Yoghourt and preparation method thereof

Abstract

The invention relates to the technical field of food, in particular to yoghourt and a preparation method thereof. The yoghourt provided by the invention is prepared from raw materials including mixed milk pulp, a leavening agent and glucoamylase, the mixed milk slurry comprises the following components in parts by weight: 150-200 parts of germinated millet slurry, 100-150 parts of millet slurry, 60-65 parts of milk powder and 80-200 parts of water. The yoghurt provided by the invention is rich in various functional components such as GABA (gamma-aminobutyric acid), polyphenol, flavone and the like, and shows excellent antioxidant activity; in the aspect of sense, through the synchronous action of addition of millet pulp and saccharifying enzyme in the fermentation process, bitterness and afterbitterness brought by germinated millet pulp are successfully solved, and the germinated millet yoghourt has the excellent quality of being sour, sweet, delicious, fine and smooth in texture, high in viscosity and low in whey precipitation rate, and is an innovative yoghourt product which is rich in nutrition, remarkable in function, excellent in texture and excellent in flavor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food technology, in particular to a yogurt and a preparation method thereof. BACKGROUND

[0002] With the improvement of people's living standards and the continuous progress of processing technology, yogurt products with specific functional properties have been increasingly concerned. In recent years, innovative products containing natural functional ingredients such as phenolic substances, flavonoids, anthocyanins and other functional ingredients have been emerging in yogurt, which can endow yogurt with various biological functions such as antioxidant, anti-diabetic, anti-obesity, anti-inflammatory, antibacterial and anti-cancer properties.

[0003] As an important food crop, millet contains rich dietary fiber, amino acids, unsaturated fatty acids, and various vitamins and minerals, which is a good source of nutrients for the human body. China is a major millet producer and has abundant millet resources. Studies have shown that the germination process can increase the content of phenolic and flavonoid substances in millet and help the accumulation of gamma-aminobutyric acid (GABA). GABA is an important inhibitory neurotransmitter that can improve the memory function of the brain and has a relieving effect on symptoms such as insomnia, depression, anxiety, and Alzheimer's disease. Therefore, adding germinated millet as a functional ingredient to yogurt can help enhance the nutritional and functional properties of yogurt.

[0004] However, there are some problems in the prior art when using germinated millet to prepare yogurt. On the one hand, due to the change of ingredients after germination, millet produces a bitter taste, resulting in a significant bitter taste of yogurt products with added germinated millet, poor taste, and limited product acceptability. On the other hand, during the germination process, the starch and protein content in millet decreases, and the polyphenol content increases, which is not conducive to the formation of yogurt, resulting in a loose network structure and soft texture of yogurt, which seriously affects the taste of the product.

[0005] In order to solve these problems, additional fruit juice is currently used, which can mask the bitter flavor of germinated millet yogurt to some extent, but modern consumers prefer natural, healthy and nutritious products. Although the additional fruit juice and sugar can improve the taste, they also mask the natural fermentation flavor of yogurt, which cannot meet the dual needs of consumers for health and deliciousness.

[0006] Therefore, it is of great significance to develop a preparation method that can effectively improve the taste of germinated millet yogurt, eliminate bitterness, and maintain the natural fermentation flavor and nutritional function of yogurt, in order to meet the needs of consumers and promote the development of functional yogurt products. SUMMARY

[0007] The present application provides a yogurt and a preparation method thereof to solve the above-mentioned problems existing in the prior art.

[0008] According to the first aspect of the present application, the present application provides a yogurt prepared from raw materials including a mixed milk slurry, a fermenting agent and a saccharifying enzyme; the mixed milk slurry includes 150-200 parts of germinated millet slurry, 100-150 parts of millet slurry, 60-65 parts of milk powder and 80-200 parts of water by weight.

[0009] The millet and the millet in the present application are essentially the same kind of grain, and the only difference is the processing state: the millet refers to the grain with husk, and the millet is the rice grain after husking.

