JPWO2012128186A1 - New baker's yeast - Google Patents

Abstract

Even after long-term refrigerated storage in raw yeast, it has a high fermentative power in a wide sugar range of dough from low sugar range to high sugar range. The baker's yeast has a high fermentative power, that is, the fermentative power storage stability is high, and it also facilitates not only the bread production process but also the delivery system and raw material inventory management, and builds a system that makes stable production of high-quality bread easier. A baker's yeast is provided.

Description

  The present invention relates to a novel baker's yeast, bread dough using the same, and a method for producing them.

  The so-called yeast that is commonly used for bread making is called a raw yeast having a moisture content of about 60 to 70% and a dry yeast having a moisture content of 10% or less. Or a form called cream yeast in an aqueous suspension state of bacterial cells. Among these, fresh yeast is the most widely used form because it is very smooth in fermentation at the early stage of bread making and can be stored in a general refrigeration facility. Yeast is a living thing, and in order to maintain stable fermentation function of raw yeast or cream yeast that has been squeezed and solidified in the most natural state, refrigerated storage is necessary. The degradation of the fermentation function is obvious when the storage is prolonged, and it has been generally used and managed by setting the shelf life to about 3 to 4 weeks.

  On the other hand, when long-term storage is inevitably necessary, it is necessary to use dry yeast, but it is necessary to avoid the problem of dispersibility and contact with cold water as much as possible. In addition, dry yeast requiring a drying process is inferior to fresh yeast in terms of cost.

  Regarding the fermentation function of raw yeast after long-term refrigerated storage, the deterioration of long-term storage in high sugar-concentrated dough and frozen dough is significant, and so far, during the long-term storage over 4 weeks in the fresh yeast state. In addition, no strain has been reported that maintains its fermentation function stably, that is, has fermentative power storage stability.

  The fermentative power characteristic of individual baker's yeast is a comprehensive function in which a plurality of genes are expressed with various relationships, and there is a functional difference between strains even in the amount of gas generated. For example, the expression of maltose utilization-related genes is highly related to sugar-free dough fermentation, and the expression of invertase activity-related genes is highly related to high sugar dough fermentation, each of which has been captured as a separate trait. Moreover, the strength of fermentation after freezing of bread dough is considered to be a frozen dough fermentation power completely different from that of non-frozen fermentation, so-called freeze-resistant fermentation power, and many genes have been implicated. Under these circumstances, although baker's yeast having enhanced each trait has been developed, there is no bacterial strain development that focuses on fermentation power after long-term refrigerated storage in a raw yeast state.

  For example, baker's yeast that can be baked with a sugar blend of about 40 parts by weight (versus flour) (Patent Document 1) or a straight method Although baker's yeast (Patent Document 2) having high sugar resistance and high osmotic pressure resistance in the middle seed method is shown, none of them shows the fermentative power after long-term refrigerated storage, so-called fermentative power storage stability. There is no suggestion. In addition, fermenting power after thawing is not shown when it is used for frozen dough which is considered to have stronger stress strength than high sugar dough after long-term refrigeration of raw yeast with high fermentation power storage stability In addition, baker's yeast (Patent Document 2 and Patent Document 3) having both high sugar dough fermentation power and freeze-resistant fermentation power has also been shown, but its function is stably maintained during long-term refrigerated storage, so-called fermentation power storage. No strains with stability are shown.

JP 2000-262275 A International Publication No. 01/021763 JP 2000-279165 A

  Baker's yeast with fermenting power storage stability, especially baker's yeast with greatly improved fermenting power storage stability with high sugar dough fermenting power and freeze-frozen fermenting power, as well as the bread manufacturing process, delivery system and raw material inventory management It is desired as a baker's yeast that can easily produce high-quality bread stably. In addition, the baker's yeast should not cause other functional deterioration in order to acquire high tolerance in a strong stress environment. Furthermore, one baker's yeast can be used in sugar-free or low-sugar doughs. It is desirable that it also has a sufficient fermentation function and can be used in various bread dough.

