Method for producing fermented coffee cultivated on grain-solid mushroom mycelium inoculum

Abstract

To provide a method for producing fermented coffee and fermented coffee produced by said method. [Solution] To this end, the present invention is characterized in that the production method includes the steps of soaking green coffee beans in an extract, sterilizing the soaked green coffee beans and then cooling them, applying a cereal grain solid seed culture to the cooled green coffee beans and culturing them, and separating the cereal grain solid seed culture from the cultured green coffee bean fermented product and then drying it.

Description

[Technical Field]

[0001] The present invention relates to a method for producing fermented coffee, which comprises the steps of applying a cereal grain solid seed to sterilized green coffee beans and culturing the solid seed, and separating the cereal grain solid seed from the cultured fermented green coffee beans and drying the separated solid seed, and the fermented coffee produced by the method. [Background technology]

[0002] Coffee belongs to the Rubiaceae family and the genus Coffea. Commercially cultivated varieties are broadly divided into Arabica, Robusta, and Liberica. Coffee, a representative beverage with a harmonious balance of bitterness, astringency, sourness, and sweetness, is the most widely consumed beverage worldwide. In Korea, the coffee market is experiencing steady growth, driven by the proliferation of specialty coffee shops and increased home consumption. Compared to other foods, coffee is known to contain higher levels of antioxidants, such as polyphenols, and to have a high ability to scavenge free radicals that cause cell damage. Recent studies have shown that roasted coffee beans contain higher levels of lipophilic antioxidants and chlorogenic acid, which have neuroprotective effects, than green coffee beans. Coffee is also known to have excellent protective effects against Alzheimer's disease, Parkinson's disease, type 2 diabetes, cholesterol, heart disease, and cirrhosis of the liver, and there is a trend toward studying the pharmacological effects of coffee beyond its mere consumption as a leisure food.

[0003] Fermented foods are foods made using the fermentation action of microorganisms such as lactic acid bacteria and yeast. Fermented foods vary depending on the type of microorganism and food ingredients, and each type of fermented food has its own unique characteristics and flavor. Fermentation can also improve the functionality of food ingredients.

[0004] Existing technology involves inoculating sterilized green coffee beans with mushroom mycelium cultivated in a liquid spawn by injecting the liquid into the beans. This results in high contamination rates due to excessive humidity, which causes uneven cultivation throughout the beans, resulting in low production yields and a black, charcoal-like color that diminishes the sensory beauty of the beans. It also produces a distinctive odor that inhibits the rich and diverse flavor and aroma of coffee, significantly reducing productivity and quality competitiveness.

[0005] Korean Patent Publication No. 2021-0101506 discloses a method for producing fermented coffee using yeast that does not require a coffee aging process, and Korean Patent Registration No. 1894295 discloses a method for processing coffee using a fermented plum extract, but these are different from the method for producing fermented coffee cultivated with grain solid mushroom mycelium seed culture of the present invention. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Korean Patent Publication No. 2021-0101506 [Patent Document 2] Korean Patent No. 1894295 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been devised in response to the above-mentioned needs, and aims to provide a method for producing fermented coffee that has excellent pharmacological properties and palatability by optimizing pretreatment, sterilization, fermentation, etc. of green coffee beans so as to reduce the bitterness unique to coffee and enhance functionality and flavor. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a method for producing fermented coffee, comprising the steps of: (1) adding apricot kernel and Rumex crispus to water, extracting, and then filtering to produce an extract; (2) soaking green coffee beans in the extract produced in step (1); (3) lining a basket in a sterilizer with ivy leaves and placing the soaked green coffee beans in step (2) on the ivy leaves, followed by sterilization and cooling; (4) applying a cereal grain solid seed to the cooled green coffee beans in step (3) and culturing them; and (5) separating the cereal grain solid seed from the fermented green coffee beans cultured in step (4), and then drying them.

