A novel bakery yeast, Saccharomyces cerevisiae SPC Y76LT, with 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 baker's yeast, and more specifically to a novel baker's yeast, Saccharomyces cerevisiae SPC Y76LT, which exhibits excellent fermentation characteristics at various sugar concentrations, has excellent low-temperature sensitivity (fermentation at low temperatures and minimization of catabolism), and is excellent in frozen storage. [Background technology]

[0002] Bread comes in a variety of wheat flour dough compositions, ranging from French bread, which does not contain added sucrose such as baguettes, to white bread, which has a low sucrose content, to sweet bread, which has a high sucrose content such as bean paste bread.

[0003] There are two main methods for making bread. One is the straight method, in which the fermentation power of baker's yeast is immediately reflected, in which the wheat flour dough ingredients are kneaded, fermented, and baked all at once.

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

[0005] Meanwhile, in recent years, various bread manufacturing and distribution methods have been introduced in order to establish an efficient mass production system (a system in which bread produced in a factory is baked at the store) to supply fresh bread, and a typical example is the distribution of frozen dough and refrigerated dough. Given the variety of 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. Baker's yeast used in dough made from wheat flour with a low sucrose content is usually one with a strong ability to utilize the maltose in the wheat flour used, while baker's yeast with a high sugar (salt) tolerance is used in breads with a high sucrose content and salt concentration. Furthermore, yeast with freeze resistance or sensitivity to low temperatures is selected and used for use in frozen or refrigerated dough.

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

[0008] For consistent success in bread-making, yeast starters must be improved to adapt to the bread-making environment. Furthermore, to improve quality and expand the market, the flavor and functional properties of bread must be enhanced, and research into starter cultures is essential. Summary of the Invention [Problem to be solved by the invention]

[0009] SPC-SNU 70-1, a native yeast (Saccharomyces cerevisiae) isolated from koji in previous research, is used as an excellent bread-making yeast because of its high quality-improving effects on taste, aroma, and delayed aging.

[0010] However, SPC-SNU 70-1 has poor fermentation ability in environments with no or very low sugar content, and in environments with very high sugar content, making it difficult to use for European breads that do not contain added sugar or for sweet breads with a high sugar content. Furthermore, while quality changes must be minimized during refrigeration and frozen distribution of wheat flour dough, the conventional SPC-SNU 70-1 strain continues fermentation even at low temperatures (10°C), making quality control during distribution difficult.

[0011] Therefore, the present invention aims to provide a novel yeast that is not largely dependent on the sugar content, exhibits excellent fermentation ability even at various sugar contents, and can produce dough that exhibits minimal quality change at refrigerated and frozen distribution temperatures. [Means for solving the problem]

[0012] The present invention provides Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) which has both frozen storage ability and low temperature sensitivity.

[0013] The present invention also provides a dough for breadmaking, characterized by containing Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) which has both frozen storage stability and low temperature sensitivity.

[0014] The present invention also provides bread produced by baking a dough containing Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP), which has both frozen storage stability and low-temperature sensitivity. [Effects of the Invention]

[0015] The Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) of the present invention exhibits excellent fermentation characteristics at various sugar concentrations, and is therefore applicable to a wide range of breads, from those with low sugar content to those with high sugar content.

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

[0017] Furthermore, the dough made using the Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) of the present invention has a high trehalose content, making it suitable for frozen storage. That is, even when the dough is stored frozen and then thawed for use, the fermentation power of the strain is maintained at an excellent level, making it suitable for distribution of frozen dough. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing the development process of Saccharomyces cerevisiae SPC Y76LT of the present invention. [Figure 2] 1 shows the results of confirming the difference in ITS sequence between Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts. [Figure 3]1 shows the difference in fermentation ability between the Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts depending on the sugar concentration of the dough (1). [Figure 4] 1 shows the difference in fermentation ability between the Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts depending on the sugar concentration of the dough (2). [Figure 5] The results show that the fermentation ability of the Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts was measured at low temperatures (10°C). It can be seen that SPC Y76LT has high sensitivity to low temperatures and therefore produces less gas. [Figure 6] The results show that dough was made using the Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts, then frozen and thawed at refrigerated temperature for 8 hours, and the diameter of the dough was measured. It can be seen that the strain of the present invention (SPC Y76LT) has high cold sensitivity, so there is little change in the diameter of the dough. [Figure 7] Dough was prepared using Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts, and the dough was repeatedly cooled and thawed, followed by the production of bread. [Figure 8] FIG. 8 shows the results of measuring the degree of staling and specific volume of the bread. [Figure 9] Dough was made using the Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts, and after frozen storage for a set period of time, it was fermented and the fermentation power was measured. It was confirmed that the dough made using the strain of the present invention (SPC Y76LT) has excellent frozen storage properties and high fermentation power. [Figure 10]Dough was made using the Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts, and the time required for secondary fermentation was measured after frozen storage for various periods. Also shown are the results of measuring the height of bread made from the frozen dough. Meanwhile, it was confirmed that dough made using the bacterial strain of the present invention (SPC Y76LT) had excellent frozen storage properties, a short secondary fermentation time, and resulted in a high bread height when made into bread. DETAILED DESCRIPTION OF THE INVENTION