Therefore, the object of the present invention is to have a high fermentative power in a wide sugar range of dough from a low sugar range to a high sugar range even if stored for a long time in the fresh yeast state. It is to provide a bread yeast having a high fermenting power after thawing even when used, that is, a baker's yeast having a high fermentation power storage stability, a bread dough using the baker's yeast, and a bread obtained by baking the dough. .
Another object of the present invention is to provide baker's yeast that facilitates not only a bread production process but also a delivery system and raw material inventory management, and that can construct a system that can more easily and stably produce high-quality bread.

  As a result of intensive research to solve the above problems, the present inventors appropriately cultured a strain isolated from nature and a breeding strain prepared by crossing, dehydrated to a raw yeast state, and then subjected to a predetermined abuse preservation test. The yeast obtained by carrying out strain selection according to the above has a high fermentative power in sugar-free dough and high-sugar dough even if stored for a long time in the raw yeast state, and further contains a dough containing cells that have been stored for a long period of time. It was found that the fermenting power after thawing was high even when used for breadmaking after being stored frozen, and the present invention was completed.

  That is, in the first aspect of the present invention, a hybrid strain of baker's yeast belonging to Saccharomyces cerevisiae is refrigerated for 6 weeks in a raw yeast state, and then a sugar-free and high-sugar dough with the composition shown in Table 1 below is prepared. Fermentation power measured at 2 ° C. for 2 hours is 40 mL or more for sugar-free dough, 40 mL or more for high sugar dough A, and high sugar dough with the composition shown in Table 2 below, and pre-fermented for 90 minutes at 30 ° C. After thawing the high-sugar dough B that was frozen and stored for 2 weeks at 25 ° C for 30 minutes, it belongs to Saccharomyces cerevisiae obtained by selecting that the fermentative power measured at 38 ° C for 2 hours is 145 mL or more. It relates to baker's yeast.

In a preferred embodiment, the baker's yeast used for the selection is
Indices that fermentability measured at 38 ° C. for 2 hours is 57 mL or more by preparing a high-sugar dough A using the raw yeast bakery yeast belonging to Saccharomyces cerevisiae before long-term refrigerated storage and blended as shown in Table 1 above. A high sugar dough B is prepared with the composition shown in Table 2 above using a spore strain prepared from the strain obtained by selection and a raw yeast bakery yeast before long-term refrigerated storage belonging to Saccharomyces cerevisiae, and at 30 ° C. Produced from a strain obtained by selecting a dough that has been pre-fermented for 90 minutes and then frozen and stored for 2 weeks at 25 ° C for 30 minutes and then selecting as an indicator that the fermentation power measured at 38 ° C for 2 hours is 147 mL or more To produce a first generation cross, and leave the first generation cross in the raw yeast state in an atmosphere of 30 ° C. for 24 hours. High sugar A strain was selected by using the strain as an indicator that the ground fermenting power measured at 38 ° C. for 2 hours was 45 mL or more for the sugar-free dough and 45 mL or more for the high-sugar dough A. The dough is prepared by preparing a high-sugar dough B with the composition of No. 2, pre-fermented at 30 ° C. for 90 minutes, frozen, and frozen for 2 weeks, then thawed at 25 ° C. for 30 minutes, and then measured at 38 ° C. for 2 hours The primary screening is performed by selecting strains with an indicator that the fermentative power is 155 mL or more, selecting a plurality of strains from the first generation hybrid strains, and causing the selected first generation hybrid strains to form spores. The present invention relates to the above-mentioned baker's yeast, which is a second generation hybrid obtained by crossing.

  A preferred embodiment relates to baker's yeast as described above which is Saccharomyces cerevisiae KCY1217 (NITE BP-1058) or Saccharomyces cerevisiae KCY1222 (NITE BP-1059).

  The second of the present invention relates to a dough having the above-described baker's yeast.

  The third of the present invention relates to a bread obtained by baking from the dough described above.