[0009] The present invention also provides fermented coffee produced by the above method. [Effects of the Invention]

[0010] The fermented coffee of the present invention has the advantages of low contamination rate and high production yield by cultivating sterilized green coffee beans with a cereal grain solid starter culture. It also provides a high-quality fermented coffee with a richer coffee flavor and taste and improved functionality. [Brief explanation of the drawings]

[0011] [Figure 1] This is a photograph of the seed culture separated after culturing green coffee beans in a cereal grain solid seed culture. DETAILED DESCRIPTION OF THE INVENTION

[0012] To achieve the object of the present invention, the present invention provides (1) adding Rumex chinensis and Rumex brachycarpa to water, extracting, and then filtering to prepare an extract; (2) soaking green coffee beans in the extract produced in step (1); (3) laying ivy leaves in a basket of a sterilizer, placing the soaked green coffee beans from step (2) on the ivy leaves, and then sterilizing and cooling the beans; (4) applying a cereal grain solid inoculum to the cooled green coffee beans from step (3) and culturing it; and (5) A method for producing fermented coffee, comprising the steps of separating a cereal grain solid seed culture from the fermented green coffee beans cultured in step (4) and then drying the separated cereal grain solid seed culture.

[0013] In the method for producing fermented coffee of the present invention, the extract in step (1) can be preferably prepared by adding 4.5 to 5.5 g of Rumex japonicus and 4.5 to 5.5 g of Rumex cordata to 180 to 220 mL of water, extracting at 90 to 110°C for 2 to 4 hours, and then filtering the extract. More preferably, the extract can be prepared by adding 5 g of Rumex japonicus and 5 g of Rumex cordata to 200 mL of water, extracting at 100°C for 3 hours, and then filtering the extract.

[0014] Furthermore, in the method for producing fermented coffee of the present invention, the soaking in step (2) is preferably performed by soaking the green coffee beans in the extract at 18 to 22°C for 5 to 10 hours, and more preferably by soaking the green coffee beans in the extract at 20°C for 8 hours.

[0015] Furthermore, in the method for producing fermented coffee of the present invention, the sterilization in step (3) can be preferably carried out by laying ivy leaves in a sterilizer basket, placing the green coffee beans on the ivy leaves, and then sterilizing at 110 to 130°C for 50 to 70 minutes, followed by cooling; and even more preferably, by laying ivy leaves in a sterilizer basket, placing the green coffee beans on the ivy leaves, and then sterilizing at 121°C for 60 minutes, followed by cooling.

[0016] In order to ferment green coffee beans, the green coffee beans must be soaked and sterilized as described above. This provides moisture to the green beans, causing them to swell and soften the tissue, which allows for better cultivation.

[0017] Additionally, in the method for producing fermented coffee of the present invention, step (4) preferably involves applying a cereal grain solid starter culture to cooled green coffee beans and culturing them at 18-22°C for 20-25 days. Culturing green coffee beans under these conditions increases the content of ingredients beneficial to the human body contained in coffee, improving the taste and aroma of the coffee while reducing the bitterness of the coffee. However, if the culturing conditions are outside these ranges, the culturing effect may be insufficient or an unpleasant odor may be generated due to over-fermentation, which is undesirable.

[0018] The solid cereal grain inoculum preferably means that the grain is soaked in water, sterilized, and then inoculated with mushroom mycelium and then cultured.

[0019] The mushroom mycelium may be one or more mushroom mycelium selected from the group consisting of shiitake mushroom, phellinus linteus, Ganoderma lucidum, Poria coccinea, Aralia erinacea, Cordyceps sinensis, Unshiu grass, Poria coccinea, Oyster mushroom, Flammulina velutipes, Pleurotus eryngii, Petal mushroom, Grifola frondosa, Fusarium obtusifolia, Stag beetle mushroom, Auricularia auricularia, Willow matsutake, Stag antler Ganoderma lucidum, Matsutake, Matsutake, and truffle, but is not limited thereto.

