JP4839809B2 - New baker's yeast - Google Patents

Description

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

  Bread is baked after mixing flour, water, salt, baker's yeast, dairy products, sugars, oils and fats, taking a certain fermentation time. In the process of fermentation, baker's yeast ferments sugars such as maltose contained in wheat flour and sugar added as raw material and converts it mostly to carbon dioxide and ethanol, but in addition to this, alcohol other than ethanol Organic acids, esters, etc. are also produced, which contribute to the flavor of bread. Since firing is usually performed in an oven at around 200 ° C., the outer skin temperature rises to about 160 ° C., and the center of the inner phase also rises to about 100 ° C., and this temperature is maintained at this temperature for 10 minutes. Maintained.

  Since mold is generally low in heat resistance, blue mold spores are known to die at 82 ° C. for 10 minutes, and red mold spores at 70 ° C. for about 10 minutes. The bread immediately after leaving the oven is in a sterile state for both the epidermis and the inner phase (Non-patent Document 1). However, since the bread that has left the oven is cooled on the conveyor for several tens of minutes with the target of a central temperature of 40 ° C., contact with mold spores in the air is inevitable. Furthermore, mold spores adhere to the bread by the hands of manufacturing workers, slices, packaging, and the like, which also cause the mold of the bread (Non-patent Document 1).

  For this reason, at the production site of bread, cooling and packaging processes, dust and bread crumbs in the shipping area are cleaned, and efforts are made to reduce mold generation by reducing the number of mold spores. Patent Document 1). Moreover, in bread manufacture, a sodium propionate formulation, a sodium acetate formulation, etc. may be added as a preservative, and the mold | generation generation | occurrence | production is delayed about 1 to 2 days.

  The antibacterial action of such organic acids is not expressed until they pass through the cell membrane of microorganisms and migrate into the cell, but non-dissociated molecules pass through the cell membrane and invade into the cells rather than dissociated molecules. Because of its easy nature, antibacterial activity is higher for non-dissociated molecules (Non-Patent Document 2). For example, when various organic acids are compared, acetic acid having a high pKa is less likely to dissociate than organic acids such as succinic acid, lactic acid, malic acid, and citric acid. Is known to be higher than other organic acids and consequently exhibit strong antibacterial activity (Non-patent Document 2).

  Since the dissociation of the organic acid decreases as the pH decreases, the lower the pH, the higher the proportion of non-dissociable molecules, and the stronger antibacterial action can be exhibited (Non-patent Document 2). For example, when acetic acid and lactic acid are allowed to act simultaneously on E. coli, it is reported that increasing the non-dissociated molecular concentration of acetic acid by lowering the pH due to lactic acid increases the inhibitory effect on E. coli than controlling the pH to 5-6. (Non-patent Document 3). In fact, in soy sauce moromi, the coexistence of lactic acid and acetic acid is known to enhance the antibacterial activity by increasing the non-dissociative concentration of acetic acid due to a decrease in the pH of lactic acid (Non-Patent Document 4).

  When a sodium acetate preparation is added at the time of bread preparation to suppress mold, the pH of the dough increases because sodium acetate dissociates and generates sodium ions, and the concentration of non-dissociated acetic acid is lower than when acetic acid is added alone. Relatively decreases. For this reason, in order to keep the fungus control effect at a certain level, it is necessary to add more sodium acetate preparation than when acetic acid is added alone. The flavor becomes sour.

  On the other hand, a decrease in dough pH increases the concentration of non-dissociative acetic acid and the antibacterial activity increases as described above, but an excessive decrease in pH weakens the gluten network structure and decreases the gas retention (Non-Patent Document 5) The quality of the product may be affected.

When the produced bread is left in the air for a certain period of time and stored for several days, there is a difference in the time to the occurrence of bread mold depending on the baker's yeast used for bread making. Bread yeast (Patent Document 1), which has a slightly lower pH of crumb and has a high concentration of acetic acid by fermentation to produce bread, and a dough structure that has a high ethanol concentration and is difficult to leak from the dough. There has been a report of baker's yeast (Patent Document 2) that can delay the occurrence of bread mold by adopting it, and mold suppression due to the fermentation action of baker's yeast is attracting attention.
Mitsuaki, “Science of breadmaking (1) Science of breadmaking process”, 1991, pages 263-271 Gihodo Publishing, “Food Microbiology Handbook”, 1995, 522 pages J. et al. Appl. Bacteriol. 1983, 54, 383 Brewery, 1981, 76, 701 Direc, “BAKERY Technology Encyclopedia”, 1990, Volume 1, p. 142 JP 2004-313190 A JP 2004-049217 A

  In the present invention, bread production that suppresses the occurrence of mold without impairing the quality of the bread, such as the expansion of the bread, the inner phase, the flavor, and the like, and without the addition of a secondary material that causes a pH decrease, is achieved. The purpose is to make it possible.