  A fourth aspect of the present invention is the above-described method for producing baker's yeast, wherein (1) a high-sugar dough having the composition shown in Table 1 above using baker's yeast in a raw yeast state before long-term refrigerated storage belonging to Saccharomyces cerevisiae A spore strain prepared from a strain obtained by selecting as an indicator that the fermentability measured at 38 ° C. for 2 hours is 57 mL or more, and a raw yeast state before long-term refrigerated storage belonging to Saccharomyces cerevisiae A high-sugar dough B was prepared using baker's yeast with the composition shown in Table 2 above, and the dough that had been pre-fermented at 30 ° C. for 90 minutes and then stored frozen for 2 weeks was thawed at 25 ° C. for 30 minutes, and then at 38 ° C. A step of producing a first generation hybrid by crossing with a spore strain prepared from a strain obtained by selecting as an indicator that the fermentation power to be measured for time is 147 mL or more, (2) the first generation hybrid Raw yeast The mixture is allowed to stand in an atmosphere of 30 ° C. for 24 hours, and a sugar-free dough and a high-sugar dough A are prepared according to the composition shown in Table 1 above. After selecting a strain with the sugar dough A being 45 mL or more as an index, a high sugar dough B is prepared using the strain according to the formulation shown in Table 2 above, pre-fermented at 30 ° C. for 90 minutes, and then frozen. After thawing the frozen dough for 30 minutes at 25 ° C for the first week, the strain was selected based on the indicator that the fermentability of dough measured at 38 ° C for 2 hours is 155 mL or more, and the primary screening was conducted. A step of selecting a plurality of strains from the cross strains, (3) a step of forming a plurality of first generation cross strains selected in the step, and crossing to produce a second generation cross strain, (4) the second cross section After cultivating generation hybrids in the fresh yeast state for 6 weeks, Fermentation power of producing sugar-free dough and high-sugar dough A with the formulation of Table 1 and measuring at 38 ° C. for 2 hours is 40 mL or more for sugar-free dough, 40 mL or more for high-sugar dough A, and Table 2 above. A high-sugar dough B was prepared by blending the above, and after fermenting for 90 minutes at 30 ° C. and then frozen and stored for 2 weeks, the dough was thawed at 25 ° C. for 30 minutes and then measured at 38 ° C. for 2 hours with a fermentation power of 145 mL or more It is related with the manufacturing method of baker's yeast characterized by including the process of implementing the secondary screening which selects a strain | stump | stock using it as a parameter | index.

According to the present invention, even in a long-term refrigerated storage in a raw yeast state, it has a high fermentative ability in a wide sugar range of dough from low sugar range to high sugar range, and further uses microbial cells that have been refrigerated for a long time for frozen dough Even in this case, it is possible to provide a baker's yeast having a high fermentative power after thawing, that is, a high fermentative power storage stability. Furthermore, it is possible to provide baker's yeast that facilitates not only the bread production process but also the delivery system and raw material inventory management, and enables the construction of a system that can more easily and stably produce high-quality bread.
Moreover, by using the said baker's yeast, there exists sufficient fermenting power even after carrying out refrigeration storage or frozen storage, and can provide the dough suitable for producing bread.
Moreover, according to this invention, the baker's yeast which has the said characteristic can be obtained efficiently.
In addition, according to the present invention, by using the dough, a high-quality bread having a sufficient volume can be produced regardless of the storage state such as refrigerated storage and frozen storage.

  Hereinafter, the present invention will be described in more detail. The baker's yeast of the present invention is obtained by selecting on the basis of a specific index, belongs to Saccharomyces cerevisiae, has a high fermentative power in a wide sugar dough even when stored for a long period of time in refrigerated yeast, Even when the dough containing microbial cells that have been refrigerated for a long time is stored frozen and used for breadmaking, the fermentative power after thawing is high, that is, the fermentative power storage stability is high.