[0020] In addition, the grain may be one or more grains selected from the group consisting of brown rice, white rice, black rice, red rice, green rice, red rice, barley, black barley, oats, wheat, millet, corn, beans, rye, mung beans, pigeon oats, chestnuts, millet, adzuki beans, and buckwheat, but is not limited thereto.

[0021] Furthermore, in the method for producing fermented coffee of the present invention, step (5) preferably involves separating the cereal grain solid seed culture from the cultured fermented green coffee beans and then drying the fermented green coffee beans to a moisture content of 10 to 13% (v / w). Drying under these conditions is preferred to prevent further fermentation of the green coffee beans.

[0022] More specifically, the method for producing fermented coffee of the present invention includes: (1) adding 4.5-5.5 g of Rumex japonicus and 4.5-5.5 g of Rumex chinensis to 180-220 mL of water, extracting at 90-110°C for 2-4 hours, and then filtering to prepare an extract; (2) soaking green coffee beans in the extract prepared in step (1) at 18-22°C for 5-10 hours; (3) Placing ivy leaves in a sterilizer basket, placing the soaked green coffee beans from step (2) on the ivy leaves, and then sterilizing at 110-130°C for 50-70 minutes and cooling; (4) applying a cereal grain solid inoculum to the cooled green coffee beans of step (3) and culturing the mixture at 18 to 22°C for 20 to 25 days; and (5) The method may include a step of separating the cereal grain solid starter from the fermented green coffee beans cultured in step (4) and then drying the solid starter to a moisture content of 10 to 13% (v / w), More specifically, (1) adding 5 g of Rumex japonicus and 5 g of Rumex chinensis to 200 mL of water, extracting at 100°C for 3 hours, and then filtering to prepare an extract; (2) soaking green coffee beans in the extract prepared in step (1) at 20°C for 8 hours; (3) Placing ivy leaves in a basket of a sterilizer, placing the soaked green coffee beans from step (2) on the ivy leaves, and then sterilizing at 121°C for 60 minutes and cooling; (4) applying a cereal grain solid inoculum to the cooled green coffee beans of step (3) and culturing the mixture at 18 to 22°C for 20 to 25 days; and (5) After separating the cereal grain solid inoculum from the fermented green coffee beans cultured in step (4), the method may include a step of drying the solid inoculum to a moisture content of 10 to 13% (v / w). The present invention also provides fermented coffee produced by the above method. The present invention will be described in detail below with reference to examples, but the following examples are merely for illustrative purposes and are not intended to limit the scope of the present invention.

[0023] Production Example 1: Fermented coffee (1) 5 g of Rumex officinalis and 5 g of Rumex crispus were added to 200 mL of purified water, and the mixture was extracted at 100° C. for 3 hours and then filtered to prepare an extract. (2) 100 g of green coffee beans were soaked in 200 mL of the extract prepared in step (1) at 20° C. for 8 hours. (3) Ivy leaves were laid in a basket of a sterilizer, and the soaked green coffee beans from step (2) were placed on top of the ivy leaves. The beans were then sterilized at 121°C for 60 minutes and cooled to 20°C in a cooling room. (4) 15 mL of brown rice grain solid inoculum was evenly spread on the top of the cooled green coffee beans from step (3) and cultured in a culture room at 18-22°C for 20-25 days. 10 days after inoculation during the culture, the container was shaken to create air gaps to ensure even culture at the bottom and throughout the container. The brown rice grain solid inoculum refers to brown rice soaked in water, sterilized, and then inoculated with Shiitake mushroom mycelium, followed by culture at 25°C for 20 days. (5) After separating the brown rice grain solid seed culture from the fermented green coffee beans cultured in step (4), the fermented green coffee beans were dried to a moisture content of 10 to 13% (v / w).