[0010] The yogurt of the present application uses the mixed milk slurry composed of specific weight proportions of germinated millet slurry, millet slurry, milk powder and water, and cooperates with the fermenting agent and the saccharifying enzyme, so that the content of active ingredients such as GABA, polyphenol and flavonoid in the yogurt is significantly improved, and the antioxidant activity is improved, and the bitter taste and texture deterioration problems caused by the germinated millet are effectively solved. Among them, the addition of appropriate amount of millet slurry and saccharifying enzyme can release reducing sugar through moderate hydrolysis of starch and dextrin, thereby cooperatively embedding and masking the bitter taste of the germinated millet, and improving the viscosity and water holding capacity of the yogurt, so that the final product is outstanding in nutritional function, sweet in flavor and delicate in texture.

[0011] According to the yogurt of the present application, the addition amount of the germinated millet slurry is 20-30%. This addition amount range ensures the stable content of effective functional ingredients in the yogurt, such as GABA, polyphenol and flavonoid. At the same time, this addition amount range also balances the possible influence of the addition amount of the germinated millet slurry on the overall solid content, viscosity and taste of the yogurt, avoids the poor texture or increased bitter taste caused by too high concentration, and also prevents the insufficient contribution of functional ingredients caused by too low concentration.

[0012] According to the yogurt of the present application, the addition amount of the millet slurry is 20-30%. The appropriate amount of millet slurry can provide rich starch, dextrin and polysaccharide, which are helpful to improve the gel structure of the yogurt, increase the viscosity and water holding capacity in the subsequent enzymolysis and fermentation process, and can also adsorb and embed the bitter taste components generated by the germinated millet, so as to improve the overall taste.

[0013] According to the yogurt of the present application, the amount of the fermenting agent is 0.005-0.5% of the mass of the mixed milk slurry. This mass concentration can ensure the effective lactic acid fermentation of the yogurt, so that the lactose in the mixed milk slurry is efficiently converted into lactic acid, so as to reach the required pH value (≤4.6) of the product and form curd.

[0014] Preferably, the fermenting agent is selected from one or both of Streptococcus thermophilus and Lactobacillus bulgaricus. More preferably, the fermenting agent comprises Streptococcus thermophilus and Lactobacillus bulgaricus. Streptococcus thermophilus and Lactobacillus bulgaricus can produce a synergistic effect, accelerate the fermentation process, and impart a typical flavor and good texture to the yogurt.

[0015] According to the yogurt of the present application, the amount of the saccharifying enzyme is 0.005-0.02% of the mass of the mixed milk slurry.

[0016] In the fermentation process, the saccharifying enzyme continuously hydrolyzes starch and dextrin, and synchronously releases reducing sugars. These reducing sugars not only provide a continuous carbon source for the fermenting bacteria, but also promote the full integration of the fermentation flavor and the flavor components in the millet slurry, effectively embedding and masking the bitterness and aftertaste brought by the millet, significantly improving the sweet taste of the yogurt, so that the product has a "sweet taste in the mouth, no obvious bitterness, and no obvious aftertaste".

[0017] According to the yogurt of the present application, the milk powder is selected from one or more of whole milk powder, skim milk powder, semi-skim milk powder, concentrated milk protein powder, and whey protein powder.

[0018] According to the second aspect of the present application, the present application also provides a method for preparing the above-mentioned yogurt, comprising the following steps: Preparation of millet slurry and millet slurry: soak the germinated millet or hulled millet, beat the slurry, then perform gelatinization treatment, and finally add α-amylase to treat at 80-90℃ for 80-100min, and sieve; Mix the prepared germinated millet slurry, millet slurry, milk powder, and water to obtain a mixed milk slurry; homogenize the mixed milk slurry to obtain a homogenized liquid; after sterilization treatment of the homogenized liquid, cool it to 40-42℃, add a fermenting agent and a saccharifying enzyme, ferment, and mature.