  First, terms used in the present specification have the same meanings as those commonly used in the art, unless otherwise described below. In the present specification, the blending ratio (vs. flour, parts by weight) of the bread making main and auxiliary ingredients including the sugar blending ratio is the blending amount (parts by weight) relative to 100 parts by weight of the flour in the whole dough. Is the blending ratio (parts by weight) of the bread making main auxiliary material.

In the present invention, long-term refrigerated storage specifically refers to a state of being stored for 6 weeks in a refrigerator maintained at about 5 ° C., and even in a raw yeast state for a long period of time, it is high in a wide sugar range of dough. Baker's yeast having a fermenting power has a high fermenting power in a dough in a wide sugar range even after storage for more than 4 weeks in a temperature range of 0 ° C to 10 ° C.
Moreover, in this invention, frozen storage specifically shows the state preserve | saved with the freezer kept at about -20 degreeC.

  In the present invention, the primary cell is a cell in a raw yeast state before long-term refrigerated storage and refers to a cell within 3 days after production.

The baker's yeast of the present invention is refrigerated and stored for 6 weeks in a raw yeast state, and then, with the composition shown in Table 1, 0 parts by weight of bread dough (sugar-free dough) and 40 parts by weight of sugar dough (high sugar dough A) are prepared. The fermentation power measured at 38 ° C. for 2 hours is preferably 40 mL or more for the sugar-free dough and 40 mL or more for the high sugar dough A. More preferably, it is 45 mL or more for sugar-free dough and 45 mL or more for high-sugar dough A.
The baker's yeast is refrigerated and stored in a raw yeast state for 6 weeks, and then a bread dough (high sugar dough B) of 25 parts by weight of sugar is prepared according to the composition shown in Table 2 above, pre-fermented at 30 ° C. for 90 minutes and then frozen. The dough stored frozen for 2 weeks is thawed at 25 ° C. for 30 minutes, and then the fermentation power measured at 38 ° C. for 2 hours is preferably 145 mL or more, more preferably 155 mL or more.
The raw yeast state refers to baker's yeast with a moisture content of approximately 60 to 70% by weight.

  If the sugar-free dough or high-sugar dough A has a certain amount or more of fermenting power, it can be said that it has a high fermenting power in wide sugar bread dough. If there is a fermentative power, it can be said that there is a freezing fermentative power in high sugar dough.

  In addition, the fermenting power in this invention uses the amount of gas generation of 20g of dough measured at 38 degreeC for 2 hours as a fermenting power using Farmograph (trademark) II (made by Ato Co., Ltd.). In the case of frozen dough, as described above, 20 g of frozen dough is thawed at 25 ° C. for 30 minutes, and the amount of gas generated from 20 g of dough measured at 38 ° C. for 2 hours is defined as fermentation power.

  In general, bacterial strains whose dough fermentability has been increased excessively under culture conditions have high bacterial activity at the time of preparation. Therefore, bacterial cells in such a state have low resistance to various stresses and activity during storage. In other words, so-called fermentative power and storage stability tend to decrease. In particular, it is not easy to develop baker's yeast that maintains fermentation power for a long period of time in high-stressed high-sugar dough or frozen dough. It is not sufficient as a baker's yeast having the above, and it is preferable to show a strong fermenting power even when used for frozen dough.

  The baker's yeast having the fermentative power storage stability of the present invention is a screening (selection) from the natural world and hybrid strains of Saccharomyces cereviciae, and techniques such as hybridization, mutation treatment, and cell fusion, which are breeding techniques for baker's yeast. Can be obtained by:

  Among the above methods, for example, it can be obtained by the following method. For crossing, a spore strain is obtained from a Saccharomyces cerevisiae-preserving strain isolated from natural soil, rivers, fruits, etc., crossbreds are prepared in various combinations, and the crossed strain is used as a screening cell.

  In addition, a general fungal agar medium is used for isolation of the preserved strain. Moreover, the said spore strain | stump | stock is formed using the sporulation culture medium according to a conventional method from the isolated preservation | save strain. In addition, the hybrid strain is obtained by randomly joining haploid spores sprouting from the spore strain according to a conventional method.

