Zero-additive sweet yoghurt and method for preparing the same

Abstract

The application relates to the field of yogurt preparation, and particularly provides zero-addition sweet fermented milk and a preparation method thereof. In the preparation process, oat rice and millet are used as sweet fermented milk fermentation raw materials, and the proportion is controlled, and the sweet fermented milk and raw cow milk are subjected to secondary fermentation. On one hand, the yogurt does not contain any food stabilizing additives, fully utilizes the interaction of components of raw materials and a processing technology to form a stable system to realize shelf period organization state stability and label cleanness; on the other hand, the yogurt does not need to add white granulated sugar and artificial sweetener and other sweet substances to neutralize the product sour taste, the prepared yogurt breaks through the traditional post-addition process of grain yogurt, adopts a double fermentation process, has good texture and organization state, rich and full taste and flavor, and has a good market prospect.

Description

Technical Field

[0001] This invention relates to the field of yogurt preparation, specifically to a zero-added sweetener yogurt and its preparation method. Background Technology

[0002] Yogurt, a dairy product that combines nutrition and health benefits, is mainly made from fermented milk. It has a unique flavor that is sweet and sour and has a pleasant aroma. In addition to retaining all the nutrients of fresh milk, it is also rich in a variety of essential vitamins and calcium. The lactic acid bacteria and special biological factors in yogurt help improve the digestive function of the human gastrointestinal tract and enhance immunity, making it a healthy beverage that people choose daily.

[0003] With the increasing health awareness and changing consumption concepts, consumers have higher and higher demands for the texture, taste, cleanliness, and even function of yogurt. The development of yogurt is mainly reflected in the following aspects: First, the diversification of raw materials. Traditional yogurt mainly uses cow's milk as its raw material, but in recent years, goat's milk, camel milk, etc., have been used as the main raw materials. Plant proteins (grains, soy protein isolate, coconut, peanuts, etc.) are also added; fruit and vegetable ingredients (various fruit pieces, jams, and fruit and vegetable juices, etc.) are added; and probiotics, prebiotics, and medicinal and edible materials are added to give yogurt health benefits such as lowering cholesterol, regulating blood lipids and blood sugar, nourishing qi and blood, improving immunity, anti-oxidation, lowering blood lipids, anti-fatigue, and reducing internal heat. Second, the types and content of stabilizers in yogurt are gradually shifting from multiple compound formulations to single, reduced amounts. Some even use natural, safe, healthy, and water-soluble food raw materials such as lotus root powder, wheat starch, potato starch, rice flour, and glutinous rice flour to achieve clean labeling of yogurt.

[0004] Sweet fermented grains are a traditional grain fermentation product with a long history in my country, and also a cultural snack with distinctive Northwest regional characteristics. Made from oats and other grains, they are rich in nutrients, have a pleasant sweet and sour taste, and align with modern consumers' "natural, green, and healthy" dietary philosophy. In 2023, 11 departments, including the Ministry of Industry and Information Technology, jointly issued the "Guiding Opinions on Cultivating Traditional Advantageous Food Production Areas and Local Specialty Food Industries," clarifying the development goals of traditional advantageous food production areas and local specialty food industries. The document proposes that by 2025, a development pattern of "10 billion yuan leading enterprises, 100 billion yuan clusters, and trillion yuan industries" for local specialty foods will be basically formed, promoting local specialty foods from regional to national levels.

[0005] In the existing technology, no additive-free product combining sweet fermented mash and yogurt has been found. Therefore, it is of great significance to develop a sweet fermented mash yogurt with good texture and organization, rich and full taste and flavor, and no need to add additional stabilizers and sweeteners. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a zero-additive sweet fermented yogurt and its preparation method. On the one hand, this enriches the existing yogurt varieties, and on the other hand, the zero-additive double-fermented yogurt product with a special aroma and nutritional value can promote the regionally distinctive cultural snack of sweet fermented yogurt to the whole country.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing zero-additive sweetened fermented yogurt, wherein the sweetened fermented yogurt is prepared by fermentation of oat groats and millet, with a weight ratio of millet to oat groats of 1:1.5-3.

