JP4453829B2 - Method for producing powder soluble coffee - Google Patents

Description

  The present invention relates to a method for producing powder-soluble coffee, and more particularly, to a method for producing powder-soluble coffee in which powdered coffee can be directly dissolved in hot water or the like.

  Regular coffee is roasted using a roasting machine, and the roasted coffee beans are pulverized using a roll-type pulverizer to form powdered coffee. It is drunk by pouring hot water into this powdered coffee and extracting it. Paper filters, siphons, percolators, etc. are used as the extraction device, but all devices are for drinking filtered extracts.

  In contrast to the regular drinking of regular coffee, regular coffee that can be taken by dissolving powdered coffee directly in hot water has been developed. For example, Patent Document 1 discloses an invention in which roasted coffee beans are finely pulverized, and the fine powdered coffee is dissolved and extracted without being filtered.

In the invention described in Patent Document 1, roasted coffee beans are wet-ground and spray-dried to obtain fine powder-soluble regular coffee.
JP 2003-9768 A

  Since coffee is generally drunk after filtration, there is almost no insoluble solid content in the extract. Therefore, when coffee is drunk, the presence of a precipitate at the bottom of the container is inferior in quality. However, the above-mentioned conventional method has a large amount of insoluble precipitated solids remaining at the bottom of the container, which is not necessarily preferable in terms of quality, and has been requested to be improved.

  In addition, it is conceivable to further pulverize roasted coffee beans using a disc type, impact type, ball mill type, jet stream type, etc., but even if these methods are used, The contained oil component is separated and the finely ground coffee powder is agglomerated, so that the solid content remains at the bottom of the container.

  As a result of diligent research on the pulverization of coffee, the present inventors conducted wet pulverization of the refined roasted coffee beans, and filtered and classified particles of 50 μm or more contained in the obtained suspension in a wet state. And after drying, it became difficult for solid content to remain in a container bottom part, and it discovered that a feeling of roughness was lost at the time of drinking, and completed the present invention.

  Therefore, in view of the above-described problems of the prior art, the object of the present invention is to allow powdered coffee to be directly dissolved in hot water and to drink it, and insoluble solids do not remain at the bottom of the container, making it feel rough when drinking. It is an object of the present invention to provide a method for producing a powder-soluble coffee having no powder.

  The above-mentioned subject is achieved by the invention described in each claim. That is, the characteristic constitution of the method for producing powder soluble coffee according to the present invention is that the roasted coffee beans and water are mixed, the roasted coffee beans are wet-ground to a median diameter of 30 μm or less, and the resulting coffee suspension Is classified to 55 μm or less and then dried.

  According to this configuration, a coffee beverage that does not have a precipitate when it is dissolved and does not feel rough when drunk can be obtained without going through complicated and troublesome processes. In particular, since wet pulverization is adopted, when using other pulverization methods such as disk pulverization method, impact pulverization method, ball mill method, jet stream method, etc. Aggregation easily occurs between the pulverized particles, and a fine powder having a small median diameter cannot be obtained. On the other hand, according to the present invention, a fine powder can be reliably obtained. Further, even by freeze pulverization, it is generally difficult to make the median diameter 50 μm or less, and the pulverization cost becomes higher than wet pulverization. Thus, in the case of the present invention, since it is classified after wet pulverization, the powder can be reliably classified as fine coffee particles without agglomeration, and the equipment cost and pulverization cost can be reduced. It is suitable for actual production because fine powder with a small median diameter can be obtained reliably in a relatively short time.

  As a result, it was possible to provide a method for producing powdered soluble coffee that can be used by dissolving powdered coffee in hot water or the like as it is, and insoluble solids do not remain at the bottom of the container, and that does not feel rough during drinking.

  Before the wet pulverization, the roasted coffee beans are preferably dry pulverized or freeze pulverized in advance so that the median diameter is 100 μm or less.

  According to this configuration, it is possible to obtain coffee particles having a small median diameter in a shorter time by wet pulverization more efficiently.

  It is preferable that the wet pulverization is performed by mixing spherical beads having a diameter of 0.5 mm or less and the classification is performed using a sieve.

  According to this configuration, as described above, the finely ground coffee powder that has been wet-ground is classified by the sieve, so compared to the case of classification in a dry state (particles agglomerate with each other by the oil eluted during the grinding), Aggregation between particles does not occur, and coffee particles having a small median diameter can be obtained in a shorter time.

  An embodiment of a method for producing a powder soluble coffee according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the method for producing powder-soluble coffee according to the present embodiment roasts coffee beans by a conventional method to produce roasted coffee beans (# 1). The roasting conditions are not particularly limited as long as roasting is performed according to various roasting degrees.

