Kudzuvine root fermented milk and preparation method thereof

Abstract

The invention discloses radix puerariae fermented milk and a preparation method thereof. The method comprises the following specific operation steps: (1) pretreatment of radix puerariae; (2) extruding and puffing the radix puerariae; (3) carrying out superfine grinding on the radix puerariae; (4) blending; (5) filling and sterilizing; and (6) inoculating and fermenting. The radix puerariae is used as a main raw material, the radix puerariae is subjected to an extrusion puffing technology and superfine grinding, obtained radix puerariae powder is mixed and blended with white granulated sugar and milk powder, then mixed bacterial powder is added for fermentation, and the radix puerariae fermented milk is prepared. The prepared fermented milk is good in taste and rich in nutrition, not only can provide sufficient nutritional ingredients such as protein and vitamins, but also can provide various bioactive ingredients for a human body, and has the effects of resolving muscles and abating fever, helping produce saliva and slake thirst, raising yang and stopping diarrhea, clearing and activating the channels and collaterals and the like. Meanwhile, raw materials are wide in source and low in industrial production cost. The preparation of the radix puerariae fermented milk widens the application range of radix puerariae.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to kudzu root fermented milk and a preparation method thereof. Background Art

[0002] Fermented milk is a sweet and sour dairy product made from raw milk through high-temperature sterilization, inoculation, and constant-temperature fermentation. In China, fermented milk is popular among consumers and is one of the best-selling liquid dairy products in my country except for pasteurized milk.

[0003] Pueraria root is the root of the leguminous plant Pueraria or Pueraria lobata, which is mainly distributed in Asia and America. It is widely distributed in my country, with the most concentrated distribution in Guizhou, Yunnan, Guangdong, Guangxi, Hunan, Hubei, Jiangxi and Anhui. Pueraria root contains nutrients such as starch, dietary fiber, protein, vitamins and minerals. In addition, Pueraria root also contains many active ingredients, such as isoflavones, puerarin, saponins and polysaccharides. Pharmacological studies have shown that Pueraria root has many health benefits such as antioxidant, anti-inflammatory, hypoglycemic, weight loss, blood pressure reduction, alcohol detoxification and liver protection. In food processing, as a traditional Chinese food and herb, Pueraria root is usually used in fresh food, stir-fry, soup and tea. In recent years, Pueraria root series products have been developed at home and abroad due to their rich nutrients such as starch, isoflavones and dietary fiber.

[0004] Extrusion has been used for many years to manufacture a variety of foods, food ingredients and feeds, with the advantages of continuous operation, high productivity, high capacity, no wastewater generation, low cost and automated control. The extrusion process may cause changes in chemical and nutritional composition, including starch gelatinization and degradation, protein denaturation, lipid oxidation, vitamin degradation, anti-nutritional and phytochemical degradation, flavor formation, mineral bioavailability and dietary fiber solubility increase; extrusion also helps to change the material structure, improve solubility, expansion power, hydration properties and water holding capacity.

[0005] Micronizing is a useful tool for making ultrafine powders and has been successfully used to make powdered foods such as tea, ginger, and beet pulp powder. Studies have shown that micronizing may affect the functional properties, nutritional quality, biological activity, and product quality of powders. Micronizing can reduce the size of powder particles and change surface properties, and can degrade the tissue of plant materials, causing cell wall rupture, thereby changing their properties and promoting the release of nutrients.

[0006] In order to improve the utilization rate of Pueraria root and increase its added value, the present invention uses extrusion puffing technology and ultrafine grinding technology to mix Pueraria root powder with white sugar and milk powder, and then add mixed bacterial powder for fermentation to make Pueraria root fermented milk. The present invention can not only provide sufficient nutrients such as protein and vitamins, but also provide a variety of biologically active ingredients for the human body, and has the effects of relieving muscle and fever, promoting body fluid and quenching thirst, raising yang and stopping diarrhea, and promoting blood circulation. Summary of the invention

[0007] To achieve the above object and other related objects, the present invention provides a kudzu root fermented milk and a preparation method thereof.