[0009] Includes the following steps:

[0010] Step 1: Homogenize the raw milk;

[0011] Step 2: Add sweetened mash to the homogenized raw milk from Step 1 and stir.

[0012] Step 3: Sterilize and cool the material obtained in Step 2;

[0013] Step 4: Add lactic acid bacteria starter to the material obtained in Step 3, mix well, and carry out fermentation to obtain sweet fermented yogurt.

[0014] This invention provides a method for preparing zero-additive sweetened mashed yogurt. The sweetened mashed ...

[0015] Specifically, millet was creatively added to the oat-based formula. After the sweet fermented mash was mixed with milk, the millet's amylopectin, which accounts for over 80% of its composition, gelatinized and cooked, combined with the proteins in the milk through intermolecular forces to form a stable, high-viscosity starch-protein binary colloidal system. After fermentation, the cooling of the sweet fermented mash yogurt allowed the branched structure of the millet amylopectin molecules to weaken the tightness of the molecular chain recombination, exhibiting good anti-aging properties. The dietary fiber β-glucan in oats combined with the milk components, absorbing water and swelling, making the entire yogurt system viscous.

[0016] The addition of millet increases stickiness, improves the texture of the yogurt, enhances its fermentation properties, and brings out its unique aroma. Simultaneously, during yogurt preparation, the sweetened mash provides a carbon source for the lactic acid bacteria and accelerates the fermentation process to some extent.

[0017] Furthermore, the weight ratio of millet to oat groats is 1:2 to 3. Studies have found that the proportion of millet to oat groats added is a key factor affecting the overall performance of yogurt.

[0018] Furthermore, the sweet fermented mash is prepared using the following steps:

[0019] S1. Soak the oat groats and millet.

[0020] S2. Steam the oat rice, then add millet and mix well, steam again, and cool to room temperature;

[0021] S3. Add sweet wine yeast to the mixture after cooking in S2, stir well, and carry out fermentation to obtain sweet mash.

[0022] Furthermore, in S1, the oat groats are cleaned, washed, and soaked for 1.5 to 3 hours; the millet is washed and soaked for 0.5 to 1 hour.

[0023] Furthermore, in step S2, the cooking temperature is 80–100°C; and / or the cooking time is 1.5–3 hours.

[0024] Furthermore, in step S3, the amount of sweet wine yeast added per 1000g of oat rice and millet mixture (on a dry basis) is 4-5g.

[0025] Furthermore, in step S3, the fermentation temperature is 25–30°C; and / or the fermentation time is 24–36 h.

[0026] Furthermore, step S4 involves stirring the fermented material and then cooling it.

[0027] Furthermore, in step 1, the raw milk is preheated to 60-70°C and homogenized at 200-250 bar.

[0028] Furthermore, in step 3, the sterilization temperature is 90–95°C, and the sterilization time is 5–10 minutes.

[0029] Furthermore, in step 3, the temperature is cooled to 37–42°C.

[0030] Furthermore, the weight ratio of raw milk to sweetened mash is 80-90:10-20.

[0031] Furthermore, in step 4, the fermentation temperature is 37–42°C, and the final pH value is 4.5 ± 0.2.

[0032] Furthermore, in step 4, the fermented yogurt is cooled by turning it over, filled into containers, and then ripened to obtain stirred sweet fermented yogurt.

[0033] Furthermore, in step 4, a direct-inoculation lactic acid bacteria starter is added to the material obtained in step 3, mixed evenly, filled into bottles, transferred to a drying room for fermentation, cooled, and post-ripened to obtain set-type yogurt.

[0034] Furthermore, in step 4, the direct-inoculation lactic acid bacteria starter is one or more of the following: *Streptococcus salivarius* subsp. *thermophilus*, *Lactobacillus denudata* subsp. *bulgaricus*, and *Bifidobacterium animalis* subsp. *lactobacterium*, or a strain listed in the national announcement that can be used in food.

[0035] Furthermore, in step 4, the amount of lactic acid bacteria starter is 100-200 U / t.

[0036] Another object of the present invention is to provide a product obtained by the above-mentioned method for preparing sweetened yogurt.

[0037] Sweetened fermented yogurt prepared by the above-mentioned method.