<Cross breeding>
Spore strains are obtained from conserved strains isolated from natural soils, rivers, fruits and the like belonging to Saccharomyces cerevisiae, and hybrid strains are produced in various combinations using these spore strains. The prepared hybrid strains are cultured by the following screening cell preparation method.

<Production of screening cells>
Batch culture 5 mL of the medium having the composition shown in Table 3 is dispensed into a large test tube and 50 mL into a 500 mL Sakaguchi flask, sterilized by autoclave, and used for culture. Breeding strain 1 Platinum ears are inoculated in a large test tube, transferred to a 500 mL Sakaguchi flask after shaking culture at 30 ° C. for 1 day, and further cultured in a batch culture at 30 ° C. for 1 day. The following 5 L jar seed culture is used. In preparing the medium, molasses is used as the sugar, and the sugar concentration is adjusted to 4% (weight / volume).

-5L jar seed mother culture 2L of the medium having the composition shown in Table 4 is put into a 5L jar, and after sterilization by autoclave, the cells of five 500 mL Sakaguchi flasks are inoculated, and seed mother culture is performed under the conditions shown in Table 5. In preparing the medium, molasses is used as the sugar, and the sugar concentration is adjusted to 4% (W / V).

-5 L jar main culture 50 g of seed mother cells cultured in a 5 L jar with the medium composition shown in Table 6 as the initial solution amount are added as wet cells, and main culture is performed under the conditions shown in Table 7. Specifically, culture is performed for 13 hours, and sugar is added in portions.
The 5 L jar cultured microbial cells are centrifuged immediately after the completion of the culture, sucked and dehydrated to prepare wet microbial cells, and used for the following screening.
In addition, when measuring fermentation power in the screening in this invention, the amount of gas generation from the bread dough produced with the baker's yeast prescribed amount of each dough is measured, and the value is made into the fermentative power of this wet cell. Here, the numerical value of the specified amount of baker's yeast in the present invention is described as the amount of 65% wet cells used, and when using baker's yeast (wet cells) having a different water content, Use so that there is a pure amount, and adjust the amount of water according to the actual moisture content of wet cells.

<Screening>
As a primary screening, first, the wet cells are left in a raw yeast state in an atmosphere of 30 ° C. for 24 hours to produce a sugar-free dough and a high sugar dough A according to the composition shown in Table 1, and at 38 ° C. After selecting a strain having a dough fermentation power of 45 mL or more for a sugar-free dough and 45 mL or more for a high sugar dough A measured for 2 hours, a high sugar dough B is prepared according to the composition shown in Table 2 above, and at 90 ° C. for 90 minutes before Primary screening strain using as an indicator that the dough fermentation power measured at 38 ° C. for 2 hours after thawing treatment at 25 ° C. for 30 minutes after being fermented and frozen at −20 ° C. and frozen for 2 weeks is 155 mL or more Select. After the selected primary screening strain is refrigerated and stored for 6 weeks in a raw yeast state, a sugar-free dough and a high-sugar dough A are prepared according to the formulation shown in Table 1, and the dough fermenting power measured at 38 ° C. for 2 hours is 40 mL or more with sugar dough and 40 mL or more with high sugar dough A, and after refrigerated storage for 6 weeks, high sugar dough B is prepared with the composition of Table 2 above, pre-fermented at 30 ° C. for 90 minutes, and then frozen at −20 ° C. Then, after the dough frozen and stored for 2 weeks is thawed at 25 ° C. for 30 minutes, the dough fermentation power measured at 38 ° C. for 2 hours is selected with an index of 145 mL or more to obtain a secondary screening strain.

  As Saccharomyces cerevisiae KCY1217 selected by the above method as baker's yeast of the present invention, the accession number “NITE BP-1058” and the Saccharomyces cerevisiae KCY1222 are under the accession number “NITE BP-1059”. It has been deposited on February 21, 2011 (original deposit date) at the National Institute of Technology Patent Microorganisms Deposit Center (2-5, Kazusa-Kamashita, Kisarazu City, Chiba, Japan).