[0019] The preparation method of the yogurt optimizes the preparation process of the germinated millet milk and millet milk, and can effectively control the degradation degree and fineness of the grain matrix. On this basis, the prepared slurry is mixed with milk powder and water, and is subjected to homogenization treatment to ensure uniform and stable product texture, and sterilization treatment to ensure product safety. The polysaccharides and dextrin in the millet milk help to improve the gel structure and water holding capacity of the yogurt, and at the same time, embed and mask the undesirable flavor components of the germinated millet, thereby improving the overall texture and taste of the product. During the fermentation and maturation process by simultaneously adding a fermenting agent and a saccharifying enzyme, the saccharifying enzyme can continuously hydrolyze starch and dextrin to release reducing sugar during the fermentation process. These reducing sugars not only provide carbon sources for the fermentation bacteria, but more importantly, can further promote the fusion of fermentation flavors, effectively mask the bitter and astringent taste brought by the germinated millet, and significantly improve the taste and flavor of the yogurt. The method of the present application can efficiently prepare functional yogurt with rich nutritional functions (high GABA, polyphenol, flavonoid content and antioxidant activity) and excellent sensory quality (fine, sweet and sour, no bitter and astringent taste).

[0020] According to the preparation method of the yogurt of the present application, the temperature of the homogenization treatment is 50-70℃, and the pressure is 15-25Mpa, which helps to form a stable emulsion and improve the fineness of the yogurt.

[0021] According to the preparation method of the yogurt of the present application, the sterilization treatment is heating at 90-100℃ for 3-8min, which ensures the microbial safety of the product and promotes the moderate denaturation of milk protein, which helps to form curd and improve viscosity.

[0022] According to the preparation method of the yogurt of the present application, the fermentation is carried out to a pH value of ≤4.6, which ensures the full fermentation and the formation of product flavor.

[0023] According to the preparation method of the yogurt of the present application, the maturation temperature is 3-5℃, and the time is more than 12h (preferably 12-24h), which is beneficial to the maturation of yogurt flavor and the stability of texture, and reduces the separation of whey.

[0024] According to the preparation method of the yogurt of the present application, the germinated millet or hulled millet is soaked at 50℃-60℃ for 30-60min, and then is subjected to beating treatment, which creates good conditions for subsequent enzymolysis.

[0025] According to the preparation method of the yogurt of the present application, during the soaking and beating treatment of the germinated millet or hulled millet, the ratio of the dry weight of the material to water is 1:(3-4), which ensures the beating efficiency and the concentration of the slurry.

[0026] According to the preparation method of the yogurt of the present application, the gelatinization treatment is kept at 90-100℃ for 60-120min, which helps to fully gelatinize starch, making it easier to be hydrolyzed by α-amylase.

[0027] According to the preparation method of the yoghurt, the added amount of the alpha-amylase is 0.02-0.04% of the mass of the foxtail millet or the hulled millet, which can effectively control the degradation degree of starch and dextrin, so as to ensure that the yoghurt has moderate viscosity, better water retention and improved embedding effect of bitter taste.

[0028] According to the preparation method of the yoghurt, the sieving is sieving through a 200-mesh sieve, which ensures the fineness of the slurry and avoids the rough feeling of the final product.

[0029] According to the preparation method of the yoghurt, the preparation method of the foxtail millet is as follows: the foxtail millet is washed and soaked in water, and the foxtail millet that does not float and is not full is discarded; filter paper is placed in a culture dish, water is sprayed until saturation, the treated foxtail millet is placed in the culture dish, and the saturated gauze is covered; the soaked foxtail millet is cultured in the dark, the germination humidity is controlled to be 80%-90%, and the temperature is controlled to be 20-30 DEG C for 48-96h.

[0030] The foxtail millet is subjected to the fine control of the germination treatment, the biological enzyme system inside the foxtail millet is activated to the greatest extent, the content of the functional components with biological activity in the foxtail millet is improved, in particular, the content of gamma-aminobutyric acid (GABA), phenolic substances and flavonoids is improved, so that the subsequent prepared yoghurt has more excellent nutritional value and functional characteristics, for example, the antioxidant property is improved, the memory is improved, and the foundation for producing high-functional healthy yoghurt is laid.

