JP2024047508A - Licorice smell reduction method - Google Patents

Abstract

To provide a method for reducing a licorice smell without any complicated processes, a licorice extract whose licorice smell is reduced, and a production method thereof.SOLUTION: The inventors have found that at least one of licorice or a licorice extract can be subjected to yeast body reaction in presence of water to thereby have a reduced licorice smell.SELECTED DRAWING: None

Description

The present invention relates to a method for reducing licorice odor, a licorice extract having a reduced licorice odor, and a method for producing the same.

Licorice is a perennial plant of the genus Glycyrrhiza in the family Fabaceae, and its roots and stolons (a type of stem) are used as herbal medicines and sweeteners, and its flavonoid components are known to be useful as antioxidants. However, licorice has a unique odor called licorice odor, which can be a hindrance when it is used as food or beverage.

For example, Patent Document 1 describes a method for producing an antioxidant and antibacterial substance that does not contain odorous components by dissolving licorice extract in a solvent oil and performing molecular distillation.

Japanese Patent Application Laid-Open No. 62-223291

The present invention provides a method for reducing licorice odor without complicated steps, a licorice extract having a reduced licorice odor, and a method for producing the same.

The inventors have found that the licorice odor can be reduced by subjecting at least one of licorice or a licorice extract to a yeast cell reaction in the presence of water, and have completed the present invention.

That is, the present invention relates to the following aspects [1] to [10].
[1] A method for reducing licorice odor, comprising reacting at least one of licorice or a licorice extract with yeast cells in the presence of water to reduce the licorice odor.
[2] The method for reducing licorice odor described in [1], wherein the reaction time with the fungal cells is less than 24 hours.
[3] A method for producing a licorice extract, comprising reacting at least one of licorice or a licorice extract with yeast cells in the presence of water to reduce the licorice odor, and then heat-treating the cell reaction liquid to obtain a licorice extract with a suppressed licorice odor.
[4] The method for producing a licorice extract according to [3], wherein the reaction time with the fungal cells is less than 24 hours.
[5] A method for producing a licorice extract according to [3] or [4], characterized in that the heat-treated bacterial reaction solution is adjusted to a pH of 5.0 or less, and then subjected to solid-liquid separation to recover the liquid portion.
[6] A method for producing a licorice extract according to [3] or [4], characterized in that the heat-treated bacterial reaction solution is subjected to an enzymatic treatment with an enzyme having β-glucosidase activity.
[7] A licorice extract having a reduced licorice odor, which is obtained by reacting at least one of licorice or a licorice extract with yeast cells in the presence of water.
[8] The licorice extract according to [7], which is substantially free of glycyrrhizin.
[9] The licorice extract according to [7] or [8], which contains more liquiritigenin than liquiritin.
[10] A food or drink comprising the licorice extract according to [7] or [8].

According to the present invention, the licorice odor of licorice extract can be easily reduced by reacting with yeast cells, and a licorice extract with a suppressed licorice odor can be provided. Furthermore, the provision of a licorice extract with a suppressed licorice odor enables the licorice extract to be used in a wide range of applications, and the addition of the licorice extract can provide foods and beverages with high added value.

In the present invention, the licorice odor can be reduced by reacting at least one of licorice or a licorice extract with yeast cells in the presence of water, and a licorice extract with a suppressed licorice odor can be obtained. It is preferable to carry out the cell reaction under aerobic conditions, and it is preferable to carry out a heat treatment after the cell reaction. Furthermore, it is preferable to reduce glycyrrhizin in the licorice extract by adjusting the pH to 5.0 or less after the heat treatment, and then recovering the liquid portion by solid-liquid separation. It is also preferable to add an enzyme having β-glucosidase activity to carry out an enzymatic treatment to obtain a licorice extract containing more liquiritigenin than liquiritin.

The varieties of licorice described in the present invention include Glycyrrhiza uralensis , G. glabra , G. inflata , etc., and their roots, rhizomes, etc. can be used. The licorice used for the enzyme treatment can be a coarsely crushed licorice raw material, a powder, etc., or an extraction residue, or it can be a licorice extract extracted from the licorice raw material using water, an organic solvent, or a mixture thereof, or it can be a mixture of licorice and licorice extract, or it can be any of the above-mentioned various dried products.

Examples of the yeast according to the present invention include bacteria belonging to the genus Saccharomyces, such as Saccharomyces cerevisiae, Saccharomyces bayanus, and S. pastorianus; bacteria belonging to the genus Schizosaccharomyces, such as Schizosaccharomyces pombe; bacteria belonging to the genus Candida, such as Candida utilis; and bacteria belonging to the genus Kluyveromyces, such as Kluyveromyces marxianus. These bacteria may be used alone or in combination of two or more.

