Novel bread-making yeast Saccharomyces cerevisiae SPC Y76LT having excellent fermentation characteristics

Abstract

The present invention relates to Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP). Since the strain (SPC Y76LT) of the present invention exhibits excellent fermenting ability at various sugar contents, it can be applied to various breads with different sugar contents. In addition, the strain of the present invention exhibits low fermenting power at low temperatures and has little quality change during the cold storage and distribution process, so it is suitable for the distribution of refrigerated dough. Moreover, the dough using the strain of the present invention is suitable for the distribution of frozen dough because, even after being stored in a frozen state and then thawed for use, the fermenting power of the strain is maintained in an excellent state.

Description

Technical Field

[0001] The present invention relates to a novel bread-making yeast, and more specifically, to a novel bread-making yeast Saccharomyces cerevisiae SPC Y76LT that exhibits excellent fermentation characteristics at various sugar concentrations, has excellent cold sensitivity (fermentation and metabolism minimization at low temperatures), and has excellent freezing storage properties.

Background Art

[0002] For bread, there are various wheat flour dough compositions, from French bread without added sucrose like baguettes, white bread with a low sucrose content, to sweet bread with a high sucrose addition like filled bread.

[0003] As methods for manufacturing bread, two methods are mainly used as representatives. One is the straight method in which the fermenting power of bread yeast is immediately reflected, and it is a method of kneading the raw materials of the wheat flour dough for bread at once, fermenting, and baking.

[0004] The other is the sponge dough method in which the bread fermentation process is divided into two stages. That is, first, a sponge wheat flour dough is prepared and fermented, and then the final wheat flour dough is prepared and fermented. The sponge dough method is widely used in bread production because of its advantages such as an increase in bread volume due to an increase in the flexibility and gas retention of bread, an improvement in the mechanical resistance of the wheat flour dough, and an improvement in the flavor of bread.

[0005] Meanwhile, in recent years, various bread manufacturing and distribution methods have been introduced in order to build an efficient mass production system (a method in which bread produced in a factory is baked at the store) to supply fresh bread, and a representative example is the distribution of frozen dough and refrigerated dough. Given that there are various types of bread and the characteristics of the manufacturing and distribution processes, the selection of yeast that can optimally reflect each characteristic can be the most important factor in bread quality, and currently yeasts with various characteristics have been developed and are in commercial use.

[0006] The most typical example is baker's yeast, which has different fermentation characteristics depending on the sugar content. For bread with a low amount of sucrose added, the baker's yeast used is usually one with a strong ability to utilize the maltose in the wheat flour used, while for bread with a high amount of sucrose added and high salt concentration, baker's yeast with a strong sugar (salt) tolerance is used. Also, for use as frozen or refrigerated dough, yeast with freezing resistance or yeast sensitive to low temperatures is selected and used.

[0007] Yeast is a key element in bread making, as it is involved in fermentation and determines the taste and aroma, i.e. flavor, but until now, yeast developed and produced by a few global manufacturers has been imported and used, or starter cultures have been purchased from overseas and produced domestically in Korea. Korean fermented foods have infinite value as a material for securing domestic fermentation microbial resources. Currently, much research has been conducted on the fermentation process, but the reality is that there is a lack of research on the microorganisms actually involved in fermentation, there are only a few cases of utilizing Korea's native fermentation microorganisms as resources, and there is a lack of support at the national level.

[0008] For consistent success in bread-making, it is necessary to improve the yeast starter culture so that it can adapt to the bread-making environment. Also, in order to improve the quality and expand the market, it is necessary to increase the flavor and functional properties of bread, and research into improving starter culture is necessary. Summary of the Invention [Problem to be solved by the invention]

[0009] The indigenous yeast (Saccharomyces cerevisiae) SPC-SNU 70-1, which was isolated from koji by previous research, has high quality improvement effects such as taste, aroma, and delayed aging, and thus is used as an excellent yeast for bread making.