[0031] Preferably, the weight ratio of the foxtail millet to water during the soaking process is 1:(3-4), and the soaking time is 12-24h. This can effectively improve the uniformity and efficiency of the germination, provide high-activity germinated foxtail millet for subsequent preparation, and thus guarantee the nutritional and functional characteristics of the final yoghurt.

[0032] The present application has the following advantages: The present application combines the specific proportion of the germinated millet and the ungerminated millet, and is supplemented by the moderate amylase hydrolysis treatment, which not only effectively supplements the starch and protein that may be degraded during the germination process, optimizes the organization structure of the yoghurt, but also improves the texture by using the produced dextrin and reducing sugar. Meanwhile, the saccharifying enzyme is added synchronously during the fermentation process, and the reducing sugar and other ingredients are synchronously released, which is helpful to optimize the interaction and fusion process of the germinated millet slurry components and various components in the yoghurt during the fermentation process, form effective embedding and masking effect on the substances that may produce bitter taste, and eliminate the bad bitter taste and after-bitter taste of the germinated millet slurry to the yoghurt.

[0033] The present application makes full use of the GABA, flavones, polyphenols and other functional components generated by natural millet germination, significantly enhances the antioxidant and sleep-aiding health effects of the yogurt, and finally successfully develops a functional yogurt product which is excellent in nutrition, functionality, texture and flavor. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0035] The raw materials used in the following examples and comparative examples are as follows: Milk powder: from Anjia full-fat milk powder.

[0036] Millet: Jingu 21 millet, Jincheng Fengyuan Planting Professional Cooperative.

[0037] Amylase: Alpha-amylase from Xiasheng (Beijing) Biological Technology Development Co., Ltd.

[0038] Glucoamylase: Food-grade glucoamylase from Xiasheng (Beijing) Biological Technology Development Co., Ltd.

[0039] Mixed starter culture: Kocen YC380, including Streptococcus thermophilus and Lactobacillus bulgaricus starter culture.

[0040] Example 1 The present embodiment provides a yogurt prepared from mixed milk slurry, starter culture and glucoamylase raw materials; the composition of the mixed milk slurry is shown in Table 1 below.

[0041] The present embodiment also provides a preparation method of the yogurt, including the following steps: (1) Millet germination: wash the millet, soak it in distilled water at room temperature for 14 h (millet: water weight ratio = 1:4), discard the small millet that floats and is not full, place two layers of filter paper in a culture dish, spray distilled water until saturated, evenly spread the treated millet in the culture dish, cover with four layers of gauze sprayed with an appropriate amount of distilled water, immerse the seeds in a constant temperature incubator in the dark, control the germination humidity at 80%~90%, and germinate at 25℃ for 72 h.

[0042] (2) Preparation of sprouted millet milk and millet milk: Sprouted millet (dry basis) and water were mixed at a ratio of 1:4 by weight of the feed liquid, soaked at 50°C for 30 min, and then beaten with a cell disrupter. After gelatinization treatment (above 90°C, for 60 min), a-amylase (0.3 g / kg of sprouted millet) was added, and the mixture was treated at 85°C for 90 min. Finally, the mixture was sieved through a 200-mesh sieve to obtain sprouted millet milk.

[0043] Hulled millet and distilled water were mixed at a ratio of 1:3 by weight, soaked at 50°C for 30 min, and then beaten with a cell disrupter. After gelatinization treatment (above 90°C, for 60 min), a-amylase (0.3 g / kg of hulled millet) was added, and the mixture was treated at 85°C for 90 min. Finally, the mixture was sieved through a 200-mesh sieve to obtain millet milk.

[0044] (3) Preparation of yogurt: The water, milk powder, sprouted millet milk and millet milk prepared in step (2) were thoroughly mixed and stirred to obtain a mixed milk slurry, which was preheated to 60°C, homogenized at 20 MPa to obtain a homogenized liquid, and then heated at 95°C for 5 min. The homogenized liquid was cooled to 40-42°C, inoculated with a mixed starter (an amount of 0.01% of the mass of the mixed milk slurry), and added with saccharifying enzyme (an amount of 0.008% of the mass of the mixed milk slurry). The inoculated mixed milk slurry was incubated at 42°C until the pH value was ≤4.6, and then the yogurt was cooled and stored at 4°C for 12 h for further analysis.