[0024] Comparative Example 1: Coffee (1) 100 g of green coffee beans were soaked in 200 mL of purified water at 20°C for 8 hours. (2) The soaked green coffee beans from step (1) were placed in a sterilizer basket and sterilized at 121°C for 60 minutes, then cooled to 20°C in a cooling room. (3) The cooled green coffee beans from step (2) were dried to a moisture content of 10 to 13% (v / w).

[0025] Comparative Example 2: Fermented coffee (1) 100 g of green coffee beans were soaked in 200 mL of purified water at 20°C for 8 hours. (2) The soaked green coffee beans from step (1) were placed in a sterilizer basket and sterilized at 121°C for 60 minutes, then cooled to 20°C in a cooling room. (3) 15 mL of brown rice grain solid inoculum was evenly spread on the top of the cooled green coffee beans from step (2) and cultured in a culture room at 18-22°C for 20-25 days. After 10 days of inoculation during the culture, the container was shaken to create air gaps so that the bottom of the container and the entire container could be cultured evenly. The brown rice grain solid inoculum means that brown rice soaked in water, sterilized, and then inoculated with Lentinus edodes mycelium and cultured at 25° C. for 20 days. (4) After separating the brown rice grain solid seed culture from the fermented green coffee beans cultured in step (3), the fermented green coffee beans were dried to a moisture content of 10 to 13% (v / w).

[0026] Comparative Example 3: Fermented coffee (1) 10 g of cinnamon stick was added to 200 mL of purified water, and the mixture was extracted at 100° C. for 3 hours, followed by filtration to prepare an extract. (2) Using the extract prepared in step (1), fermented coffee was prepared in the same manner as steps (2) to (5) of Preparation Example 1.

[0027] Comparative Example 4: Fermented Coffee (1) 10 g of Rumex crispus was added to 200 mL of purified water, and the mixture was extracted at 100° C. for 3 hours and then filtered to prepare an extract. (2) Using the extract prepared in step (1), fermented coffee was prepared in the same manner as steps (2) to (5) of Preparation Example 1.

[0028] Comparative Example 5: Fermented Coffee (1) 5 g of Rumex officinalis and 5 g of Rumex crispus were added to 200 mL of purified water, and the mixture was extracted at 100° C. for 3 hours and then filtered to prepare an extract. (2) 100 g of green coffee beans were soaked in 200 mL of the extract prepared in step (1) at 20° C. for 8 hours. (3) The soaked green coffee beans from step (2) were placed in a basket in a sterilizer and sterilized at 121°C for 60 minutes, then cooled to 20°C in a cooling room. (4) Fermented coffee was produced using the cooled green coffee beans from step (3) in the same manner as steps (4) and (5) of Production Example 1. [Example]

[0029] Example 1. Beta-glucan analysis Beta-glucan in the samples was measured using a Megazyme kit (Mushroom and Yeast β-glucan Assay Procedure K-YBGL, Megazyme, Ireland).

[0030] First, for total glucan, 100 mg of crushed sample passed through a 100-mesh sieve was placed in a tube, and 1.5 mL of 37% HCl was added. The tube was then placed in a thermostatic water bath at 30°C for 45 minutes to decompose. 10 mL of distilled water was then added, vortexed, and incubated at 100°C for 2 hours. After cooling to room temperature, 10 mL of 2N KOH was added, and the mixture was adjusted to 100 mL with 200 mM sodium acetate buffer and thoroughly mixed. Next, 0.1 mL of the supernatant was mixed with 0.1 mL of exo-1,3-β-glucanase plus β-glucosidase dissolved in 200 mM sodium acetate buffer, 0.2 mL of acetate buffer was added for the reagent blank, and 0.1 mL of D-glucose standard was mixed with 0.1 mL of acetate buffer for the D-glucose standard, and then incubated at 40°C for 60 minutes. Next, 3 mL of GOPOD (glucose oxidase / peroxidase mixture) was added and incubated at 40°C for 20 minutes, after which the absorbance was measured at 510 nm.

