Yeast fungus, yeast powder and its use in wheat flour food processing

Abstract

The present invention discloses a yeast, yeast powder, and its use in processing flour-based foods, wherein the yeast is CDLB-YE05 Kazachstania servazzii yeast, preserved at the Institute of Microbiology, Chinese Academy of Sciences, on July 17, 2023, with storage number CGMCC NO. 27948 and storage address at No. 3, Courtyard, No. 1, Beichen West Road, Chaoyang District, Beijing. The CDLB-YE05 Kazachstania servazzii yeast provided by the present invention is used to prepare yeast powder, which is then used in processing flour-based foods to increase the polysaccharide compounds produced by the yeast's propagation metabolism in dough, thereby increasing the viscosity of the food, improving the chewiness of the flour-based foods, and enhancing the flavor and mouthfeel.

Description

[Technical Field]

[0001] The present invention relates to the technical field of microorganisms, in particular to yeasts, yeast powders and their use in flour food processing. [Background technology]

[0002] Flour foods are very popular among Chinese people. For thousands of years, our ancestors have handcrafted large quantities of flour foods with local flavors and textures in each region. These flour foods are chewy and delicious, and some local flour foods have even become traditional local delicacies. However, with the advancement of industry, it is very difficult in modern society to machine-produce the unique textures and flavors of traditional flour foods in each region. Research has shown that this is due to the differences in the yeast strains available to different regions and people. When different yeast strains are inoculated into dough, different metabolic products such as carbon dioxide, organic acids, alcohols, alcohol compounds, sugar compounds, and ester compounds are produced during the metabolism of fermented starch, and it is these metabolic products that allow the flour foods produced to express different flavors. The more sugar compounds there are, the more viscous the starch will be, and the more lipid compounds there are, the more fragrant the noodles will be and the richer the texture will be, which is the main reason why noodles have a chewy texture and a rich texture. In contrast, when making flour foods using machines, the yeast fermentation process is not used, and therefore the texture unique to traditional flour foods from each region cannot be created.

[0003] Therefore, there is an urgent need to provide new yeast strains capable of producing sugar and lipid compounds to improve the texture and aroma of flour foods. Summary of the Invention

[0004] The object of the present invention is to provide a yeast, a yeast powder and its use in processing wheat flour foods, which solve the problem that various wheat flour foods made by conventional processes are not chewy enough and have a bad mouthfeel.

[0005] To achieve the above objectives, the first technical solution of the present invention is realized as the CDLB-YE05 Kazachstania servazzii yeast fungus, which is stored at the Institute of Microbiology, Chinese Academy of Sciences on July 17, 2023, with the storage number CGMCC NO. 27948 and the storage address at No. 3, Courtyard, No. 1, Beichen West Road, Chaoyang District, Beijing.

[0006] Furthermore, the nucleotide sequence of said yeast is as shown in SEQ No. 1.

[0007] The second technical solution of the present invention is obtained by mixing yeast culture, skim milk powder, and sorbitan monostearate, followed by freeze-drying and grinding, and adding 60g-80g of skim milk powder and 9g-10g of sorbitan monostearate per 1kg of yeast culture; The yeast culture is realized as a yeast powder prepared from the yeast cultured with the yeast.

[0008] Furthermore, the yeast powder has a moisture content of 10% or less, a protein content of 4% or more, an ash content of 10% or less, and a yeast cell count of 10% or less. 7 CFU or more.

[0009] Furthermore, the yeast culture The yeast is activated for 16 to 48 hours, then inoculated into a mixed medium, water is added, the mixture is stirred uniformly, and the mixture is cultured under aerobic conditions at 15 to 35°C for 20 to 72 hours to obtain the yeast.

[0010] Furthermore, the mixed medium Weigh out 720 to 880 parts by mass of malt, 90 to 110 parts by mass of soybeans, and 90 to 110 parts by mass of glutinous rice. The weighed substances are baked at 120°C for 2 hours, then crushed and mixed to obtain the powder.

[0011] The third technical solution of the present invention is realized as the use of the yeast powder in wheat flour food processing.

[0012] Furthermore, as a specific method, In S1, weigh out 0.08 to 0.1 parts yeast powder, 100 to 110 parts flour, 28 to 30 parts water, 0.1 to 0.15 parts salt, and 0.1 to 0.15 parts edible alkali in mass ratios. In S2, the weighed yeast powder, wheat flour, edible salt, edible alkali and water are mixed to form dough, and the dough is fermented for 3 to 6 hours to produce a flour food product.

