JP7778321B2 - Method for producing alcoholic fermented honey - Google Patents

Description

The present invention relates to a method for producing an alcoholic fermentation product of honey.

Mead, made by fermenting honey, has long been produced in Europe and other regions. Honey is less susceptible to alcoholic fermentation than grape juice or wort, and the higher the honey's sugar content (honey-derived Brix), the more difficult it is to ferment. Therefore, traditionally, the honey was diluted with water so that its sugar content was less than 20%, and then fermented with yeast to produce alcohol, but even then the alcohol content reached was only around 2% to 3%. If the alcohol content of the produced alcohol is high, it is possible to either produce the product with the high alcohol content or adjust the alcohol content, allowing for greater freedom in production, so a high alcohol content is desirable for mead as well.

Therefore, in order to promote alcoholic fermentation of honey by yeast, various methods have been proposed to add additives to raw materials. For example, adding rice koji for shochu (see Patent Document 1), adding sake koji and brown sugar (see Patent Document 2), and adding peanut seed husks (see Patent Document 3) are some of them.

However, the applicants believe that a substance that promotes the alcoholic fermentation of honey should have a good image as an ingredient for mead and be popular with consumers.

Patent Document 1 also proposes adding rice koji for shochu to promote the alcoholic fermentation of honey, as well as increasing the alcohol content by carrying out alcoholic fermentation in two stages. Specifically, Patent Document 1 describes how the alcohol content can be increased by adding yeast to honey diluted with water, then adding rice koji for shochu to carry out primary fermentation, and then adding honey in an amount 1 to 1.5 times the weight used in the primary fermentation, and carrying out secondary fermentation. However, carrying out alcoholic fermentation in two stages has the problem of being a complicated and time-consuming process.

Patent No. 4376256 Japanese Patent Application Laid-Open No. 2005-158 Japanese Patent Application Laid-Open No. 2006-197933

In light of the above-mentioned circumstances, the first objective of the present invention is to provide a method for producing an alcoholic fermented product of honey that can increase the alcohol content by adding a substance that has a good image and is likely to be popular with consumers. The second objective is to provide a method for producing an alcoholic fermented product of honey that can increase the alcohol content using a simple process.

In order to solve the above problems, the method for producing an alcoholic fermented product of honey according to the present invention comprises the steps of:
"Alcoholic fermentation is carried out by maintaining a raw material liquid containing honey, water, yeast, and royal jelly protein hydrolysate at room temperature."

As mentioned above, honey is inherently difficult to ferment into alcohol, and simply fermenting honey with yeast results in an alcoholic fermentation product with a low alcohol content of only 2% to 3%. After examining a variety of ingredients, the inventors discovered that royal jelly protein hydrolysate promotes the alcoholic fermentation of honey, leading to the present invention.

"Alcoholic fermentation product of honey" refers to the alcoholic fermentation product of honey using yeast, before the solids are removed (clarified). Mead is obtained by clarifying the alcoholic fermentation product of honey. Furthermore, honey vinegar is obtained by further acetic acid fermentation of mead or the alcoholic fermentation product of honey before clarifying.

"Royal jelly protein hydrolysate" is made by hydrolyzing and depolymerizing proteins separated from royal jelly.

Since royal jelly protein hydrolysate is derived from royal jelly, which, like honey, is a bee product, it has a good image as a raw material ingredient for mead (and even honey vinegar), and is readily accepted by consumers. Therefore, the present invention solves the first problem of providing a method for producing an alcoholic fermentation product of honey that can increase the alcohol content by adding a substance that has a good image and is likely to be popular with consumers.

In addition to the above configuration, the method for producing an alcoholic fermented product of honey according to the present invention further comprises:
"The alcoholic fermentation is carried out in only one stage without adding honey again."

"One-stage" alcoholic fermentation differs from the two-stage alcoholic fermentation attempted in the aforementioned Patent Document 1, in that new honey is added after alcoholic fermentation by yeast has progressed to a certain extent, and this new honey is also subjected to alcoholic fermentation. In contrast, "one-stage" alcoholic fermentation is a production method in which no honey is added to the raw material liquid after alcoholic fermentation has begun.