  The roasted coffee beans are first ground to a median diameter of about 100 μm or less as a pretreatment before being wet ground (# 2). The pulverization method in this case is not particularly limited, and various pulverization methods such as dry, wet, and freeze pulverization can be employed. Although this preliminary treatment is not always necessary, it is desirable to carry out wet grinding performed in the next step in order to efficiently perform a predetermined particle size in a short time.

  The primary pulverized roasted coffee beans and water are mixed, and wet secondary pulverization is performed to a median diameter of 30 μm or less (# 3). In order to pulverize roasted coffee beans to a median diameter of 30 μm or less, processing at the actual production level is difficult with dry or freeze pulverization, and the processing time at the actual production level can be achieved only by wet pulverization. The wet pulverization is preferably performed so that the ratio of the powdered roasted coffee beans to water is in the range of 1: 5 to 1:20. When the ratio of roasted coffee powder to water is increased from 1: 5, the fluidity of the suspension is lowered during wet pulverization, and there is a risk of causing operational problems such as clogging in the apparatus. Conversely, if the ratio of roasted coffee powder to water is increased from 1:20, the pulverization efficiency is lowered, which is not preferable.

  This wet pulverization preferably employs bead-type pulverization using zirconia beads having a particle size of about 0.3 to 0.5 mm. When zirconia beads having a particle size of less than 0.3 mm are used, it takes time to pulverize to a predetermined particle size, resulting in low pulverization efficiency and when using zirconia beads having a particle size of more than 0.5 mm. Takes a long processing time until it is pulverized to a uniform particle size.

  Next, the obtained coffee suspension is classified using a stainless steel or resin sieve having an opening of 55 μm or less (# 4) to remove coffee powder of 50 μm or more. Thereby, insoluble solid content can be removed at the time of drinking, and a rough feeling can be eliminated reliably.

  Thereafter, the classified coffee liquid is dried (# 5). When the drying process is performed with a spray dryer equipped with a pressure nozzle or a high-speed atomizer, fine coffee powder particles can be obtained, and the drying cost is lower than when the drying process is performed by a freeze-drying method or the like.

  The coffee powder thus obtained is dissolved and dispersed in hot water or cold water, and is provided as a coffee beverage with almost no precipitation and no feeling of roughness.

Hereinafter, examples will be described more specifically.
Example 1
Coffee beans roasted by a conventional method (about 200 ° C., about 10 minutes) were pulverized to a median diameter of about 30 μm by a dry pulverizer. The obtained coffee powder was mixed with ion-exchanged water at a ratio of powder: water = 1: 10 for about 15 minutes with a disperser (manufactured by OMNI), and this mixture was mixed with spherical zirconia, having a diameter of about 0.5 mm. The beads were put into an imex pulverizer (bead mill), and wet pulverized four times at a rotational speed of 2000 rpm, a peripheral speed of 10 m / sec, and a flow rate of 200 mL / min to a median diameter of about 20 μm or less. While appropriately adding water to the suspension containing the ground coffee powder, the mixture was filtered using a stainless steel sieve having a mesh size of 53 μm to classify and remove coffee powder of 50 μm or more. Thereafter, the suspension subjected to the classification treatment was sprayed using a spray dryer (manufactured by MOBILE MINOR 2000 NIRO A / S) having a high-speed atomizer, suspension slurry concentration: 6.5 wt%, introduction temperature: 280 ± 5 ° C., discharge Spray drying was performed under conditions of a temperature of 110 ± 5 ° C. and an atomizer supply pressure of 400 kPa to obtain coffee powder.

Regarding the obtained coffee powder, 140 g of 2 g of coffee powder was dissolved and the precipitation state was visually observed, and the particle size was measured using a laser diffraction / scattering particle size measuring device (model: LA920 wet, manufactured by Horiba Seisakusho). .
(Comparative Example 1)
Using the same coffee beans as in Example 1, roasting under the same conditions, mixing in a ratio of coffee powder: water = 1: 10 with ion-exchanged water without pre-grinding in advance, and this mixture is a disc. Mill (model name: Serendipita Mini, manufactured by Masuko Sangyo Co., Ltd.), clearance 40 μm, disc rotation speed 2000 rpm, roasted coffee supply rate: 0.2 (kg / min), water supply rate: 24 L / min By pulverizing under conditions, a suspension containing coffee powder was obtained. The obtained suspension was spray-dried under the same conditions as in Example 1 to be powdered, dissolved in hot water as in Example 1, and observed for precipitation, and the particle size distribution was measured.
(Comparative Example 2)
Using the same coffee beans as in Example 1, roasting was performed under the same conditions, and as a preliminary pulverization, the median diameter was pulverized to about 30 μm with a dry pulverizer as in Example 1. The obtained coffee powder was mixed with a disperser under the same conditions as in Example 1, and the mixture was put into a bead mill and wet-pulverized four times to obtain a coffee powder solution. However, unlike Example 1, no classification treatment was performed. The obtained suspension was spray-dried under the same conditions as in Example 1 to obtain coffee powder. The obtained powder was dissolved in hot water in the same manner as in Example 1 to observe the precipitation state, and the particle size distribution was measured.
(Comparative Example 3)
The coffee beans were roasted under the same conditions as in Example 1 and the coffee beans roasted as pre-ground were freeze-ground at −130 ° C. with a freeze pulverizer (manufactured by Liquid Gas Co.) to obtain coffee powder. Got. The obtained powder was dissolved in hot water in the same manner as in Example 1 to observe the precipitation state, and the particle size distribution was measured.