[0013] Furthermore, the flour foods include noodles, dumplings, wontons, and Chinese rice cakes.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] By preparing yeast powder using the yeast provided by the present invention and using the yeast powder in processing flour foods, the polysaccharide compounds produced by the propagation metabolism of the yeast in flour can be increased, the viscosity of the flour foods can be increased, the chewiness of the flour foods can be improved, and the mouthfeel can be made better. [Brief explanation of the drawings]

[0016] [Figure 1] This is the colony morphology of CDLB-YE05 Kazachstania servazzii yeast on potato dextrose agar medium. [Figure 2] This shows the colony morphology of CDLB-YE05 Kazachstania servazzii yeast on a wort medium. [Figure 3] FIG. 1 is a comparison diagram of the content of polysaccharide compounds produced by different yeast strains. [Figure 4] (a) Colony morphology of yeast powder, (b) Colony morphology of active dry yeast (high sugar type), (c) Colony morphology of active dry yeast (low sugar type), and (d) Colony morphology of winemaking yeast species. [Figure 5] 1 is a glucose standard curve. [Figure 6] FIG. 1 is a diagram comparing the concentrations of polysaccharide compounds in samples from each group in Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in more detail below in combination with specific examples. It should be understood that the specific examples described herein are only for the purpose of illustrating the present invention, and are not intended to limit the present invention.

[0018] In the description of the present invention, it should be made clear that orientations or positional relationships indicated by terms such as "vertical," "lateral," "longitudinal," "front," "rear," "left," "right," "upper," "lower," "horizontal," etc. are based on the drawings and are merely intended to facilitate explanation of the present invention. The described devices or elements do not necessarily have a specific orientation or position, and should not be construed as limiting the present invention. In the description of the present invention, it should be made clear that, unless otherwise clearly defined or limited, the terms "attach," "couple," and "connect" should be understood broadly, for example, to mean fixedly connected, detachably connected, integrally connected, directly connected, or indirectly connected via an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0019] Example 1 The yeast was isolated, purified, and identified.

[0020] 1) Sample source: Lanzhou ramen dough Among all types of wheat flour foods, Lanzhou ramen is a local dish with a unique regional flavor. It takes a long time to make and the dough contains a large number and variety of yeast strains, making it particularly chewy and giving it a unique mouthfeel and aroma.

[0021] 2) Culture medium: Potato dextrose agar (PDA), wort medium The specific ingredients per liter of potato dextrose agar were 300.0 g potato (extract leach powder), 20.0 g glucose, 15.0 g agar, and 0.1 g chloramphenicol.

[0022] The specific components per liter of wort medium were 130.0 g of powdered malt extract and 0.1 g of chloramphenicol.

[0023] 3) Reagents and equipment used [Table 1]

[0024] 4) Isolation of a single strain Weigh out 25 g of Lanzhou ramen dough and add 225 mL of sterile saline to make a 1:10 homogeneous sample solution. Dilute it 10 times to make a 10 6 The gradient sample was prepared as a homogeneous solution. For each dilution, 1 mL of the sample homogenous solution was drawn up and placed in two flat plates, and 20 mL of potato dextrose agar medium cooled to 46°C was weighed and poured into the flat plates. After cooling and solidifying, the plates were cultured in a fungal incubator at 28°C for 5 days. Colony morphology was observed, and single colonies were selected from among them. The selected single colonies were continuously streaked onto potato dextrose agar plates, and the morphology of the single colonies was observed until a different single strain was isolated.

[0025] 5) Screening for strains that do not produce gas Prepare 180 mL of wort medium, sterilize it at 115 ° C for 15 minutes under high pressure, cool it, and distribute it into 18 15 mL sterilized glass test tubes. Remove the air from the Durham tube and set the Durham tube opening downwards into each test tube. A single strain obtained in 4) was selected and inoculated into the wort medium of each test tube. Each test tube was sealed with an air-permeable filtration membrane and cultured with shaking at 30±1°C and a rotation speed of 160 r / min for 72 hours. The turbidity rate and gas production during the growth of the strain were observed, and a strain with a fast turbidity rate and no gas production was selected.