In the present invention, royal jelly protein hydrolysate effectively promotes alcoholic fermentation of honey, making it possible to produce an alcoholic fermented honey product with a high alcohol content through a simple process of alcoholic fermentation at room temperature in only one stage. Therefore, in addition to the first object, the present invention also solves the second object of providing a method for producing an alcoholic fermented honey product that can increase the alcohol content through a simple process.

In addition to the above configuration, the method for producing an alcoholic fermented product of honey according to the present invention further comprises:
"The mass of the solid content of the honey is 25 g to 35 g and the mass of the royal jelly protein hydrolysate is 0.1 g to 4.0 g per 100 ml of the raw material liquid."

By using this configuration, it is possible to produce an alcoholic fermentation product of honey with a high alcohol content, at least 8% alcohol, as described in detail below.

Furthermore, as mentioned above, when honey has a high sugar content, i.e., when the honey solids content is high, it is difficult to ferment it into alcohol. However, in this configuration, the royal jelly protein hydrolysate promotes the alcoholic fermentation of honey, making it possible to produce an alcoholic fermented honey product with a high alcohol content, even though the honey solids content is very high, with a solids mass of 25g to 35g per 100ml of raw material liquid.

In addition to the above configuration, the method for producing an alcoholic fermented product of honey according to the present invention further comprises:
"The mass of the royal jelly protein hydrolysate is set to 0.5 g to 2.0 g."

By using this configuration, it is possible to produce an alcoholic fermented product of honey with an alcohol content of at least 10% or more, as described in detail below.

Furthermore, with this configuration, it is possible to produce an alcoholic fermented product of honey with a high alcohol content of at least 10% or more in a short fermentation period of two weeks or less, as will be described in detail below.

As described above, the present invention solves the first problem of providing a method for producing an alcoholic fermented product of honey that can increase the alcohol content by adding a substance that has a good image and is likely to be popular with consumers. It also solves the second problem of providing a method for producing an alcoholic fermented product of honey that can increase the alcohol content using a simple process.

A method for producing an alcoholic fermented product of honey, which is a specific embodiment of the present invention, is described below. In this embodiment, the method for producing an alcoholic fermented product of honey involves maintaining a raw material liquid containing honey, water, yeast, and royal jelly protein hydrolysate at room temperature, thereby causing alcoholic fermentation in a single stage. The resulting alcoholic fermented product can be separated into mead. For example, the supernatant after centrifugation of the alcoholic fermented product, the filtrate after filtration, or the filtrate after further filtration after centrifugation can be used to produce mead.

In this manufacturing method, royal jelly protein hydrolysate promotes the alcoholic fermentation of honey, making it possible to produce a high-alcohol fermented honey product, and ultimately a high-alcohol mead, in a practical fermentation period using honey that is normally difficult to ferment.

In the past, because it was not possible to obtain mead with a high alcohol content, it was common to add pre-made alcohol to a low-alcohol content liquid obtained by fermenting honey, a process known as "post-alcohol addition," to produce mead. In contrast, the production method of this embodiment produces an alcoholic fermentation product of honey with a high alcohol content, eliminating the need for such post-alcohol addition. Furthermore, because honey with a high sugar content is more difficult to ferment, it was common to produce mead from a low-sugar content raw material liquid by diluting honey with water, and then add honey to the mead to enhance the honey flavor, a process known as "post-honey addition." In contrast, the production method of this embodiment eliminates the need for such post-honey addition by alcoholically fermenting a raw material liquid containing a high amount of honey solids, thereby producing an alcoholic fermentation product of honey rich in honey flavor.

First, the results of a search for substances that promote the alcoholic fermentation of honey (hereinafter referred to as "fermentation promoters") are explained using Table 1. For the search, a raw material solution containing honey, water, yeast, and candidate fermentation promoters was used. The yeast concentration in the raw material solution was 5.0 x ¹⁰⁶ cells/ml, and the honey content per 100 ml (milliliters) of raw material solution was kept constant at 24 g. In addition, 0.18 g of lactic acid per 100 ml of raw material solution was added to the raw material solution in order to suppress the growth of unwanted bacteria during the alcoholic fermentation process.