  The baker's yeast obtained above may be adjusted to a dry yeast form according to a conventional method.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” and “%” are based on weight. In addition, as strains, the strains according to the present invention, two baker's yeast strains (SG, GA) commercially available from Kaneka Corporation as a control strain, and one baker's yeast strain (US) commercially available from Oriental Yeast Industry are used. It was.

<Dough fermentation power measurement method>
The baker's yeast of Examples and Comparative Examples was stored under the predetermined conditions described later. In accordance with Table 1, Nisshin Flour Mills “Cameriya” (registered trademark) is used as wheat flour, a specified amount of sugar and water or salt is prepared as a sugar suspension, and the dough is prepared with the baker's yeast using a Hobart tabletop mixer. After mixing, the amount of gas generated in 20 g of the main body dough after mixing was measured at 38 ° C. for 2 hours using Pharmagraph (registered trademark) II, and the accumulated gas amount was used as the dough fermentation power of each baker's yeast. .

<Method of measuring resistance to freezing and fermenting>
The baker's yeast obtained in Examples and Comparative Examples was refrigerated for 6 weeks in a raw yeast state. According to Table 2 above, Nissin Flour Powered Kamelia is used as wheat flour, and a prescribed amount of sugar and water or salt is prepared as a sugar suspension. The dough is mixed with the baker's yeast using a Hobart tabletop mixer, After 20 g of pre-fermented dough for 20 minutes at 30 ° C., it was frozen at −20 ° C. to obtain frozen dough. The frozen dough was stored frozen at −20 ° C. for 2 weeks, thawed at 25 ° C. for 30 minutes, and then the amount of gas generated was measured at 38 ° C. for 2 hours using Pharmagraph (registered trademark) II. The integrated gas amount was defined as the resistance to freezing fermentation of each baker's yeast.

(Examples 1 to 3 and Comparative Examples 1 to 3) Cross breeding and strain selection Strains with higher sugar dough fermenting ability than our Saccharomyces cerevisiae preservation strain (GA) prepared by crossing and strains isolated from nature, and freezing resistance A high fermentative strain was used as the original strain.

The original strain having a high sugar dough fermenting power equal to or higher than GA was obtained as follows.
First, a high sugar dough A was prepared with GA in the raw yeast state before long-term refrigerated storage, and fermented at 38 ° C. for 2 hours to measure the fermentative power (57 mL).
Next, a high sugar dough fermenting power was measured for baker's yeast belonging to many Saccharomyces cerevisiae separated from nature such as soil, pond, river, etc. in the same manner as GA, and the high sugar of the GA Thirty strains having a value equal to or higher than the dough fermentation power were selected and used as the original strain.
In addition, the baker's yeast separated from the natural world was also used when selecting the following strain having high freezing and fermenting power.

A strain having a high resistance to freeze fermentation that is equal to or higher than GA was obtained as follows.
First, the high sugar dough B shown in Table 2 above was prepared using GA in a raw yeast state before long-term refrigerated storage, pre-fermented at 30 ° C. for 90 minutes, and then frozen for 2 weeks at 25 ° C. And thawed for 30 minutes, and then fermented at 38 ° C. for 2 hours to measure the fermentative power (147 mL).
Next, the bread-free yeast belonging to many Saccharomyces cerevisiae that has been separated from the natural world such as soil, ponds, rivers, etc. according to conventional methods was measured for freeze-resistant fermentative power in the same manner as GA, and freeze-resistant fermentation of said GA Thirty strains showing a value equal to or higher than the force were selected and used as the original strain.