[0045] Example 2 This example provides a yogurt, which is different from Example 1 in that the mixed milk slurry is different, as shown in Table 1.

[0046] The preparation method of the yogurt of this example is the same as that of Example 1.

[0047] Example 3 This example provides a yogurt, which is different from Example 1 in that the mixed milk slurry is different, as shown in Table 1.

[0048] The preparation method of the yogurt of this example is the same as that of Example 1.

[0049] Example 4 This example provides a yogurt, which is different from Example 1 in that the amount of saccharifying enzyme is 0.005% of the mass of the mixed milk slurry.

[0050] Example 5 This example provides a yogurt, which is different from Example 1 in that the amount of saccharifying enzyme is 0.015% of the mass of the mixed milk slurry.

[0051] Example 6 The present example provides a yogurt, which is different from Example 1 in that the amount of saccharifying enzyme is 0.020% of the mass of the mixed milk slurry.

[0052] Comparative Example 1 The present comparative example provides a yogurt, which is different from Example 1 in that it is prepared from a mixed milk slurry and a ferment, and the mixed milk slurry does not contain millet slurry and foxtail millet slurry, and the composition is shown in Table 1 below.

[0053] The preparation method of the yogurt of the present comparative example is different from Example 1 in that steps (1) and (2) are not included, and the foxtail millet slurry, millet slurry and saccharifying enzyme are not added in step (3).

[0054] Comparative Example 2 The present comparative example provides a yogurt, which is different from Example 1 in that the mixed milk slurry does not contain millet slurry, and the composition is shown in Table 1 below.

[0055] The preparation method of the yogurt of the present comparative example is different from Example 1 in that the millet slurry is not prepared in step (2), and the millet slurry is not added in step (3).

[0056] Comparative Example 3 The present comparative example provides a yogurt, which is different from Example 1 in that the raw material composition does not contain saccharifying enzyme.

[0057] The preparation method of the yogurt of the present comparative example is different from Example 1 in that in step (3), before fermentation, only the ferment is inoculated, and no saccharifying enzyme is added.

[0058] Comparative Example 4 The present comparative example provides a yogurt, which has the same raw material composition as Example 1.

[0059] The preparation method of the yogurt of the present comparative example is different from Example 1 in that in step (2), in the preparation of the foxtail millet slurry and the millet slurry, after the addition of α-amylase, it is treated at 60°C for 80 min.

[0060] Comparative Example 5 The present comparative example provides a yogurt, which is different from Example 1 in that the millet slurry is 50 parts and the water is 188 parts.

[0061] Comparative Example 6 The present comparative example provides a yogurt, which is different from Example 3 in that the millet slurry is 50 parts and the water is 238 parts.

[0062] Comparative Example 7 The present comparative example provides a yogurt, which is different from Example 1 in that the millet slurry is 200 parts and the water is 38 parts.

[0063] Comparative Example 8 This comparative example provides a yogurt, the raw material composition of which differs from that of Example 1 in that the germinated millet milk is 250 parts and the water is 88 parts.

[0064] Table 1

[0065] The yogurts of the examples and comparative examples were subjected to the following performance tests: (1) Whey separation rate After 25 g of yogurt was centrifuged at 2900 x g for 20 min at 4°C using an R-404A high-speed refrigerated centrifuge (ThermoFisher, Germany), the supernatant was weighed, and the whey separation rate was calculated according to formula (1).

[0066] (1) (2) Apparent viscosity The apparent viscosity of the yogurt sample was measured at 5°C according to the operating instructions of the Brookfield DV-III viscometer (Brookfield Engineering Laboratories Inc.). The measurement was performed using a V-63 spindle at a speed of 5 rpm and using a helical path, for a time of 60 s.