[0026] 6) Screening for strains that do not produce alcohol The non-gas-producing strains screened in 5) were diluted 10-fold to 10 6 A gradient of sample homogenous solutions was prepared. For each dilution level, 1 mL of the sample homogenous solution was drawn up and placed into two sterilized flat plates. 20 mL of potato dextrose agar medium cooled to 46°C was weighed and poured into the flat plates. After cooling and solidifying, the plates were cultured at 28°C in a fungal incubator for 5 days. The colony morphology was observed, and medium to large single colonies with smooth surfaces and even edges were selected. The medium- and large-sized single colonies were inoculated into the wort medium, and cultured at 30±1°C and 160 r / min for 72 hours with shaking to obtain a bacterial solution. 1 mL of the bacterial solution was drawn up, 1 mL of potassium dichromate solution with a molar concentration of 0.1 mol / L was added, and the mixture was shaken. The color change of the mixture was observed. A strain that did not change color was selected and the above screening steps were repeated until a yeast strain that produced neither gas nor alcohol was selected.

[0027] The yeast strain that produces neither gas nor alcohol was inoculated into a wort medium together with the yeast strain that produces both gas and alcohol obtained by the above process, and their propagation and metabolism were observed. As a result, it was found that the yeast strain that produces neither gas nor alcohol made the wort medium more viscous and had a rose aroma.

[0028] 7) Purification and genome sequencing of a yeast strain that produces neither gas nor alcohol Prepare 100 mL of wort medium in an Erlenmeyer flask, sterilize at 115°C for 15 minutes under high pressure, and then store in a cool, dry place. A small amount of wort medium was added to a yeast strain that does not produce gas or alcohol, and the suspension was then poured into the wort medium in an Erlenmeyer flask, sealed with a breathable filtration membrane, and cultured with shaking at 28±1°C and 120 r / min for 48 hours. The wort fungal suspension was centrifuged and washed, and the resulting fungal pellet was quickly frozen in liquid nitrogen and placed in a sample tube. The fungal species was identified at the Shenzhen Municipal Institute of Metrology and Quality Control for identification. 18sRNA was used to identify the yeast CDLB-YE05 Kazachstania servazzii. The sample was then sent to the Wuhan Sequencing Center of China University for genome sequencing. The nucleotide sequence of the yeast CDLB-YE05 Kazachstania servazzii was SEQ No. 1 and shown in Table 2.

[0029] [Table 2] JPEG2025530048000004.jpg116170

[0030] 8) Colony morphology of CDLB-YE05 Kazachstania servazzii yeast The CDLB-YE05 Kazachstania servazzii yeast was inoculated onto a potato dextrose agar plate and cultured at 28°C for 5 days. Colony morphology was observed, and as shown in Figure 1, the CDLB-YE05 Kazachstania servazzii yeast colonies were milky white, round, smooth, opaque, non-reflective, and had even edges.

[0031] The CDLB-YE05 Kazachstania servazzii yeast was inoculated into a wort medium and cultured at 30°C for two days. The CDLB-YE05 Kazachstania servazzii yeast was cloudy, had no pellicle, no membrane, an estery aroma, and no unpleasant odor. Observation of the cell morphology of the CDLB-YE05 Kazachstania servazzii yeast under a microscope revealed that the cell morphology was ascospherical, as shown in Figure 2.

[0032] 9) Genome characteristics of CDLB-YE05 Kazachstania servazzii yeast The CDLB-YE05 Kazachstania servazzii yeast strain has one genome, with a total length of 13,468,544 bp, 5,415 genes, and a GC content of 34.25%. The total length of the genes accounts for 66.81% of the total genome length. There are 6,260 exons, accounting for 64.51% of the total genome length. There are 5,415 CDS regions, accounting for 64.51% of the total genome length. There are 845 introns, accounting for 2.31% of the total genome length. The total number of non-coding RNA (ncRNA) copies is 1,046 reads, accounting for 0.8106% of the total genome length. The total number of repetitive sequences is 2,034,046 bp, accounting for 15.1022% of the total genome length.