The bacterial cell reaction described in the present invention is not particularly limited as long as it can reduce the licorice odor of the licorice extract, but can be carried out by mixing at least one of licorice or licorice extract with yeast cells in the presence of water and reacting them, and commercially available yeast cells may be used, or a culture of yeast cultured by a known method may be mixed and reacted. Although it is not particularly limited as long as the licorice extract of the present invention can be obtained, at the start of the reaction, it is preferable that the yeast is contained in an amount of 1 x ¹⁰⁶ to 1 x ¹⁰¹⁰ cfu per 1 g of licorice, more preferably 5 x ¹⁰⁶ to 5 x ¹⁰⁹ cfu, and even more preferably 1 x ¹⁰⁷ to 1 x ¹⁰⁹ cfu.

The reaction conditions are preferably aerobic conditions such as stirring by shaking or the like and aeration, and the water content during the reaction is preferably 50 to 98% by weight, more preferably 60 to 95% by weight. The reaction temperature is preferably 10 to 50° C., more preferably 20 to 45° C. The reaction time is not particularly limited as long as the licorice odor can be reduced, but is preferably less than 24 hours, more preferably 5 minutes to 20 hours, even more preferably 10 minutes to 16 hours, particularly preferably 20 minutes to 12 hours, and most preferably 30 minutes to 6 hours. By carrying out the reaction in a short time, the licorice odor can be reduced while costs can be reduced.

In the present invention, it is preferable to heat treat the bacterial cell reaction solution after the bacterial cell reaction to perform sterilization or the like. The heating temperature can be, for example, 50 to 150° C., preferably 60 to 140° C., more preferably 70 to 130° C., and even more preferably 80 to 125° C. The heating time can be, for example, 1 minute to 6 hours, preferably 2 minutes to 5 hours, and more preferably 5 minutes to 3 hours. The heating may be performed under any of normal pressure conditions, pressurized conditions, and reduced pressure conditions, but pressurized conditions are preferred.

In the present invention, in addition to suppressing the licorice odor of the licorice extract, it is preferable to reduce the glycyrrhizin in the licorice extract, and after the heat treatment, the pH may be adjusted to preferably 5.0 or less, more preferably 4.5 or less, and even more preferably 3.0 to 4.0, and then the solution may be recovered by solid-liquid separation. The pH can be adjusted using an organic acid such as citric acid, lactic acid, or acetic acid, or an inorganic acid such as hydrochloric acid, phosphoric acid, or sulfuric acid. The liquid portion can be recovered by solid-liquid separation, for example, by cross-flow filtration, diatomaceous earth filtration, filter filtration, or centrifugation.

In the present invention, it is also preferable to make the licorice extract contain more liquiritigenin than liquiritin, and it is preferable to add an enzyme having β-glucosidase activity to the heat-treated bacterial cell reaction solution to perform enzymatic treatment. If it is after the bacterial cell reaction, the solution obtained by adjusting the pH to 5.0 and separating the solid and liquid may be enzymatically treated. By this enzymatic treatment, the glycoside liquiritin is converted to the aglycone liquiritigenin, and the absorbability of flavonoids useful as antioxidants and the like into the body can be increased. The enzyme used for the enzymatic treatment is not particularly limited as long as it has β-glucosidase activity, and examples thereof include enzymes derived from microorganisms such as Penicillium, Aspergillus, Pseudomonas, Rhizomucor, Cryptococcus, and Microbacterium, and enzymes derived from plants such as almond. Examples of enzyme preparations that can be used include Aromase (registered trademark) (manufactured by Amano Enzyme Co., Ltd.), Sumiteam (registered trademark) BGA (manufactured by Shin Nippon Chemical Industry Co., Ltd.), and the like. Furthermore, other enzymes such as cellulase, hemicellulase, pectinase, naringinase, hesperidinase, protease, and lipase may be used in combination.

The enzyme treatment may be carried out in the presence of water, and the water content during the enzyme treatment is not particularly limited as long as the enzyme-treated product of the present invention can be obtained, but is preferably 40 to 99% by weight, more preferably 50 to 98% by weight. The amount of enzyme added is not particularly limited as long as the enzyme reaction can be carried out under the conditions, but is preferably 0.1 to 30 parts by weight, more preferably 0.2 to 20 parts by weight, when the solid content derived from the licorice raw material is 100 parts by weight as an enzyme preparation. The treatment conditions can be appropriately set in consideration of the optimal pH and temperature of the enzyme, and the pH and temperature stability, and examples thereof include treatment at pH 2 to 8 and 10 to 70°C, and preferably pH 3 to 7 and 20 to 60°C. The treatment time can be appropriately adjusted depending on the treatment conditions, and examples thereof include 5 minutes to 30 hours, and preferably 10 minutes to 24 hours.