[0067] (3) Free polyphenol content determination The free phenol content was determined by the Folin-Ciocalteu method, and a calibration curve was established using gallic acid as the reference substance for determining polyphenols. The results are expressed in milligrams of gallic acid equivalent (GAE) per 100 g of yogurt sample (mg GAE / 100 g).

[0068] (4) Flavonoid content determination The total flavonoid content was determined by the NaNO2-Al(NO3)3-NaOH colorimetric method. In an alkaline nitrite solution, flavonoids form a red complex with aluminum ions that has a characteristic absorption peak at 510 nm. The total flavonoid content in the sample can be calculated by measuring the absorbance of the reaction product at 510 nm.

[0069] 10 mg of rutin was dissolved in a 10 mL volumetric flask with a methanol-acetonitrile (1:1) solution to obtain a 1 mg / mL rutin standard stock solution. 0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 mL were taken and diluted to 5 mL to prepare standard curves of 0, 20, 40, 60, 80, 100, and 120 μg / mL, respectively.

[0070] In 1 mL extract / standard solution, add 0.3 mL of NaNO2 (5%) solution, mix and stand at room temperature for 5 min, then add 0.3 mL of Al(NO3)3 (10%) solution, mix and stand at room temperature for 5 min, finally add 2 mL of 1 mol / L NaOH solution, shake well, and place in a dark room for 20 min. Immediately read the absorbance value at 510 nm. Take the rutin standard solution as the abscissa and the absorbance value as the ordinate to obtain the standard curve: y = 0.0018x + 0.0384, R 2 = 0.9964. The sample determination result is expressed in terms of rutin equivalent (mg / 100 g).

[0071] (5) Determination of γ-aminobutyric acid (GABA) content Reference Zhang et al. used colorimetric method to determine the content of GABA. The sample was mixed with deionized water at a material-liquid ratio of 1:5 (g / mL), shaken at 150 r / min and 40°C for 1 h, then centrifuged at 4°C and 10000 rpm for 10 min, and the supernatant was taken for determination of GABA content.

[0072] Take 10 mg of GABA standard and dilute to 10 mL with distilled water to obtain a 1 mg / mL GABA standard stock solution. Take 0, 0.25, 0.5, 1, 1.5, and 2 mL respectively and dilute to 5 mL to prepare standard curves of 0, 50, 100, 200, 300, and 400 μg / mL.

[0073] Collect half a milliliter of extract / standard solution, and add 0.2 mL of 0.2 mol / L -1 borate buffer (pH 9.0), 1 mL of 5% phenol and 0.4 mL of 9% sodium hypochlorite in turn. After strong shaking, the mixture was placed in boiling water for 10 minutes, then in an ice bath for 20 minutes (it can be cooled to room temperature), and constantly shaken until blue appeared. Finally, add 2 mL of 60% ethanol. Perform colorimetric analysis of the sample at a wavelength of 640 nm. Linear regression between the absorbance value and the standard GABA content gives the standard curve: y = 0.001x + 0.0517, R 2 = 0.9991.

[0074] (6) ABTS free radical scavenging activity Take 5.0 mL of 7 mmol / L ABTS solution, add 88.0 μL of 140 mmol / L potassium persulfate, and react at room temperature for 12-16 h in the dark to form an ABTS free radical stock solution. At 734 nm, dilute the ABTS free radical stock solution with a volume fraction of 70% ethanol (absorbance is 0.6-0.7 after dilution) and reserve. Accurately take 0.1 mL of the sample solution, add 3.9 mL of the diluted ABTS free radical stock solution with an absorbance of 0.6-0.7, mix well, and react at room temperature for 6 min (avoiding light), and measure the absorbance A at 734 nm 样品 At the same time, take 3.9 mL of the diluted ABTS free radical stock solution with an absorbance of 0.6-0.7, add 0.1 mL of a 1:1 volume ratio methanol / acetonitrile solution, and measure the absorbance A at 734 nm 对照 The ABTS free radical scavenging rate is calculated as follows: (2) Wherein, A 样品 is the absorbance of the supernatant sample, and A 对照 is the absorbance of the 1:1 volume ratio methanol / acetonitrile solution.

