Lactic acid bacteria fermentation complex microbial inoculant and application thereof in preparation of aleurone layer yoghurt

Abstract

The invention discloses a lactic acid bacteria fermentation complex microbial inoculant and application thereof in preparation of aleurone layer yoghourt, the lactic acid bacteria fermentation complex microbial inoculant is composed of a basic fermentation agent, an auxiliary fermentation agent and a functional fermentation agent, the basic fermentation agent is composed of streptococcus thermophilus and lactobacillus bulgaricus, and the auxiliary fermentation agent is composed of streptococcus thermophilus and lactobacillus bulgaricus. The auxiliary leavening agent is prepared from lactococcus lactis and lactobacillus acidophilus, and the functional leavening agent is prepared from lactobacillus plantarum ZP-6 and leuconostoc mesenteroides DM12. According to the aleurone layer yoghourt, the content of dietary fibers, protein, calcium, trace elements and other nutritional ingredients in the yoghourt is increased, the hardness, the adhesiveness, the chewiness, the taste and the flavor of the yoghourt are improved, the defects of common yoghourt are overcome by adding the wheat aleurone layer into the yoghourt, the flavor of the yoghourt is enriched, meanwhile, the nutritional value of the yoghourt is increased, the GI value is reduced, and the nutritional value of the yoghourt is increased. A reliable preparation process is provided for the wheat aleurone layer yoghourt, and the utilization value of the wheat by-product aleurone layer is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of aleurone yogurt, and in particular relates to a lactic acid bacteria fermentation composite bacterial agent and application thereof in the preparation of aleurone yogurt. Background Art

[0002] Wheat aleurone is the innermost layer of the seed cortex of cereal crops, located between the seed coat and the endosperm. It is rich in dietary fiber, minerals, beneficial lipids, vitamins, phenolic acids, lignans and other nutrients. Wheat aleurone is widely added to baked foods such as bread and biscuits as a nutritional supplement. The aleurone added to food provides the human body with sufficient nutrients. Among them, high dietary fiber has a good sense of fullness, can promote intestinal peristalsis, stabilize blood sugar and blood lipids, relieve and relieve constipation, and is a good meal replacement food for people who control blood sugar and weight. High protein can promote human growth and development, improve human immunity, and maintain balanced nutrition. In addition, wheat aleurone can also provide about 40% of grain minerals, mainly including phosphorus, potassium, magnesium, zinc and iron. The main element phosphorus in the aleurone layer is mostly in the form of inositol esterification products. Potassium plays a certain role in maintaining myocardial function; iron plays a role in transportation and hematopoiesis in the human body, and has an important impact on human health; magnesium and zinc are important elements that constitute many coenzymes involved in body metabolism.

[0003] Yogurt is a fermented dairy product made from cow's milk, goat's milk, etc., with the addition of sugar, lactic acid bacteria and other substances, and then fermented at a certain temperature. Yogurt is mainly divided into stirred yogurt, solidified yogurt and drinking yogurt according to the production process. According to the taste, it can be divided into plain yogurt, sucrose-free yogurt, fruit-flavored yogurt, cereal yogurt or fruit and cereal mixed yogurt. Yogurt has important physiological functions. It can regulate the balance of intestinal microbial flora, inhibit harmful microorganisms that produce strong carcinogens (nitrite), and reduce the content of harmful substances; fermentation produces lactic acid, reducing the risk of lactose intolerance. Because yogurt is rich in protein and nutrients such as calcium and potassium, it can also supplement certain nutrients needed by the human body.

[0004] Lactic acid bacteria fermentation can improve the body's utilization of nutrients in cereals. Lactic acid bacteria fermentation significantly reduces the phytic acid content in cereal foods. By reducing the chance of chelation between phytic acid and minerals in cereals, the mineral content of cereal foods is increased. Commonly used bacteria for yogurt fermentation include thermophilic Streptococcus, Bulgarian Lactobacillus, Lactococcus lactis, and Lactobacillus plantarum. Thermophilic Streptococcus and Bulgarian Lactobacillus are the main industrial starter strains for fermenting yogurt. Lactococcus lactis is the most representative strain of the genus Lactococcus and is widely used in fermenting cheese, yogurt, kimchi and other foods.