[0038] The yogurt preparation process of this invention, due to the addition of sweetened mash rich in prebiotics such as β-glucan, sterilized yeast cells, and other precursor substances suitable for lactic acid bacteria growth, promotes the proliferation of lactic acid bacteria, especially probiotics, during yogurt fermentation, shortens the fermentation time, and results in yogurt with a live lactic acid bacteria count higher than 10^6. 9 The CFU / g sweet fermented yogurt production process, through creative design and research of traditional sweet fermented yogurt and regular yogurt production processes, is simple to prepare and suitable for large-scale promotion, which is of great significance for accelerating the marketization of sweet fermented yogurt.

[0039] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0040] 1. This invention provides a method for preparing zero-additive sweetened mashed yogurt, wherein the sweetened mashed ...

[0041] 2. The sweet fermented mash prepared by this invention has higher nutritional value and a more pleasant taste. After fermentation, the oats and millet have increased contents of organic acids, free amino acids, and unsaturated fatty acids such as linoleic acid and oleic acid. The reducing sugar, especially glucose, content is 25-40g / 100g, and the β-glucan content is 15-20g / 100g.

[0042] 3. The yogurt preparation process of this invention, due to the addition of sweetened mash rich in prebiotics such as β-glucan, sterilized yeast cells, and other precursor substances suitable for lactic acid bacteria growth, promotes the proliferation of lactic acid bacteria, especially probiotics, during yogurt fermentation, shortens the fermentation time, and results in yogurt with a live lactic acid bacteria count higher than 10. 9 CFU / g.

[0043] 4. This invention creatively designs and studies traditional sweet fermented mash and ordinary yogurt processes. The preparation process of the sweet fermented mash yogurt is simple and suitable for large-scale promotion, which is of great significance for accelerating the marketization process of sweet fermented mash yogurt. Attached Figure Description

[0044] Figure 1 This is a process diagram for preparing the zero-additive sweetener yogurt of this application. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] Example 1

[0047] A zero-additive sweet fermented yogurt and its preparation method, the raw materials for preparation include: (1) sweet fermented raw materials, all on a dry basis: 70 parts of oat rice, 30 parts of millet, 4g / kg of sweet wine yeast; (2) yogurt raw materials: 90 parts of raw milk, 10 parts of sweet fermented yogurt, 100U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deutzia subsp. bulgaricus fermentation agent.

[0048] Its preparation steps include:

[0049] (1) Remove the outer skin of oat rice, take 70 parts, wash and soak for 2 hours; take 30 parts of millet, wash and soak for 1 hour, add water to oat rice and steam at 90°C under normal pressure for 1 hour, then add the soaked millet, stir and mix and continue to steam for 0.5 hours, gently stir and cool to room temperature;

[0050] (2) Add 4g / kg of Angel Yeast Co., Ltd. sweet wine starter to the sweet mash raw material obtained in step (1) and cool it to room temperature, stir it evenly, and ferment it at 30℃ for 24h;

[0051] (3) After fermentation is complete, the mixture is stirred and then cooled and stored.

[0052] (4) Take another 90 portions of raw milk, preheat to 65°C, homogenize at 200 bar, and put the material into a temporary storage tank;

[0053] (5) Add 10 portions of the sweet mash obtained in step (3) to the material in the temporary storage tank in step (4), stir and mix well, sterilize at 95°C for 10 minutes, and cool to 42°C;

[0054] (6) Inoculate Streptococcus thermophilus subsp. and Lactobacillus bulgaricus subsp. fermentation agent into the yogurt base in step (5) at an inoculation rate of 100 U / t.

[0055] (7) Ferment at 42℃ until the endpoint (pH=4.5±0.2), turn the container over to cool, fill, and ripen to obtain stirred sweet fermented yogurt.

[0056] Example 2

[0057] A zero-additive sweet fermented yogurt and its preparation method, the raw materials for preparation include: (1) sweet fermented raw materials, all on a dry basis: 75 parts of oat rice, 25 parts of millet, 4.5 g / kg of sweet wine yeast; (2) yogurt raw materials: 88 parts of raw milk, 12 parts of sweet fermented yogurt, 150 U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deuterans subsp. bulgaricus fermentation agent.