[0010] However, SPC-SNU 70-1 has a problem that it is difficult to use for European bread without sugar addition or for sweet bread with a high sugar content because its fermentation power is low in an environment without sugar or with a very low sugar content and in an environment with a very high sugar content. Moreover, although it is required that quality changes be minimized during the refrigerated and frozen distribution of wheat flour dough, the conventional SPC-SNU 70-1 strain has a problem that fermentation proceeds even at a low temperature (10°C), making it difficult to manage the quality during distribution.

[0011] Therefore, the present invention aims to provide a novel yeast that does not greatly depend on the sugar content, exhibits excellent fermentation ability at various sugar contents, and can produce dough with minimized quality changes at refrigerated and frozen distribution temperatures.

Means for Solving the Problems

[0012] The present invention provides Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both frozen storability and low temperature sensitivity.

[0013] In addition, the present invention provides a bread-making dough product characterized by containing Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both frozen storability and low temperature sensitivity.

[0014] Furthermore, the present invention provides a bread produced by baking a bread dough product containing Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP), which has both cold storage properties and low temperature sensitivity.

Advantages of the Invention

[0015] Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) of the present invention exhibits excellent fermentation characteristics at various sugar concentrations, so it can be widely applied from bread with low sugar content to bread with high sugar content.

[0016] In addition, Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) of the present invention is suitable for the distribution of refrigerated dough because fermentation is suppressed at refrigerated temperatures.

[0017] Moreover, the dough using Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) of the present invention has a high trehalose content, so it has excellent cold storage properties. That is, even when the dough is stored frozen and then thawed and used, the fermentation power of the strain is maintained in an excellent state, so it is suitable for the distribution of frozen dough.

Brief Description of the Drawings

[0018]

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Mode for Carrying Out the Invention

[0019] The present invention provides Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP). Further, the present invention provides dough and bread using the Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP).

[0020] In prior research (Korean Registered Patent No. 10-1551839), the native yeast Saccharomyces cerevisiae, SPC-SNU 70-1 isolated from koji has a high effect of improving quality such as taste, aroma, and delaying aging, so it is used as an excellent bread-making yeast.

[0021] However, the SPC-SUN70-1 strain has low fermenting power in an environment without sugar or with very low sugar and in an environment with high sugar, so it was somewhat difficult to produce various types of bread dough. Also, the dough using the SPC-SUN70-1 strain has a problem that it is not suitable for distribution in the form of refrigerated dough because it has low cold sensitivity.

[0022] In contrast, Y76LT of the present invention exhibits excellent fermenting power regardless of the sugar content of the dough, so it can be used for the production of more various types of bread.

[0023] In addition, the SPC Y76LT of the present invention has high cold sensitivity. Therefore, the dough using the strain of the present invention is suppressed in fermentation during the refrigerated distribution process, and the quality change of the dough is minimized.

[0024] In addition, the SPC Y76LT of the present invention is excellent in the productivity of trehalose. Therefore, the dough using the strain of the present invention has excellent frozen storage properties. That is, even after the dough using the strain of the present invention is stored in a frozen state and then thawed and used for bread production, the fermenting power of the strain is maintained in an excellent state.

[0025] Trehalose is synthesized as an energy source and is known to play an important role in stress response that can withstand water deficiency or ice formation due to its property of retaining water. Therefore, the trehalose productivity of the strain is a measure by which the shelf life of yeast, the freeze tolerance of dough made from yeast, and the high sugar tolerance can be confirmed.

[0026] Hereinafter, the content of the present invention will be described in more detail using the following examples or experimental examples. However, the scope of the rights of the present invention is not limited to the following examples or experimental examples, and also includes modifications within the equivalent technical idea.

