the desired pH. In this case, the pH of the product liquid may exceed 5.5, but it is preferable to perform the filling at room temperature in order to prevent the formation of deposits in the filling device 7.

[0034] As mentioned above, coffee bean extract contains organic acids. Among these organic acids, phytic acid forms insoluble salts in the presence of metal ions such as calcium and magnesium ions. These salts form sparingly soluble deposits at various points in the manufacturing equipment 1. For example, if these deposits form on a filter, they can cause the filter to clog. Also, if these deposits form on instruments such as flow meters, they can cause inaccurate measurements.

[0035] The inventors of this invention discovered that the formation behavior of deposits derived from phytate depends on pH, and thus completed the present invention. As shown in Figure 2, no phytate formation was observed under conditions of pH 5.5 or lower. On the other hand, the amount of phytate formation reached a maximum value around pH 5.7 and remained generally constant above pH 5.8. Details of this experiment are described in the Examples section.

[0036] It has been conventionally known that deposits derived from phytates tend to be a problem in processes where the raw material liquid is at a relatively high temperature. In particular, a tendency for a large amount of deposits to be generated has been observed in the sterilization device 6. On the other hand, deposits were less likely to be generated in the mixing device 5 and other devices where the raw material liquid is handled at around room temperature.

[0037] Based on the above findings, it is expected that if the pH is 5.5 or lower, the formation of deposits derived from phytates will be suppressed even in processes that involve relatively high temperatures. In this invention, we succeeded in preventing the formation of deposits in the sterilization device 6 by lowering the pH of the raw material liquid supplied to the sterilization device 6, where deposit formation is commonly observed in conventional methods, to 5.5 or lower.

[0038] Although the raw material liquid is handled at a relatively high temperature in extraction device 2, the formation of deposits was rarely a major problem in extraction device 2. This is thought to be because, in conventional methods of manufacturing coffee beverages, the raw material liquid has a relatively low pH (often around 4-5) and is handled in extraction device 2 and dilution device 3.

[0039] In conventional methods for manufacturing coffee beverages, the pH of the prepared solution is often adjusted to a value greater than 6 in the mixing device 5. This is a measure to suppress the acidity of the coffee beverage. As a result of this pH adjustment, the prepared solution, which is in a pH range where phytates are easily formed, is heated in the sterilization device 6, and it is thought that this made it easier for deposits to form.

[0040] [Examples] The present invention will be further described below with reference to examples. However, the following examples are not limiting to the present invention.

[0041] (Preparation of sample solution) A sample solution was obtained by adding water and a 5% sodium carbonate aqueous solution to a coffee concentrate extracted using a known method. The water content of the sample solution was set to 99.2% by mass. Eight sample solutions were prepared with different amounts of 5% sodium carbonate aqueous solution added, and the pH of each sample solution was set to 4.9, 5.4, 5.5, 5.6, 5.7, 5.8, 6.2, and 6.6.

[0042] (Test equipment) The test apparatus 10 used in this embodiment comprises a sample liquid storage tank 11 for storing the sample liquid, a constant temperature bath 12 for maintaining the sample liquid storage tank 11 at a constant temperature, a pump 13 for drawing up the sample liquid from the sample liquid storage tank 11, a flow device 14 through which the sample liquid drawn up by the pump 13 flows, and a heating furnace 15 for housing the flow device 14 (Figure 3). The flow device 14 has a flow path 16 through which the sample liquid flows, and a stainless steel plate 17 arranged facing the flow path 16. When the sample liquid is stored in the sample liquid storage tank 11 and the pump 13 is operated, the sample liquid flows through the flow device 14 and comes into contact with the stainless steel plate 17. Since the flow device 14 is heated by the heating furnace 15, the sample liquid and the stainless steel plate 17 come into contact under heating conditions. This configuration simulates the environment in which raw material liquid comes into contact with stainless steel components in the manufacturing process of coffee beverages.

[0043] Infrared spectroscopy was used to qualitatively analyze the deposits adhering to the stainless steel plate 17. The equipment and measurement conditions used in this analysis were as follows. Device: Nicolet(registered trademark) 6700FT-IR (Manufactured by Thermo Fisher) Light source IR Detector MCT / A Beam Splitter KBr Measurement Accessory: Specular Reflectance No window treatment Number of scans: 64

[0044] To quantitatively analyze the deposits adhering to the stainless steel plate 17, hydrophilic interaction chromatography (HILIC) was performed. The analytical apparatus 20 used for this analysis comprises a mobile phase supply device 21, a sample injection device 22, an analytical column device 23, a reaction solution supply device 24, a reaction coil 25, and a UV detection device 26 (Figure 4). The mobile phase supply device 21 is a device for quantitatively supplying the mobile phase. In this embodiment, the mobile phase was a 1% trifluoroacetic acid and 20 mmol / L sodium trifluoroacetate solution (solvent: water / acetonitrile = 40 / 60), and the mobile phase supply rate was set to 0.80 mL per minute. The sample injection device 22 is a device for injecting the sample into the system of the analytical apparatus 20. In this embodiment, the injection volume was 0.5 μL. The analytical column apparatus 23 is a device that flows the mobile phase and sample through an analytical column maintained at a predetermined temperature. In this embodiment, the analytical column was TSKgel® Amide-80 3μm (manufactured by Tosoh Corporation), and the temperature was set to 30°C. The reaction solution supply device 24 is a device that adds the reaction solution to the effluent from the analytical column apparatus 23 so that it can be detected by the UV detection device 26. In this embodiment, the reaction solution was a mixed solution of 2.5 mmol / L iron(III) nitrate aqueous solution and 0.3 mol / L perchloric acid, and the reaction solution supply rate was set to 0.32 mL per minute (40% of the mobile phase supply rate). The reaction coil 25 is a coil that flows these mixed solutions to ensure sufficient reaction time between the effluent and the reaction solution. The UV detection device 26 is a known UV detection device, and in this embodiment, the detection wavelength was set to 295 nm.