[0058] Its preparation steps include:

[0059] (1) Remove the outer skin of oat rice, take 75 parts, wash and soak for 3 hours; take 25 parts of millet, wash and soak for 0.5 hours, add water to oat rice and cook at 95°C under normal pressure for 1.2 hours, then add the soaked millet, stir and mix and continue to cook for 0.5 hours, gently stir and cool to room temperature;

[0060] (2) Add 4.5g / kg of Angel Yeast Co., Ltd. sweet wine starter to the sweet mash raw material obtained in step (1) and cool it to room temperature, stir it evenly, and ferment it at 28℃ for 30h;

[0061] (3) After fermentation is complete, the mixture is stirred and then cooled and stored.

[0062] (4) Take another 88 portions of raw milk, preheat to 70°C, homogenize at 200 bar, and put the material into a temporary storage tank;

[0063] (5) Add 12 parts of sweet fermented mash to the material in the temporary storage tank in step (4), stir and mix well, sterilize at 90°C for 10 minutes, and cool to 42°C;

[0064] (6) Inoculate Streptococcus thermophilus subsp. and Lactobacillus bulgaricus subsp. Germania into the yogurt base at an inoculation rate of 150 U / t, and stir well;

[0065] (7) Fill the container and transfer it to a drying room at 42°C to ferment until the end point (pH = 4.5 ± 0.2). Cool and allow it to mature to obtain set-type sweet fermented yogurt.

[0066] Example 3

[0067] A zero-additive sweet fermented yogurt and its preparation method, the raw materials for preparation include: (1) sweet fermented raw materials, all on a dry basis: 65 parts of oat rice, 35 parts of millet, 5g / kg of sweet wine yeast; (2) yogurt raw materials: 80 parts of raw milk, 20 parts of sweet fermented yogurt, 100U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deuterans subsp. bulgaricus fermentation agent, and 50U / t of Bifidobacterium animalis subsp. lactis.

[0068] Its preparation steps include:

[0069] (1) Oat rice, remove the outer skin, take 65 parts, wash and soak for 2 hours; take 35 parts millet, wash and soak for 1.5 hours, add water to oat rice and cook at 100℃ under normal pressure for 1 hour, then add the soaked millet, stir and mix and continue to cook for 0.5 hours, gently stir and cool to room temperature;

[0070] (2) Add 5g / kg of Angel Yeast Co., Ltd. sweet wine starter to the sweet mash raw material obtained in step (1) and cool it to room temperature, stir it evenly, and ferment it at 25℃ for 36h;

[0071] (3) After fermentation is complete, the mixture is stirred and then cooled and stored.

[0072] (4) Take another 80 portions of raw milk, preheat to 65°C, homogenize at 220 bar, and put the material into a temporary storage tank;

[0073] (5) Add 20 parts of sweet fermented mash to the material in the temporary storage tank in step (4), stir and mix well, sterilize at 95°C for 8 minutes, and cool to 37°C;

[0074] (6) 100 U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus bulgaricus subsp. saliva, and 50 U / t of Bifidobacterium animalis subsp. lactis were inoculated into the yogurt substrate;

[0075] (7) Ferment at 37℃ until the endpoint (pH=4.5±0.2), turn the container over to cool, fill, and ripen to obtain stirred sweet fermented yogurt.

[0076] Comparative Example 1

[0077] Compared to Example 1, Comparative Example 1 changed the raw materials for preparing sweet fermented mash. Millet was not added in Comparative Example 1. The other processes for preparing sweet fermented mash yogurt were the same as in Example 1. The specific preparation process is as follows:

[0078] A zero-additive sweet fermented yogurt and its preparation method, the raw materials for preparation include: (1) sweet fermented raw materials, all on a dry basis: 100 parts of oat rice, 4g / kg of sweet wine yeast; (2) yogurt raw materials: 90 parts of raw milk, 10 parts of sweet fermented yogurt, fermented with 100U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deutgenae subsp. bulgaricus.

