Method for producing fermented coffee using grain solid mushroom mycelium inoculum

Abstract

The present invention relates to a method for producing fermented coffee and fermented coffee produced by the method, the method comprising: a step of soaking coffee beans in an extraction liquid; a step of sterilizing the soaked coffee beans and then cooling them; a step of inoculating cereal grain solid spores on the cooled coffee beans and then culturing them; and a step of separating the cereal grain solid spores from the cultured coffee beans and then drying them.

Description

Technical Field

[0001] This invention relates to a method for making fermented coffee and the fermented coffee made by the method. The method includes the steps of: coating a grain particle solid inoculum onto cooled green coffee beans for cultivation; and the steps of separating the grain particle solid inoculum from the fermented green coffee beans and then drying it. Background Technology

[0002] Coffee belongs to the genus *Coffea* in the family Rubiaceae. Commercially cultivated varieties are mainly divided into three types: Arabica, Robusta-canephora, and Liberica. Coffee is a representative beverage that blends bitterness, astringency, sourness, and sweetness, and is one of the most widely consumed consumer foods worldwide. In South Korea, the coffee market is also experiencing continuous growth due to the prevalence of specialty coffee shops and increased personal and household consumption. It is known that coffee contains higher levels of antioxidants such as polyphenols than other foods, thus possessing a strong ability to scavenge free radicals that induce cell damage. Recent reports indicate that lipophilic antioxidants and chlorogenic acid, which have protective effects on nerve cells, are present in higher amounts in roasted whole coffee beans than in green coffee beans. Furthermore, coffee also has excellent protective effects against Alzheimer's disease, Parkinson's disease, type 2 diabetes, cholesterol, heart disease, and cirrhosis. Therefore, beyond the concept of a consumer food, many studies have been conducted on the pharmacological effects of coffee.

[0003] Fermented foods are foods made using the fermentation process of microorganisms such as lactic acid bacteria or yeast. There are many types of fermented foods depending on the type of microorganism and the food materials used, and each fermented food has its own unique characteristics and flavor. Fermentation can improve the functionality of food ingredients.

[0004] The existing technology involves spraying liquid mushroom mycelium cultured in liquid culture onto sterilized green coffee beans for inoculation. This process results in high contamination rates, uneven overall cultivation, low yield, charcoal-like color, and poor sensory quality due to excessive moisture. Furthermore, the unique off-flavors hinder the rich and diverse flavors and aromas of the coffee, leading to a significant decline in productivity and quality competitiveness.

[0005] Korean Patent Publication No. 2021-0101506 discloses a method for making fermented coffee using yeast that does not require a coffee ripening process, and Korean Registered Patent No. 1894295 discloses a method for processing coffee using plum fermentation extract, but these are different from the method of making fermented coffee using grain solid mushroom mycelium culture of the present invention. Summary of the Invention

[0006] Technical issues

[0007] This invention is made in accordance with the aforementioned requirements, and its purpose is to provide a coffee making method that reduces the characteristic bitterness of coffee while improving its functionality and flavor by optimizing the pretreatment, sterilization, and fermentation of green coffee beans, thereby giving the coffee excellent pharmacological properties and appeal.

[0008] Problem-solving methods

[0009] To achieve the objective of this invention, this invention provides a method for preparing fermented coffee, characterized by comprising:

[0010] (1) Add senna and styrax to water, extract and filter to prepare the extract;

[0011] (2) The step of soaking green coffee beans in the extract prepared in step (1);

[0012] (3) Lay ivy leaves on the tray of the sterilizer, place the soaked green coffee beans from step (2) on the ivy leaves, and then perform sterilization and cooling.

[0013] (4) The grain solid inoculum is coated onto the cooled green coffee beans from step (3) for cultivation; and

[0014] (5) The step of drying the grain solid inoculum after isolating it from the coffee bean fermentation culture cultivated in step (4).

[0015] In addition, the present invention provides a fermented coffee produced by the method described above.