[0075] (7) DPPH free radical scavenging activity The measurement method of DPPH free radical scavenging activity is as follows: 100 μL of supernatant is mixed with 100 μL of DPPH solution (0.2 mM, 95% methanol), and then incubated at 37 °C in the dark for 30 min. The absorbance is measured at 517 nm, and the DPPH free radical scavenging rate is calculated as follows: (3) Wherein, A 样品 is the absorbance of the supernatant sample, and A 对照 is the absorbance of the 1:1 volume ratio methanol / acetonitrile solution.

[0076] Test results Table 2 Analysis results of active ingredients and antioxidant activity in yogurt

[0077] As can be seen from Table 2, the active ingredient content of the yogurt of Examples 1 and 3 is significantly improved compared with the ordinary yogurt of Comparative Example 1, the GABA content is increased by 119% and 104% respectively; the polyphenol content is increased by 397% and 291% respectively; the flavonoid content is increased by 1071% and 732% respectively. The antioxidant activity is obviously enhanced, and the DPPH free radical scavenging rate of Examples 1 and 3 is increased by 391% and 345% respectively compared with Comparative Example 1; the ABTs free radical scavenging rate is increased by 310% and 246% respectively. It is shown that the addition of the sprouted millet slurry in the method of the application can effectively improve the nutritional and functional properties of ordinary yogurt.

[0078] Table 3 Texture quality and taste evaluation results of yogurt products

[0079] As can be seen from Table 3, Examples 1-3 are yogurt prepared by adding a certain proportion of sprouted millet slurry and unsprouted millet slurry with moderate hydrolysis in the scope of the application, and the texture and flavor are obviously better than Comparative Examples 2-4, which shows that the use of moderate millet slurry enzymatic treatment and simultaneous saccharification enzyme treatment during fermentation to release reducing sugar is helpful for the interaction and integration between the components of sprouted millet slurry and other components during fermentation, and has good effect on masking the bitter and aftertaste of yogurt caused by sprouted millet slurry. Through the implementation of the application, a functional yogurt product with good nutritional function, physicochemical quality and flavor can be obtained. Examples 4-6 use different amounts of saccharifying enzyme compared with Example 1, the saccharifying enzyme dosage in Example 4 is 0.005%, and the yogurt has slightly lower sweetness than Example 1, but no obvious bitterness and aftertaste. Examples 5 and 6 use higher saccharifying enzyme dosage, and the texture and taste of the yogurt have no obvious difference from Example 1, which shows that the addition of saccharifying enzyme in an amount of more than 0.005% can improve the bitterness, and the effect is better when the addition amount is 0.01% or more.

[0080] Comparative Example 1 does not add millet slurry and sprouted millet slurry, and does not contain saccharifying enzyme, and has the normal texture of ordinary yogurt, but the taste is slightly sour and astringent. Comparative Example 2 only adds sprouted millet slurry, which has an adverse effect on the texture and taste of yogurt, the texture is not good, there is obvious bitterness, and the aftertaste is strong.

[0081] Comparative Example 3 and Comparative Example 4 both added germinated millet slurry and un-germinated millet slurry, but Comparative Example 3 did not add saccharifying enzyme for simultaneous fermentation, and Comparative Example 4 used different starch enzyme hydrolysis treatment conditions than Example 1. Although the texture and taste were improved compared to Comparative Example 2, there was still a relatively obvious bitter taste and aftertaste. Compared to Comparative Example 4, the texture of Comparative Example 3 was improved, and the bitter taste was somewhat alleviated, indicating that moderate enzyme hydrolysis of millet slurry, to achieve a moderate ratio of starch, dextrin and polysaccharide in the millet slurry, can effectively alleviate the deterioration of yogurt texture caused by germinated millet slurry, and to some extent alleviate the bitter taste.