[0079] Its preparation steps include:

[0080] (1) Oat rice, remove the outer skin, take 100 portions, wash, soak for 2 hours, add water to oat rice and steam at 90℃ for 1.5 hours under normal pressure, and cool to room temperature;

[0081] (2) Add 4g / kg of Angel Yeast Co., Ltd. sweet wine starter to the sweet mash raw material obtained in step (1) and cool it to room temperature, stir it evenly, and ferment it at 30℃ for 24h;

[0082] (3) After fermentation is complete, the mixture is stirred and then cooled and stored.

[0083] (4) Take another 90 portions of raw milk, preheat to 65°C, homogenize at 200 bar, and put the material into a temporary storage tank;

[0084] (5) Add 10 parts of sweet fermented mash to the material in the temporary storage tank in step (4), stir and mix well, sterilize at 95°C for 10 minutes, and cool to 42°C;

[0085] (6) Inoculate the yogurt base with Streptococcus salivarius thermophilus subsp. and Lactobacillus deutzia subsp. bulgaricus starter at an inoculation rate of 100 U / t;

[0086] (7) Ferment at 42℃ until the endpoint (pH=4.5±0.2), turn the container over to cool, fill, and ripen to obtain stirred sweet fermented yogurt.

[0087] Comparative Example 2

[0088] Compared to Example 2, Comparative Example 2 changed the raw materials for preparing sweet fermented mash. Millet was not added in Comparative Example 2, but the other processes for preparing sweet fermented mash yogurt were the same as in Example 2. The specific preparation process is as follows:

[0089] A zero-additive sweet fermented yogurt and its preparation method, the raw materials for preparation include: (1) sweet fermented raw materials, all on a dry basis: 100 parts of oat rice, 4.5g / kg of sweet wine yeast; (2) yogurt raw materials: 88 parts of raw milk, 12 parts of sweet fermented yogurt, 150U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deutzia subsp. bulgaricus fermentation agent.

[0090] Its preparation steps include:

[0091] (1) Oat rice, remove the outer skin, take 100 portions, wash, soak for 3 hours, add water to oat rice and steam at 95℃ for 1.7 hours under normal pressure, and cool to room temperature;

[0092] (2) Add 0.03 parts of Angel Yeast Co., Ltd. sweet wine yeast to the sweet mash raw material obtained in step (1) and cool it to room temperature, stir it evenly, and ferment it at 28°C for 30 hours;

[0093] (3) After fermentation is complete, the mixture is stirred and then cooled and stored.

[0094] (4) Take another 88 portions of raw milk, preheat to 70°C, homogenize at 200 bar, and put the material into a temporary storage tank;

[0095] (5) Add 12 parts of sweet fermented mash to the material in the temporary storage tank in step (4), stir and mix well, sterilize at 90°C for 10 minutes, and cool to 42°C;

[0096] (6) Inoculate Streptococcus thermophilus subsp. and Lactobacillus bulgaricus subsp. Germania into the yogurt base at an inoculation rate of 150 U / t, and stir well;

[0097] (7) Fill the container and transfer it to a drying room at 42°C to ferment until the end point (pH = 4.5 ± 0.2). Cool and allow it to mature to obtain set-type sweet fermented yogurt.

[0098] Comparative Example 3

[0099] In the preparation of sweet fermented yogurt in Comparative Example 3, the sweet fermented yogurt was not fermented. Instead, the raw materials of the sweet fermented yogurt were mixed with the yogurt and fermented once. The specific operation is as follows.

[0100] A zero-additive sweetened mashed yogurt and its preparation method, the raw materials for preparation include: (1) sweetened mashed raw materials, all on a dry basis: 65 parts of oat rice and 35 parts of millet; (2) yogurt raw materials: 80 parts of raw milk, 20 parts of sweetened mashed mashed, 100 U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deuterans subsp. bulgaricus starter culture, and 50 U / t of Bifidobacterium animalis subsp. lactis.

[0101] Its preparation steps include:

[0102] (1) Oat rice, remove the outer skin, take 65 parts, wash and soak for 2 hours; take 35 parts white millet, wash and soak for 1.5 hours, add water to oat rice and steam at 100℃ under normal pressure for 1 hour, then add the soaked millet, stir and mix and continue to steam for 0.5 hours, gently stir and cool to room temperature;

[0103] (2) Refrigerate.