[0005] Yogurt is rich in nutrients such as protein and vitamins, and rich in mineral calcium, but low in trace elements such as iron and zinc. Cereals are rich in minerals. Adding cereals to yogurt can increase the mineral content, and yogurt fermentation can also improve the utilization rate of cereal minerals. At present, there are cereal yogurts such as black rice, oatmeal yogurt, and fruit oatmeal chewing yogurt on the market, but there is no relevant research on the optimal formula and quality index determination of wheat aleurone yogurt.

[0006] The present invention develops a wheat aleurone yogurt with extremely high nutritional content by selecting laboratory strains and adding wheat aleurone layer, enriching the cereal yogurt market and improving the utilization rate of the wheat byproduct aleurone layer. The present invention provides theoretical support for the application value of wheat aleurone layer and provides reference data for the quality indicators of wheat aleurone yogurt, which has practical significance. Summary of the invention

[0007] The invention aims to provide a lactic acid bacteria fermentation composite bacterial agent and application thereof in the preparation of aleurone yogurt, wherein the aleurone yogurt not only increases the content of nutritional components such as dietary fiber, protein, calcium, trace elements and the like in the yogurt, but also improves the hardness, adhesiveness, chewiness, mouthfeel and flavor of the yogurt, improves the deficiencies of ordinary yogurt by adding wheat aleurone into the yogurt, enriches the flavor of the yogurt, and improves the nutritional value of the yogurt, reduces the GI value, provides a reliable production process for wheat aleurone yogurt, and increases the utilization value of the aleurone layer, a byproduct of wheat.

[0008] The present invention adopts the following technical scheme to achieve the above-mentioned purpose, a lactic acid bacteria fermentation composite bacterial agent, characterized in that: the lactic acid bacteria fermentation composite bacterial agent is composed of a basic fermentation agent, an auxiliary fermentation agent and a functional fermentation agent, wherein the basic fermentation agent is composed of thermophilic Streptococcus and Bulgarian Lactobacillus, the auxiliary fermentation agent is composed of Lactococcus lactis and Lactobacillus acidophilus, and the functional fermentation agent is composed of Lactobacillus plantarum ZP-6 and Leuconostoc mesenteroides DM12. Lactobacillus plantarum ZP-6 was deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration on July 31, 2024, with a deposit number of CGMCC No. 31420, and the address of the depository unit is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and is classified and named as Lactobacillus plantarum; Leuconostoc mesenteroides DM12 was deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration on March 28, 2024, with a deposit number of CGMCC No.30178, the depository address is: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the classification name is: Leuconostoc mesenteroides.

[0009] Furthermore, the weight ratio of the basic leavening agent, the auxiliary leavening agent and the functional leavening agent is 2:3:3.

[0010] The invention discloses an application of the lactic acid bacteria fermentation composite bacterial agent in the preparation of aleurone yogurt.

[0011] Furthermore, the endosperm yogurt is prepared from the following raw materials in weight percentage: 5%-10% white sugar, 2%-14% lactic acid bacteria fermentation compound bacterial agent, 5%-25% endosperm, and the remainder is pure milk. The fermentation temperature is 39-43° C. and the fermentation time is 12-28 hours.

[0012] Furthermore, the aleurone yogurt is prepared from the following raw materials in the following weight percentage ratios: 7% white sugar, 5% lactic acid bacteria fermentation compound bacterial agent, 16% aleurone layer, and the balance is pure milk. The fermentation temperature is preferably 41° C., and the fermentation time is preferably 25 hours.

[0013] Further, the application of the lactic acid bacteria fermentation composite bacterial agent in the preparation of lactic acid bacteria fermentation stirred aleurone yogurt is characterized in that the specific process is:

[0014] Step S1, frying: filter the wheat starch layer to remove impurities, fry over low heat until it turns slightly yellow, and let it cool for later use;

[0015] Step S2, sterilization: boiling and sterilizing the yogurt container for 20 minutes, and naturally cooling and drying for later use;

[0016] Step S3, fermentation: pure milk and white sugar are mixed in proportion, pasteurized, cooled, inoculated with a lactic acid bacteria fermentation compound agent, mixed evenly, and packaged into sealed bottles, and the sealed bottles are placed in a constant temperature incubator for constant temperature fermentation;

[0017] Step S4, post-ripening: after fermentation, transfer to a 4°C refrigerator for refrigeration for more than 12 hours for post-ripening;

[0018] Step S5, stirring: adding the fried wheat aleurone layer into the fermented yogurt and stirring evenly to prepare the lactic acid bacteria fermented stirred aleurone layer yogurt.