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

[0020] The native yeast Saccharomyces cerevisiae, SPC-SNU 70-1, isolated from koji in a previous study (Korean Patent Registration No. 10-1551839), is used as an excellent baker's yeast due to its high quality improvement effects, including taste, aroma, and delayed aging.

[0021] However, the SPC-SUN70-1 strain has low fermentation ability in environments with no or very low sugar content and in environments with high sugar content, making it somewhat difficult to produce various types of bread dough.In addition, dough using the SPC-SUN70-1 strain has low sensitivity to low temperatures, making it unsuitable for distribution in the form of refrigerated dough.

[0022] In contrast, the yeast Y76LT of the present invention exhibits excellent leavening ability regardless of the sugar content of the dough, and can therefore be used to produce a wider variety of breads.

[0023] Furthermore, the SPC Y76LT of the present invention is highly cold-sensitive, and therefore, when dough is made using the strain of the present invention, fermentation is suppressed during refrigerated distribution, minimizing changes in dough quality.

[0024] Furthermore, the SPC Y76LT of the present invention has excellent trehalose productivity, and therefore dough prepared using the strain of the present invention has excellent frozen storage properties. That is, even if dough prepared using the strain of the present invention is stored frozen and then thawed and used to make bread, the fermentation ability of the strain is maintained at an excellent level.

[0025] Trehalose is synthesized as an energy source and is known to play an important role in stress response, allowing yeast to withstand conditions such as water deficiency or freezing, due to its ability to retain water. Therefore, the trehalose productivity of a strain can be used as a measure to determine the shelf life of yeast, the freezing tolerance of dough made with yeast, and the tolerance to high sugars.

[0026] The present invention will be described in more detail below using the following examples and experimental examples. However, the scope of the present invention is not limited to the following examples and experimental examples, and includes modifications in the technical ideas equivalent thereto.

[0027] Example 1: Selection of Saccharomyces cerevisiae SPC Y76LT A novel yeast was developed by mating tetrads of Saccharomyces cerevisiae SPC-SNU 70-1 (KCTC 12776BP, Korean Patent No. 10-1551839) isolated from koji and various yeasts (Figure 1). The developed strain was named "SPC Y76LT" and deposited at the Korea Institute of Bioscience and Biotechnology (November 10, 2021) with the accession number "KCTC 14767BP."

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

[0029] Meanwhile, by examining the sequence differences in the internal transcribed spacer (ITS) regions of the yeasts used in the development process (Figure 2), it was confirmed that Saccharomyces cerevisiae SPC Y76LT has genetic differences from the various yeasts used in the breeding process. This means that the Saccharomyces cerevisiae SPC Y76LT of the present invention is a novel yeast that is different from the yeasts used in the breeding.

[0030] On the other hand, in FIG. 2, the sequence of Saccharomyces cerevisiae SPC Y76LT is used as a reference, and the parts that differ from the yeast sequence used for mating are shown in red.

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

[0032] [Table 1]

[0033] [Table 2]

[0034] From Tables 1 and 2, it can be seen that the Saccharomyces cerevisiae SPC Y76LT of the present invention exhibits biochemical properties different from those of the strain used for mating in Example 1. This means that the 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) Saccharomyces cerevisiae (SPC Y76LT) of the present invention was inoculated into a sterilized YM (Yeast Malt) medium and then cultured at 30° C. for 24 hours.