[0104] (3) Take another 80 portions of raw milk, preheat to 65°C, homogenize at 220 bar, and put the material into a temporary storage tank;

[0105] (4) Add 20 portions of the unfermented sweet mash raw material obtained in step (2) to the material in the temporary storage tank in step (4), stir and mix well, sterilize at 95°C for 8 minutes, and cool to 37°C;

[0106] (6) 100 U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus bulgaricus subsp. saliva, and 50 U / t of Bifidobacterium animalis subsp. lactis were inoculated into the yogurt substrate;

[0107] (7) Ferment at 37℃ until the endpoint (pH=4.5±0.2), turn the container over to cool, fill, and ripen to obtain stirred sweet fermented yogurt.

[0108] Comparative Example 4

[0109] Comparative Example 4 differs from Example 1 in the way the sweetened mash and yogurt are added. The sweetened mash undergoes only one fermentation, and the yogurt is physically mixed with it. The specific operation is as follows:

[0110] A zero-additive sweet fermented yogurt and its preparation method, the raw materials for preparation include: (1) sweet fermented raw materials, all on a dry basis: 70 parts of oat rice, 30 parts of millet, 4g / kg of sweet wine yeast; (2) yogurt raw materials: 90 parts of raw milk, 10 parts of sweet fermented yogurt, 100U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deutzia subsp. bulgaricus fermentation agent.

[0111] Its preparation steps include:

[0112] (1) Remove the outer skin of oat rice, take 70 parts, wash and soak for 2 hours; take 30 parts of millet, wash and soak for 1 hour, add water to oat rice and steam at 90°C under normal pressure for 1 hour, then add the soaked millet, stir and mix and continue to steam for 0.5 hours, gently stir and cool to room temperature;

[0113] (2) Add 4g / kg of Angel Yeast Co., Ltd. sweet wine starter to the sweet mash raw material obtained in step (1) and cool it to room temperature, stir it evenly, and ferment it at 30℃ for 24h;

[0114] (3) After fermentation is complete, the mixture is stirred and then cooled and stored.

[0115] (4) Take another 90 portions of raw milk, preheat to 65°C, homogenize at 200 bar, and put the material into a temporary storage tank;

[0116] (5) The material in the temporary storage tank of step (4) is sterilized at 95°C for 10 minutes and then cooled to 42°C;

[0117] (6) Inoculate the yogurt base with Streptococcus salivarius thermophilus subsp. and Lactobacillus deutzia subsp. bulgaricus starter at an inoculation rate of 100 U / t;

[0118] (7) Ferment at 42℃ until the endpoint (pH=4.5±0.2), turn the container over to cool, add 10 portions of the sweet fermented mash obtained in step (3), stir evenly, fill, and ripen to obtain stirred sweet fermented mash yogurt.

[0119] Comparative Example 5

[0120] Comparative Example 5 differs from Example 1 in that the proportion of millet added is changed, but everything else is the same as in Example 1. The specific operation is as follows:

[0121] A zero-additive sweet fermented yogurt and its preparation method, the raw materials for preparation include: (1) sweet fermented raw materials, all on a dry basis: 50 parts of oat rice, 50 parts of millet, 4g / kg of sweet wine yeast; (2) yogurt raw materials: 90 parts of raw milk, 10 parts of sweet fermented yogurt, 100U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deutzia subsp. bulgaricus fermentation agent.

[0122] Its preparation steps include:

[0123] (1) Remove the outer skin of oat rice, take 50 portions, wash and soak for 2 hours; take 50 portions of millet, wash and soak for 1 hour, add water to oat rice and steam at 90°C under normal pressure for 1 hour, then add the soaked millet, stir and mix and continue to steam for 0.5 hours, gently stir and cool to room temperature;

[0124] (2) Add 4g / kg of Angel Yeast Co., Ltd. sweet wine starter to the sweet mash raw material obtained in step (1) and cool it to room temperature, stir it evenly, and ferment it at 30℃ for 24h;

[0125] (3) After fermentation is complete, the mixture is stirred and then cooled and stored.

