JPH0823954A - Mutant yeast - Google Patents

Abstract

PURPOSE:To obtain a mutant yeast capable of producing a product having good fragrance of an alcoholic drink such as SAKE (rice wine), SHOCHU (Japanese spirits distilled from sweet potatoes, rice, etc.), beer or wine, a food such as bread, confectionery or pickle, a cosmetic, etc. CONSTITUTION:Each of various kinds of yeasts belonging to SAKE yeast, SHOCHU yeast, beer yeast, wine yeast and bread yeast is subjected to a treatment for mutation. Treated yeasts are grown in a cerulenin-containing medium and a strain of yeast which is derived by mutation and capable of producing caproic acid and/or ethyl caproate in large quantity is selected to establish the objective mutant yeast.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mutant yeast capable of producing a highly fragrant alcoholic beverage and the like. More specifically, the present invention relates to a mutant yeast which produces a large amount of caproic acid and / or ethyl caproate among aroma components by mutation, and comprises a sake yeast, a shochu yeast, a beer yeast, a wine yeast or a baker's yeast. It belongs to
By using these to produce alcoholic beverages such as sake, shochu, beer and wine, foods such as bread, confectionery and pickles, cosmetics and the like, it is possible to produce each product having a good scent.

[0002]

2. Description of the Related Art Generally, aroma is an important factor that determines the quality of alcoholic beverages and foods, and aroma ester ethyl caproate is one of the preferable aroma components similar to apple aroma. This ethyl caproate is
It is produced by yeast from caproic acid and ethanol, but generally its amount is too small.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a mutant yeast capable of producing a large amount of aroma components.

[0004]

As a result of the study of the present inventors, it has been revealed that caproic acid is the rate-limiting factor in the production of ethyl caproate in yeast.
And, this caproic acid is generated in the middle of the fatty acid biosynthesis system of yeast, but since it is not accumulated as caproic acid and changes to the next compound, ethyl caproate derived from caproic acid It was also found that the quantity would be very small. Thus, the present inventors have intensively studied for a mutant yeast having a mutation in fatty acid synthase and a large amount of caproic acid, and were able to select and obtain a mutant yeast that produces a large amount of this. is there.

In the present invention, to obtain a mutant yeast, any method may be used as a mutation method. The physical method of mutation includes ultraviolet irradiation and radiation irradiation, and the chemical method includes mutagenizing agents such as ethyl methanesulfonate, N-methyl-N-nitro-N-nitrosoguanidine, nitrous acid and acridine. There is a mutation method of suspending in a solution such as a system dye.

[0006] In the present invention, these mutation methods can be used as appropriate, but have a feature of selecting mutant yeast. That is, the growth medium of the mutant strain must contain cerulenin. Cerulenin is known as an antibiotic that inhibits fatty acid synthase, and acquiring resistance to cerulenin means that a change has occurred in fatty acid synthase or its function. Therefore, when the properties of this cerulenin-resistant strain were examined, it was found that there were many strains in which the intermediate fatty acid containing caproic acid was increased compared to the parent strain.

[0007] Cerulenin may be added to either a solid medium or a liquid medium, and is 10 to 100 µM, preferably 25 to 100 µM.
Add about μM before use. As the treated yeast, any of yeasts such as sake yeast, shochu yeast, brewer's yeast, wine yeast, and baker's yeast can obtain a cerulenin-resistant strain.
After mutagenizing various yeasts, the yeasts are transferred to a cerulenin-containing medium, cultured at 30 ° C. for about one week to isolate the grown strains, and yeasts capable of producing caproic acid well may be employed.

[0008] The mutant yeast obtained here is capable of producing caproic acid well in any of sake yeast, shochu yeast, beer yeast, wine yeast and baker's yeast. If alcoholic beverages such as beer and wine, foods such as bread, confectionery, pickles, and cosmetics are manufactured, each product having a large amount of ethyl caproate and a good fragrance can be manufactured. Next, examples and reference examples of the present invention will be described.