[0016] Invention Effects

[0017] The fermented coffee of this invention is cultured using grain-based solid inoculum in sterilized green coffee beans, resulting in advantages such as low contamination rate and high production efficiency. Furthermore, it can further enrich the flavor and taste of the coffee and improve its functionality, thereby providing high-quality fermented coffee. Attached Figure Description

[0018] Figure 1 This is a photo of the inoculum being isolated after coffee beans have been cultured using grain-based solid inoculum. Detailed Implementation

[0019] To achieve the objective of this invention, this invention provides a method for preparing fermented coffee, characterized by comprising:

[0020] (1) Add senna and styrax to water, extract and filter to prepare the extract;

[0021] (2) The step of soaking green coffee beans in the extract prepared in step (1);

[0022] (3) Lay ivy leaves on the tray of the sterilizer, place the soaked green coffee beans from step (2) on the ivy leaves, and then perform sterilization and cooling.

[0023] (4) The grain solid inoculum is coated onto the cooled green coffee beans from step (3) for cultivation; and

[0024] (5) The step of drying the grain solid inoculum after isolating it from the coffee bean fermentation culture cultivated in step (4).

[0025] In the method for making fermented coffee of the present invention, for the extract in step (1), preferably 4.5-5.5g of senna and 4.5-5.5g of moss acid are added to 180-220mL of water, and the extract is extracted at 90-110℃ for 2-4 hours and then filtered. More preferably, 5g of senna and 5g of moss acid are added to 200mL of water, and the extract is extracted at 100℃ for 3 hours and then filtered.

[0026] In addition, in the method for making fermented coffee of the present invention, for the soaking in step (2), it is preferable to soak the green coffee beans in the extract at 18-22°C for 5-10 hours, and more preferably to soak the green coffee beans in the extract at 20°C for 8 hours.

[0027] In addition, in the method for making fermented coffee of the present invention, for the sterilization of step (3), it is preferable to lay ivy leaves on the tray of the sterilizer, and after laying green coffee beans on the ivy leaves, sterilize at 110-130°C for 50-70 minutes. More preferably, it is preferable to lay ivy leaves on the tray of the sterilizer, and after laying green coffee beans on the ivy leaves, sterilize at 121°C for 60 minutes and then cool.

[0028] As mentioned above, the fermentation of green coffee beans requires soaking and sterilization in order to swell and soften the tissue by providing moisture to the beans, thereby achieving a good culturing effect.

[0029] Furthermore, in the method for making fermented coffee of the present invention, step (4) preferably involves coating solid grain cultures onto cooled green coffee beans and culturing them at 18-22°C for 20-25 days. Cultivating green coffee beans under these conditions can increase the content of beneficial components in coffee, enhance its taste and flavor, and reduce its bitterness. However, if the cultivation conditions exceed these ranges, the cultivation effect will be negligible or off-flavors may occur due to over-fermentation, which is therefore undesirable.

[0030] The grain solid inoculum refers to the culture preferably formed by inoculating mushroom mycelium into grains that have been soaked in water and then sterilized.

[0031] The mushroom mycelium may be one or more of the following mushroom myceliums selected from a group consisting of shiitake mushroom, mulberry mushroom, reishi mushroom, poria cocos mushroom, button mushroom, lion's mane mushroom, cordyceps sinensis, turkey tail mushroom, poria cocos, oyster mushroom, enoki mushroom, king oyster mushroom, hydrangea mushroom, maitake mushroom, birch polypore, long-stemmed mushroom, wood ear fungus, willow matsutake mushroom, antler reishi mushroom, matsutake mushroom, matsutake mushroom, and truffle mushroom, but is not limited to this.

[0032] In addition, the grains may be one or more of the following: brown rice, white rice, black rice, red rice, green rice, barley, rye, oats, sorghum, corn, rye, mung beans, Job's tears, millet, red beans, and buckwheat, but are not limited thereto.

[0033] Furthermore, in the method for making fermented coffee of the present invention, step (5) preferably involves isolating grain solid microorganisms from the cultured green coffee bean fermentation product and then drying them to a moisture content of 10%-13% (v / w). To prevent further fermentation of the green coffee beans, drying is preferably performed under the same conditions as described above.