[0045] (Test methods and results) Using the test apparatus 10 described above, each sample solution was circulated through the circulation device 14. For all sample solutions, the temperature of the constant temperature bath 12 was set to 25°C, and the temperature of the heating furnace was set to 85°C. The flow rate of the pump 13 was set to 0.9 g per minute. After circulating the sample solutions through the circulation device 14 for 24 hours, the stainless steel plate 17 was observed. No deposits were observed on the stainless steel plate 17 in the tests using sample solutions with pH values ​​of 4.9, 5.4, and 5.5. Deposits were observed on the stainless steel plate 17 in the tests using sample solutions with pH values ​​of 5.6, 5.7, 5.8, 6.2, and 6.6.

[0046] In cases where deposits were observed on the stainless steel plate 17, qualitative analysis of the deposits was performed using infrared spectroscopy. In all cases, it was confirmed that the deposits contained phytic acid.

[0047] For examples where deposits were observed on the stainless steel plate 17 (pH 5.6-6.6), quantitative analysis of the deposits was performed using hydrophilic interaction chromatography. The results of the quantitative analysis are shown in Figure 2. Figure 2 also shows the amount of precipitation (0 in both cases) for examples where no deposits were observed on the stainless steel plate 17 (pH 5.4 and 5.5) to clearly indicate the pH boundary at which changes in the amount of precipitation occur. As can be seen in Figure 2, the amount of precipitation of deposits was maximized when a sample solution with a pH of 5.7 was used. Furthermore, in the region where the pH of the sample solution was 5.8 or higher, the amount of precipitation of deposits was generally constant.

[0048] From these results, it was found that if the pH of the raw material liquid in contact with the stainless steel component under heating is 5.5 or lower, the formation of deposits derived from phytate can be suppressed. This invention was completed by applying this finding to the manufacturing process of coffee beverages.

[0049] [Other Embodiments] Finally, other embodiments of the method for producing coffee beverages according to the present invention will be described. Note that the configurations disclosed in each of the following embodiments can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise.

[0050] In the above embodiment, a configuration including a step of adjusting the pH of the preparation solution to 5.5 or less in the blending device 5 was described as an example. However, in the present invention, as long as the pH of the raw material solution is 5.5 or less, the presence or absence of a step to adjust the pH of the raw material solution is optional. For example, if the pH of the extract obtained from coffee beans is 5.5 or less, a step to adjust the pH is not necessarily required. However, even if the pH of the extract is 5.5 or less, there is no prejudice to providing a step to adjust the pH for the purpose of flavor adjustment, etc.

[0051] In the above embodiment, a configuration using a basic pH adjusting agent was described as an example. However, the type of pH adjusting agent is not limited in the present invention.

[0052] In the above embodiment, a configuration in which the product liquid is filled into a PET bottle was described as an example. However, the type of container is not limited in the present invention.

[0053] The order of steps in the method for producing a coffee beverage according to the present invention is not limited to the above embodiment. The order of steps can be appropriately changed depending on the type of container, etc. For example, if the container is a can, the order of the sterilization step and the filling step is reversed from the above embodiment. That is, after filling the can with the prepared liquid and sealing it, the can is heated and pressurized to sterilize the contents (prepared liquid). In this case, the prepared liquid is sterilized inside the can, and the product liquid is completed. The temperature when filling the prepared liquid is, for example, 80°C or higher in order to prevent the growth of microorganisms in the filling device and to reduce the oxygen content of the product liquid. This temperature environment may be a temperature environment in which deposits derived from phytates can be generated, so the generation of deposits in the filling device can be prevented by setting the pH of the raw material liquid at the filling stage (before sterilization) to 5.5 or lower. However, performing the filling step after the sterilization step, as in the above embodiment, is preferable because it allows for operations such as pH adjustment to be applied to the product liquid after sterilization, thus increasing the flexibility of the product.

[0054] In the method for producing a coffee beverage according to the present invention, the raw material liquid is not limited as long as it contains coffee bean extract and has a pH of 5.5 or less. Therefore, the raw material liquid may contain dairy products, sugars, etc. However, the formation of deposits derived from phytates is particularly problematic when producing coffee beverages that do not contain dairy products, so it is more preferable to apply the present invention when the raw material liquid does not contain dairy products.

[0055] With regard to other configurations, the embodiments disclosed herein are illustrative in all respects, and it should be understood that the scope of the present invention is not limited thereto. Those skilled in the art will readily understand that modifications can be made as appropriate without departing from the spirit of the invention. Therefore, other embodiments modified without departing from the spirit of the invention are naturally included within the scope of the present invention. [Industrial applicability]

[0056] This invention can be applied to the production of coffee beverages. [Explanation of symbols]

[0057] 1: Manufacturing equipment 2:Extraction device 3: Dilution device 4: Storage tank for mixed liquid 5: Mixing device 6: Sterilizer 7: Filling device

Claims

1. A method for producing a coffee beverage, comprising a step of sterilizing a raw material liquid containing coffee bean extract and having a pH of 5.5 or lower.

2. The manufacturing method according to claim 1, further comprising the step of adjusting the pH of the raw material liquid to 5.5 or less.

3. The manufacturing method according to claim 1, further comprising the step of adding a basic pH adjusting agent to the sterilized raw material liquid.

4. The manufacturing method according to claim 1, further comprising the step of filling a container with the sterilized raw material liquid.

5. The manufacturing method according to any one of claims 1 to 4, wherein the raw material liquid does not contain dairy products.

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