[0033] 10) CDLB-YE05 Kazachstania servazzii yeast strain storage In a sterile environment, a single colony of CDLB-YE05 Kazachstania servazzii yeast was picked using an inoculation loop and inoculated into 250 mL of sterilized wort. After shaking evenly, expansion culture was carried out at a constant temperature of 28±1°C for 48 hours. The wort was then sampled and examined under a microscope to observe the formation and distribution of ascospherical colonies. If the field of view was filled with ascospherical yeast, expansion culture was successful. If not, the culture was continued until expansion culture was successful, with microscopic examination performed every 2 hours.

[0034] In a sterile environment, 17.5 g of skim milk powder was added to 250 mL of the bacterial seed solution that had been successfully expanded, and after uniform mixing, the mixture was freeze-dried. The freeze-dried powder was collected and the colony count of CDLB-YE05 Kazachstania servazzii yeast was 10 7 The detection of a number greater than CFU was used as the storage standard.

[0035] Freeze-dried powder of CDLB-YE05 Kazachstania servazzii yeast was dispensed into cryopreservation tubes at 0.1 g per tube, placed in vacuum-sealed bags, labeled, and stored at an ultra-low temperature of -80°C.

[0036] The CDLB-Y E05 Kazachstania servazzii yeast fungus was preserved at the Institute of Microbiology, Chinese Academy of Sciences on July 17, 2023, with storage number CGMCC NO. 27948 and storage address at No. 3, Courtyard, No. 1, Beichen West Road, Chaoyang District, Beijing.

[0037] 11) Production of polysaccharide compounds from CDLB-YE05 Kazachstania servazzii yeast The CDLB-YE05 Kazachstania servazzii yeast was inoculated into a wort medium along with four yeast strains that produce both gas and alcohol, which were isolated from the dough, and cultured for 24 hours. 10 mL of the wort fermentation liquid was weighed out after 0 hours, 4 hours, 8 hours, 12 hours, 16 hours, 20 hours, and 24 hours of fermentation. The wort fermentation liquid was centrifuged at 3500 r / min for 30 minutes, the cells were discarded, 1.5 g of trichloroacetic acid was added to the resulting supernatant, and after uniformly suspending it, it was left to stand at 4°C for 1 hour. The suspension was centrifuged at 11,000 r / min for 1 minute, the protein precipitate was discarded, and the resulting supernatant was transferred to a dialysis bag approximately 15 cm long. The dialysis bag was placed in a beaker containing distilled water and dialyzed at 4°C for 1 hour, after which the extracorporeal dialysis solution was replaced. After 2 more hours of dialysis, the extracorporeal dialysis solution was replaced again, and the suspension was dialyzed for another 3 hours.

[0038] After dialysis, the extracorporeal dialysate was discarded, the solution in the dialysis bag was transferred to a 100 mL volumetric flask, and water was added to the flask to obtain a test sample.

[0039] The experimental samples were diluted to different gradients, and the absorbance at 490 nm was measured. The concentrations of polysaccharide compounds in different experimental samples were calculated according to the glucose standard curve and regression equation. The detection results are shown in Figure 3. The CDLB-YE05 Kazachstania servazzii yeast strain was able to produce more polysaccharide compounds during fermentation in wort medium than the other four yeast strains that produced both gas and alcohol separated from the dough.

[0040] Example 2 Mixed media and yeast cultures were prepared in the following steps.

[0041] 1) Preparation of mixed medium: 720-880g of malt, 90-110g of soybeans, and 90-110g of glutinous rice were weighed out, and each substance was baked at 120°C for 2 hours, then crushed and mixed uniformly to obtain a mixed medium.

[0042] 2) Preparation of yeast cultures: The freeze-dried powder of the CDLB-YE05 Kazachstania servazzii yeast obtained in Example 1 was activated in a wort medium for 16 to 48 hours, and then added to a mixed medium at an inoculation rate of 1% (w / m). 800 g to 1,000 g of mineral water was added per 1 kg of the mixed medium and stirred uniformly. Sterile air was introduced at a flow rate of 1 L / min, and the mixture was cultured at 15°C to 35°C under aerobic conditions for 20 to 72 hours to obtain a yeast culture.

[0043] The CDLB-YE05 Kazachstania servazzii yeast can grow and reproduce in a mixed medium, and can decompose and convert large proteins and starch granules in the mixed medium to produce ester flavor compounds and polysaccharide compounds. After 20 to 72 hours of cultivation, the produced ester flavor compounds, polysaccharide compounds, and medium components together constitute a yeast culture, whose total acidity is 30 mL / 100 g or less, whose viable cell rate is 55% or more, and whose polysaccharide compound content measured by the phenol-sulfuric acid method is 1 mg / mL or more.