The licorice extract of the present invention can be produced by the method described above. The licorice extract may be made into a concentrated or dried product by vacuum concentration, membrane concentration, drum drying, air drying, spray drying, vacuum drying, freeze drying, or a combination thereof.

The licorice extract of the present invention is not particularly limited as long as it is a licorice extract with a suppressed licorice odor, but it is preferable that the licorice odor is weaker and almost undetectable compared to a licorice extract that has not been subjected to a yeast cell reaction. By suppressing the licorice odor, the effect of the licorice odor on the final food or drink when using the licorice extract can be suppressed, and the licorice extract can be used widely.

In addition, the licorice extract of the present invention is preferably a licorice extract with a suppressed licorice odor, and is further preferably a licorice extract that is substantially free of glycyrrhizin, and "substantially free of glycyrrhizin" means that, in the measurement of glycyrrhizin in a sample, when a reversed-phase column C18 is used in HPLC and an absorption spectrum at 254 nm is measured with a UV detector, the amount is below the detection limit, and more specifically, when glycyrrhizin is measured under the HPLC conditions described in the Examples, the amount is below the detection limit. By being substantially free of glycyrrhizin, the glycyrrhizin content in the licorice extract can be suppressed, and therefore excessively strong sweetness can be suppressed, and by suppressing the sweetness that is a problem when using the licorice extract for purposes other than as a sweetener, the licorice extract can be widely used.

The licorice extract of the present invention preferably contains liquiritigenin, and the liquiritigenin content per 1 g of solid content is preferably 0.5 μg or more, more preferably 1.0 μg or more, even more preferably 1.5 μg or more, particularly preferably 3.0 μg or more, and most preferably 5.0 μg or more. It is also preferable to obtain 0.2 mg or more, more preferably 0.3 mg or more, even more preferably 0.5 mg or more, and particularly preferably 1 mg or more of liquiritigenin per 1 g of licorice raw material.

Furthermore, the licorice extract of the present invention preferably contains more liquiritigenin than liquiritin, and is not particularly limited as long as the liquiritigenin content in the licorice extract is greater than the liquiritin content, but the liquiritigenin content is preferably 1.5 times or more than the liquiritin content, more preferably 2 times or more, even more preferably 5 times or more, and particularly preferably contains liquiritigenin and does not substantially contain liquiritin.The term "does not substantially contain liquiritin" means that when the liquiritin in a sample is measured by using a reversed phase column C18 in HPLC and measuring the absorption spectrum at 254 nm with a UV detector, it is below the detection limit, and more specifically, when liquiritin is measured under the HPLC conditions described in the examples, it is below the detection limit.

The licorice extract of the present invention can be added to various foods and beverages. The amount of licorice extract added is not particularly limited, but the content of licorice extract in various foods and beverages is preferably 0.001 to 50% by weight, more preferably 0.005 to 20% by weight, and even more preferably 0.01 to 10% by weight, and each food and beverage contains preferably 0.1 to 200 mg of liquiritigenin, and more preferably 0.2 to 100 mg.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. In the present invention, all percentages are by weight unless otherwise specified.

0.2 g of yeast (Kaneka Instant Dry Yeast Green, Kaneka Foods Co., Ltd.) and 36 g of tap water were added to 4 g of licorice powder (Fukuda Ryu Co., Ltd.), and reacted with the bacteria while shaking at 37° C. for 1 hour, and then heat-treated (90° C., 10 minutes). Next, the pH of the heat-treated bacterial reaction solution was adjusted to 3.5 with citric acid (Example 1-1) or without pH adjustment (Example 1-2), and centrifuged (2000×G, 10 minutes) to recover the supernatant, thereby obtaining 26.5 g of licorice extract of Example 1-1 and 26 g of licorice extract of Example 1-2.

[Comparative Example 1]
36 g of tap water was added to 4 g of licorice powder (manufactured by Fukuda Ryu Co., Ltd.), and the mixture was shaken at 37° C. for 1 hour, followed by heat treatment (90° C., 10 minutes). Next, the mixture was centrifuged (2000×G, 10 minutes) without pH adjustment (Comparative Example 1-1) or after adjusting the pH to 3.5 with citric acid (Comparative Example 1-2), and the supernatant was collected to obtain 27 g of licorice extract of Comparative Product 1-1 and 27 g of licorice extract of Comparative Product 1-2.