[0027] [Example 1: Selection of Saccharomyces cerevisiae SPC Y76LT] After separating the tetrads of Saccharomyces cerevisiae SPC-SNU 70-1 (KCTC 12776BP, Korean Registered Patent No. 10-1551839) excavated from koji and various yeasts, they were mated to develop a new yeast (Figure 1). The developed strain was named "SPC Y76LT" and deposited at the Korea Research Institute of Bioscience and Biotechnology on November 10, 2021, and given the deposit number "KCTC 14767BP".

[0028] Figure 1 is a schematic diagram showing the development process of Saccharomyces cerevisiae SPC Y76LT of the present invention.

[0029] On the other hand, as a result of identifying the differences in the sequences of the ITS (internal transcribed spacer) regions of the yeasts used in the development process (Figure 2), it was confirmed that Saccharomyces cerevisiae SPC Y76LT has genetic differences from various yeasts used in the mating process. This means that Saccharomyces cerevisiae SPC Y76LT of the present invention is a new yeast different from the yeasts used for mating.

[0030] On the other hand, in Figure 2, based on the sequence of Saccharomyces cerevisiae SPC Y76LT, the parts that are different from the yeast sequences used in mating are shown in red.

[0031] [Example 2: Experiment to investigate the differences in biochemical characteristics of different yeasts using VITEK-2 analysis] In this example, VITEK-2 analysis was used to confirm the differences in biochemical characteristics between Saccharomyces cerevisiae SPC Y76LT of the present invention and various yeasts (Table 1, Table 2).

[0032]

Table 1

[0033]

Table 2

[0034] From Tables 1 and 2, it can be confirmed that Saccharomyces cerevisiae SPC Y76LT of the present invention exhibits biochemical characteristics different from those of the strain used for mating in Example 1 above. This means that Saccharomyces cerevisiae SPC Y76LT of the present invention is a novel yeast different from the strain used for mating.

[0035] [Example 3: Obtaining Saccharomyces cerevisiae SPC Y76LT] 1) After inoculating Saccharomyces cerevisiae SPC Y76LT of the present invention into a sterilized YM (Yeast Malt) medium, it was cultured at 30 °C for 24 hours.

[0036] 2) After inoculating the culture of 1) above into 100 ml of a sterilized YPD (Yeast Peptone Dxtrose) medium, it was cultured at 30 °C for 24 hours.

[0037] 3) After inoculating 50 ml of the culture of 2) above into 500 ml of a sterilized YPD medium, it was cultured at 30 °C for 24 hours.

[0038] 4) After inoculating the culture of 3) above into a culture solution containing molasses, urea, phosphoric acid, and vitamin B group using a jar-fermenter, it was cultured at 30 °C for 24 hours.

[0039] 5) After inoculating 60 g of the cultured cells obtained by centrifuging the culture solution of 4) above into a culture solution containing molasses, urea, phosphoric acid, and vitamin B group using a jar-fermenter, it was cultured at 30 °C for 14 to 16 hours.

[0040] 6) The culture of 5) above was centrifuged, washed, and dehydrated to obtain yeast with a solid content of 34% (w / w).

[0041] [Experimental Example 1: Confirmation of the Difference in Sugar Fermentation Ability of Saccharomyces cerevisiae SPC Y76LT due to Sugar Concentration Difference and Temperature Difference] In this experimental example, an attempt was made to confirm the difference in sugar fermentation ability of the strain Saccharomyces cerevisiae SPC Y76LT of the present invention due to changes in sugar concentration and temperature.

[0042] 1) Confirmation of the difference in sugar fermentation ability due to changes in sugar concentration

[0043] After producing a dough having the composition ratio shown in Table 3 below, 25 g of the dough was taken, and the fermentation ability was measured using a gas generating power measuring machine under the temperature condition of 30°C (Figs. 3 and 4).

[0044]

Table 3

[0045] From Figs. 3 and 4, it can be confirmed that Saccharomyces cerevisiae SPC Y76LT of the present invention has excellent fermentation ability regardless of the sugar concentration.

