JPH07147972A - New saccharomyces cerevisiae and use thereof - Google Patents

Abstract

PURPOSE:To obtain the yeast capable of producing SAKE (Japanese rice wine) having organoleptically prominent characteristics such as the possession of an aroma entirely different in elegance from that of conventional SAKE in an aroma which is perceived in keeping the SAKE in the mouth and has not hitherto been strongly felt so much in the conventional SAKE and provide a method for screening the yeast. CONSTITUTION:This yeast belongs to Saccharomyces cerevisiae and is capable of manifesting the sensitivity to a culture medium containing 2mM/l caproic acid. This method for screening the yeast from yeasts belonging to the genus Saccharomyces is to select the yeast capable of manifesting the sensitivity to the culture medium containing 2mM/l caproic acid by using a culture medium containing 2 to 5mM/l caproic acid. Furthermore, the method for producing SAKE is to use the yeast.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention contains yeasts belonging to Saccharomyces cerevisiae which are sensitive to a medium containing 2 mM / l of caproic acid, yeasts belonging to the genus Saccharomyces containing 2 mM / l to 5 mM / l of caproic acid. The present invention relates to a yeast screening method comprising selecting a yeast having sensitivity to a medium containing 2 mM / l of caproic acid by using the medium, and a method for producing sake by producing sake using the above yeast.

[0002]

2. Description of the Related Art The scent of sake is an important factor in determining quality. Isoamyl acetate, ethyl caproate, and the like are known as the gorgeous scent components of sake. These scent components produce the scent of sake as a rising scent, but they are also important components in the scent.
Here, the standing scent is a scent that is felt when the boar mouth is brought close to the nose when drinking sake, and the incense scent is a scent that is felt when it is contained in the mouth.

Conventionally, in order to obtain sake with a high aroma, highly refined rice has been used or a method of brewing at a temperature lower than a normal fermentation temperature has been used. A method that combines both elements is so-called ginjo-zukuri, and using this method, sake with a distinctive aroma called ginjo-ka can be brewed. In addition, recently, a method of mutating yeast to obtain sake with high aroma has been developed, and 5,5,5-trifluoro-D, L-leucine resistant strain is used to obtain sake with high aroma of isoamyl acetate. And the method using a 4-aza-D, L-leucine resistant strain (JP-A-1-257423). In addition, there is a method using a cerulenin-resistant strain to obtain sake having a high scent of ethyl caproate (JP-A-63-309175). Further, a method for obtaining sake with high aroma of both by using a canavanine-resistant strain (JP-A-2-1)
3368) is also known.

[0004]

[Problems to be Solved by the Invention] Conventional sake having a high fragrance, that is, sake obtained by low-temperature brewing using high-polished rice typified by Ginjo liquor, is a so-called ginjo fragrance with a sensory excellent scent. Have. Ginjo incense is mainly composed of esters such as ethyl caproate and isoamyl acetate, and you can feel a banana-like incense or apple-like incense. They are similar to each other because they are characterized by Ginjo scent, and they are uniform.

Also, in the case of conventional sake using mutated yeast, ethyl caproate and isoamyl acetate are the main components, and although the scent is very strong, it is still included in the category of Ginjo scent and is standard. Further, there is a case that the balance of the scent is disturbed by an artificial operation, and the components contained in a large amount have an adverse effect such that the scent and taste are unpleasant.

[0006] In view of the present situation, the present inventors have proposed a novel yeast, a screening method for the yeast, and a sake using the yeast, for producing sake that gives an excellent aroma as a novel aroma different from ginjo aroma. To provide a manufacturing method of.