[0019] Further, the application of the lactic acid bacteria fermentation composite bacterial agent in the preparation of lactic acid bacteria fermented aleurone layer flavored yogurt is characterized by the specific process of:

[0020] Step S1, boiling: filter the wheat starch layer to remove impurities, accurately weigh it, add pure water in a weight ratio of 1:6, boil it on low heat for 1 hour to precipitate nutrients, filter it and let it stand at room temperature for later use;

[0021] Step S2, sterilization: boiling and sterilizing the yogurt container for 20 minutes, and naturally cooling and drying for later use;

[0022] Step S3, fermentation: pure milk, white sugar, and aleurone juice are mixed in proportion, pasteurized, cooled, inoculated with lactic acid bacteria and lactic acid bacteria fermentation composite bacterial agent, mixed evenly, and then packaged into sealed bottles, and the sealed bottles are placed in a constant temperature incubator for constant temperature fermentation;

[0023] Step S4, post-ripening: after the fermentation is completed, the yogurt is transferred to a refrigerator at 4°C for refrigeration for more than 12 hours for post-ripening to produce aleurone flavored yogurt fermented by lactic acid bacteria.

[0024] Further, the application of the lactic acid bacteria fermentation composite bacterial agent in the preparation of lactic acid bacteria aleurone fermentation type yogurt is characterized in that the specific process is:

[0025] Step S1, crushing: filtering the wheat endosperm to remove impurities, weighing accurately and setting aside;

[0026] Step S2, sterilization: boiling and sterilizing the yogurt container for 20 minutes, and naturally cooling and drying for later use;

[0027] Step S3, fermentation: pure milk, white sugar, and aleurone layer are mixed in proportion, pasteurized, cooled, inoculated with a lactic acid bacteria fermentation compound agent, mixed evenly, and packaged into sealed bottles, and the sealed bottles are placed in a constant temperature incubator for constant temperature fermentation for 25 hours;

[0028] Step S4, post-ripening: after fermentation is completed, the yogurt is transferred to a refrigerator at 4°C for refrigeration for more than 12 hours for post-ripening to produce aleurone fermented yogurt.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] 1. The present invention uses wheat aleurone layer, pure milk and white sugar as raw materials to fill the gap in the market for cereal yogurt, while improving the utilization rate of wheat byproduct aleurone layer. It also improves the nutritional value of yogurt, introduces more abundant calcium, dietary fiber, vitamins and trace elements, and the combination of aleurone layer and yogurt makes the taste more mellow and the flavor better. The invention provides theoretical support for the application value of wheat aleurone layer and provides reference data for the quality indicators of wheat aleurone layer yogurt, which has practical significance.

[0031] 2. The present invention uses thermophilic streptococcus, bulgaricus lactobacillus, lactococcus lactis, lactobacillus acidophilus, leuconostoc mesenteroides, lactobacillus rhamnosus and lactobacillus plantarum as functional fermentation agents to make aleurone yogurt, and the ability to decompose lactose is greater than that of other strains, enriching the lactic acid bacteria strains of fermented yogurt on the market. And by adjusting the ratio of the three fermentation agents to improve the function of grain utilization, the fermented yogurt tissue state is made more delicate and smooth, and the texture is more uniform. The addition of the lactic acid bacteria fermentation composite bacterial agent helps to maintain the balance of intestinal flora, stimulate intestinal peristalsis, and is beneficial to digestion and absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 These are the yogurt bottled pictures of Example 3, Example 4, Example 5, Example 6, and Comparative Example 1.

[0033] Figure 2 The sensory evaluation results of the two strain fermented yogurts in Example 1 are shown.

[0034] Figure 3 The sensory evaluation results of stirred aleurone yogurt under different process conditions in Example 2 are shown.