[0044] The following Examples 3 to 5 relate to the preparation of yeast powder, and the specific details are as follows.

[0045] Example 3 The yeast culture obtained in Example 2 was used to prepare yeast powder, and the specific process is as follows:

[0046] 70g of skim milk powder and 9.5g of sorbitan monostearate were added to 1000g of yeast culture, mixed uniformly, freeze-dried, and then ground to obtain yeast powder, which had a moisture content of ≦10%, a protein content of ≧4%, an ash content of ≦10%, and a yeast cell count of ≧10. 7 It was CFU.

[0047] Example 4 The yeast culture obtained in Example 2 was used to prepare yeast powder, and the specific process is as follows:

[0048] To 1000 g of the yeast culture, 60 g of skim milk powder and 9 g of sorbitan monostearate were added, and the mixture was homogeneously mixed, then freeze-dried and polished to obtain yeast powder.

[0049] Example 5 The yeast culture obtained in Example 2 was used to prepare yeast powder, and the specific process is as follows:

[0050] 80 g of skim milk powder and 10 g of sorbitan monostearate were added to 1000 g of yeast culture, mixed uniformly, freeze-dried, and polished to obtain yeast powder.

[0051] The following Examples 6 to 9 are examples of the use of yeast powder in wheat flour food processing, and the specific details are as follows.

[0052] Example 6 The yeast powder obtained in Example 3 was used to process wheat flour foods to improve the texture and aroma of noodles and to make the noodles firmer. The specific method is as follows:

[0053] 1 g of the yeast powder obtained in Example 3 and 1 kg of wheat flour were weighed out, and 280 g of water, 1 g of edible salt, and 1 g of edible alkali were added and kneaded. The dough was then fermented for 4 hours at 20°C to 26°C and for 3 hours at 27°C to 30°C. The fermented dough was processed into noodles, and the breaking strength of the cooked noodles was tested. When the cross section of the cooked noodles was larger than 2 mm x 2 mm, the breaking strength was 15 g or more.

[0054] Example 7 The amount of wheat flour added in Example 6 was adjusted to 1.1 kg, and the other process steps were the same as in Example 6.

[0055] Example 8 0.8 g of the yeast powder obtained in Example 3 and 1 kg of wheat flour were weighed out, and 300 g of water, 1.5 g of edible salt, and 1.5 g of edible alkali were added and kneaded, followed by fermentation at 20°C to 26°C for 4 hours and at 27°C to 30°C for 3 hours. The fermented dough was processed into noodles, and the breaking strength of the cooked noodles was tested.

[0056] Example 9 In Example 8, the amount of wheat flour added was adjusted to 1.1 kg, and the other process steps were the same as in Example 8.

[0057] Example 10 is a comparative experiment on the use of yeast powder and other common yeasts in wheat flour foods, and is specifically as follows.

[0058] Example 10 After adding the yeast powder prepared in Example 3 and other common yeast strains to wheat flour, the chewiness of the noodles was assessed by detecting the growth state of the colonies during fermentation, changes in the content of polysaccharide compounds, and the breaking force of the noodles.

[0059] 1) Selected yeast species and their sources

[0060] [Table 3]

[0061] 2) Culture medium: Potato dextrose agar (PDA), wort medium The specific ingredients per liter of potato dextrose agar were 300.0 g potato (extract leach powder), 20.0 g glucose, 15.0 g agar, and 0.1 g chloramphenicol.

[0062] The specific components per liter of wort medium were 130.0 g of powdered malt extract and 0.1 g of chloramphenicol.

[0063] 3) Reagents and raw materials

[0064] [Table 4]

[0065] 4) Experimental facilities and equipment [Table 5]

[0066] 5) Experimental process 5.1 Preparation of yeast seed solution 5.1.1 Activation of bacterial species The yeast powder obtained in Example 3, the active dry yeast (high sugar type), the active dry yeast (low sugar type), and the wine-brewing yeast strain were each weighed and inoculated into 10 mL of wort medium at an inoculum amount of 0.1% (w / v), followed by aerobically fermenting at 30°C for 24 hours.