[0034] The method for preparing fermented coffee according to the present invention, more specifically, includes:

[0035] (1) Add 4.5-5.5g of Senna alexandrina and 4.5-5.5g of Sorrel to 180-220mL of water, extract at 90-110℃ for 2-4 hours, and then filter to prepare the extract;

[0036] (2) Soaking green coffee beans in the extract prepared in step (1) for 5-10 hours at 18-22°C;

[0037] (3) Lay ivy leaves on the tray of the sterilizer and place the soaked green coffee beans from step (2) on the ivy leaves, then sterilize at 110-130°C for 50-70 minutes and then cool.

[0038] (4) The step of coating the grain solid inoculum onto the cooled green coffee beans in step (3) and culturing them at 18-22°C for 20-25 days; and

[0039] (5) After isolating the grain solid inoculum from the coffee bean fermentation cultured in step (4), dry it to a moisture content of 10-13% (v / w).

[0040] More specifically, it includes:

[0041] (1) Add 5g of Scutellaria baicalensis and 5g of styrax to 200mL of water, extract at 100℃ for 3 hours, and then filter to prepare the extract.

[0042] (2) Soaking green coffee beans in the extract prepared in step (1) at 20°C for 8 hours;

[0043] (3) Lay ivy leaves on the tray of the sterilizer and place the green coffee beans soaked in step (2) on the ivy leaves, and then sterilize and cool at 121°C for 60 minutes.

[0044] (4) The step of coating the cooled green coffee beans with grain-based inoculum in step (3) and then culturing them at 18-22°C for 20-25 days; and

[0045] (5) The step of separating the grain solid inoculum from the coffee bean fermentation cultured in step (4) and drying it to a moisture content of 10%-13% (v / w).

[0046] The present invention also provides fermented coffee prepared by the method.

[0047] The following describes the embodiments of the present invention in detail. However, the embodiments described below are merely illustrative of the present invention, and the content of the present invention is not limited to the embodiments described below.

[0048] Example 1: Fermented Coffee

[0049] (1) Add 5g of Senna alexandrina and 5g of Sorrel to 200mL of purified water and extract at 100℃ for 3 hours. Then filter to prepare the extract.

[0050] (2) Soak 100g of green coffee beans in 200mL of the extract prepared in step (1) for 8 hours at 20°C.

[0051] (3) Place ivy leaves on the tray of the sterilizer, place the soaked green coffee beans from step (2) on the ivy leaves, sterilize at 121°C for 60 minutes, and then cool to 20°C in the cooling chamber.

[0052] (4) Spread 15 mL of brown rice grain solid inoculum evenly on the top of the cooled green coffee beans from step (3), and incubate in a culture room at 18-22°C for 20-25 days. During the incubation process, shake the container 10 days after inoculation to create air gaps, thereby ensuring uniform incubation at the bottom and throughout the container.

[0053] The brown rice grain solid inoculum refers to brown rice that has been sterilized after being soaked in water and then inoculated with shiitake mushroom mycelium, and then cultured at 25°C for 20 days.

[0054] (5) After separating the brown rice grain solid culture from the fermented green coffee beans cultured in step (4), the fermented green coffee beans are dried to a moisture content of 10% to 13% (v / w).

[0055] Comparative Example 1: Coffee

[0056] (1) Soak 100g of green coffee beans in 200mL of purified water at 20℃ for 8 hours.

[0057] (2) Place the coffee beans soaked in step (1) on the tray of the sterilizer, then sterilize at 121°C for 60 minutes and cool to 20°C in the cooling chamber.

[0058] (3) Dry the cooled green coffee beans from step (2) to a moisture content of 10% to 13% (v / w).

[0059] Comparative Example 2: Fermented Coffee

[0060] (1) Soak 100g of green coffee beans in 200mL of purified water at 20℃ for 8 hours.

[0061] (2) Place the soaked green coffee beans from step (1) on the tray of the sterilizer, sterilize at 121°C for 60 minutes, and cool to 20°C in the cooling chamber.