  As a result of intensive research to solve the above problems, the present inventors have compared the bread produced by conventional baker's yeast, because the pH of the crumb is low enough not to reduce the gas holding power of the dough. Succeeded in breeding baker's yeast that can increase the non-dissociative acetic acid concentration by increasing the acetic acid concentration without affecting the texture because it has little effect on bread swelling and internal phase, and completed the present invention It came to do.

  That is, the first of the present invention relates to baker's yeast capable of setting the non-dissociative acetic acid concentration of bread crumbs obtained by baking to 130 ppm or more. In a preferred embodiment, the baker's yeast is KSY68-9290 strain (accession number: FERM P-20204), KSY85-596 strain (accession number: FERM P-20295) belonging to Saccharomyces cerevisiae. Relating to baker's yeast. 2nd of this invention is related with the bread dough containing the baker's yeast of the said description. The third aspect of the present invention is obtained by baking a dough containing wheat flour, baker's yeast, saccharides, salt, dairy products, fats and oils as main components, and no other auxiliary materials that cause a pH lowering factor. A bread, characterized in that the non-dissociative acetic acid concentration of the bread crumb is 130 ppm or more. 4th of this invention is related with the manufacturing method of the bread which uses the said bread yeast.

  When bread is produced using the baker's yeast of the present invention, the pH of the crumb is lower and the acetic acid concentration is higher than that of bread produced with the conventional baker's yeast, thereby increasing the concentration of non-dissociated acetic acid. Mold can be suppressed without affecting the texture, volume and flavor.

  Hereinafter, the present invention will be described in more detail. The terms used in the present specification have the same meanings as those commonly used in the art unless otherwise specified below.

  In this specification, the ratio (%) of sugar, salt, and other bread-making auxiliary materials refers to the weight ratio to flour. For example, a sugar content of 6% means that 6 g of sugar is used for 100 g of flour in bread dough. In the present specification, “other bread-making auxiliary materials” refer to materials used for bread-making other than flour, salt and water, and examples thereof include sugar, isomerized sugar, dairy products, and fats and oils. It is not limited to.

  The baker's yeast of the present invention is a mold-inhibiting baker's yeast, and the mold produced in the bread produced using the baker's mold is not limited to the conventional baker's yeast, but the mold of bread produced using the conventional mold-inhibiting baker's yeast. Slower than occurrence. The method for producing bread is not particularly limited, but the medium seed method is preferred industrially. In the present invention, a characteristic that hardly causes mold in bread is referred to as mold suppression. In addition, the conventional baker's yeast here is baker's yeast with low mold suppression property used from before. In addition, the mold-inhibiting baker's yeast is higher in acetic acid production than conventional baker's yeast. For example, baker's yeast described in Japanese Patent Application Laid-Open No. 2004-313190 (National Institute of Advanced Industrial Science and Technology, Patent Organism Depositary Accession Number: FERM) It refers to baker's yeast such as P-18863).

  It is a feature of the present invention that the non-dissociated acetic acid concentration of bread crumbs prepared using the baker's yeast of the present invention is 130 ppm or more. Furthermore, it is preferable that the concentration of non-dissociative acetic acid in crumb is 200 ppm or more in view of the degree of mold inhibition. When the concentration of non-dissociative acetic acid in the crumb is 130 ppm or more, sufficient mold suppression is obtained. This seems to be because the baker's yeast of the present invention produces a larger amount of non-dissociated acetic acid than the conventional baker's yeast. The concentration of non-dissociated acetic acid in the crumbs of bread produced using conventional baker's yeast was less than 120 ppm at most when the FERM P-18863 was used. In addition, in the production of bread, lactic acid bacteria in the air are slightly mixed, but the production of non-dissociative acetic acid by it is insignificant, even if the production amount of non-dissociable acetic acid is large depending on the production environment, The undissociated acetic acid concentration in the bread crumb was less than 120 ppm even when FERM P-18863 was used as described above.