[0035] FIG. 4 is a response surface and contour map of the process optimization of stirred aleurone yogurt in Example 2. DETAILED DESCRIPTION

[0036] The above contents of the present invention are further described in detail below through examples, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies implemented based on the above contents of the present invention belong to the scope of the present invention.

[0037] Example 1

[0038] The invention discloses a method for preparing lactic acid bacteria fermented yogurt, which comprises the following steps: transferring freeze-dried powder of thermophilic streptococcus, bulgaricus lactobacillus, lactococcus lactis, lactobacillus acidophilus, enterobacterium mesenteroides, lactobacillus rhamnosus and lactobacillus plantarum to skim milk culture medium, continuously subculturing for 3 times, and restoring the vitality of each strain, wherein thermophilic streptococcus + bulgaricus lactobacillus constitute basic fermentation agent A, lactococcus lactis + lactobacillus acidophilus constitute auxiliary fermentation agent B, and lactobacillus plantarum + enterobacterium mesenteroides constitute functional fermentation agent C. The container for preparing yogurt is boiled and sterilized for 20 minutes, and naturally cooled and dried for standby use. The container is prepared according to the proportion of 100 mL of pure milk and 7 wt% of white granulated sugar, pasteurized, inoculated with lactic acid bacteria after cooling, and fermented with the above single fermentation agent, two fermentation agents and three fermentation agents according to different proportions respectively, mixed evenly and then divided into sealed bottles, and the sealed bottles are placed in a constant temperature incubator and fermented at 41° C. for 25 hours. After fermentation is completed, the container is transferred to a 4° C. refrigerator for refrigeration for more than 12 hours for post-ripening.

[0039] Example 2

[0040] A method for preparing a stirred aleurone yogurt fermented by lactic acid bacteria is carried out according to the following steps: filtering the wheat aleurone layer to remove impurities, frying it over a low fire and stirring it continuously, and when it turns slightly yellow, serving it out and cooling it for later use. Boiling and sterilizing the yogurt preparation container for 20 minutes, cooling and drying it naturally for later use. Mixing the mixture according to the ratio of 100 mL of pure milk and 3 wt%-11 wt% of white sugar, pasteurizing it, inoculating lactic acid bacteria after cooling, and inoculating 2 wt%-14 wt% of the starter according to the weight ratio of A:B:C=2:3:3. After mixing evenly, dispensing it into sealed bottles, and placing the sealed bottles in a constant temperature incubator at 38-46°C for constant temperature fermentation for 16-32 hours. After fermentation is completed, transferring it to a 4°C refrigerator for refrigeration for more than 12 hours for post-ripening. Weighing the fried wheat aleurone layer, adding it to the fermented yogurt according to the ratio of 5 wt%-25 wt%, stirring evenly to prepare a stirred aleurone yogurt.

[0041] Example 3

[0042] A method for preparing lactic acid bacteria fermented yogurt is carried out according to the following steps: a yogurt preparation container is boiled and sterilized for 20 minutes, and then naturally cooled and dried for standby use. Pure milk 100 mL and white sugar 7 wt% are mixed and pasteurized, and lactic acid bacteria are inoculated after cooling, and the starter ratio is A: B: C = 2: 3: 3 and 5 wt% is inoculated. After mixing evenly, the mixture is divided into sealed bottles, and the sealed bottles are placed in a constant temperature incubator and fermented at 41° C. for 25 hours. After fermentation is completed, the mixture is transferred to a 4° C. refrigerator for refrigeration for more than 12 hours for post-ripening.

[0043] Example 4

[0044] A method for preparing a stirred yogurt fermented with lactic acid bacteria is carried out according to the following steps: filtering the wheat aleurone to remove impurities, frying it over a low fire and stirring it continuously, and when it turns slightly yellow, serving it out and cooling it for later use. Boiling and sterilizing the container for preparing yogurt for 20 minutes, cooling and drying it naturally for later use. Mixing the mixture according to the ratio of 100 mL of pure milk and 7 wt% of white sugar, pasteurizing it, inoculating lactic acid bacteria after cooling, and inoculating 5 wt% of the starter according to the ratio of A:B:C=2:3:3. After mixing evenly, packing it into sealed bottles, and placing the sealed bottles in a constant temperature incubator and fermenting them at a constant temperature of 41°C for 25 hours. After fermentation is completed, transferring it to a refrigerator at 4°C for refrigeration for more than 12 hours for post-ripening. Weighing the fried wheat aleurone layer, adding it to the fermented yogurt at a ratio of 16 wt%, and stirring evenly to prepare a stirred aleurone layer yogurt.