[0036] 2) The culture obtained in 1) above was inoculated into 100 ml of sterilized YPD (Yeast Peptone Dextrose) medium and then cultured at 30° C. for 24 hours.

[0037] 3) 500 ml of sterilized YPD medium was inoculated with 50 ml of the culture obtained in 2) above, and then cultured at 30°C for 24 hours.

[0038] 4) Using a jar fermenter, the culture obtained in 3) was inoculated into a culture solution containing molasses, urea, phosphoric acid, and B vitamins, and then cultured at 30°C for 24 hours.

[0039] 5) Using a jar fermenter, 60 g of the cultured cells obtained by centrifuging the culture solution in 4) was inoculated into a culture solution containing molasses, urea, phosphoric acid, and B vitamins, and then cultured at 30°C for 14 to 16 hours.

[0040] 6) The culture obtained in 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 due to differences in sugar concentration and temperature of Saccharomyces cerevisiae (SPC Y76LT)] In this experiment, the present invention was investigated to confirm the difference in sugar fermentation ability of the strain Saccharomyces cerevisiae SPC Y76LT depending on the sugar concentration and temperature.

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

[0043] After preparing the dough having the composition ratio shown in Table 3 below, 25 g of the dough was taken and the fermentation power was measured using a gas generation power measuring device at a temperature of 30°C (Figures 3 and 4).

[0044] [Table 3]

[0045] 3 and 4, it can be seen that the 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 temperature change After preparing the 8% sugar dough (Table 3), 25 g of dough was taken and the amount of gas generated was measured at 10°C for 10 hours using a gas generation force measuring device (Figure 5).

[0047] 3 and 5, it can be seen that the strain of the present invention (SPC Y76LT) has high cold sensitivity, and therefore its leavening power is low at low temperatures (10°C). This means that even if dough made using the strain of the present invention (SPC Y76LT) is distributed refrigerated, quality changes can be minimized.

[0048] [Experimental Example 2: Experiment to confirm the cold sensitivity of Saccharomyces cerevisiae SPC Y76LT] In this experiment, the cold sensitivity of Saccharomyces cerevisiae SPC Y76LT of the present invention was confirmed.

[0049] To this end, frozen dough was prepared using the bacterial strain of the present invention (SPC Y76LT), and the diameter of the dough was measured. The diameter was then measured after thawing to determine whether there was any change. Furthermore, bread was prepared using the dough that had been repeatedly frozen and thawed, and the baking properties of the bread were then determined. The specific experimental methods and results are as follows:

[0050] 1) Fabric manufacturing The dough ingredients in Table 4 were added to a mixer (SK101S MIXER) and mixed at low speed for 5 minutes and then at high speed for 5 minutes to prepare the dough. The dough was then placed in a proofing chamber at 27°C and 85% relative humidity for 10 minutes, after which it was divided into portions of a certain size. The dough was then frozen in a quick freezer (-30°C) for 1 hour and then stored frozen at -18°C.

[0051] Meanwhile, to add yeast, yeast (SPC Y76LT) with a solid content of 34% (w / w) prepared in Example 3 was used, and yeast products SPC70-1 and commercial yeast A were used as controls. In this case, the amount of water and the amount of yeast added were varied depending on the solid content of each yeast product, and dough was prepared.

[0052] [Table 4]

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

[0054] 6, it can be seen that the dough made using the bacterial strain of the present invention (SPC Y76LT) showed the smallest change in diameter, from 8.1 cm to 9.4 cm. This means that the bacterial strain of the present invention (SPC Y76LT) is highly cold-sensitive and therefore has low leavening power at low temperatures, and that even if the dough made using the bacterial strain of the present invention (SPC Y76LT) is distributed refrigerated, the quality change is minimized.

[0055] 3) Bread-making characteristics confirmation experiment The frozen dough produced in "1) Dough Production" above was subjected to three cycles of cold thawing (thawing at room temperature for 1 hour, then freezing at -18°C for 1 hour). After thawing at 4°C for 12 hours, the dough was left at room temperature for 1 hour to bring the temperature of the dough to 18°C, rolled into balls, and placed in a bread pan. The dough was placed in a proofing oven and fermented for 70 minutes at 35°C and 85% relative humidity. The dough was then placed in an oven and baked for 35 minutes at an upper heat of 170°C and a lower heat of 210°C, producing loaf bread (Figure 7).