Since all these original strains are diploid, they are formed in a spore-forming medium (composition: potassium acetate 0.3%, agar 1.5%), and cross breeding and strain selection are performed in the next step. did.
(1) A spore strain prepared from a strain exhibiting high sugar dough fermentation ability equal to or greater than GA and a spore strain prepared from a strain exhibiting freeze-resistant fermentation resistance equal to or greater than GA are crossed to obtain a large number of first generation hybrid strains. Was made.
(2) From the first generation hybrid strain, in addition to the same evaluation as in the case of the former strain, it was allowed to stand in a raw yeast state at 30 ° C. for 24 hours. Select 40 strains of bread dough (sugar-free dough and high-sugar dough A), and select strains with a dough fermentation ability of 45 mL or more for sugar-free dough and 45 mL or more for high-sugar dough A measured at 38 ° C for 2 hours. After that, a bread dough (high sugar dough B) with 25 parts by weight of sugar was prepared according to the formulation of Table 2, fermented at 30 ° C. for 90 minutes, frozen, and frozen at -20 ° C. for 2 weeks. After thawing for 30 minutes, primary screening was performed using as an index that the dough fermentation power measured at 38 ° C. for 2 hours was 155 mL or more, and 20 strains were selected from the first generation hybrids.
(3) Aiming at each improvement of dough fermentation power, freezing fermentation resistance, and preservation fermentation power, further, spores were formed again from the first generation hybrid strains, and the spore strains were crossed to produce second generation hybrid strains.
(4) From the second generation hybrid strain, in addition to the primary screening, a sugar-free dough and a high-sugar dough A were prepared with the composition shown in Table 1 above even after long-term refrigeration for 6 weeks in a refrigerator (about 5 ° C.). Fermentation power measured at 38 ° C. for 2 hours is 40 mL or more for the sugar-free dough and 40 mL or more for the high-sugar dough A, and a high-sugar dough B is prepared with the composition shown in Table 2 above, and 90 minutes at 30 ° C. The dough which has been pre-fermented and stored frozen at -20 ° C. for 2 weeks is thawed at 25 ° C. for 30 minutes and then measured at 38 ° C. for 2 hours. A secondary screening was carried out using as an index to obtain the Saccharomyces cerevisiae KCY1229 strain (Example 3) in addition to the KCY1217 strain (Example 1) and the KCY1222 strain (Example 2). The results are summarized in Tables 8 and 9.

(Examples 4 to 6, Comparative Examples 4 to 6) Breadmaking test Results of evaluating the freeze-fermenting fermentative power of strains after refrigerated storage in a refrigerator (about 5 ° C) for 6 weeks according to the breadmaking formulation shown in Table 10 Is shown in Table 11.
From the results of Table 11, the breads obtained by baking in Examples 4 to 6 were compared with the breads obtained by baking in Comparative Examples 4 to 6 when frozen for 1 week or 3 months. The volume was significantly large.
Therefore, compared with three commercially available yeast strains, the yeast of the present invention has a sufficient bread volume even when frozen for a long period of 1 to 3 months of bread dough prepared using cells after long-term refrigerated storage. It shows that it shows the functionality to do.

Claims (6)

Bread yeast belonging to Saccharomyces cerevisiae is refrigerated and stored for 6 weeks in a raw yeast state, and then the sugar-free and high-sugar dough with the composition shown in Table 1 is prepared. 40 mL or more at high sugar dough A, 40 mL or more at high sugar dough A, and high sugar dough B prepared by pre-fermenting for 90 minutes at 30 ° C. after pre-fermenting at 30 ° C. for 90 minutes at 25 ° C. A baker's yeast belonging to Saccharomyces cerevisiae obtained by selecting with an indicator that the fermentative power measured at 38 ° C. for 2 hours is 145 mL or more after thawing for 30 minutes.