[0045] Example 5

[0046] A method for preparing a lactic acid bacteria fermented aleurone layer flavored yogurt is carried out according to the following steps: filtering the wheat aleurone layer to remove impurities, accurately weighing it, adding pure water in a weight ratio of 1:6, and boiling it on a low fire for 1 hour to precipitate nutrients, paying attention to the evaporation of water during boiling, continuously replenishing pure water to maintain the ratio of the two, filtering out the aleurone layer juice with an 80-mesh filter after boiling, and standing it to room temperature for use. Boil and sterilize the yogurt container for 20 minutes, cool and dry it naturally for use. Prepare pure milk 100mL, white sugar 7wt%, and aleurone layer juice 16wt% to replace pure milk, pasteurize it, inoculate lactic acid bacteria after cooling, and inoculate 5wt% of the starter according to the ratio of A:B:C=2:3:3. After mixing evenly, divide it into sealed bottles, put the sealed bottles into a constant temperature incubator and ferment them at 41°C for 25 hours. After fermentation, transfer it to a 4°C refrigerator for refrigeration for more than 12 hours for post-ripening.

[0047] Example 6

[0048] A method for preparing lactic acid bacteria aleurone fermented yogurt is carried out according to the following steps: the wheat aleurone layer is crushed into a fine powder state by a crusher, and large particles are filtered out by a filter screen, and the powder is weighed accurately for use. The yogurt preparation container is boiled and sterilized for 20 minutes, and naturally cooled and dried for use. The mixture is prepared according to the proportion of 100 mL of pure milk, 7 wt% of white sugar, and 16 wt% of aleurone layer, and pasteurized. After cooling, lactic acid bacteria are inoculated, and the fermentation agent is inoculated with 5 wt% according to the ratio of A:B:C=2:3:3. After mixing evenly, the mixture is divided into sealed bottles, and the sealed bottles are placed in a constant temperature incubator and fermented at a constant temperature of 41°C for 25 hours. After fermentation is completed, the mixture is transferred to a 4°C refrigerator for refrigeration for more than 12 hours for post-ripening.

[0049] Comparative Example 1

[0050] This comparative example 1 is commercially available yogurt.

[0051] In this test example, a sensory evaluation was performed on Example 1 and Example 2, and the evaluation was performed according to Table 1 and Table 2. According to GB19302-2010 "National Food Safety Standard Fermented Milk", a sensory evaluation panel consisting of 10 teachers and students with tasting experience and different genders evaluated the sensory properties of yogurt.

[0052] Table 1 Sensory evaluation standards for lactic acid bacteria fermented yogurt

[0053]

[0054] Table 2 Sensory evaluation standard of stirred aleurone yogurt

[0055]

[0056]

[0057] The yogurt fermented with a single starter culture in Example 1 was tasted by a sensory evaluation panel and compared and scored according to the scoring criteria.

[0058] Table 3 Single fermentation agent fermentation evaluation results

[0059]

[0060] The results showed that the color, smell and texture of yogurt fermented by basic fermentation agent A, auxiliary fermentation agent B and functional fermentation agent C were good and similar; the main difference was the taste of yogurt. Yogurt fermented by C alone was sweeter than that fermented by A and B alone, and the pH at the end of fermentation was higher. The taste of yogurts of A and B was similar, and the pH at the end of fermentation of yogurt fermented by A was the lowest.

[0061] The yogurts fermented by the two strains in Example 1 were tasted by a sensory evaluation panel and compared and scored according to the scoring criteria.