  In addition, there is a sour bread specially made by adding lactic acid bacteria to bread dough as an auxiliary material, and it contains a large amount of non-dissociative acetic acid, which is a product of lactic acid bacteria, but sour bread is intended to produce a sour taste. Therefore, it is not included in the present invention.

  In addition, in this invention, although it demonstrates centering on the mold | fungi control effect in the bread produced by the middle seed method including the Example, the bread produced by the mixing | blending and manufacturing method other than bread is also based on the baker's yeast of this invention. Has the effect of inhibiting mold. The bread seed method of the present invention is a general bread manufacturing method, and includes the following steps, for example. Mix 70% of the total flour used in bread making with yeast and water to make a medium dough, ferment at 27 ° C for about 4 hours, return to the mixer, leave the remaining flour and sugar in the medium dough In this method, fats and oils, a dairy product and an appropriate amount of water are added, and the mixture is further fermented and finally baked.

  The baker's yeast of the present invention can be obtained, for example, by the following method. For breeding, spore strains are obtained from Saccharomyces cerevisiae stocks, hybrid strains are prepared in various combinations, and screening cells are screened by the following method to screen for strains with high non-dissociated acetic acid concentration. Produced. Subsequently, using the produced bacterial cells for screening, a seed dough medium method for screening bread was prepared, the pH and acetic acid concentration of the dough were measured, and the non-dissociated acetic acid concentration was calculated from these measured values. The baker's yeast of the present invention is not particularly limited to cross breeding as long as the non-dissociated acetic acid concentration of the produced bread crumb is 130 ppm or more, screening from nature, mutation treatment, cell fusion It can also be obtained by breeding techniques such as.

  In the present invention, it is preferable to select baker's yeast belonging to Saccharomyces cerevisiae in order to make the non-dissociative acetic acid concentration of bread crumb produced by the seed method of bread bread more than 130 ppm, Of these, the KSY68-9290 strain and the KSY85-596 strain are more preferred. The KSY68-9290 strain and the KSY85-596 strain were identified as Saccharomyces cerevisiae. The KSY68-9290 strain was designated as FERM P-20204 (accession number) on September 6, 2004, and the KSY85-596 strain was designated as November 2004. On December 12, it was deposited as FERM P-20295 (Accession Number) at the National Institute of Advanced Industrial Science and Technology, Patent Biological Deposit Center (Chuo 1st, East 1-chome, Tsukuba City, Ibaraki, Japan).

  Examples of the present invention will be described below, but these are only illustrative of the present invention, and the present invention is not limited to these examples. In the examples, “parts” and “%” are based on weight. Regarding the materials used in the following examples, “Camelia” (made by Nisshin Flour Milling Co., Ltd.) is used for the flour, “East Food C” (made by Kaneka) is used for the yeast food, and “Snow” is used for the shortening. "Light" (manufactured by Kaneka Corporation) was used. As the emulsifier, “Panmac 200B” (manufactured by Riken Vitamin Co., Ltd.) was used. Other bread-making materials and bread-making auxiliary materials used were those available from general retailers. Moreover, baker's yeast FERM P-18863 described in JP-A-2004-313190 was used as a control strain.

<Method for preparing cells for screening>
The medium having the composition shown in Table 1 was dispensed in a large test tube in a volume of 5 ml and a 500 ml Sakaguchi flask in an amount of 50 ml, sterilized by autoclave, and used for the following culture. Breeding strain 1 platinum ears were inoculated into a large test tube, shake cultured at 30 ° C. for 1 day, subcultured in a 500 ml Sakaguchi flask, and cultured at 30 ° C. for 1 day with shaking. Thereafter, the mixture was centrifuged and sucked and dehydrated with Nutsche to prepare wet cells.

<Method of making seed dough in screening bread>
The dough was prepared by the dough composition shown in Table 2 and the steps shown in Table 3.

<Dough pH, acetic acid concentration measurement method>
The pH and acetic acid concentration of the prepared dough were measured by the following methods. 20 g of the dough subjected to proofing was mixed with 80 ml of distilled water and crushed with a homogenizer at 12000 rpm for 5 minutes to obtain a crushed liquid. The pH was measured with a pH meter, and then the dough pH was obtained. Immediately after the pH measurement, 1 ml of 10% benzalkonium chloride was added, 50 ml of the crushed liquid was centrifuged at 17000 × g (gravity) for 10 minutes, 4.5 ml of the supernatant was separated, and 10% perchloric acid was added in an amount of 0.1%. After 5 ml was added and mixed well, the mixture was centrifuged at 17000 × g (gravity) for 10 minutes, and the supernatant was filtered with a syringe filter having a pore size of 0.45 μm to obtain a sample solution. The sample solution was subjected to measurement of acetic acid concentration ([conjugated base] + [conjugated acid], hereinafter also referred to as AcC) in the dough by high performance liquid chromatography (HPLC). The analysis conditions by HPLC are as follows.
HPLC: SHIMAZU LC10A
Column: SCR101H
Column temperature: 60 ° C
Detector: SPD10A (475 nm)
Flow rate: 1 ml / min
Mobile phase: Perchloric acid solution (pH 2.2)