[0046] 2) Confirmation of the difference in sugar fermentation ability due to changes in temperature After producing an 8% sugar dough (Table 3), 25 g of the dough was taken, and the amount of gas generated was measured using a gas generating power measuring machine for 10 hours under the temperature condition of 10°C (Fig. 5).

[0047] Comparing Fig. 3 and Fig. 5, it can be confirmed that in the strain (SPC Y76LT) of the present invention, since the low temperature sensitivity is high, the fermentation ability is low in the low temperature (10°C) state. This means that even if the dough using the strain (SPC Y76LT) of the present invention is distributed in the refrigerated state, the quality change can be minimized.

[0048] [Experimental Example 2: Low Temperature Sensitivity Confirmation Experiment of Saccharomyces cerevisiae SPC Y76LT] In this experimental example, an attempt was made to confirm the cold sensitivity of Saccharomyces cerevisiae SPC Y76LT of the present invention.

[0049] Therefore, after manufacturing frozen dough using the strain (SPC Y76LT) of the present invention, the diameter of the dough was measured, and the diameter after thawing was measured to confirm the presence or absence of changes. In addition, after manufacturing bread using the dough that had been repeatedly frozen and thawed, the baking properties of the bread were confirmed. The specific experimental methods and results are as follows.

[0050] 1) Dough production The dough composition components in Table 4 were put into a mixer (SK101S MIXER) and stirred at low speed for 5 minutes and at high speed for 5 minutes to produce dough. The produced dough was placed in a fermenter at 27°C and 85% relative humidity and aged for 10 minutes, and then the dough was divided into a certain size. Then, it was frozen in a quick-freezer (-30°C) for 1 hour and stored frozen at -18°C.

[0051] On the other hand, in order to add yeast, the yeast (SPC Y76LT) with a solid content of 34% (w / w) produced in Example 3 was used, and yeast products of SPC70-1 and commercial yeast A were used as the control group. At this time, considering the solid content for each yeast product, the water supply amount and the yeast addition amount were varied to produce dough.

[0052]

Table 4

[0053] 2) Experiment for measuring diameter change The diameter of the frozen dough produced in the above "1) Dough production" was measured, and the diameter of the dough was measured after thawing at 10°C for 8 hours (Figure 6).

[0054] From Figure 6, it can be confirmed that for the dough using the strain (SPC Y76LT) of the present invention, the change in diameter is the smallest, from 8.1 cm to 9.4 cm. This means that since the strain (SPC Y76LT) of the present invention has high low-temperature sensitivity, its fermenting power is low at low temperatures. It also means that even if the dough using the strain (SPC Y76LT) of the present invention is distributed in a refrigerated state, the quality change can be minimized.

[0055] 3) Experiment for confirming bread-making characteristics Regarding the frozen dough produced in the above-mentioned "1) Dough production", thawing and freezing (thawing at room temperature for 1 hour, freezing at -18°C for 1 hour) were repeated 3 times. After thawing at 4°C for 12 hours, it was exposed at room temperature for 1 hour to bring the dough temperature to 18°C, rounded, and placed in a bread pan. The dough was put into a fermenter and fermented at 35°C and 85% relative humidity for 70 minutes. The dough was put into an oven and baked at an upper heating temperature of 170°C and a lower heating temperature of 210°C for 35 minutes to produce bread (Figure 7).

[0056] After cooling the produced bread at room temperature for about 2 hours, the pH, TTA (acidity), and moisture content were measured, and a sensory test was conducted to show the scores for texture and flavor (Table 5). Also, the degree of staling and specific volume were measured using a specific volume measuring machine and a physical property measuring machine (Figure 8).

[0057]

Table 5

[0058] From Figure 7, it can be confirmed that the height of the bread using the strain (SPC Y76LT) of the present invention is the highest.

[0059] Also, from Figure 8, it can be confirmed that the specific volume of the bread using the strain (SPC Y76LT) of the present invention is the largest. On the other hand, the degree of staling was measured immediately after bread production and on the 4th day, and it can be confirmed that the staling rate of the bread using the strain (SPC Y76LT) of the present invention is the lowest.