[0062] The evaluation results are as follows Figure 2 As shown, the results show that when A:B=1:1, 2:3, 3:1, 3:2, the yogurt tastes better and has a higher sensory score. When A:B=2:3, 3:1, 3:2, the yogurt surface is smooth and the texture is the best. When B:C=1:1, the yogurt tastes better and has a better texture, and the sensory score is the highest. When A:C=2:1, 2:3, 3:1, 3:2, the yogurt tastes better and has a higher sensory score. When A:C=1:1, the sensory score is less than 80 points.

[0063] Three strains of bacteria were mixed for fermentation based on two strains of bacteria, and four inoculation ratios were selected based on experimental conditions. The sensory evaluation team tasted the yogurt and scored it according to the scoring criteria, and measured the pH change of the yogurt.

[0064] Table 4 Mixed fermentation results of three fermentation agents

[0065]

[0066]

[0067] The results showed that the fermentation end point pH was the lowest when the starter culture A:B:C=2:3:3, and the pH did not change much during refrigeration. Since yogurt will undergo post-acidification during storage, post-acidification will affect the taste of aleurone yogurt, so choosing yogurt with a small pH change during refrigeration is beneficial to the development of the grain yogurt market.

[0068] Based on comprehensive sensory scores, fermentation time, pH and other factors, the A:B:C inoculation ratio of 2:3:3 is most suitable for fermenting and making aleurone yogurt.

[0069] For Example 2, important fermentation conditions such as the amount of composite bacteria inoculation, the amount of aleurone added, and the amount of white sugar added in the lactic acid bacteria fermented stirred aleurone yogurt need to be further determined.

[0070] The yogurt fermented in Example 2 was tasted by a sensory evaluation panel and compared and scored according to the scoring criteria.

[0071] Figure 3 It reflects the sensory evaluation results of the compound bacteria inoculation amount, the amount of endosperm added, the amount of white sugar added, and the fermentation yogurt at different times and temperatures.

[0072] The results show that when the inoculation amount of the composite bacterial agent is 5wt%, the yogurt fermentation state is better, the organizational state is very stable, the texture is uniform, and the taste score is also high. When the amount of the endosperm layer added is 15wt%, in terms of organizational state, it not only has the organizational state of stirred yogurt, but also has the granularity of cereal yogurt. In terms of taste, it has the rich taste of yogurt and the cereal flavor of wheat endosperm layer. When the amount of white sugar added is 7wt%, the yogurt has moderate sweetness and sourness, uniform texture, rich taste, and the highest sensory score. When the fermentation time is 24h, the yogurt is completely coagulated, the texture is uniform, and the taste is moderately sweet and sour. When the fermentation temperature is 41℃, the fermented yogurt has a more uniform texture, a higher score for organizational state, and the highest overall sensory score.

[0073] According to the above single factor experimental results, based on the Box-Behnken principle, a three-factor three-level response surface experiment was conducted on the three factors of aleurone addition (A), white sugar addition (B) and fermentation time (C) that had a greater impact on the sensory score of the stirred aleurone acid in Implementation 2. The production process of wheat aleurone yogurt was optimized, and the results of the response surface experiment on the optimization of aleurone yogurt process are shown in Table 5.

[0074] Table 5 Response surface test results for process optimization of aleurone yogurt

[0075]

[0076]

[0077] The response surface and contour map are shown in Figure 4. The obtained data were subjected to multivariate regression fitting using Design Expert 10 software, and the obtained quadratic regression equation was:

[0078] Y=90.60+1.63A+1.38B-7.00C-0.25AB-1.50AC+0.50BC-4.68A2-2.17B2-14.93C2

[0079] The optimal processing technology of wheat aleurone yogurt obtained by the response surface of Design Expert 10 software is as follows: the amount of aleurone added is 15.883g / 100mL, the amount of white sugar added is 6.871%, the fermentation time is 25.070h, and the sensory score is 91.006 points.

[0080] Considering the actual situation, the production process conditions of aleurone yogurt were adjusted to 16 g / 100 mL of aleurone, 7 wt% of white sugar, and 25 h of fermentation time. Experimental verification was carried out under this condition, and the average sensory score under this condition was 91.5.

[0081] According to the above optimal yogurt making process, the yogurts of Examples 3, 4, 5, and 6 were made, and a yogurt was purchased from the market for comparative analysis.