[0062] (3) Spread 15 mL of brown rice grain solid inoculum evenly on the top of the cooled green coffee beans from step (2), and incubate in a culture room at 18-22°C for 20-25 days. During the incubation process, shake the container 10 days after inoculation to create gaps, thereby ensuring uniform incubation at the bottom and throughout the container.

[0063] The brown rice grain solid inoculum refers to brown rice inoculated with shiitake mushroom mycelium, which has been soaked in water and then sterilized, and then cultured at 25°C for 20 days.

[0064] (4) After separating the brown rice grain solid inoculum from the green coffee bean fermentation cultured in step (3), the green coffee bean fermentation culture is dried to a moisture content of 10% to 13% (v / w).

[0065] Comparative Example 3: Fermented Coffee

[0066] (1) Add 10g of Mesembryanthemum to 200mL of purified water and extract at 100℃ for 3 hours, then filter to obtain the extract.

[0067] (2) Using the extract prepared in step (1), fermented coffee is made in the same manner as steps (2) to (5) of preparation example 1.

[0068] Comparative Example 4: Fermented Coffee

[0069] (1) Add 10g of Mesembryanthemum to 200mL of purified water, extract at 100℃ for 3 hours, and then filter to obtain the extract.

[0070] (2) Using the extract prepared in step (1), fermented coffee is made in the same manner as steps (2) to (5) of Example 1.

[0071] Comparative Example 5: Fermented Coffee

[0072] (1) Add 5g of Senna alexandrina and 5g of styrax acid to 200mL of purified water, extract at 100℃ for 3 hours, and then filter to prepare the extract.

[0073] (2) Soak 100g of green coffee beans in 200mL of the extract prepared in step (1) for 8 hours at 20°C.

[0074] (3) After placing the soaked green coffee beans from step (2) on the tray of the sterilizer, sterilize them at 121°C for 60 minutes, and then cool them to 20°C in the cooling room.

[0075] (4) Using the cooled green coffee beans from step (3), fermented coffee is made in the same manner as steps (4) to (5) of Example 1.

[0076] Example 1: β-glucan analysis

[0077] β-glucan in the samples was determined using the Megazyme kit (Mushroom and Yeast β-glucan assay procedure K-YBGL, Megazyme, Ireland).

[0078] First, 100 mg of the pulverized sample (passed through a 100-mesh sieve) was placed in a test tube, and 1.5 mL of 37% HCl was added. The tube was then placed in a 30°C water bath for 45 minutes to decompose the sample. Next, 10 mL of distilled water was added, and the mixture was vortexed and incubated at 100°C for 2 hours. Afterward, while cooling to room temperature, 10 mL of 2NKOH was added, and the volume was brought to 100 mL with 200 mM sodium acetate buffer. The mixture was then thoroughly mixed. Then, add 0.1 mL of exo-1,3-β-glucanase + β-glucanase dissolved in 200 mM sodium acetate buffer to 0.1 mL of the supernatant. Add a reagent blank to 0.2 mL of acetate buffer. Mix 0.1 mL of D-glucose standard with 0.1 mL of acetate buffer in the D-glucose standard solution and incubate at 40 °C for 60 minutes. Then add 3 mL of LGOPOD (glucose oxidase / peroxidase mixture) and incubate at 40 °C for 20 minutes. Finally, measure the absorbance at 510 nm.

[0079] For α-glucan, 100 mg of pulverized sample (passed through a 100-mesh sieve) was placed in a test tube, and 2 mL of 2M KOH was added and mixed for 20 minutes. Then, 8 mL of 1.2M sodium acetate buffer was added and mixed again, followed by 0.2 mL of amyloglucosidase plus invertase. The mixture was incubated at 40°C 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. After incubation at 40°C for 20 minutes, the absorbance was measured at 510 nm. The β-glucan content was quantified by subtracting the α-glucan content from the total glucan content.

[0080] Table 1

[0081] β-glucan in fermented coffee (%)

[0082] Types of fermented coffee β-glucan (%) Comparative Example 1 5.6±0.2 Comparative Example 1 ND (Not Detected) Comparative Example 2 2.3±0.1

[0083] The results showed that no β-glucan was detected in the coffee of Comparative Example 1, and the β-glucan content in the fermented coffee of Comparative Example 2 was higher than that in the fermented coffee of Comparative Example 1.