[0007]

[Means for Solving the Problems] The present inventors have conducted intensive studies to produce sake having a good flavor. From the yeasts belonging to the genus Saccharomyces, caproic acid was converted to caproic acid using a medium containing caproic acid. When we screened the yeast showing susceptibility, it was found that caproic acid 2
It was found that yeast showing sensitivity in the medium containing mM / l gave excellent sake having a strong overtone scent which felt a mango-like aroma and a guaber-like aroma different from ginjo aroma. Moreover, the present yeast does not have resistance to each of 5,5,5-trifluoro-D, L-leucine, 4-aza-D, L-leucine, cerulenin and canavanine, and Confirmed that they are different.

The present invention was completed based on the above findings, and caproic acid is selected from yeasts belonging to the genus Saccharomyces, which belong to Saccharomyces cerevisiae and are sensitive to a medium containing 2 mM / l of caproic acid. 2 mM
A method for screening yeast, which comprises selecting a yeast showing sensitivity to a medium containing 2 mM / l of caproic acid using a medium containing 1 / l to 5 mM / l, and producing sake using the above yeast Is a method of producing sake.

The yeast of the present invention is obtained as follows. Preferably, a suspension of sake brewing yeast containing the mutant strain is smeared on an ordinary medium and cultured to produce colonies. Then, the same colony is inoculated into both of the screening medium not containing caproic acid and the screening medium containing caproic acid, and then cultured. By comparing both cultures, a strain that grows in a medium containing no caproic acid but does not grow in a medium containing caproic acid is selected as a caproic acid sensitive strain.

[0010] Since caproic acid is a growth inhibitor for yeast, the increased sensitivity to caproic acid compared to the parent strain is presumed to have caused some change in cell membrane function. When normal sake brewing is carried out using this caproic acid-sensitive strain, sake which has a strong overtone aroma different from the ginjo aroma is obtained organoleptically. As the yeast for sake brewing, any yeast may be used as long as it is a yeast usually used for sake brewing.
No. 8, No. 9, No. 10, No. 10 and other association-type yeasts are preferable,
In particular, Association Nos. 701 and 901 are preferable because good incense can be obtained.

These yeasts for sake brewing are usually subjected to mutation treatment and then screened by the above means. Examples of the mutagenesis treatment for obtaining the mutant strain include chemical mutagenesis using a mutagenizing agent such as ethyl methanesulfonate, N-methyl-N-nitro-N-nitrosoguanidine, nitrous acid, and acridine dye. Alternatively, a physical mutation using ultraviolet rays, radiation or the like may be used. In addition, the target strain can be obtained by natural induction with a very low probability even without performing mutation treatment.

As the screening medium used in the present invention, for example, glucose, sucrose, galactose, maltose, etc. which can be assimilated are used as the carbon source, and ammonium sulfate, urea, ammonium dihydrogen phosphate etc. are used as the nitrogen source. Is used to which inorganic salts and vitamins are added. Particularly preferred is a yeast nitrogen base manufactured by Difco, to which glucose has been added.

The concentration of caproic acid in the medium used for screening the caproic acid-sensitive strain is 2 mM / l to 5
mM / l, preferably 3 mM / l to 4 mM / l. If the concentration is 5 mM / l or more, all the strains cannot grow, and if the concentration is 2 mM / l or less, all the strains grow well, and in any case, screening cannot be performed. Culturing in the screening medium may be performed under ordinary conditions, and the culturing temperature is generally 20 to 30 ° C, preferably 30 ° C.
Before and after, the number of culture days is 1 to 7 days, preferably about 3 days. Regarding the susceptibility, it is judged that the susceptibility is as follows when the number of cells in the medium containing caproic acid is less than half that of the medium in the screening medium not containing caproic acid. It is preferable that the growth is hardly observed.

As a yeast thus screened, a yeast belonging to Saccharomyces cerevisiae and showing sensitivity to a medium containing 2 mM / l of caproic acid was obtained. One strain of the yeast was Saccharomyces cerevisiae K7.
The strain was named 01-A10 (hereinafter abbreviated as K701-A10), and the strain was deposited under the deposit number FERM P-13985 at the Institute of Biotechnology, Institute of Industrial Science and Technology.