<Calculation method of non-dissociative acetic acid concentration in bread dough>
The concentration of non-dissociated acetic acid was determined from the Henderson-Hasselbalch equation (pH = pKa + log [conjugated base] / [conjugated acid] from the dough pH, acetic acid concentration (AcC), and pKa value (4.74) of acetic acid measured by the above method. ] Source: Tokyo Kagaku Doujin, “Corn Stamp Biochemistry (5th edition)”, 1988, p. 13).
Non-dissociation type acetic acid concentration = AcC / {10 ^(pH-pKa) +1}

<Bacteria preparation method for bread making test>
Batch culture 5 ml of the medium having the composition shown in Table 4 was dispensed into a large test tube and 50 ml into a 500 ml Sakaguchi flask, sterilized by autoclave, and used for cultivation. Breeding strain 1 Inoculate all platinum ears in a large test tube, shake culture at 30 ° C for 1 day, transfer to 500 ml Sakaguchi flask, and further culture at 30 ° C for 1 day by tube culture. The body was subjected to the following 5 L jar seed culture.

-5L jar seed culture The culture medium 2L of the composition of Table 5 was put into the 5L jar, and after sterilization by autoclave, the microbial cells for five 500 ml Sakaguchi flasks were inoculated, and seed culture was performed on the conditions of Table 6.

-5 L jar main culture 50 g of seed mother cells cultured in a 5 L jar with the medium composition shown in Table 7 was added as wet cells, and main culture was performed under the conditions shown in Table 8. Specifically, culture was performed for 13 hours, and sugar was added in portions during the 12-hour culture. The 5 L jar main cultured cells were centrifuged immediately after completion of the culture, and sucked and dehydrated with Nutsche to obtain wet cells, which were used in the following examples. When used in the experiment, the moisture content of the wet cells was measured, and the amount used was converted to 65% moisture.

<Method of measuring pH and acetic acid concentration of punk crumb>
The crumb pH and acetic acid concentration were measured by the following methods. 20 g of the crumb of the pan after cooling was mixed with 80 ml of distilled water and crushed with a homogenizer at 12000 rpm for 5 minutes to obtain a crushed liquid. The pH of the crushed liquid was measured with a pH meter to obtain crumb pH. Centrifuge 50 ml of the crushed liquid at 17000 × g (gravity) for 10 minutes, collect 4.5 ml of the supernatant, add 0.5 ml of 10% perchloric acid, mix well, and then 10 minutes at 17000 × g (gravity). Centrifugation was performed, and the supernatant was filtered through a syringe filter having a pore diameter of 0.45 μm to obtain a sample solution. The sample solution was subjected to high performance liquid chromatography (HPLC) to measure the concentration of acetic acid in the crumb. The analysis conditions by HPLC are the same as the analysis conditions in the dough.

<Calculation method of non-dissociative acetic acid concentration in punk crumb>
The calculation method of non-dissociation type acetic acid concentration of punk crumb is based on the calculation method of dough.

<Evaluation method by mold-inhibiting coating method>
First, the prepared bread was allowed to stand in the air for one day, then sealed with a nylon bag and allowed to stand at 20 ° C. for 10 days to weigh 0.3 g of the bread in which mold was sufficiently grown, and suspended in 10 ml of sterile water. To the initial concentration. Furthermore, a suspension was prepared by diluting this initial concentration suspension with another sterilized water 10 times to 100000 times. In the mold generation test, the bread of the target sample was sliced at a thickness of 2 cm, and 30 μl of the four-level mold suspensions with the dilution ratios of 100 times, 1000 times, 10000 times, and 100000 times were crumbed with n = 4. After applying to the part, it was sealed with a nylon bag and left at 20 ° C. for 2-3 days. The mold inhibitory property was comprehensively determined from the difference in the dilution ratio of the mold suspension where mold started to develop on the surface of the crumb, and the difference in growth such as the density and spread of mold compared at the same dilution ratio.