[0082] Figure 1 This is a product bottling diagram of Examples 3, 4, 5, 6 and Comparative Example 1.

[0083] The texture characteristics of Examples 3, 4, 5, 6 and Comparative Example 1 were analyzed.

[0084] The hardness, elasticity, adhesion, stickiness, chewiness and cohesion of yogurt are important indicators for evaluating the texture characteristics of yogurt. These indicators can reflect the taste, viscosity and other characteristics of yogurt.

[0085] The TPA texture test uses a 35mm cylindrical probe and uses the TPA-25N time-interval program to measure. The detection speed is set to 60mm / min, the deformation is 10%, the initial force is 0.01N, the maximum force range is 25N, and the test distance is 32mm. To ensure the accuracy of the measurement parameters, the yogurt sample must be measured immediately after being taken out of the 4℃ refrigerator. All samples are tested 3 times and the results are averaged.

[0086] Table 6 Yogurt texture index

[0087]

[0088]

[0089] The results showed that the taste of aleurone yogurt was softer than that of plain fermented yogurt, and its viscosity increased, but it lost the gelatinous texture of yogurt.

[0090] A comparative analysis of minerals was performed on Examples 3, 4, 5, 6 and Comparative Example 1.

[0091] Accurately measure 1mL of each yogurt into the microwave digestion inner tube, add 6mL of nitric acid, slowly tighten the screw cap, and digest according to the microwave digestion instrument program steps. After cooling, take out the digestion inner tube and place it in the acid removal machine. Remove the acid at 140℃ until about 1-2mL of liquid remains in the tube. After the acid removal is completed, adjust the volume and perform a blank test at the same time.

[0092] The standard solutions of each element were prepared according to the national standard method, the appropriate current size and slit width were set, and the mineral elements were determined using a flame atomic absorption spectrophotometer at the element wavelength fixed by the instrument system.

[0093] Table 7 Comparison of mineral content

[0094]

[0095] The results showed that the trace elements calcium, iron and zinc in the aleurone yogurt were significantly higher than those in the control yogurt. The copper content in each yogurt was less than the threshold value that could be detected by flame atomic absorption spectrometry.

[0096] The protein, dietary fiber, fat, vitamin E, vitamin B contents and glycemic index (GI) of Examples 3, 4, 5, 6 and Comparative Example 1 were tested.

[0097] The protein content is determined according to the method in GB 5009.5-2016 "National Food Safety Standard for the Determination of Protein in Food". The dietary fiber content is determined according to the method in GB 5009.88-2014 "National Food Safety Standard for the Determination of Dietary Fiber in Food". The fat content is determined according to the method in GB 5009.6-2016 "National Food Safety Standard for the Determination of Fat in Food". The vitamin E and vitamin B content are determined according to the method in GB 5009.82-2016 "National Food Safety Standard for the Determination of Vitamin A, D and E in Food". The GI value is determined according to the method in WS / T 652-2019 "Method for the Determination of the Glycemic Index of Food".

[0098] Table 8 Comparison of nutrient content

[0099]

[0100] The results showed that the contents of protein, dietary fiber, fat, vitamin E and vitamin B in aleurone yogurt were significantly greater than those in the control yogurt, and the GI value of aleurone yogurt was lower than that of the control, indicating that adding aleurone can effectively increase the nutritional content of yogurt and slow down the rise of blood sugar.

[0101] The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the scope of the principles of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. A lactic acid bacteria fermentation composite agent, characterized in that: The lactic acid bacteria fermentation composite bacterial agent is composed of a basic fermentation agent, an auxiliary fermentation agent and a functional fermentation agent, wherein the basic fermentation agent is composed of thermophilic Streptococcus and bulgaricus, the auxiliary fermentation agent is composed of Lactococcus lactis and Lactobacillus acidophilus, and the functional fermentation agent is composed of Lactobacillus plantarum ZP-6 and Leuconostoc mesenteroides DM12. Lactobacillus plantarum ZP-6 was deposited in the General Microbiology Center of China National Microbiological Culture Collection on July 31, 2024, with a deposit number of CGMCC No.31420, and Leuconostoc mesenteroides DM12 was deposited in the General Microbiology Center of China National Microbiological Culture Collection on March 28, 2024, with a deposit number of CGMCC No.30178.