As a fermentation promoter, we focused on royal jelly, which, like honey, is a bee product that has a good image as a raw material for mead and is likely to be popular with consumers.We prepared the following raw material solutions: Sample E1, in which raw royal jelly (referred to as "raw RJ" in the table) was used as the candidate substance; Sample E2, in which dried royal jelly (referred to as "dried RJ" in the table), which was made by drying and powdering raw royal jelly, was used as the candidate substance; Sample E3, in which the residue of royal jelly extracted with alcohol (referred to as "RJ extraction residue" in the table), was used as the candidate substance; Sample E4, in which royal jelly obtained by enzymatic hydrolysis (referred to as "RJ enzymatic hydrolysate" in the table), was used as the candidate substance; and Sample E5, in which royal jelly protein hydrolysate (referred to as "RJpep" in the table), which was made by enzymatic hydrolysis of the residue of royal jelly extracted with alcohol, was used as the candidate substance. Apart from bee products, a raw material solution of sample E6 was also prepared using diammonium phosphate ((NH ₄ ) ₂ HPO ₄ ), which is sometimes used as a culture medium for microorganisms, as the candidate substance.

The amount of each candidate substance added to the raw material solution was determined so that the amount of assimilable nitrogen was approximately the same. The amount of assimilable nitrogen was measured by formol titration using the Kyoto Electronics Manufacturing Co., Ltd. automatic titration system AT-710/CHA-700.

For comparison, a raw material solution of sample R was prepared in the same manner as above, except that no candidate substances for fermentation promotion were added. The raw material solutions of sample R and samples E1 to E6 were each kept at room temperature (25°C) for five days to allow alcoholic fermentation. The fermented solution was centrifuged (3000 rpm, 5 minutes), and the supernatant was filtered through quantitative filter paper, after which the alcohol content of the solution was measured. The alcohol content was measured using an SDK system manufactured by Kyoto Electronics Manufacturing Co., Ltd. The alcohol content of each sample is shown in Table 1.

As can be seen from Table 1, sample R, the comparative example (i.e., a sample to which no candidate substances for promoting fermentation were added), had a low alcohol content of 1.9%. However, sample E1, to which fresh royal jelly was added, and sample E2, to which dried royal jelly was added, had an even lower alcohol content of 0.1%, suggesting that alcoholic fermentation had hardly progressed. Decenoic acid, which is contained in royal jelly, is said to have antibacterial properties, and it is thought that in the raw material solutions containing fresh royal jelly and dried royal jelly, which contain decenoic acid, the antibacterial properties of decenoic acid inhibit alcoholic fermentation. This is supported by the fact that sample E3 and sample E5, from which decenoic acid was removed as an alcohol-soluble component, had higher alcohol content.

Samples E4 and E5, which were made by enzymatically hydrolyzing royal jelly or components derived from it, also had high alcohol content. This suggests that the reduction in molecular weight achieved by enzymatic hydrolysis has an advantageous effect on promoting alcoholic fermentation. Sample E5, which uses royal jelly protein hydrolysate that has undergone both the removal of decenoic acid and the reduction in molecular weight achieved by enzymatic hydrolysis, had the highest alcohol content and was found to be the most effective of the candidate substances listed above in promoting the alcoholic fermentation of honey by yeast.

The above confirmed that royal jelly protein hydrolysate has the ability to promote alcoholic fermentation of honey by yeast. Therefore, a more detailed study was conducted to examine its effect of promoting alcoholic fermentation in a raw material solution containing honey, water, yeast, and royal jelly protein hydrolysate, by varying the amount of royal jelly protein hydrolysate added. Furthermore, as mentioned above, alcoholic fermentation is difficult when honey has a high sugar content (high honey solids content). Therefore, to determine the extent to which the honey solids content can be increased by promoting alcoholic fermentation with royal jelly protein hydrolysate, the mass of honey solids added to the raw material solution was also varied.

Specifically, the yeast concentration in the raw material liquid was kept constant at 5.0 x ¹⁰⁶ cells/ml, the mass of honey solids per 100 ml of raw material liquid was varied to 25 g, 35 g, or 40 g, and the mass of royal jelly protein hydrolysate was varied to 0.1 g, 0.5 g, 1.0 g, 2.0 g, 4.0 g, 6.0 g, or 8.0 g for each, to prepare a total of 21 types of raw material liquid.