<Evaluation method of mold inhibitory property against growth of mold that naturally falls on bread surface>
The prepared bread is left in the air for 90 minutes and allowed to cool, then sealed with a nylon bag and stored at 25 ° C for 24 days. The spread of mold that has fallen spontaneously on the surface of the bread is compared to determine mold inhibition. did.

(Example 1) Cross breeding and screening Spore strains were obtained from a plurality of diploid Saccharomyces cerevisiae strains stored by the Company, and hybrid strains were prepared in various combinations using these spore strains. The produced various hybrid strains and FERM P-18863 were cultured by the above-described screening cell preparation method, and the dough was prepared by the screening bread medium seed method preparation method using the obtained cells. The pH and acetic acid concentration of the dough were measured to calculate the non-dissociation type acetic acid concentration, and a strain that produced non-dissociation type acetic acid higher than FERM P-18863 was selected. Subsequently, the microbial cells were prepared by the above-described 5L jar-based microbial cell preparation method for bread making test, and bread was prepared according to the above-mentioned seed method for bread. The KSY68-9290 strain and the KSY85-596 strain of the present invention, which can solve the problems of the invention, from the pH of the prepared bread crumb, the non-dissociated acetic acid concentration calculated from the measurement value of the acetic acid concentration, and the evaluation of the occurrence of mold of bread Selected.

(Example 2) Evaluation of KSY68-9290 strain A medium-sized bread test was performed on KSY68-9290 in the dough composition shown in Table 9 and the steps shown in Table 10. Table 11 shows the crumb pH and acetic acid concentration of the prepared bread and the non-dissociative acetic acid concentration calculated from the pH and acetic acid concentration. The mold growth state in the mold inhibitory evaluation is shown in FIGS. FIG. 1 shows the growth state of the mold when the mold suspension is applied, and FIG. 2 shows the growth state of the mold that naturally falls on the surface of the bread.

(Comparative example 1) Conventional baker's yeast evaluation The non-dissociation type acetic acid density | concentration measurement and mold | fungi inhibitory evaluation were performed like Example 2 except having used control strain FERM P-18863 as baker's yeast. Table 11 shows the crumb pH and acetic acid concentration of the prepared bread and the non-dissociative acetic acid concentration calculated from the pH and acetic acid concentration. Moreover, the growth state of the mold in the mold inhibitory evaluation is shown in FIGS.

  The crumb pH using KSY68-9290 was slightly lower than the crumb pH used with FERM P-18863. On the other hand, the acetic acid concentration was higher in the crumbs using KSY68-9290 than in the crumbs using FERM P-18863. Thus, in bread using KSY68-9290, non-dissociation type acetic acid concentration uses FERM P-18863 having high mold inhibition property described in Patent Document 1 due to low pH and high acetic acid concentration. It was characterized by greatly exceeding the bread.

  In addition, when looking at FIG. 1, the occurrence of mold on the bread after 2 days has been observed only up to a 100-fold dilution with bread using KSY68-9290, but 1000-fold with bread using FERM P-18863. Mold generation has progressed to the part, and compared with the coated part of 100 times, the mold generation is lighter in bread using KSY68-9290. As for the occurrence of mold after 3 days, the bread using KSY68-9290 can only be seen up to a dilution ratio of 1000 times, but the bread using FERM P-18863 has a mold generation up to 10,000 times. . In addition, when compared with the application parts having a 1000-fold dilution ratio, bread using KSY68-9290 is less susceptible to mold. Further, when FIG. 2 is seen, molds were observed on the bread surface in the bread using FERM P-18863, but not in the bread using KSY68-9290. Thus, the progress of mold generation was suppressed as compared with bread produced using FERM P-18863. JP-A-2004-313190 shows that FERM P-18863 has higher mold-inhibiting ability than conventional baker's yeast, but KSY68-9290 of the present invention is a non-dissociation type that greatly exceeds FERM P-18863. By generating acetic acid, the level of mold suppression was further improved.

(Example 3) Evaluation of KSY85-596 strain In the same manner as in Example 2, the bread dough composition shown in Table 9 and the process shown in Table 10 were performed for medium-sized bread tests on KSY85-596 strain. Table 12 shows the crumb pH, acetic acid concentration, and non-dissociated acetic acid concentration calculated from the pH and acetic acid concentration of the prepared bread. The mold growth state in the mold inhibitory evaluation is shown in FIGS. FIG. 3 shows the growth state of the mold when the mold suspension is applied, and FIG. 4 shows the growth state of the mold that naturally falls on the surface of the bread.