[0008] To achieve the above purpose and other related purposes, the technical solution provided by the present invention is: a kudzu root fermented milk, the raw material formula of the kudzu root fermented milk includes the following raw materials in percentage by mass: 3-5% puffed kudzu root powder, 5-9% white sugar, 5-9% milk powder, and 0.15-0.25% mixed bacterial powder.

[0009] To achieve the above-mentioned purpose and other related purposes, the technical solution provided by the present invention is: a method for preparing Pueraria fermented milk, comprising the following steps:

[0010] Step 1: Pueraria root pretreatment

[0011] Rinse the kudzu root with clean water, dry until the moisture content is less than or equal to 5%, and grind to obtain kudzu root powder;

[0012] Step 2: Extrusion and expansion of Pueraria root

[0013] Extruding and puffing the kudzu root powder;

[0014] Step 3: Ultrafine grinding of Pueraria root

[0015] The expanded kudzu root powder is taken out, first crushed to an average particle size of 20-60 mesh, and then crushed to an average particle size of 200-400 mesh using a vibrating superfine grinder to obtain expanded kudzu root powder;

[0016] Step 4: Deployment

[0017] 3-5% puffed kudzu root powder, 5-9% white sugar, 5-9% milk powder;

[0018] Step 5: Filling and sterilization

[0019] After the materials in step 4 are prepared, they are put into glass beverage bottles and sterilized at 90-98° C. for 20-40 minutes to obtain fermentation raw materials;

[0020] Step 6: Inoculation and fermentation

[0021] The fermentation raw material is cooled to 40-44°C, mixed with fermentation bacterial powder, and fermented at 435-45°C for 7-8h to obtain Pueraria fermented milk.

[0022] The preferred technical solution is: in step 1, the drying temperature is 80-120°C.

[0023] The preferred technical solution is: in step 2, the process parameters are: controlling the moisture content at 17-21%, the screw speed at 100-150r / min, the extrusion temperature at 160-180°C, and the feed rate at 12-16kg / h.

[0024] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0025] (1) Enriched the development and application of Pueraria products

[0026] For a long time, kudzu root has been mainly used to produce kudzu root powder, which has low added value and few deep-processed products. The present invention uses kudzu root and other plant raw materials to make kudzu root fermented milk, which fills the gap of its deep-processed products and provides consumers with a convenient, fast, healthy and delicious beverage choice.

[0027] (2) Unique taste

[0028] Pueraria root has a unique fragrance, which combines with the sweet and sour taste of fermented milk to produce a novel and pleasant taste experience. This unique flavor is highly recognizable and attractive in the market.

[0029] (3) Nutritional complementation

[0030] Fermented milk is rich in beneficial ingredients such as lactic acid bacteria and active peptides, which interact with nutrients such as isoflavones in Pueraria to produce more bioactive substances and have a more comprehensive promoting effect on human health. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a process flow chart of the present invention.

[0032] Figure 2 The effect of bacterial strain ratio on the acidity, pH and sensory quality of fermented milk.

[0033] Figure 3 This is the effect of the inoculum size on the acidity, pH and sensory quality of fermented milk.

[0034] Figure 4 To study the effect of kudzu root powder addition on the acidity, pH and sensory quality of fermented milk.

[0035] Figure 5 To study the effect of the amount of white sugar added on the acidity, pH and sensory quality of fermented milk. DETAILED DESCRIPTION

[0036] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in the embodiments.

[0037] See also Figure 1-5 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance, and any structural modification, change in proportional relationship or adjustment of size. The following examples are provided to better understand the present invention, but are not intended to limit the present invention. The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all purchased from conventional biochemical reagent stores unless otherwise specified.