[0009]

Example A haploid yeast (hereinafter abbreviated as K-7-H) isolated from the Japan Brewing Association No. 7 yeast was inoculated into 5 ml of YPD medium (1% yeast extract, 2% peptone, 2% glucose). After culturing for one day, the cells were collected and washed. 5 ml of 0.2 M phosphate buffer (pH 8.0) was added to the washed cells.
0.25 ml of a 40% glucose solution and 0.25 ml of ethyl methanesulfonate were added, and mutagenesis was performed at 30 ° C. for 1 hour with gentle stirring. After the treatment, the cells are washed with sterilized water, and YPD containing cerulenin (final concentration 25 μM) is used.
It was spread on an agar medium (YPD medium plus 2% agar). Many cerulenin-resistant strains grown on this medium were
NBC medium (Difco yeast nitrogen base 0.
67%, glucose 2%, casamino acid 1%)
After culturing at 0 ° C. for 3 days, the concentration of caproic acid in the medium was measured. Here, strain 7-C-8 having improved caproic acid-producing ability as compared with the parent strain was obtained. This strain was sent to MIC by FERM.
Deposited as P-8452. Table 1 shows the concentration of caproic acid in the medium when 7-C-8 and the parent strain K-7-H were cultured in a YNBC medium at 30 ° C. for 3 days.

[0010] As shown in Table 1, the 7-C-8 strain was found to produce about 6 times as much caproic acid as the parent strain.

[0011]

[Reference Example 1] Mutant yeast 7-C-8 (FERM P-84)
52) and Sake No. 7 were used to produce sake with the blended formulation shown in Table 2 below.

[0012]

The yeast was fermented at 15 ° C. for 15 days after adding 2 g of the cultured yeast by wet cell weight. Table 3 shows the components of the obtained sake.

Table 3 -C-8 Association No. 7 Sake degree -5.0 -6.0 Alcohol (%) 18.5 18.4 Acidity (ml) 3.10 3.15 Amino acid degree (ml) 2.35 2.50 Ethyl caproate (ppm) 5.3 1.1 Caproic acid (ppm) 20.5 3.5

[0015] As a result, among the aroma components of sake, ethyl caproate, which is one of the most important aromas, increased about five times that of the parent strain, and the apple-like scent was strongly recognized by a sensory test. In addition, caproic acid, one of the substrates of ethyl caproate, was increased about 6-fold as compared to the parent strain.
Cerulenin is an inhibitor of fatty acid synthase,
Since the biosynthesis of caproic acid in yeast is performed by fatty acid synthase, it is considered that this resistant strain has an increased amount of caproic acid due to mutation in fatty acid synthase.

[0016]

Reference Example 2 Mutant yeast 7-C-8 (FERM P-84
52) and wine yeast Saccharomyces
The wine was brewed with cerevisiae (IAM 4274). Glucose was added to fresh Koshu grape juice to adjust the sugar content to 24%. To 1 L of this fruit juice, 2 g of each yeast was added as a wet cell weight, and the mixture was fermented at 18 ° C. for 7 days. The ingredients of the wine obtained here are shown in Table 4.

Table 4 Table 7-C-8 IAM 4274 Alcohol (%) 11.8 12.0 Total acid (ml) 7.3 7.2 Reducing sugar (%) 0.8 0.8 Caproic acid (ppm) 15.5 3.8 Ethyl caproate (ppm) 2.0 0.4

The wine using 7-C-8 was a new type of ethyl caproate, which is five times higher than IAM 4274, and organoleptically different from previous wines.

[0019]

[Reference Example 3] Mutant yeast 7-C-8 (FERM P-84)
52) and wine yeast Saccharomyces
Brandy was produced using cerevisiae (IAM 4274). Fresh Koshu grape juice was supplemented with glucose to adjust the sugar content to 24%. 1L of this juice
Add 2g of each yeast as wet cell weight to 18 ℃
Fermented for 7 days. The obtained fermentation broth was distilled under reduced pressure using a rotary evaporator. Table 5 shows the components of the brandy thus obtained.

