Novel brewer's yeast SPC Y76LT for making bread with excellent fermentation characteristics

Abstract

The invention relates to Saccharomyces cerevisiae SPC Y76L (KCTC 14767BP) and a preparation method of the Saccharomyces cerevisiae SPC Y76L (KCTC 14767BP). The strain (SPC Y76LT) shows excellent fermentation capability in various sugar contents, so that the strain can be applied to bread with various sugar contents. Moreover, the strain of the present invention shows low fermentation power at low temperatures, and has little change in mass during refrigerated circulation, and thus is suitable for circulation of refrigerated dough. Moreover, even if the dough using the strain of the present invention is stored in a frozen state and then thawed and used, the fermentation power is maintained in an excellent state, and thus the strain is suitable for the circulation of frozen dough.

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 (minimizing fermentation and metabolism at low temperatures), and has excellent frozen storage properties. Background Art

[0002] Breads are made from a variety of doughs, including French bread without added sucrose, such as baguette, white bread with a low sucrose content, and sweet bread with a high sucrose content, such as red bean paste bread.

[0003] There are two main methods for preparing bread. One is a continuous method that immediately reacts the fermentation power of baker's yeast, in which the dough ingredients are kneaded into dough, fermented, and baked at one time.

[0004] Another method is the spongedough method, which divides the bread fermentation process into two steps. Specifically, a first step involves preparing and fermenting a sponged dough, followed by a final step. The spongedough method offers advantages such as increased bread volume by improving the bread's softness and gas retention, enhancing the dough's mechanical resistance, and improving the bread's flavor. Therefore, it is frequently used in breadmaking.

[0005] Meanwhile, in modern times, a variety of bread preparation and distribution methods have been introduced to establish efficient mass production systems for supplying fresh bread (methods such as bread produced in bakery stores). Representative examples include the distribution of frozen and refrigerated dough. Considering the diverse nature of bread types, preparation, and distribution processes, the selection of yeast that best reflects these characteristics is arguably the most crucial factor in bread quality. Yeasts with a wide range of properties are currently being developed and used commercially.

[0006] A typical example is baker's yeast, which has different fermentation characteristics depending on sugar content. For bread dough with low sucrose content, yeast with a strong ability to utilize most of the maltose in the flour used is used. For bread with high sucrose content and salt concentration, yeast with high sugar (and salt) tolerance is used. Furthermore, for use as frozen or refrigerated dough, yeast with freeze-tolerance or sensitivity to low temperatures is selected and used.

[0007] Yeast, involved in fermentation, is a key factor in breadmaking, contributing to its taste, aroma, and flavor. However, yeast developed and produced by several international companies has traditionally been imported, with imported strains purchased from abroad for domestic production. Fermented foods in Korea hold immense value as a resource for securing domestic fermentation microorganisms. While much research has been conducted on the fermentation process, actual research on the microorganisms responsible for fermentation remains insufficient. Consequently, there are few examples of domestic fermentation microorganisms being utilized as resources, and national resources remain insufficient.

[0008] To ensure consistent bread fermentation success and to ensure yeast is optimally adapted to the breadmaking environment, bacterial strain improvement is necessary. Furthermore, research into bacterial strain improvement is necessary to improve quality, expand market opportunities, and enhance the flavor and functional properties of bread. Summary of the Invention

[0009] Technical issues

[0010] Previous studies have shown that SPC-SNU 70-1, a native yeast (Saccharomyces cerevisiae; brewer's yeast) isolated from koji rice, has high effects on improving taste and flavor, delaying staling, and other qualities, making it an excellent yeast for breadmaking.

[0011] However, SPC-SNU 70-1 exhibits low fermentation activity in environments with no or very low levels of sugar, as well as in environments with very high levels of sugar. This makes it difficult to use in European breads without added sugar or in sweet breads with high sugar content. Furthermore, while quality variations must be minimized during refrigerated and frozen distribution of dough, the existing SPC-SNU 70-1 strain ferments even at low temperatures (10°C), making quality control difficult during distribution.

[0012] Therefore, an object of the present invention is to provide a novel yeast that is not largely dependent on sugar content, exhibits excellent fermentation ability at various sugar contents, and can prepare dough with minimized quality changes at refrigerated and frozen distribution temperatures.

[0013] Technical Solution

[0014] The present invention provides Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both cryopreservability and low-temperature sensitivity.