[0084] Example 2: DPPH free radical scavenging ability

[0085] To determine the antioxidant capacity of each coffee variety, its antioxidant activity was assessed by its hydrogen electron-donating ability. Samples were diluted with distilled water, and 100 μl of each sample was mixed with 900 μl of DPPH solution (100 μM). These mixtures were reacted in the dark for 30 minutes, and then the absorbance was measured at 517 nm. The hydrogen electron-donating ability was calculated by averaging the results of each experiment, and the decrease in absorbance in the control region was then calculated using the following formula.

[0086] DPPH free radical scavenging capacity (%) = (AB) / A × 100

[0087] A: Absorbance of DPPH solution without added sample

[0088] B: Absorbance of the reaction between DPPH in the reaction solution and the sample

[0089] Table 2

[0090] Antioxidant activity (%) of fermented coffee

[0091] Types of fermented coffee DPPH free radical scavenging capacity (%) Production example 1 69.2±1.4 Comparative Example 1 45.3±0.9 Comparative Example 2 55.2±2.1 Comparative Example 3 61.0±1.3 Comparative Example 4 59.3±1.8 Comparative Example 5 62.8±1.0

[0092] The DPPH free radical scavenging ability of fermented coffee was measured after dilution, and the results are shown in Table 2. The results show that the fermented coffee prepared in Example 1 had the highest DPPH free radical scavenging ability.

[0093] Example 3: Sensory Detection

[0094] Sensory evaluation was conducted on 50 participants using coffees prepared in Example 1 and the Comparative Example. Each type of coffee was medium-roasted, ground, and then ingested by the participants using a hand-drip hot water extraction method. Aroma, taste, smoothness, and overall palatability were differentiated using a five-point scale repeated three times, and the average value was calculated. The scale was represented as follows: 1 point: Very Poor, 4 points: Poor, 3 points: Average, 4 points: Good, 5 points: Excellent.

[0095] Table 3

[0096] Sensory examination of coffee

[0097] Coffee types aroma smell Softness body hobby Comparative Example 1 4.5 4.4 4.2 4.3 Comparative Example 1 3.3 3.4 3.5 3.3 Comparative Example 2 3.8 3.7 3.8 3.5 Comparative Example 3 3.9 3.9 3.9 3.7 Comparative Example 4 4.0 4.0 4.0 3.9 Comparative Example 5 4.1 3.9 4.0 3.8

[0098] Sensory evaluation was performed on each coffee extract, and the results are shown in Table 3. The results show that the fermented coffee from Example 1 scored higher in all aspects than the coffee from Comparative Example 1, indicating that the fermented coffee from Example 1 has a high β-glucan content and good antioxidant activity, making it suitable for consumer preferences.

Claims

1. A method for preparing fermented coffee, characterized in that, include: (1) Add 4.5-5.5 g of Senna alexandrina and 4.5-5.5 g of Sorrel to 180-220 mL of water, extract at 90-110℃ for 2-4 hours, and then filter to prepare the extract; (2) Soaking green coffee beans in the extract prepared in step (1) for 5-10 hours at 18-22°C; (3) Lay ivy leaves on the tray of the sterilizer and place the soaked green coffee beans from step (2) on the ivy leaves, then sterilize at 110-130°C for 50-70 minutes and then cool. (4) The step of coating the grain solid inoculum onto the cooled green coffee beans in step (3) and culturing them at 18-22°C for 20-25 days; and (5) After isolating the grain solid inoculum from the coffee bean fermentation cultured in step (4), the grain solid inoculum is dried to a moisture content of 10-13%.

2. The method for preparing fermented coffee according to claim 1, characterized in that, Grains are one or more selected from a group consisting of brown rice, white rice, black rice, red rice, green rice, barley, rye, oats, sorghum, corn, mung beans, Job's tears, millet, red beans, and buckwheat.

3. A fermented coffee produced by the method of claim 1 or claim 2.

Images