The royal jelly protein hydrolysate used here was "Royal Jelly Peptide Powder (product name)" manufactured by Nisshin Honey Co., Ltd. This is made by mixing dried royal jelly with ethanol, decomposing the precipitated insoluble royal jelly protein (equivalent to the ethanol extraction residue) with a protease, and purifying the resulting hydrolysate by filtration, then drying and powdering it.

The yeast used was the "Foam-Free G Yeast," a type of yeast that produces little foam and is part of the "G Yeast" series, an original yeast developed by Gifu Prefecture to support sake breweries within the prefecture. It has also been proposed to increase the yeast concentration in order to increase the alcohol content (see, for example, Japanese Patent No. 3121872). This patent document specifies an extremely high concentration of yeast per ml of honey water, ranging from 4 x ¹⁰ to 12 x ¹⁰ or more. In contrast, the yeast concentration of 5.0 x ¹⁰ cells/ml used in this embodiment is a typical concentration used in regular beer production.

The amount of lactic acid added to inhibit the growth of unwanted bacteria during the alcohol fermentation process was set at 0.2 g per 100 ml of raw material liquid.

Each prepared raw material liquid was kept at room temperature (25°C) to allow alcoholic fermentation, and the alcohol content was measured after a specified period of time. The timing for measuring the alcohol content was empirically determined to be when the carbon dioxide loss reached 10g, as this serves as an indicator of changes in alcohol content. The carbon dioxide loss was calculated by measuring the mass of the raw material liquid, including the container, on an electronic balance and calculating the mass loss from the previous measurement. Furthermore, the alcohol content was measured using the SDK system manufactured by Kyoto Electronics Manufacturing Co., Ltd., as described above.

Table 2 shows the measured alcohol content and the period up to the alcohol content measurement (fermentation period) for each raw material liquid. In Table 2, samples marked with an * in the fermentation period column are samples for which the rate of carbon dioxide loss tended to saturate before the carbon dioxide loss reached 10g, and fermentation was terminated before the carbon dioxide loss reached 10g, and the alcohol content was measured.

As shown in Table 2, when the mass of honey solids per 100 ml of raw material liquid was 25 g, a high alcohol content of 8% or more was obtained across the entire range of royal jelly protein hydrolysate masses from 0.1 g to 8.0 g. Up to a mass of 4.0 g, the fermentation period tended to decrease as the mass of royal jelly protein hydrolysate increased; however, as the mass of royal jelly protein hydrolysate increased beyond that, the fermentation period tended to increase and the alcohol content tended to decrease. This suggests that there is an optimum range for the amount of royal jelly protein hydrolysate added to promote the alcoholic fermentation of honey, and that adding too much does not have an advantageous effect on promoting alcoholic fermentation.

When the mass of honey solids was 35g per 100ml of raw material liquid, the mass of royal jelly protein hydrolysate that resulted in an alcohol content of 8% or more ranged from 0.1g to 4.0g. Up to a mass of 1.0g, the fermentation period tended to decrease as the mass of royal jelly protein hydrolysate increased. However, as the mass of royal jelly protein hydrolysate increased, the fermentation period tended to increase and the alcohol content tended to decrease. This also supports the idea that there is an optimum range for the amount of royal jelly protein hydrolysate added to promote the alcoholic fermentation of honey, and that adding too much does not have a beneficial effect on promoting alcoholic fermentation.

In addition, the time it took for the carbon dioxide loss to reach 10g was longer when the mass of honey solids per 100ml of raw material liquid was 35g than when it was 25g. Furthermore, when the mass of honey solids per 100ml of raw material liquid was 40g, only the sample with a mass of royal jelly protein hydrolysate of 1.0g had an alcohol content exceeding 8%. This suggests that adding too much royal jelly protein hydrolysate does not have an advantageous effect on promoting alcoholic fermentation, and that when the mass of honey solids is large, even if the mass of royal jelly protein hydrolysate is too small, it is insufficient to promote alcoholic fermentation.