[0015] The present invention also provides a bread dough comprising Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both freeze-storability and low-temperature sensitivity.

[0016] Furthermore, the present invention provides bread, characterized in that the bread is prepared by baking yeast containing Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) having both freeze-storability and low-temperature sensitivity.

[0017] Effects of the Invention

[0018] The Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP) of the present invention exhibits excellent fermentation characteristics at various sugar concentrations and can therefore be widely used in breads ranging from low-sugar breads to high-sugar breads.

[0019] Furthermore, the fermentation of the Saccharomyces cerevisiae SPC Y76LT (KCTC14767BP) of the present invention is suppressed at refrigerated temperatures and is therefore suitable for refrigerated dough distribution.

[0020] Furthermore, dough using the Saccharomyces cerevisiae SPC Y76LT (KCTC14767BP) of the present invention has excellent frozen storage properties due to its high trehalose content. This means that even if the dough is stored frozen and then thawed for use, the fermentative power of the strain is retained, making it suitable for frozen dough distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram showing the development process of Saccharomyces cerevisiae SPC Y76LT of the present invention.

[0022] Figure 2 This is to confirm the difference in ITS sequence between Saccharomyces cerevisiae SPC Y76LT of the present invention and other yeasts.

[0023] Figure 3 and Figure 4 The figure shows the difference in fermentation ability between the present invention's Saccharomyces cerevisiae SPC Y76LT and other yeasts at different dough sugar concentrations.

[0024] Figure 5The fermentation performance of the present invention's Saccharomyces cerevisiae SPC Y76LT and other yeasts at low temperatures (10°C) was measured. It was confirmed that SPC Y76LT had a low gas generation rate due to its high low-temperature sensitivity.

[0025] Figure 6 The diameter of dough prepared using the present invention's Saccharomyces cerevisiae SPC Y76LT and other yeasts was measured after being frozen and stored for 8 hours after thawing at refrigerated temperature. It was confirmed that the dough diameter varied little due to the high low-temperature sensitivity of the present invention's strain (SPC Y76LT).

[0026] Figure 7 The present invention shows bread produced by preparing dough using the Saccharomyces cerevisiae SPC Y76LT and other yeasts and repeatedly freezing and thawing the dough.

[0027] Figure 8 The determination is shown Figure 7 The results of the bread's aging degree and specific volume.

[0028] Figure 9 Doughs were prepared using the present invention's Saccharomyces cerevisiae SPC Y76LT and other yeasts, and then frozen and stored for different periods of time. The doughs were then fermented and their fermentation activity was measured. It was confirmed that the dough using the present invention's strain (SPC Y76LT) had excellent frozen storage properties and high fermentation activity.

[0029] Figure 10 The present invention presents dough prepared using the yeast strain Saccharomyces cerevisiae SPC Y76LT and other yeasts, and then frozen for different periods of time. The results show the results of measuring the height of bread made from the frozen dough. It was confirmed that dough prepared using the strain of the present invention (SPC Y76LT) exhibited excellent freezer storage properties, a short secondary fermentation time, and a high height when made into bread. DETAILED DESCRIPTION

[0030] The present invention provides Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP), and also provides dough and bread using the Saccharomyces cerevisiae SPC Y76LT (KCTC 14767BP).

[0031] SPC-SNU 70-1, a native yeast (Saccharomyces cerevisiae; brewer's yeast) isolated from koji rice through previous research (Korean Patent No. 10-1551839), has high effects on improving taste and flavor, delaying staling, and other qualities, making it an excellent yeast for breadmaking.

[0032] However, the SPC-SNU 70-1 strain exhibits low fermentability in environments with no or very low levels of sugar, as well as in environments with very high levels of sugar. This makes it somewhat unsuitable for preparing dough for various breads. Furthermore, dough produced using the SPC-SUN 70-1 strain is not very sensitive to low temperatures, making it unsuitable for distribution as refrigerated dough.

[0033] In contrast, Y76LT of the present invention exhibits excellent fermentability regardless of the sugar content of the dough and can therefore be used in the preparation of a wider variety of breads.

[0034] Furthermore, the SPC Y76LT of the present invention has high low-temperature sensitivity, and the fermentation of dough produced using the strain of the present invention is suppressed during refrigerated distribution, thereby minimizing changes in the quality of the dough.