[Evaluation test]
For Example Product 1-1, Example Product 1-2, Comparative Product 1-1, and Comparative Product 1-2, the pH and solid content were measured according to a conventional method, and the contents of liquiritin, liquiritigenin, and glycyrrhizin were measured using HPLC under the following conditions, with the results shown in Table 1. In addition, each extract was diluted 10 times with tap water and the flavor was evaluated, with the results shown in Table 1. The flavor was evaluated as follows: ◯ for almost no licorice odor, × for a strong licorice odor, ◯ for almost no sweetness, and × for a strong sweetness.
<HPLC measurement conditions>
Detector: UV detector (254 nm)
Column: Inertsil ODS-EP (inner diameter 4.6 mm, length 250 mm, manufactured by GL Sciences Inc.)
Mobile phase A: 15% by volume acetonitrile aqueous solution (containing 0.1% by volume phosphoric acid)
Mobile phase B: 80% acetonitrile aqueous solution (containing 0.1% phosphoric acid)
Gradient: Mobile phase A to mobile phase B gradient (50 min)
Flow rate: 0.8 ml/min Column temperature: 40° C.
Standards: Liquiritin (for official herbal medicine testing, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), Liquiritigenin (for official herbal medicine testing, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and Glycyrrhizin (for official herbal medicine testing, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were each appropriately diluted with 50% by volume acetonitrile aqueous solution, and calibration curves for each were prepared.

The licorice extracts of the examples 1-1 and 1-2 obtained by carrying out a bacterial cell reaction using yeast had almost no licorice odor, and it was found that the licorice odor was suppressed compared to the strong licorice odor of the licorice extracts of the comparative examples 1-1 and 1-2 not carrying out a bacterial cell reaction. In addition, by adjusting the heat-treated bacterial cell reaction liquid to an acidic state and recovering the centrifugal supernatant, a licorice extract with almost no sweetness was obtained, and glycyrrhizin was not detected in this licorice extract under the above measurement conditions.

0.4 g of yeast (Saf Instant Yeast Gold, Lesaffre) and 36 g of tap water were added to 4 g of licorice powder (Fukuda Ryu Co., Ltd.), and reacted with the bacteria while shaking at 30°C for 3 hours, and then heat-treated at 90°C for 10 minutes (Examples 2-1 and 2-3) or at 121°C for 10 minutes (Examples 2-2 and 2-4). Next, the pH of the heat-treated bacterial reaction solution was adjusted to 3.5 with citric acid (Examples 2-1 and 2-2) or was not adjusted (Examples 2-3 and 2-4), and centrifuged (2000 x G, 10 minutes) to recover each supernatant. To each supernatant, 0.02 g of Sumizyme (registered trademark) BGA (manufactured by Shin Nippon Chemical Industry Co., Ltd.), a β-glucosidase preparation, was added and subjected to enzyme treatment at 60° C. for 1 hour, thereby obtaining 24 g of licorice extract as Example 2-1, 24.5 g of licorice extract as Example 2-2, 24 g of licorice extract as Example 2-3, and 24.5 g of licorice extract as Example 2-4. Evaluation tests were performed on Examples 2-1 to 2-4 in the same manner as above, and the results are shown in Table 2.

Finally, in the embodiment samples 2-1 to 2-4 obtained by enzymatic treatment with a β-glucosidase preparation, liquiritin was not detected under the above measurement conditions, and liquiritigenin was detected at 315 to 412 ppm. In addition, by adjusting the temperature to acidic after heat treatment and recovering the centrifugal supernatant, a licorice extract with almost no sweetness was obtained, and glycyrrhizin was not detected in the licorice extract under the above measurement conditions. Furthermore, in the heat treatment after the reaction of the fungus body, the pressurized heating gave a slightly higher liquiritigenin content after the enzymatic treatment than the normal pressure heating, but it was found that either heating condition was acceptable.

Claims (10)

A method for reducing licorice odor, comprising reacting at least one of licorice or a licorice extract with yeast cells in the presence of water to reduce the licorice odor. 2. The method for reducing licorice odor according to claim 1, wherein the reaction time with the fungus is less than 24 hours. This method for producing a licorice extract is characterized in that at least one of licorice or a licorice extract is reacted with yeast cells in the presence of water to reduce the licorice odor, and the reaction liquid of the cells is heat-treated to obtain a licorice extract with a suppressed licorice odor. 4. The method for producing a licorice extract according to claim 3, wherein the reaction time with the fungus is less than 24 hours. 5. The method for producing a licorice extract according to claim 3 or 4, characterized in that the heat-treated bacterial reaction liquid is adjusted to a pH of 5.0 or less, and then subjected to solid-liquid separation to recover the liquid portion. 5. The method for producing a fermented licorice extract according to claim 3 or 4, characterized in that the heat-treated bacterial reaction solution is treated with an enzyme having β-glucosidase activity. The licorice extract having a reduced licorice odor is obtained by reacting at least one of licorice and a licorice extract with yeast cells in the presence of water. 8. The licorice extract of claim 7, which is substantially free of glycyrrhizin. 9. The licorice extract according to claim 7 or 8, which contains more liquiritigenin than liquiritin. A food or drink comprising the licorice extract according to claim 7 or 8.