Until the following Comparative Example 6, the obtained suspension was spray-dried under the same conditions as in Example 1 to pulverize the coffee, and dissolved in hot water as in Example 1 to give a precipitated state. While observing, the particle size distribution was measured using a laser diffraction / scattering particle size measuring device (model: LA920 wet, manufactured by Horiba Seisakusho).
(Comparative Example 4)
The same coffee beans as in Example 1 were roasted under the same conditions, and the roasted coffee beans were frozen and pulverized at −130 ° C. with a freeze pulverizer (manufactured by Liquid Gas). The obtained coffee powder was mixed with ion exchange water at a ratio of coffee powder: water = 1: 10 to obtain a suspension. This suspension was mixed with a disperser for about 15 minutes, and filtered using a stainless steel sieve having a mesh size of 53 μm while adding water to the homogenized suspension appropriately to obtain a coffee suspension.
(Comparative Example 5)
The same coffee beans as in Example 1 were roasted under the same conditions, and the roasted coffee beans were frozen at −130 ° C. using a freeze pulverizer (manufactured by Liquid Gas) in the same manner as in Comparative Example 4. Crushed. The obtained coffee powder was mixed with ion exchange water at a ratio of coffee powder: water = 1: 10 to obtain a suspension. This suspension was mixed with a disperser for about 15 minutes, and filtered with a stainless steel sieve having an opening of 75 μm while adding water to the homogenized suspension as appropriate to obtain a coffee suspension.
(Comparative Example 6)
The same coffee beans as in Example 1 were roasted under the same conditions, and the roasted coffee beans were frozen at −130 ° C. using a freeze pulverizer (manufactured by Liquid Gas) in the same manner as in Comparative Example 4. Crushed. The obtained coffee powder was mixed with ion exchange water at a ratio of coffee powder: water = 1: 10 to obtain a suspension. This suspension was mixed with a disperser for about 15 minutes, and filtered with a stainless steel sieve having an opening of 106 μm while adding water to the homogenized suspension as appropriate, to obtain a coffee suspension.

  Among the steps of Example 1 and Comparative Examples 1 to 6, the main steps are summarized in Table 1, and the particle size distribution of the obtained coffee powder and the evaluation results for drinking are shown in Tables 2 and 3, respectively. .

表２、３に結果から、実施例１の場合、比較例１〜６に比べて、溶解時の沈殿は極めて少なく、飲用時のザラツキ感もみられず、コーヒー飲料として優れていることがわかる。その場合、湿式粉砕によりメジアン径を２０μｍ以下程度にまですること（実施例１と比較例４の対比）と、５５μｍ以下にまでろ過・分級処理する（実施例１と比較例２，４〜６の対比）ことを共に行うことが効果的である。

From the results in Tables 2 and 3, it can be seen that in Example 1, compared with Comparative Examples 1 to 6, precipitation at the time of dissolution is extremely small, and no rough feeling at the time of drinking is observed, which is excellent as a coffee beverage. In that case, the median diameter is reduced to about 20 μm or less by wet pulverization (contrast between Example 1 and Comparative Example 4), and the filtration and classification are performed to 55 μm or less (Example 1 and Comparative Examples 2, 4 to 6). It is effective to do this together.

The flowchart which shows the manufacturing method of the powder soluble coffee which concerns on one Embodiment of this invention.

Claims (3)

A method for producing powder-soluble coffee, comprising mixing roasted coffee beans and water, wet-grinding the roasted coffee beans to a median diameter of 30 μm or less, classifying the resulting coffee suspension to 55 μm or less, and then drying. The method for producing powder-soluble coffee according to claim 1, wherein the roasted coffee beans are dry-grinded or freeze-milled in advance before the wet pulverization to reduce the median diameter to 100 µm or less. The method for producing powder-soluble coffee according to claim 1 or 2, wherein the wet pulverization is performed by mixing spherical beads having a diameter of 0.5 mm or less, and the classification is performed using a sieve.

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