[0035] Furthermore, the excellent trehalose productivity of the SPC Y76LT strain of the present invention improves the frozen storage properties of dough produced using the strain. Specifically, even when dough produced using the strain of the present invention is stored frozen and then thawed for use in bread making, the fermentative power of the strain is maintained at an excellent level.

[0036] Trehalose is known to be synthesized from energy sources and has the property of retaining water, thus playing an important role in the stress response, enabling the organism to withstand water shortages and freezing conditions. Therefore, the trehalose production of a strain is a metric that can be used to determine the shelf life of yeast, the freeze tolerance of dough made from the yeast, and the tolerance to high sugars.

[0037] The present invention will be described in more detail below through the following examples and experimental examples. However, the scope of the present invention is not limited to the following examples and experimental examples, and variations of equivalent technical concepts are also included.

[0038] [Example 1: Screening of Saccharomyces cerevisiae SPC Y76LT]

[0039] After isolating the brewer's yeast Saccharomyces cerevisiae SPC-SNU 70-1 (KCTC12776BP, Korean Patent No. 10-1551839) from koji, and tetrads of various yeasts, new yeasts were screened by mating. Figure 1 The developed strain was named “SPC Y76LT” and deposited at the Korea Biotechnology Research Institute (November 10, 2021) with the deposit number “KCTC 14767BP”.

[0040] Figure 1 Schematic diagram showing the development process of Saccharomyces cerevisiae SPC Y76LT of the present invention.

[0041] On the other hand, the results of identifying sequence differences in the internal transcribed spacer (ITS) region of yeast used in the development process ( Figure 2 ), it was confirmed that Saccharomyces cerevisiae SPC Y76LT was genetically different from the various yeasts used in the mating process. This indicates that the Saccharomyces cerevisiae SPC Y76LT of the present invention is a novel yeast that is different from the yeast used in the mating process.

[0042] on the other hand, Figure 2 The sequence of Saccharomyces cerevisiae SPC Y76LT was used as a reference, and the portions that differ from the yeast sequence used in mating are marked in red.

[0043] [Example 2: Experiment to Identify Differences in Biochemical Properties of Different Yeasts Using VITEK-2 Analysis]

[0044] In this example, the differences in biochemical properties between the Saccharomyces cerevisiae SPC Y76LT of the present invention and various yeasts were confirmed by VITEK-2 analysis (Table 1, Table 2).

[0045] [Table 1]

[0046]

[0047]

[0048]

[0049] [Table 2]

[0050]

[0051]

[0052]

[0053] As shown in Tables 1 and 2, it was confirmed that the Saccharomyces cerevisiae SPCY76LT of the present invention exhibited biochemical properties different from those of the strain used in mating in Example 1. This indicates that the Saccharomyces cerevisiae SPCY76LT of the present invention is a novel yeast different from the strain used in mating.

[0054] [Example 3: Obtaining Saccharomyces cerevisiae SPC Y76LT]

[0055] 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.

[0056] 2) The culture obtained in 1) was inoculated into 100 ml of sterilized YPD (Yeast Peptone Dextrose) medium, and then cultured at 30° C. for 24 hours.

[0057] 3) 500 ml of sterilized YPD medium was inoculated with 50 ml of the culture obtained in 2) and cultured at 30° C. for 24 hours.

[0058] 4) The culture obtained in 3) was inoculated into a culture solution containing honey, urea, phosphoric acid, and B vitamins using a fermenter, and then cultured at 30° C. for 24 hours.

[0059] 5) 60 g of the bacterial cells obtained by centrifugation of the culture solution in 4) were inoculated into a culture solution containing honey, urea, phosphoric acid, and B vitamins using a culture vessel (fermentation tank), and cultured at 30° C. for 14 to 16 hours.

[0060] 6) After centrifuging the culture in 5), yeast having a solid content of 34% (w / w) was obtained by washing and dehydrating.

[0061] [Experimental Example 1: Confirmation of the Difference in Sugar Fermentation Ability of Saccharomyces cerevisiae SPC Y76LT with Differences in Sugar Concentration and Temperature]

[0062] In this experimental example, the difference in sugar fermentation ability of the strain Saccharomyces cerevisiae SPCY76LT of the present invention with changes in sugar concentration and temperature was confirmed.