[0126] (4) Take another 90 portions of raw milk, preheat to 65°C, homogenize at 200 bar, and put the material into a temporary storage tank;

[0127] (5) Add 10 portions of the sweet mash obtained in step (3) to the material in the temporary storage tank in step (4), stir and mix well, sterilize at 95°C for 10 minutes, and cool to 42°C;

[0128] (6) Inoculate the yogurt base with Streptococcus salivarius thermophilus subsp. and Lactobacillus deutzia subsp. bulgaricus starter at an inoculation rate of 100 U / t;

[0129] (7) Ferment at 42℃ until the endpoint (pH=4.5±0.2), turn the container over to cool, fill, and ripen to obtain stirred sweet fermented yogurt.

[0130] Comparative Example 6

[0131] Comparative Example 6 differs from Example 1 in the proportion of millet added, but otherwise remains the same as Example 1. The specific operation is as follows:

[0132] A zero-additive sweet fermented yogurt and its preparation method, the raw materials for preparation include: (1) sweet fermented raw materials, all on a dry basis: 80 parts of oat rice, 20 parts of millet, 4g / kg of sweet wine yeast; (2) yogurt raw materials: 90 parts of raw milk, 10 parts of sweet fermented yogurt, 100U / t of Streptococcus salivarius thermophilus subsp. and Lactobacillus deuterans subsp. bulgaricus fermentation agent.

[0133] Its preparation steps include:

[0134] (1) Take 80 parts of oat rice, remove the outer skin, wash and soak for 2 hours; take 20 parts of millet, wash and soak for 1 hour, add water to oat rice and steam at 90°C under normal pressure for 1 hour, then add the soaked millet, stir and mix and continue to steam for 0.5 hours, stir gently and cool to room temperature.

[0135] (2) Add 4g / kg of Angel Yeast Co., Ltd. sweet wine starter to the sweet mash raw material obtained in step (1) and cool it to room temperature, stir it evenly, and ferment it at 30℃ for 24h;

[0136] (3) After fermentation is complete, the mixture is stirred and then cooled and stored.

[0137] (4) Take another 90 portions of raw milk, preheat to 65°C, homogenize at 200 bar, and put the material into a temporary storage tank;

[0138] (5) Add 10 portions of the sweet mash obtained in step (3) to the material in the temporary storage tank in step (4), stir and mix well, sterilize at 95°C for 10 minutes, and cool to 42°C;

[0139] (6) Inoculate the yogurt base with Streptococcus salivarius thermophilus subsp. and Lactobacillus deutzia subsp. bulgaricus starter at an inoculation rate of 100 U / t;

[0140] (7) Ferment at 42℃ until the endpoint (pH=4.5±0.2), turn the container over to cool, fill, and ripen to obtain stirred sweet fermented yogurt.

[0141] Experiment 1

[0142] Fermentation time, viable count, and sensory evaluation were recorded for the sweet fermented yogurts prepared in Examples 1-3 and Comparative Examples 1-6. The results are shown in Table 1. The sweet fermented yogurts prepared by the dual fermentation process have a full aroma and stable texture.

[0143] The detection of viable bacteria count should refer to GB 4789.35 "National Food Safety Standard - Microbiological Examination of Food - Lactic Acid Bacteria Examination".

[0144] Ten professional yogurt R&D engineers evaluated the yogurts from the examples and comparative samples, referring to RHB 104 "Sensory Evaluation Guidelines for Fermented Milk".

[0145] Experiment 2

[0146] The reducing sugar content and β-glucan content of the sweet mash used in Examples 1-3 and Comparative Examples 1-6 were determined, and the results are shown in Table 2.

[0147] The reducing sugar content is determined by direct determination according to GB 5009.7 "National Food Safety Standard: Determination of Reducing Sugars in Food".

[0148] The β-glucan content was determined according to the method in NY / T 2006 "Determination of β-glucan content in cereals and their products".