[0056] The bread was cooled at room temperature for about 2 hours, and then the pH, TTA (acidity), and moisture content were measured. A sensory test was conducted and the texture and flavor were scored (Table 5). The staling degree and specific volume were also measured using a specific volume measuring instrument and a physical property measuring instrument (Figure 8).

[0057] [Table 5]

[0058] From FIG. 7, it can be seen that the height of the bread made using the strain of the present invention (SPC Y76LT) was the highest.

[0059] 8 also confirms that the specific volume of the bread made using the bacterial strain of the present invention (SPC Y76LT) was the largest. On the other hand, the staling rate was measured immediately after making the bread and on the fourth day, and it was confirmed that the staling rate of the bread made using the bacterial strain of the present invention (SPC Y76LT) was the lowest.

[0060] On the other hand, sensory tests confirmed that the remaining two yeasts (SPC-SUN70-1 and SPC Y76LT) had a softer texture and better flavor than commercial yeast. SPC Y76LT had the best texture, which is thought to be due to the difference in specific volume.

[0061] [Experimental Example 3: Experiment to confirm the frozen storage of Saccharomyces cerevisiae SPC Y76LT] In this experiment, an attempt was made to confirm the excellent frozen storage properties of Saccharomyces cerevisiae SPC Y76LT of the present invention.

[0062] To this end, we aimed to measure the trehalose productivity of the strain of the present invention (SPC Y76LT). Furthermore, we also aimed to measure the difference in fermentation power and the difference in specific volume of the bread produced by freezing the dough prepared in Experimental Example 2, 1) above.

[0063] 1) Trehalose productivity measurement experiment

[0064] The yeast (SPC Y76LT) obtained in Example 3 with a solid content of 34% (w / w) was diluted with distilled water and heated at 85°C for 25 minutes to extract trehalose. The extract was cooled to room temperature, centrifuged, and filtered through a 0.45 μm nylon membrane filter paper. The trehalose content was measured using a liquid chromatography time differential refractometer. The concentrated culture medium of the strain (SPC Y76LT) of the present invention contained 13.58% (w / w) trehalose, confirming its excellent productivity.

[0065] Meanwhile, trehalose is synthesized as an energy source and is known to play an important role in stress response, which allows plants to withstand conditions such as water deficiency or freezing, due to its ability to retain water.

[0066] 2) Experiment to measure the difference in fermentation power depending on the time of storing the dough frozen

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

[0068] From FIG. 9, it can be seen that the strain of the present invention (SPC Y76LT) has excellent frozen storage properties, and therefore maintains excellent fermentation power and produces a high amount of gas even when the dough is stored in a frozen state for a long period of time.

[0069] In addition, the dough produced in Experimental Example 2, 1) was frozen and stored (for 1, 3, 5, and 7 weeks), and then placed in a proofer and fermented at 35°C and 85% relative humidity, and the time it took to reach 95% of the bread case height was measured (Figure 10). Figure 10 confirms that the dough maintained its excellent fermentation power despite being stored frozen for a long period of time, and that fermentation took less time.

[0070] 3) Experiment to measure the difference in height of bread products depending on the time of storing frozen dough The dough prepared in Experimental Example 2-1) was frozen and stored for 1, 3, 5, and 7 weeks. Bread was then prepared using the dough. The bread was cooled at room temperature for approximately 2 hours, and the height of the bread was measured (FIG. 10).

[0071] From Figure 10, it can be seen that the height of the finished bread made using the strain of the present invention (SPC Y76LT) is high. This is because the bread made using the strain of the present invention (SPC Y76LT) exhibits excellent fermentation power even when the dough is stored frozen for a long time. [Accession number]

[0072] JPEG0007826567000006.jpg161170

Claims

1. Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) is both frozen storage compatible and cold sensitive.

2. A bread dough comprising Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both frozen storage stability and low temperature sensitivity.

3. Bread characterized by being produced by baking a dough containing Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both frozen storage stability and low temperature sensitivity.

Images