The baker's yeast used for the selection according to claim 1,
Indices that fermentability measured at 38 ° C. for 2 hours is 57 mL or more by preparing a high-sugar dough A using the raw yeast bakery yeast belonging to Saccharomyces cerevisiae before long-term refrigerated storage and blended as shown in Table 1 above. A high sugar dough B is prepared with the composition shown in Table 2 above using a spore strain prepared from the strain obtained by selection and a raw yeast bakery yeast before long-term refrigerated storage belonging to Saccharomyces cerevisiae, and at 30 ° C. Produced from a strain obtained by selecting a dough that has been pre-fermented for 90 minutes and then frozen and stored for 2 weeks at 25 ° C for 30 minutes and then selecting as an indicator that the fermentation power measured at 38 ° C for 2 hours is 147 mL or more The first generation hybrid strain by crossing with the spore strain
The first generation hybrid strain is left in a raw yeast state at 30 ° C. for 24 hours, and a sugar-free dough and a high sugar dough A are prepared according to the composition shown in Table 1 and measured at 38 ° C. for 2 hours. After selecting a strain with an index that the power is 45 mL or more for the sugar-free dough and 45 mL or more for the high-sugar dough A, a high-sugar dough B is prepared using the strain according to the formulation in Table 2 above, at 30 ° C. A dough that has been pre-fermented for 90 minutes, frozen, and frozen for 2 weeks is thawed at 25 ° C for 30 minutes, and then the strain is selected based on the indicator that the dough fermentation power measured at 38 ° C for 2 hours is 155 mL or more. Primary screening, select multiple strains from the first generation hybrids,
The baker's yeast according to claim 1, wherein the baker's yeast is a second generation hybrid obtained by spore formation of the selected first generation hybrid.   The baker's yeast according to claim 1 or 2, which is Saccharomyces cerevisiae KCY1217 (NITE BP-1058) or Saccharomyces cerevisiae KCY1222 (NITE BP-1059).   Dough which has the baker's yeast in any one of Claims 1-3.   A bread obtained by baking the dough according to claim 4. It is a manufacturing method of the baker's yeast in any one of Claims 1-3, Comprising: The manufacturing method of baker's yeast characterized by including the process of the following (1)-(5).
(1) A high sugar dough A is prepared with the composition shown in Table 1 above using raw yeast bakers yeast before long-term refrigerated storage belonging to Saccharomyces cerevisiae, and the fermentation power measured at 38 ° C. for 2 hours is 57 mL or more A spore strain prepared from a strain obtained by selecting that as an indicator,
A high-sugar dough B is prepared using the baker's yeast in a raw yeast state before long-term refrigerated storage belonging to Saccharomyces cerevisiae, and a dough that has been pre-fermented at 30 ° C. for 90 minutes and then frozen for 2 weeks. After thawing treatment at 25 ° C. for 30 minutes, a spore strain prepared from a strain obtained by selecting as an indicator that the fermentation power measured at 38 ° C. for 2 hours is 147 mL or more,
(2) The first generation hybrid strain is left in a raw yeast state in an atmosphere of 30 ° C. for 24 hours, and the sugar-free dough and the high After producing a sugar dough A and selecting a strain with an indicator that the dough fermentation power measured at 38 ° C. for 2 hours is 45 mL or more for the sugar-free dough and 45 mL or more for the high sugar dough A, the strain is used to A high-sugar dough B is prepared with the composition shown in Table 2, pre-fermented at 30 ° C. for 90 minutes, frozen, and frozen for 2 weeks, and then thawed at 25 ° C. for 30 minutes, and then measured at 38 ° C. for 2 hours. A step of selecting a strain by selecting a strain using an indicator that the dough fermentation power is 155 mL or more and performing a primary screening, and selecting a plurality of strains from the first generation hybrid strain (3) A plurality of first generation hybrids selected in the above step Spore formation and crossing to produce second generation hybrid Step (4) After refrigerated storage of the second generation hybrid strain in the raw yeast state for 6 weeks, a sugar-free dough and a high-sugar dough A are prepared according to the formulation shown in Table 1 and measured at 38 ° C. for 2 hours. However, the sugar-free dough is 40 mL or more, the high-sugar dough A is 40 mL or more, and the high-sugar dough B is prepared according to the formulation shown in Table 2 above. Step of performing secondary screening for selecting strains with an indicator that the fermentative power measured at 38 ° C. for 2 hours after thawing treatment at 25 ° C. for 30 minutes is 145 mL or more