Next, in producing sake using the present yeast, it can be produced according to a conventional method for producing a regular brewed sake or ordinary sake, or according to a method for producing a ginjo sake. For example, in the method for producing a brewed liquor, rice as a raw material is Yamada Nishiki, 500 million stones, Nihonbare, etc., generally at a rice polishing rate of 50 to 70%, preferably at a rice polishing rate of 60 to 70%.
Used as. The koji is then made in the koji room for 2-3 days. In the method for producing ordinary sake, the above raw rice is used at a rice polishing rate of 60 to 75%, preferably at a rice polishing rate of 70%.

[0016] As a charging method, for example, a normal three-stage charging is used for fermentation for 12 to 24 days at 10 to 20 ° C. The yeast used here is a jar fermenter, and molasses contains ammonium sulfate, urea, potassium dihydrogen phosphate,
The cells were cultured in a medium containing magnesium sulfate at 30 ° C. for 1 day, and the cells were collected and washed. The moromi fermented in this manner is separated into sake and lees by a conventional method to obtain the desired sake.

[0017]

EXAMPLES Examples of the present invention will now be described in detail, but the present invention is not limited thereto.

[0018]

[Example 1] Association 701 distributed from the Japan Brewing Association
No. (hereinafter abbreviated as K701) is a complete medium YP
D medium (1% yeast extract, 2% peptone, 2 glucose
%), And cultured at 30 ° C. for 1 day. This was collected and washed, and a 0.2 M / l phosphate buffer solution (pH 8.0) containing 2% glucose and 0.3% ethyl methanesulfonate.
After the suspension, the cells were shaken at 30 ° C. for 1 hour for mutation treatment.

The mutagenized yeast suspension was smeared on the agar medium of the above YPD medium and cultured to form colonies.
Then, a screening medium, YNB agar medium (Difco Yeast Nitrogen Base 0.67)
%, Glucose 2%, agar 2%) and caproic acid 3
Inoculation of both YNB agar medium containing mM / 1 to
It was cultured at 30 ° C. for 3 days. YNB without caproic acid
A colony that grew on the agar medium and did not grow on the YNB agar medium containing caproic acid was selected as a caproic acid-sensitive strain. One of the strains obtained here was inoculated into a YPD medium having a glucose concentration of 10% and cultured at 30 ° C. for 7 days, and the concentrations of isoamyl acetate, ethyl caproate, etc. in the medium were measured. The results are shown in Table 1.

[0020]

[Table 1]

As shown in Table 1, in the medium in which the obtained caproic acid-sensitive strain (K701-A10) was cultured, the parent strain (K
701), the amount of isoamyl acetate and ethyl caproate was slightly higher and the amount of caproic acid was slightly lower than that of the culture medium. Furthermore, regarding K701-A10, 5, 5, 5-
A resistance test was carried out for trifluoro-D, L-leucine, 4-aza-D, L-leucine, cerulenin, and canavanine. The results are shown in Table 2.

[0022]

[Table 2]

From the results shown in Table 2, K701-A10 was obtained from these 5,5,5-trifluoro-D, L-leucine, 4-
It was confirmed that it was a susceptible strain, showing no resistance to any of aza-D, L-leucine, cerulenin and canavanine. The resistance test was conducted on YNB agar medium.
5,5-trifluoro-D, L-leucine, 4-aza-
K701-A10 was cultured at 30 ° C. for 7 days on a medium containing D, L-leucine, cerulenin and canavanine at 1 mM / l, 48 mM / l, 0.025 mM / l and 0.34 mM / l, respectively, to form colonies. The method of determining the presence or absence of resistance was used depending on whether or not to do.

[0024]

Example 2 Sake was produced by using the yeasts of K701-A10 and K701 with the preparations shown in Table 3.