[0149] Table 1

[0150]

[0151]

[0152] Table 2

[0153] Example 1 38.2±0.2 16.4±0.6 Example 2 38.5±0.4 19.1±0.3 Example 3 33.6±0.5 15.8±0.2 Comparative Example 1 33.5±0.4 19.5±0.2 Comparative Example 2 35.8±0.4 19.6±0.3 Comparative Example 3 3.5±0.1 15.8±0.4 Comparative Example 4 38.2±0.2 16.4±0.6 Comparative Example 5 28.9±0.5 14.6±0.3 Comparative Example 6 39.2±0.7 19.2±0.3

[0154] As can be seen from the test data in Tables 1 and 2, this invention uses oat rice and millet as raw materials for sweet fermentation, and controls the proportion of these materials. The sweet fermentation is then carried out with raw milk in a secondary fermentation process. On the one hand, it contains no food stabilizing additives, fully utilizing the interaction of the raw materials and processing technology to form a stable system, achieving stable shelf-life texture and clean labeling. On the other hand, the yogurt does not require the addition of white sugar or artificial sweeteners to neutralize the acidity. The prepared yogurt breaks through the traditional post-fermentation process of grain yogurt, employing a double fermentation process. Its texture and structure are excellent, and its taste and flavor are rich and full-bodied, indicating a promising market prospect.

[0155] Meanwhile, the sweet fermented mash prepared by this invention has higher nutritional value and a more pleasant taste. The fermented oats and millet contain increased levels of organic acids, free amino acids, and unsaturated fatty acids such as linoleic acid and oleic acid. The reducing sugar content, especially glucose, is 25–40 g / 100 g, and the β-glucan content is 15–20 g / 100 g.

[0156] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing zero-added sweetened yogurt, characterized in that, Sweet mash is prepared by fermentation of oat rice and millet, with a weight ratio of millet to oat rice of 1:1.5 to 3. The sweet mash contains 25 to 40 g of glucose and 15 to 20 g of β-glucan. Includes the following steps: Step 1: Homogenize the raw milk; Step 2: Add sweetened mash to the homogenized raw milk from Step 1 and stir. Step 3: Sterilize and cool the material obtained in Step 2; Step 4: Add lactic acid bacteria starter to the material obtained in Step 3, mix well, and carry out fermentation to obtain sweet fermented yogurt; The weight ratio of raw milk to sweetened mash is 80-90:10-20.

2. The method for preparing zero-added sweetened yogurt according to claim 1, characterized in that, The weight ratio of millet to oat rice is 1:2 to 3.

3. The method for preparing zero-added sweetened yogurt according to claim 1, characterized in that, Sweet fermented mash is prepared using the following steps: S1. Soak the oat groats and millet. S2. Steam the oat rice, then add millet and mix well, steam again, and cool to room temperature; S3. Add sweet wine yeast to the mixture after cooking in S2, stir well, and carry out fermentation to obtain sweet mash.

4. The method for preparing zero-added sweetened yogurt according to claim 3, characterized in that, In step S2, the cooking temperature is 80–100°C; and / or the cooking time is 1.5–3 hours.

5. The method for preparing zero-added sweetened yogurt according to claim 4, characterized in that, In step S3, the fermentation temperature is 25–30°C; and / or the fermentation time is 24–36 h.

6. The method for preparing zero-added sweetened yogurt according to claim 1, characterized in that, In step 3, the sterilization temperature is 90~95℃ and the sterilization time is 5~10min.

7. The method for preparing zero-added sweetened yogurt according to claim 1, characterized in that, In step 4, the fermentation temperature is 37–42℃, and the final pH value is 4.5 ± 0.

2.

8. According to claim 1 7. The method for preparing zero-added sweetened yogurt according to any one of the claims, characterized in that, In step 4, the fermented yogurt is cooled by turning it over, then filled into containers and allowed to mature further to obtain stirred sweet fermented yogurt.

9. According to claim 1 7. The method for preparing zero-added sweetened yogurt according to any one of the claims, characterized in that, In step 4, lactic acid bacteria starter is added to the material obtained in step 3, mixed evenly, filled into containers, and transferred to a drying room for fermentation. Processing, cooling, and post-ripening yields set-type sweet fermented yogurt.

10. A device as claimed in claim 1 Sweetened yogurt prepared by any one of the following methods: 9.

Images