As described above, honey is inherently difficult to alcoholically ferment, and previously only mead with an alcohol content of approximately 2% to 3% could be produced from honey diluted to a sugar content of 20 or less. However, according to the production method of this embodiment, the royal jelly protein hydrolysate promotes alcoholic fermentation of honey by yeast, making it possible to produce a high-alcohol fermented honey product from a raw material solution containing honey, water, and yeast, with a high solids content of 25 g to 35 g per 100 ml of raw material solution, i.e., a high-alcohol fermented honey product, from a raw material solution with a high sugar content.

In particular, when the mass of honey solids is 25 g to 35 g per 100 ml of raw material liquid containing honey, water, and yeast, and the mass of royal jelly protein hydrolysate is 0.1 g to 4.0 g, an alcoholic fermentation product of honey with an alcohol content of at least 8% or more (alcohol content 8.4% to 12.6%) can be produced through a single alcoholic fermentation stage.

Furthermore, when the mass of honey solids is 25g to 35g per 100ml of raw material liquid containing honey, water, and yeast, and the mass of royal jelly protein hydrolysate is 0.5g to 2.0g, it is possible to produce an alcoholic fermentation product of honey with a high alcohol content of at least 10% alcohol (10.3 to 12.6% alcohol) through a single alcoholic fermentation stage. This range has the advantage of allowing the fermentation period to be as short as two weeks or less (7 to 14 days), enabling the production of an alcoholic fermentation product of honey with a high alcohol content in a short period of time.

Furthermore, the manufacturing method of this embodiment makes it possible to produce a high-alcohol fermented honey product from honey that is not naturally prone to alcoholic fermentation, eliminating the need for the above-mentioned "post-alcohol addition" to increase the alcohol content. Mead produced by the manufacturing method of this embodiment will be labeled with ingredients such as "honey (origin)" and "royal jelly protein hydrolysate." In contrast, mead with post-alcohol addition will include "brewer's alcohol" in the ingredient labeling. Therefore, mead with a high alcohol content achieved by the manufacturing method of this embodiment and mead with an increased alcohol content due to post-alcohol addition can be distinguished "as a product" by the product labeling.

In addition, the manufacturing method of this embodiment uses a raw material liquid with a high mass of honey solids, which results in an alcoholic fermentation product of honey that is rich in honey flavor, and ultimately a mead that is rich in honey flavor. Therefore, there is no need to perform the "post-honey addition" described above for the purpose of adding honey flavor. Mead that has post-honey addition will have not only the honey flavor but also a sweet taste. In contrast, the manufacturing method of this embodiment can provide a mead that is rich in honey flavor, even if it is dry.

The present invention has been described above using preferred embodiments, but the present invention is not limited to the above embodiments, and as described below, various improvements and design modifications are possible without departing from the spirit of the present invention.

For example, in the above embodiment, lactic acid is added to the raw material liquid to suppress the growth of unwanted bacteria during the alcohol fermentation process, but lactic acid can be substituted for pH adjusters commonly used in food production, such as citric acid.

In addition to producing mead as the final product, the method for producing an alcoholic fermented product of honey of the present invention can also be used as part of a production method in which the alcoholic fermented product of honey obtained by alcoholic fermentation, or the mead after separation, is further subjected to acetic acid fermentation to produce honey vinegar.

Furthermore, while the above embodiment illustrates a case in which alcoholic fermentation is carried out in only one stage without adding honey again, this does not exclude a production method in which alcoholic fermentation is carried out multiple times.

Claims (3)

A raw material liquid containing honey, water, yeast, and royal jelly protein hydrolysate is kept at room temperature to cause alcoholic fermentation ,
The mass of the solid content of the honey is set to 25 g to 35 g and the mass of the royal jelly protein hydrolysate is set to 0.1 g to 4.0 g per 100 ml of the raw material liquid.
A method for producing an alcoholic fermentation product of honey, comprising: 2. The method for producing an alcoholic fermented product of honey according to claim 1, wherein the alcoholic fermentation is carried out in a single step without adding honey again. The method for producing an alcoholic fermentation product of honey according to claim 1 or 2, characterized in that the mass of the royal jelly protein hydrolysate is 0.5 g to 2.0 g.