[0038] (1) Single factor test of bacterial species ratio

[0039] Taking pH, acidity and sensory quality as evaluation indicators, the fixed strain inoculation amount was 0.1% (m / v), the addition amount of puffed kudzu root powder was 2%, the addition amount of white sugar was 7%, and the addition amount of milk powder was 7%. The effect of different strain ratios (Streptococcus thermophilus: Lactobacillus bulgaricus: Lactobacillus plantarum = 1:1:1, 1:1:2, 1:1:3, 1:2:1, 1:3:1, 2:1:1, 3:1:1) on the quality of fermented milk was explored.

[0040] (2) Single factor test of bacterial inoculation volume

[0041] Taking pH, acidity and sensory quality as evaluation indicators, the ratio of different bacterial species was fixed at Streptococcus thermophilus: Lactobacillus bulgaricus: Lactobacillus plantarum = 1:2:1, the addition amount of puffed Pueraria powder was 2%, the addition amount of white sugar was 7%, and the addition amount of milk powder was 7%. The effect of different bacterial species inoculation amounts (0.05, 0.10, 0.15, 0.20 and 0.25%) on the quality of fermented milk was explored.

[0042] (3) Single factor test of kudzu root addition

[0043] Taking pH, acidity and sensory quality as evaluation indicators, the ratio of different bacterial strains was fixed at Streptococcus thermophilus: Lactobacillus bulgaricus: Lactobacillus plantarum = 1:2:1, the bacterial inoculation amount was 0.1% (m / v), and the milk powder addition amount was 7%. The effect of different addition amounts of puffed Pueraria powder (1, 2, 3, 4 and 5%) on the quality of fermented milk was explored.

[0044] (4) Single factor test of white sugar addition

[0045] Taking pH, acidity and sensory quality as evaluation indicators, the ratio of different bacterial strains was fixed at 1:2:1:Streptococcus thermophilus:Lactobacillus bulgaricus:Lactobacillus plantarum, the inoculum amount was 0.1% (m / v), the addition amount of puffed kudzu root powder was 2%, and the addition amount of milk powder was 7%. The effect of different amounts of white sugar added (5, 6, 7, 8 and 9%) on the quality of fermented milk was explored.

[0046] (5) Sensory evaluation of Pueraria lobata fermented milk

[0047] The sensory evaluation of Pueraria fermented milk was conducted by a well-trained sensory evaluation panel consisting of 10 members aged 20-30 (5 females and 5 males), all of whom were familiar with the evaluation of fermented milk products and had sensory evaluation experience. The experiment was conducted in a sensory laboratory that meets ISO international standards, and the fermented milk was evaluated in four aspects: color, smell, texture and taste, and scored using a 100-point system.

[0048] Example 1: Pueraria lobata fermented milk and preparation method thereof

[0049] The specific operation steps of a method for preparing Pueraria fermented milk are as follows:

[0050] (1) Pretreatment of kudzu root: Select kudzu root without pests and mildew, rinse with clean water, remove dust and other impurities, and place in a constant temperature drying oven (80°C) until the moisture content is ≤5%, and grind with a traditional Chinese medicine grinder to an average particle size of 20 mesh.

[0051] (2) Extrusion puffing of kudzu root: Weigh the crushed kudzu root, control the water content at 17%, the screw speed at 100 r / min, the extrusion temperature at 160°C, and the feed rate at 12 kg / h;

[0052] (3) Ultrafine grinding of Pueraria root: Take out the expanded Pueraria root, first grind it with a traditional Chinese medicine grinder until the average particle size of the material is 20 mesh, and then grind it with a vibrating ultrafine grinder until the average particle size of the material is 200 mesh.

[0053] (4) Preparation: 3% puffed kudzu root powder, 5% white sugar, 5% milk powder, and 0.15% mixed bacterial powder.

[0054] (5) Filling and sterilization: After the above materials are prepared, they are placed in glass beverage bottles and sterilized at 95°C for 20 minutes. Then, they are cooled to room temperature to obtain the sterilized materials.