(Comparative example 2) Conventional baker's yeast evaluation The non-dissociation type acetic acid density | concentration measurement and mold | fungi inhibitory evaluation were performed like Example 3 except having used control strain FERM P-18863 as baker's yeast. Table 12 shows the crumb pH, acetic acid concentration, and non-dissociated acetic acid concentration calculated from the pH and acetic acid concentration of the prepared bread. Moreover, the growth state of the mold in the mold inhibitory evaluation is shown in FIGS.

  The pH of the crumb using the KSY85-596 strain was slightly lower than the pH of the crumb used in FERM P-18863. On the other hand, as for the acetic acid concentration, the crumb using KSY85-596 strain exceeded the crumb using FERM P-18863. Thus, in bread using the KSY85-596 strain, non-dissociation type acetic acid concentration is higher than that of FERM P-18863 described in Patent Document 1 due to low pH and high acetic acid concentration. It was characterized by greatly exceeding the bread used.

  In addition, when looking at FIG. 3, the occurrence of mold on the bread after the passage of 2 days can be seen only up to a 100-fold dilution in the bread using the KSY85-596 strain, but 1000 in the bread using the FERM P-18863. Mold generation has progressed to the doubled portion, and compared to the 100-fold coated portion, the mold generation is lighter in bread using the KSY85-596 strain. After 3 days, the bread using the KSY85-596 strain showed only a slight occurrence of mold at the dilution ratio of 10,000 times, but the bread using the FERM P-18863 clearly showed mold generation at the 10,000 times part. Progressing. Further, when FIG. 4 is seen, molds were observed on the bread surface in the bread using FERM P-18863, but not in the bread using KSY85-596. Thus, the progress of mold generation was suppressed as compared with bread produced using FERM P-18863. JP-A-2004-313190 shows that FERM P-18863 has higher mold-suppression than conventional baker's yeast, but the KSY85-596 strain of the present invention is a non-dissociated type that exceeds FERM P-18863. By generating acetic acid, the level of mold suppression was further improved.

  Both the KSY68-9290 strain and the KSY85-596 strain of the present invention produce a lower pH and higher concentration of acetic acid than FERM P-18863 described in JP-A-2004-313190. Increased the effect of inhibiting mold in bread.

The mold generation and growth state of bread after a few days at 20 ° C. are shown. Upper right: KSY68-9290 (after 2 days), lower right: KSY68-9290 (after 3 days), upper left: FERM P-18863 (after 2 days), lower left: FERM P-18863 (after 3 days). Further, in one slice pan, a sample in which the mold suspensions with a dilution ratio of 100 times, 1000 times, 10000 times, and 100,000 times were applied in the vertical direction from the top, and the same mold suspension was applied in the horizontal direction. 4 points were arranged. It shows the occurrence of mold on bread after 24 days at 25 ° C., and the growth state of the mold that occurred naturally. Top: FERM P-18863, bottom: KSY68-9290. The mold generation and growth state of bread after a few days at 20 ° C. are shown. Upper right: KSY85-596 (after 2 days), lower right: KSY85-596 (after 3 days), upper left: FERM P-18863 (after 2 days), lower left: FERM P-18863 (after 3 days). In one slice pan, four mold suspensions with a dilution ratio of 100 times, 1000 times, 10000 times, and 100,000 times were applied in the vertical direction from the top, and the same mold suspension was applied in the horizontal direction. Four samples were arranged. It shows the occurrence of mold on bread after 24 days at 25 ° C., and the growth state of the mold that occurred naturally. Top: FERM P-18863, bottom: KSY85-596.

Claims (4)

Sa Kkaromisesu cerevisiae belonging to KSY68-9290 strain (accession number: FERM P-20204) or KSY85-596 strain (accession number: FERM P-20295) features and to Rupa down yeast that it is. A bread dough containing the baker's yeast according to claim 1 . Bread obtained by baking wheat flour, dough yeast according to claim 1 , sugar, salt, dairy product, fats and oils, and other ingredients that do not contain any additional ingredients that cause pH reduction A bread characterized by having a non-dissociative acetic acid concentration in the bread crumb of 130 ppm or more. The manufacturing method of the bread which uses the baker's yeast of Claim 1 .