2. The lactic acid bacteria fermentation composite agent according to claim 1, characterized in that: The weight ratio of the basic leavening agent, the auxiliary leavening agent and the functional leavening agent is 2:3:

3.

3. Use of the lactic acid bacteria fermentation composite agent according to claim 1 or 2 in the preparation of aleurone yogurt.

4. The use according to claim 3, characterized in that: The endosperm yogurt is prepared from the following raw materials in weight percentage: 5%-10% white sugar, 2%-14% lactic acid bacteria fermentation compound bacterial agent, 5%-25% endosperm, and the balance is pure milk. The fermentation temperature is 39-43° C. and the fermentation time is 12-28 hours.

5. The use according to claim 3, characterized in that: The endosperm yogurt is prepared from the following raw materials in the following weight percentage ratios: 7% white sugar, 5% lactic acid bacteria fermentation compound bacterial agent, 16% endosperm, and the balance is pure milk. The fermentation temperature is preferably 41° C., and the fermentation time is preferably 25 hours.

6. Use of the lactic acid bacteria fermentation composite bacterial agent according to claim 1 or 2 in the preparation of lactic acid bacteria fermentation stirred aleurone yogurt, characterized in that The specific process is: Step S1, frying: filter the wheat starch layer to remove impurities, fry over low heat until it turns slightly yellow, and let it cool for later use; Step S2, sterilization: boiling and sterilizing the yogurt container for 20 minutes, and naturally cooling and drying for later use; Step S3, fermentation: pure milk and white sugar are mixed in proportion, pasteurized, cooled, inoculated with a lactic acid bacteria fermentation compound agent, mixed evenly, and packaged into sealed bottles, and the sealed bottles are placed in a constant temperature incubator for constant temperature fermentation; Step S4, post-ripening: after fermentation, transfer to a 4°C refrigerator for refrigeration for more than 12 hours for post-ripening; Step S5, stirring: adding the fried wheat aleurone layer into the fermented yogurt and stirring evenly to prepare the lactic acid bacteria fermented stirred aleurone layer yogurt.

7. Use of the lactic acid bacteria fermentation composite bacterial agent according to claim 1 or 2 in the preparation of lactic acid bacteria fermented aleurone layer flavored yogurt, characterized in that The specific process is: Step S1, boiling: filter the wheat starch layer to remove impurities, accurately weigh it, add pure water in a weight ratio of 1:6, boil it on low heat for 1 hour to precipitate nutrients, filter it and let it stand at room temperature for later use; Step S2, sterilization: boiling and sterilizing the yogurt container for 20 minutes, and naturally cooling and drying for later use; Step S3, fermentation: pure milk, white sugar, and aleurone juice are mixed in proportion, pasteurized, cooled, inoculated with lactic acid bacteria and lactic acid bacteria fermentation composite bacterial agent, mixed evenly, and then packaged into sealed bottles, and the sealed bottles are placed in a constant temperature incubator for constant temperature fermentation; Step S4, post-ripening: after the fermentation is completed, the yogurt is transferred to a refrigerator at 4°C for refrigeration for more than 12 hours for post-ripening to produce aleurone flavored yogurt fermented by lactic acid bacteria.

8. Use of the lactic acid bacteria fermentation composite bacterial agent according to claim 1 or 2 in the preparation of lactic acid bacteria aleurone fermentation type yogurt, characterized in that The specific process is: Step S1, crushing: filtering the wheat endosperm to remove impurities, weighing accurately and setting aside; Step S2, sterilization: boiling and sterilizing the yogurt container for 20 minutes, and naturally cooling and drying for later use; Step S3, fermentation: pure milk, white sugar, and aleurone layer are mixed in proportion, pasteurized, cooled, inoculated with a lactic acid bacteria fermentation compound agent, mixed evenly, and packaged into sealed bottles, and the sealed bottles are placed in a constant temperature incubator for constant temperature fermentation for 25 hours; Step S4, post-ripening: after fermentation is completed, the yogurt is transferred to a refrigerator at 4°C for refrigeration for more than 12 hours for post-ripening to produce aleurone fermented yogurt.

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