[0060] On the other hand, according to the sensory evaluation, it was confirmed that in the case of the remaining two types of yeast (SPC-SUN70-1, SPC Y76LT) compared with commercial yeast, the texture was soft and the flavor was good. In terms of texture, SPC Y76LT is the most excellent, which is judged to be due to the difference in specific volume.

[0061] [Experimental Example 3: Experiment for Confirming the Refrigerated Storability of Saccharomyces cerevisiae SPC Y76LT] In this experimental example, an attempt was made to confirm the excellent refrigerated storability of Saccharomyces cerevisiae SPC Y76LT of the present invention.

[0062] Therefore, an attempt was made to measure the trehalose productivity of the strain (SPC Y76LT) of the present invention. In addition, while the dough produced in 1) of Experimental Example 2 was stored frozen, an attempt was made to measure the difference in fermentation power according to the frozen storage time and the difference in the specific volume of the produced bread.

[0063] 1) Measurement Experiment of Trehalose Productivity

[0064] The yeast (SPC Y76LT) with a solid content of 34% (w / w) obtained in Example 3 was diluted with distilled water and heated at 85°C for 25 minutes to extract trehalose. After the extract was cooled to room temperature, it was centrifuged and filtered through a 0.45 μm nylon membrane filter paper, and then the trehalose content was measured using a liquid chromatography differential refractometer. It was confirmed that the concentrated culture solution of the strain (SPC Y76LT) of the present invention has a trehalose content of 13.58% (w / w), indicating an excellent production amount.

[0065] On the other hand, trehalose is synthesized as an energy source and is known to play an important role in stress response that can withstand water deficiency or ice formation due to its property of retaining water.

[0066] 2) Measurement experiment on the difference in fermentation power according to the freezing storage time of the dough

[0067] The dough produced in 1) of the above Experimental Example 2 was frozen and stored (1 week, 3 weeks, 5 weeks, 7 weeks). Then, 25 g of the dough was taken, and at a temperature condition of 30 °C, the amount of gas generated was measured for 4 hours using a gas generation force measuring machine (Figure 9).

[0068] From Figure 9, since the strain (SPC Y76LT) of the present invention is excellent in freezing storage property, it can be confirmed that excellent fermentation power is maintained despite long-term storage of the dough in the frozen state, and the gas generation amount is high.

[0069] Also, after the dough produced in 1) of the above Experimental Example 2 was frozen and stored (1 week, 3 weeks, 5 weeks, 7 weeks), the dough was put into a fermenter and fermented at 35 °C and a relative humidity of 85%, and the time to reach 95% of the height of the bread pan was measured (Figure 10). From Figure 10, it can be confirmed that excellent fermentation power is maintained despite long-term storage of the dough in the frozen state, and the fermentation takes less time.

[0070] 3) Measurement experiment on the height difference of the bread products according to the freezing storage time of the dough The dough produced in 1) of the above Experimental Example 2 was frozen and stored (1 week, 3 weeks, 5 weeks, 7 weeks). Then, bread was produced with the said dough. After the produced bread was cooled at room temperature for about 2 hours, the height of the bread was measured (Figure 10).

[0071] From Figure 10, in the case of the bread using the strain (SPC Y76LT) of the present invention, it can be confirmed that the height of the finished product is high. This is the result of the bread using the strain (SPC Y76LT) of the present invention showing excellent fermentation power even when the freezing storage time of the dough is long.

Deposit number

[0072] JPEG2025524183000007.jpg161170

Claims

**Claim 1** Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both cold storage stability and cold sensitivity. **Claim 2** A bread dough product characterized by containing Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both cold storage stability and cold sensitivity. **Claim 3** A bread characterized by being produced by baking a bread dough product containing Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both cold storage stability and cold sensitivity.

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