[0063] 1) Confirming differences in sugar fermentability with changes in sugar concentration

[0064] After preparing the dough having the composition ratio of Table 3 below, 25 g of dough was taken and the fermentation power was measured by a gas generating force measuring instrument at a temperature of 30°C ( Figure 3 、 Figure 4 ).

[0065] [Table 3]

[0066]

[0067] like Figure 3 and Figure 4 As shown, it was confirmed that the Saccharomyces cerevisiae SPCY76LT of the present invention has excellent fermentative ability regardless of the sugar concentration.

[0068] (2) Confirming the difference in sugar fermentability with temperature changes

[0069] After preparing the sugar 8% dough (Table 3), 25 g of the dough was taken and the gas generated by the gas generation force measuring instrument was measured at a temperature of 10°C for 10 hours ( Figure 5 ).

[0070] Compare Figure 3 and Figure 5 The strain of the present invention (SPC Y76LT) was found to be highly sensitive to low temperatures, with its fermentation capacity decreasing at low temperatures (10°C). This suggests that even when dough using the strain of the present invention (SPC Y76LT) is refrigerated, quality changes can be minimized.

[0071] [Experimental Example 2: Confirmation of Low-Temperature Sensitivity of Saccharomyces cerevisiae SPC Y76LT]

[0072] In this experimental example, the low temperature sensitivity of the Saccharomyces cerevisiae SPC Y76LT of the present invention was confirmed.

[0073] To this end, frozen dough was prepared using the strain of the present invention (SPC Y76LT). The diameter of the dough was then measured, and any changes in diameter were confirmed by measuring the diameter after thawing. Furthermore, bread was prepared using the repeatedly frozen and thawed dough to assess its bakery properties. The specific experimental methods and results are as follows.

[0074] 1) Prepare the dough

[0075] The dough ingredients listed 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 a dough. The dough was then placed in a fermenter at 27°C and 85% relative humidity and allowed to mature for 10 minutes. The dough was then divided into desired sizes. The dough was then frozen in a blast freezer (-30°C) for 1 hour and then stored at -18°C.

[0076] On the other hand, yeast (SPC Y76LT) with a solid content of 34% (w / w) prepared in Example 3 was used, and yeast products of SPC 70-1 and commercial yeast A were used as controls. In this case, doughs were prepared with different water and yeast addition amounts, taking into account the solid content of the different yeast products.

[0077] [Table 4]

[0078] raw material Weight ratio Strong powder 100 Improver 1.0 Monoglycerides 0.3 refined salt 2.0 refined white sugar 14 skimmed milk powder 3 butter 10 milk 20 yeast 2.0 Water supply 44

[0079] 2) Diameter change measurement experiment

[0080] The diameter of the dough prepared in the step "1) preparing dough" was measured. After thawing at 10°C for 8 hours, the diameter of the dough was measured. Figure 6 ).

[0081] like Figure 6 As shown, the diameter of the dough using the strain of the present invention (SPC Y76LT) was confirmed to vary minimally from 8.1 cm to 9.4 cm. This indicates that the strain of the present invention (SPC Y76LT) is highly sensitive to low temperatures and exhibits low fermentation capacity at low temperatures, allowing dough using the strain of the present invention (SPC Y76LT) to be distributed with minimal quality variation even when refrigerated.

[0082] 3) Bread making characteristics confirmation experiment

[0083] The frozen dough prepared in "1) preparing the dough" is repeatedly frozen and thawed (thawed at room temperature for 1 hour and frozen at -18°C for 1 hour) 3 times. After thawing at 4°C for 12 hours, it is exposed to room temperature for 1 hour to make the temperature of the dough 18°C, kneaded into a round ball and placed in a bread box. The dough is placed in a fermenter and fermented at 35°C and 85% relative humidity for 70 minutes. The dough is placed in an oven and baked at 170°C on the upper fire and 210°C on the lower fire for 35 minutes to prepare bread ( Figure 7 ).

[0084] The prepared bread was cooled at room temperature for about 2 hours, and then the pH, TTA (acidity) and water content were measured. The taste and flavor scores were shown by sensory testing (Table 5). In addition, the aging degree and specific volume ( Figure 8 ).

[0085] [Table 5]

[0086] project Commercial yeast A SPC-SUN 70-1 SPC Y76LT pH 5.41 5.49 5.40 TTA(6.6 / 8.5) 2.33 / 4.96 2.20 / 4.79 2.36 / 4.99 Moisture content (%) 39.33％ 39.23％ 39.27％ Taste 8.0 6.5 8.5 Flavor 7.6 8.0 8.2

[0087] like Figure 7 As shown, it was confirmed that the bread using the strain of the present invention (SPC Y76LT) had the highest height.