[0067] 5.1.2 Microscopic examination of fungal species Microscopic examination was performed on the four activated yeast species, and the colony morphology was shown in Figure 4. In Figure 4, (a) is the colony morphology of yeast powder, (b) is the colony morphology of activated dry yeast (high sugar type), (c) is the colony morphology of activated dry yeast (low sugar type), and (d) is the colony morphology of wine-making yeast species.

[0068] 5.1.3 Adjustment of colony count in bacterial seed solution To ensure the consistency of the experimental conditions, the colony numbers of different activated yeast strains were adjusted together, and the specific steps were as follows:

[0069] The spectrophotometer was zeroed using fresh wort, and the OD600 values ​​of the different bacterial strains were measured. The strains were gradually diluted with fresh wort to adjust the OD600 value to 0.5, and the corresponding bacterial strain concentrations were approximately 10 7It was about CFU / mL.

[0070] 5.2 Preparation of a glucose standard curve 50 mg of standard glucose was weighed into a volumetric flask, and an appropriate amount of distilled water was added up to the 500 mL mark. The flask was then shaken uniformly to prepare a 100 μg / mL standard glucose solution. The standard glucose solution, distilled water, 5% phenol solution, and concentrated sulfuric acid were then added as shown in Table 6, shaken thoroughly, heated in a boiling water bath for 30 minutes, removed, shaken uniformly, cooled, and left at room temperature for 20 minutes before measuring the absorbance at 490 nm.

[0071] As shown in FIG. 5, a standard curve was plotted with the glucose concentration on the horizontal axis and the absorbance on the vertical axis, and a regression equation was determined.

[0072] [Table 6]

[0073] 5.3 Inoculation and fermentation of wheat flour with yeast Each ingredient was added according to the proportions in Table 7, resulting in a total of five groups. Each group contained 500g of flour, 1g of salt, and 1g of alkali. 5mL of the yeast solution from groups A, B, C, and D and the blank from group E were added to 140mL of drinking water and mixed evenly. After uniform mixing, the yeast-containing drinking water was gradually added to the flour and stirred evenly for 30 minutes. The dough was then fermented at a constant temperature of 30°C for 4 hours.

[0074] [Table 7]

[0075] 5.4 Extraction of polysaccharide compounds produced by wheat flour fermentation The specific steps are as follows:

[0076] For the fermentation of wheat flour, 3g samples were taken every 0.5h, and the samples were spread evenly and semi-dried by blowing air at 50℃. The temperature was then gradually increased to 80℃ until the samples solidified. After cooling, the samples were crushed and passed through a sieve with a mesh diameter of 0.9mm. The sieved samples were mixed evenly and then placed in a wide-mouth bottle, sealed, and stored.

[0077] 1.0 g of the sieved sample was weighed and placed in a 50 mL stoppered centrifuge tube, 5 mL of water was added to infiltrate the sample, 20 mL of absolute ethanol was gradually added, and the mixture was thoroughly shaken to obtain a uniform mixture.

[0078] The mixture was subjected to ultrasonic extraction for 30 min and centrifuged for 10 min, after which the insoluble matter was washed with 10 mL of ethanol and then centrifuged.

[0079] The insoluble matter was slowly transferred to a stoppered Erlenmeyer flask using 30 mL of water, sealed with a breathable sealing membrane, and then extracted in a boiling water bath for 2 hours. The mixture was cooled to room temperature, and the filtrate was filtered for use.

[0080] The filtrate was transferred to a dialysis bag approximately 15 cm long, and the dialysis bag was placed in a 1000 mL beaker containing distilled water. After 1 hour of dialysis at 4°C, the extracorporeal dialysate was replaced, followed by 2 hours of dialysis, after which the extracorporeal dialysate was replaced again, and finally, after 3 hours of dialysis, the extracorporeal dialysate was replaced again.

[0081] After the dialysis was completed, the extracorporeal dialysate was removed, the solution in the dialysis bag was transferred to a 100 mL volumetric flask, and water was added to the flask to obtain a test sample.