[0082] Comparative Example 5 and Comparative Example 6 respectively compared to Example 1 and Example 3, used less millet slurry, and the yogurt still had a significant bitter taste and aftertaste. Comparative Example 7 compared to Example 1 used more millet slurry, and the yogurt had a better taste, and was not significantly different from Example 1, but the texture was not fine enough, and there were white small particles, which may be related to the poor hydration of milk powder protein.

[0083] Comparative Example 8 added more germinated millet slurry, causing protein flocculation, which may be due to the increase in the amount of millet slurry, and the high content of polyphenols caused the interaction between millet slurry and milk protein molecules to be destroyed. Further experiments found that if a lower amount of germinated millet slurry (<100 parts) was added, the GABA and antioxidant effects would be reduced.

[0084] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A yoghurt, characterized in that, Prepared from raw materials including mixed milk slurry, leavening agent and saccharifying enzyme; the mixed milk slurry includes malted millet slurry 150-200 parts, millet slurry 100-150 parts, milk powder 60-65 parts and water 80-200 parts by weight.

2. The yoghurt according to claim 1, characterized in that, The mass concentration of the malted millet in the malted millet slurry is 20-30%; the mass concentration of millet in the millet slurry is 20-30%.

3. The yoghurt according to claim 1 or 2, characterized in that, The weight ratio of the malted millet slurry to the millet slurry is (1-2):

1.

4. The yoghurt according to any one of claims 1 to 3, characterized in that, The amount of the leavening agent is 0.005-0.5% of the mass of the mixed milk slurry; preferably, the leavening agent is selected from one or both of Streptococcus thermophilus and Lactobacillus bulgaricus.

5. The yoghurt according to any one of claims 1 to 4, characterized in that, The amount of the saccharifying enzyme is 0.005-0.02% of the mass of the mixed milk slurry.

6. The yoghurt according to any one of claims 1 to 5, characterized in that, The milk powder is selected from one or more of full-fat milk powder, skim milk powder, semi-skim milk powder, concentrated milk protein powder and whey protein powder.

7. Process for the preparation of a yoghurt according to any one of claims 1 to 6, characterized in that, Comprising the following steps: Preparation of malted millet slurry and millet slurry: soaking malted millet or hulled millet, beating, then gelatinization treatment, finally adding α-amylase for 80-100 min at 80-90℃, sieving; Mixing the prepared malted millet slurry, millet slurry, milk powder and water to obtain a mixed milk slurry; homogenizing the mixed milk slurry to obtain a homogenized liquid; after sterilization treatment of the homogenized liquid, cooling to 40-42℃, adding leavening agent and saccharifying enzyme, fermentation, maturation.

8. The method of preparing a yogurt according to claim 7, characterized in that, The temperature of the homogenization treatment is 50-70℃, and the pressure is 15-25MPa; And / or, the sterilization treatment is heating at 90-100℃ for 3-8 min; And / or, the fermentation is to pH≤4.6; And / or, the maturation temperature is 3-5℃, and the time is more than 12 h.

9. The method of preparing a yoghurt according to claim 7 or 8, characterized in that, Soaking malted millet or hulled millet at 50-60℃ for 30-60 min; then beating And / or, during the soaking of malted millet or hulled millet, the ratio of dry material weight to water is 1:(3-4); And / or, the gelatinization treatment is at 90-100℃ for 60-120 min; And / or, the addition amount of α-amylase is 0.02-0.04% of the mass of the malted millet or the hulled millet; And / or, the sieving is through a 200-mesh sieve.

10. The method of preparing a yoghurt according to any one of claims 7-9, characterized in that, The preparation method of the malted millet is as follows: washing millet, soaking, discarding the millet that floats and is not full; placing filter paper in a culture dish, spraying water until saturation, placing the treated millet in the culture dish, covering the sprayed gauze, and culturing the soaked millet in the dark, controlling the germination humidity at 80-90%, and germinating at 20-30℃ for 48-96 h; Preferably, the weight ratio of millet to water during soaking is 1:(3-4), and the soaking time is 12-24 h.

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