[0025]

[Table 3]

As the raw material rice, Nihonbare (produced in 1992) was milled to a rice polishing rate of 70% and used. Koji is 2 according to the standard method
Koji was made daily in the koji room. The preparation method was divided into 3 days, the first day was first added, the first day was set, the third day was added, and the fourth day was added, followed by fermentation at 13 ° C. for 15 days. Yeast was added at 1 g by wet cell weight at the time of initial addition. The yeasts used here were cultured in a medium containing molasses 10%, ammonium sulfate 0.5%, urea 1%, potassium dihydrogen phosphate 0.5%, and magnesium sulfate 0.05% at 30 ° C. for 1 day. Then
Bacteria were collected and washed. After the fermentation was completed, the lees and sake were separated by a conventional method. The ingredients of the sake thus obtained are shown in Table 4.

[0027]

[Table 4]

As shown in Table 4, the results of K7 were the same as those in Table 1.
01-A10 contained slightly more isoamyl acetate and ethyl caproate and slightly less caproic acid than K701. In addition, 20 panelists performed a sensory evaluation of both sake using a two-point preference method, and the results are shown in Table 5.

[0029]

[Table 5]

In the sake obtained according to the present invention, the amount of isoamyl acetate and ethyl caproate, which are the main components of the ginjo scent, was only slightly higher in terms of instrumental analysis. 16 people recognized it as a liquor with a high aroma, and a statistically significant difference was recognized at a risk rate of 5% or less.

[0031]

[Example 3] Next, under the same conditions as Example 2, 2190
26 kg of alcohol for brewing (100% concentration) was added to this to make it a real brewed sake, and it was stored in the upper tank for 3 months. This was lowered, and water was added to adjust the alcohol concentration to 15%. This test liquor and the commercially available ginjo liquor, junmai liquor, undiluted liquor, honjo liquor, and Kamijo ordinary liquor (5 points each) were used as the sukiki liquor by the 20 panelists. Table 6 shows the evaluation results of the standing scents of representative panelists, Table 7 shows the evaluation results of the scents of the panelists, and Table 8 shows a summary of the evaluation results of all the panelists.

[0032]

[Table 6]

[0033]

[Table 7]

[0034]

[Table 8]

As a result, 4 points and 3 points of high scent of ginjo sake and honjoshu, respectively, are normal ginjo scents with both an incense and incense, while other sake has both an incense and scent. It was few. Regarding the scent characteristics of this ginjo scent, many panelists pointed out the fresh feeling common to banana-like and apple-like scents. On the other hand, the sake produced by the method of the present invention has a strong aroma different from the usual ginjo aroma, and a plurality of panelists have a strong glossy sensation that is common with the fruit mango-like aroma and guaber-like aroma. It pointed out. Thus, it was evaluated that the sake according to the method of the present invention has a unique and preferable aroma in containing aroma, which is completely different from other sake.

When all of the 26 brands were exposed to the sake of the present invention in a blind test, all of them answered correctly, and all of them recognized that the location of the judgment was incense.

[0037]

INDUSTRIAL APPLICABILITY According to the present invention, a yeast that belongs to Saccharomyces cerevisiae and is sensitive to a medium containing 2 mM / l of caproic acid can be provided, and a screening method therefor can be provided. It is possible to provide a method for producing sake having a sensually distinctive characteristic that it has a scent that is completely different from that of sake in the scent that is not so strongly conscious of conventional sake.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C12R 1: 865)

Claims (4)

[Claims] 1. A yeast belonging to Saccharomyces cerevisiae and sensitive to a medium containing 2 mM / l of caproic acid. 2. The yeast is Saccharomyces cerevisiae K.
The yeast according to claim 1, which is 701-A10 (FERM P-13985). 3. A yeast showing sensitivity to a medium containing 2 mM / l of caproic acid is selected from yeasts belonging to the genus Saccharomyces by using a medium containing 2 mM / l to 5 mM / l of caproic acid. Screening method for yeast. 4. A method for producing sake, which comprises producing sake using the yeast according to claim 1.