[0088] And, as Figure 8 As shown, it was confirmed that the bread using the strain of the present invention (SPC Y76LT) had the largest specific volume. On the other hand, the staling rate was measured immediately after bread preparation and 4 days later, and it was confirmed that the bread using the strain of the present invention (SPC Y76LT) had the slowest staling rate.

[0089] On the other hand, sensory testing confirmed that the other two yeasts (SPC-SUN 70-1 and SPC Y76LT) had a smoother mouthfeel and better flavor than the commercial yeast. SPC Y76LT exhibited the best mouthfeel, which was believed to be due to differences in specific volume.

[0090] [Experimental Example 3: Confirmation of the Freezing Storage Properties of Saccharomyces cerevisiae SPC Y76LT]

[0091] In this experimental example, the excellent cryopreservability of the Saccharomyces cerevisiae SPC Y76LT of the present invention was confirmed.

[0092] To this end, the trehalose productivity of the strain of the present invention (SPC Y76LT) was measured. Furthermore, the dough prepared in 1) of Experimental Example 2 was frozen and stored, and the differences in fermentation ability and specific volume of the prepared bread were measured at different freezing storage times.

[0093] 1) Trehalose production measurement experiment

[0094] The yeast (SPCY76LT) obtained in Example 3, which had 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 0.45μm nylon filter paper. The trehalose content was measured using liquid chromatography-differential refractometer. The trehalose content in the concentrated culture broth of the strain of the present invention (SPC Y76LT) was confirmed to be 13.58% (w / w), indicating excellent productivity.

[0095] On the other hand, it is known that trehalose is synthesized from energy sources and has the property of retaining water, and therefore plays an important role in the stress response to withstand water shortage or freezing conditions.

[0096] 2) Experimental measurement of fermentation ability differences of doughs stored in frozen state for different times

[0097] The dough prepared in 1) of Experimental Example 2 was frozen and stored (1 week, 3 weeks, 5 weeks, and 7 weeks). Then, 25 g of the dough was taken and the amount of gas generated during 4 hours was measured using a gas generation force measuring instrument at a temperature of 30°C ( Figure 9 ).

[0098] like Figure 9 As shown, it was confirmed that the strain of the present invention (SPC Y76LT) has excellent frozen storage properties, and even when the dough is stored in a frozen state for a long time, it still maintains excellent fermentation ability and a high gas generation amount.

[0099] Furthermore, the dough prepared in 1) of Experimental Example 2 was frozen and stored for 1 week, 3 weeks, 5 weeks, and 7 weeks. The dough was then placed in a fermenter and fermented at 35° C. and a relative humidity of 85%. The time to 95% of the bread box height was measured ( Figure 10 ).like Figure 10 As shown, it can be confirmed that even if the dough is stored in a frozen state for a long time, it still maintains excellent fermentation ability and the required fermentation time is short.

[0100] 3) Experiment on measuring the height difference of bread products with different dough freezing storage time

[0101] The dough prepared in 1) of Experimental Example 2 was frozen and stored (1 week, 3 weeks, 5 weeks, 7 weeks). Then, bread was prepared using the dough. After cooling the prepared bread at room temperature for about 2 hours, the height of the bread was measured ( Figure 10 ).

[0102] like Figure 10 As shown, it was confirmed that the bread produced using the strain of the present invention (SPC Y76LT) had a high finished product height. This is because the bread produced using the strain of the present invention (SPC Y76LT) had excellent fermentation ability even when the dough was frozen and stored for a long time.

[0103]

Claims

1. A yeast strain of Saccharomyces cerevisiae SPC Y76LT with a deposit number of KCTC 14767BP that has both cryopreservability and low-temperature sensitivity.

2. A bread dough, characterized in that: The present invention comprises Saccharomyces cerevisiae SPC Y76LT with the deposit number KCTC 14767BP, which has both cryopreservability and low-temperature sensitivity.

3. A bread, characterized in that: The bread dough is prepared by baking bread dough containing Saccharomyces cerevisiae SPC Y76LT, which has both freeze-storability and low-temperature sensitivity and is deposited under the number KCTC 14767BP.

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