[0082] 5.5 Measurement of polysaccharide compounds The experimental samples prepared in 5.4 were diluted at different gradients, and the absorbance at 490 nm was measured. The concentrations of polysaccharide compounds in the experimental samples were calculated according to the glucose standard curve and regression equation. As shown in Figure 6, after adding the yeast powder obtained in Example 3, the content of polysaccharides produced in the dough by fermentation gradually increased as the fermentation time increased. Since the content of polysaccharides is proportional to the viscosity of the noodles, this improved the breaking strength of the noodles and made them chewier.

[0083] 5.6 Yeast count measurement The experimental samples were taken after 0.5 hours and 4 hours of fermentation, and the number of live yeast cells was measured using the plate count method. The medium used for detection was potato dextrose agar medium.

[0084] As shown in Table 9, the detection results showed that the yeast powder obtained in Example 3 had the fastest propagation rate during dough fermentation.

[0085] 5.7 Measurement of the breaking strength of noodles obtained from each sample After fermentation for 4 hours, the dough from each of the different treatment groups was rolled out according to standardized manufacturing standards, reassembled, and cut into strips. The cross-sectional size of the noodles was 3.5mm x 3.5mm. After 150 seconds of boiling, the noodles were cooled in water and the length between the two ends of the noodles was fixed at 10cm. A tension gauge was used to measure the breaking force when the noodles were pulled to pieces. 35 measurements were taken for each treatment group, and the original data was recorded as shown in Table 8. The maximum and minimum values ​​were excluded from each group, and the average value of the remaining data was calculated as shown in Table 9.

[0086] [Table 8]

[0087] [Table 9]

[0088] As described above, when the yeast species in the processed composition of a flour food is changed by a single factor, the metabolic products of the yeast in the dough change, and the yeast powder provided by the present invention produces large amounts of polysaccharide compounds during metabolism. Considering that the content of polysaccharide compounds in the dough is proportional to its viscosity, adding the above yeast powder to the processing of flour foods can improve the chewiness and mouthfeel of the flour food.

[0089] The above are merely preferred specific embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by a person skilled in the art within the technical scope described in the present invention are included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined according to the claims.

Claims

1. CDLB-YE05 is a Kazachstania servazzii yeast fungus, characterized in that it was preserved at the Institute of Microbiology, Chinese Academy of Sciences on July 17, 2023, with storage number CGMCC NO. 27948 and storage address at No. 3, Courtyard, No. 1, Beichen West Road, Chaoyang District, Beijing.

2. 2. The yeast according to claim 1, wherein the nucleotide sequence of the yeast is as set forth in SEQ No.

1.

3. A yeast powder prepared from the yeast according to claim 1 or 2, wherein the yeast powder is obtained by mixing a yeast culture, skim milk powder, and sorbitan monostearate, followed by freeze-drying and grinding, and 60 g to 80 g of skim milk powder and 9 g to 10 g of sorbitan monostearate are added per kg of yeast culture; A yeast powder characterized in that the yeast culture is cultured using the yeast.

4. Moisture content is 10% or less, protein content is 4% or more, ash content is 10% or less, and yeast count is 10% or less. ７ The yeast powder according to claim 3, characterized in that it has a cell count of CFU or more.

5. The yeast culture is The yeast powder according to claim 3 is obtained by activating the yeast for 16 to 48 hours, inoculating it into a mixed medium, adding water and stirring uniformly, and then culturing it under aerobic conditions at 15 to 35 ° C. for 20 to 72 hours.

6. The mixed medium is Weigh out 720 to 880 parts by mass of malt, 90 to 110 parts by mass of soybeans, and 90 to 110 parts by mass of glutinous rice, The yeast powder according to claim 5, characterized in that it is obtained by baking each weighed substance at 120°C for 2 hours, then grinding and mixing them.

7. Use of the yeast powder according to any one of claims 3 to 6 in wheat flour food processing.

8. As a specific method, In S1, weigh out yeast powder 0.08 to 0.1, wheat flour 100 to 110, water 28 to 30, edible salt 0.1 to 0.15, and edible alkali 0.1 to 0.15 in mass ratio, 8. The use of yeast powder in wheat flour food processing according to claim 7, characterized in that in S2, the weighed yeast powder, wheat flour, edible salt, edible alkali and water are mixed to form dough, and the dough is fermented for 3 to 6 hours to produce wheat flour food.

9. The use of yeast powder in processing wheat flour foods according to claim 8, characterized in that the wheat flour foods include noodles, dumplings, wontons and Chinese rice cakes.

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