Table 5 -C-8 IAM 4274 Alcohol (%) 49 51 n-Propanol (ppm) 90 73 iso-Butanol (ppm) 250 288 Iso-Amyl alcohol (ppm) 1490 1530 Isoamyl acetate (ppm) 4 5.5 5.0 Ethyl caproate (ppm) 10.5 1.6

The brandy using 7-C-8 had a high ethyl caproate concentration, and was functionally different from the conventional brandy.

[0022]

[Reference Example 4] Mutant yeast 7-C-8 (FERM P-84)
52) and brewer's yeast Saccharomyces
Beer was brewed using uvarum (IFO 0565). 1 L of water was added to 160 g of malt, saccharified by heating, and then filtered to obtain wort. 2 g of hops were added thereto, and after boiling, the hops were removed, and after cooling, water was added to bring the total amount to 1 L. To 1 L of this wort, 2 g of each yeast as wet cell weight was added, and fermented at 15 ° C. for 10 days. Table 6 shows the components of the beer obtained here.

Table 6 -C-8 IFO 0565 Alcohol (%) 4.0 4.2 Extract (%) 3.6 3.5 Caproic acid (ppm) 8.3 2.2 Ethyl caproate (ppm) ) 1.5 0.2

As shown in Table 6, the beer brewed with 7-C-8 was a new type of beer which had a high caproic acid concentration and was also organoleptically different from conventional beers.

[0025]

[Reference Example 5] Mutant yeast 7-C-8 (FERM P-84)
52) and brewer's yeast Saccharomyces
Whiskey was produced using uvarum (IFO 0565). 1 L of water was added to 160 g of malt, the mixture was saccharified by heating and then filtered to obtain wort. This was cooled and then watered to bring the total amount to 1 L. To 1 L of this wort, 2 g of each yeast was added as a wet cell weight, and fermentation was carried out at 15 ° C. for 10 days. This fermentation liquid was distilled under reduced pressure with a rotary evaporator to obtain whiskey. Table 7 shows the components of the whiskey thus obtained.

Table 7-C-8 IFO 0565 alcohol (%) 5049 n-propanol (ppm) 95 67 iso-butanol (ppm) 112 224 iso-amyl alcohol (ppm) 865 935 isoamyl acetate (ppm) 2 2.0 1.5 Ethyl caproate (ppm) 17.2 2.1

As shown in Table 7, the whiskey produced from 7-C-8 had a high concentration of ethyl caproate and was also organoleptically different from conventional whiskeys.

[0028]

[Reference Example 6] Mutant yeast 7-C-8 (FERM P-84)
52) and the Shochu No. 2 yeast of the Brewing Society were used to produce shochu with the preparation composition shown in Table 8.

[0029]

2 g of the wet yeast cells as a weight of the wet cells was added to the preparation composition shown in Table 8 to carry out one-stage preparation. 1 at 15 ° C
After fermentation for 4 days, the mash was distilled under reduced pressure on a rotary evaporator. The components of the obtained shochu are ninthly displayed.

Table 9 Table 7-C-8 Shochu No.2 alcohol (%) 25.2 25.4 n-propanol (ppm) 90 98 iso-butanol (ppm) 215 248 iso-amyl alcohol (ppm) 504 526 Acetic acid Isoamyl (ppm) 2.9 3.2 Ethyl caproate (ppm) 8.2 1.9

The shochu using 7-C-8 was a new type of shochu with a high concentration of ethyl caproate and a sensory new type.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Suginami, 247 Minamihama-cho, Fushimi-ku, Kyoto City Laurel Wreath Stock Company

Claims (3)

[Claims] 1. A mutant yeast belonging to sake yeast, shochu yeast, brewer's yeast, wine yeast or baker's yeast, which has a large amount of caproic acid and / or ethyl caproate among aroma components due to mutation. 2. A mutant yeast that produces a large amount of caproic acid and / or ethyl caproate among aroma components due to mutation is obtained from a strain grown in a cerulenin-containing medium by subjecting various yeasts to mutation treatment. The mutant yeast according to claim 1, wherein 3. A mutant yeast 7-C-8, which belongs to sake yeast and has a large amount of caproic acid and / or ethyl caproate among aroma components due to mutation.