[0031] For α-glucan, 100 mg of ground sample passed through a 100-mesh sieve was placed in a tube, and 2 mL of 2M KOH was added and mixed for 20 minutes. After adding 8 mL of 1.2M sodium acetate buffer and mixing, 0.2 mL of amyloglucosidase plus invertase was added, mixed well, and incubated in a 40°C water bath for 30 minutes. 0.1 mL of the supernatant was added to 0.1 mL of 200 mM sodium acetate buffer and 3 mL of GOPOD, and incubated at 40°C for 20 minutes. Absorbance at 510 nm was measured. Calculations were based on total glucan content, with α-glucan content subtracted to quantify β-glucan content.

[0032] [Table 1]

[0033] As a result, no β-glucan was detected in the coffee of Comparative Example 1, and the fermented coffee of Production Example 1 had a higher β-glucan content than the fermented coffee of Comparative Example 2.

[0034] Example 2. DPPH radical scavenging ability To determine the antioxidant capacity of each coffee, antioxidant activity was measured by hydrogen electron donating capacity. Samples were diluted with distilled water, and 10 μL of each sample was mixed with 900 μL of DPPH solution (100 μM) and stirred. The mixed samples were incubated in the dark for 30 minutes, and then the absorbance was measured at 517 nm. Each experiment was repeated three times to calculate the average, and the decrease in absorbance compared to the control was calculated using the following formula:

[0035] DPPH radical scavenging ability (%) = (AB) / A × 100 A: Absorbance of DPPH solution without sample added B: Absorbance of the reaction between DPPH and the sample in the reaction solution

[0036] [Table 2]

[0037] The fermented coffee was diluted and the DPPH radical scavenging ability was measured, and the results are shown in Table 2. As a result, it was found that the fermented coffee of Production Example 1 had the highest DPPH radical scavenging ability.

[0038] Example 3. Sensory test A sensory test was conducted on 50 sensory testers for the coffees of Production Example 1 and the Comparative Example. Each coffee was roasted to a medium roast, crushed, and hand-dripped with hot water to obtain a coffee extract. The aroma, taste, softness, and overall preference were categorized using a 5-point scale with 1 point: very bad, 2 points: bad, 3 points: average, 4 points: good, and 5 points: excellent, and the average was calculated and shown. The test was repeated three times.

[0039] [Table 3]

[0040] The results of the sensory test of the extracts from each coffee are shown in Table 3. As a result, the fermented coffee of Preparation Example 1 received higher scores in all categories than the coffees of the Comparative Examples, indicating that the fermented coffee of Preparation Example 1 has a high β-glucan content, excellent antioxidant activity, and is well-liked by consumers.

Claims

1. (1) adding 4.5-5.5 g of Rumex officinalis and 4.5-5.5 g of Rumex crispus to 180-220 mL of water, extracting at 90-110°C for 2-4 hours, and then filtering to prepare an extract; (2) soaking green coffee beans in the extract prepared in step (1) at 18-22°C for 5-10 hours; (3) placing ivy leaves in a basket of a sterilizer, placing the soaked green coffee beans from step (2) on the ivy leaves, and then sterilizing the beans at 110-130°C for 50-70 minutes, followed by cooling; (4) applying a cereal grain solid inoculum to the cooled green coffee beans of step (3) and culturing the mixture at 18 to 22°C for 20 to 25 days; and (5) A method for producing fermented coffee, comprising the steps of separating a cereal grain solid seed culture from the fermented green coffee beans cultured in step (4) and then drying the solid seed culture to a moisture content of 10 to 13% (v / w).

2. 2. The method for producing fermented coffee according to claim 1, wherein the grain is one or more grains selected from the group consisting of brown rice, white rice, black rice, red rice, green rice, red rice, barley, black barley, oats, wheat, sorghum, corn, beans, rye, mung beans, pigeon oats, chestnuts, millet, adzuki beans, and buckwheat.

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