[0055] (6) Inoculation and fermentation: Take out the sterilized material, cool it to 40°C, and inoculate mixed fermentation bacteria powder (Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum). Seal the mixture and put it in an oven at 41°C for 7 hours.

[0056] Example 2: Pueraria lobata fermented milk and preparation method thereof

[0057] (1) Pretreatment of kudzu root: Select kudzu root without pests and mildew, rinse with clean water, remove dust and other impurities, and place in a constant temperature drying oven (100°C) until the moisture content is ≤5%, and grind with a traditional Chinese medicine grinder to an average particle size of 40 mesh.

[0058] (2) Extrusion puffing of kudzu root: Weigh the crushed kudzu root, control the water content at 19%, the screw speed at 125 r / min, the extrusion temperature at 170°C, and the feed rate at 14 kg / h;

[0059] (3) Ultrafine grinding of Pueraria root: Take out the expanded Pueraria root, first grind it with a traditional Chinese medicine grinder until the average particle size of the material is 40 mesh, and then grind it with a vibrating ultrafine grinder until the average particle size of the material is 300 mesh.

[0060] (4) Preparation: 4% puffed kudzu root powder, 7% white sugar, 7% milk powder, and 0.20% mixed bacterial powder.

[0061] (5) Filling and sterilization: After the above materials are prepared, they are placed in glass beverage bottles and sterilized at 95°C for 30 minutes. Then, they are cooled to room temperature to obtain the sterilized materials.

[0062] (6) Inoculation and fermentation: Take out the sterilized material, cool it to 42°C, and inoculate mixed fermentation bacteria powder (Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum). Seal the mixture and put it in an oven at 41°C for fermentation for 7.5 hours.

[0063] Example 3: Pueraria fermented milk and preparation method thereof

[0064] (1) Pretreatment of kudzu root: Select kudzu root without pests and mildew, rinse with clean water, remove dust and other impurities, and place in a constant temperature drying oven (120°C) until the moisture content is ≤5%, and grind with a traditional Chinese medicine grinder to an average particle size of 60 mesh.

[0065] (2) Extrusion puffing of kudzu root: Weigh the crushed kudzu root, control the moisture content to 17-21%, the screw speed to 150 r / min, the extrusion puffing temperature to 180°C, and the feed rate to 16 kg / h;

[0066] (3) Ultrafine grinding of Pueraria root: Take out the expanded Pueraria root, first grind it with a traditional Chinese medicine grinder until the average particle size of the material is 20-60 mesh, and then grind it with a vibrating ultrafine grinder until the average particle size of the material is 400 mesh.

[0067] (4) Preparation: 5% puffed kudzu root powder, 9% white sugar, 9% milk powder, and 0.30% mixed bacterial powder.

[0068] (5) Filling and sterilization: After the above materials are prepared, they are filled into glass beverage bottles and sterilized at 95° C. for 40 minutes. Then, the fermented milk is cooled to room temperature to obtain Pueraria fermented milk.

[0069] (6) Inoculation and fermentation: Take out the sterilized fermented milk, cool it to 44°C, and inoculate mixed fermentation bacteria powder (Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum). Seal the mixture and put it in an oven at 41°C for fermentation for 8 hours.

[0070] Experimental example

[0071] like Figure 2 As shown in the figure, when the bacterial ratio is 3:1:1, the fermented milk has the lowest pH (4.25) and the highest acidity (86°T); when the bacterial ratio is 1:3:1, the fermented milk has the highest pH (4.49) and the lowest acidity (79.9°T). Overall, as the proportion of cocci decreases, the acidity of Pueraria fermented milk decreases and the pH increases. Both too high and too low ratios of bacilli to cocci will affect the quality of fermented milk. Figure 2 It can be seen from Figure B that the sensory quality score of Pueraria lobata fermented milk is the highest (83.6 points) when the strain ratio is 3:1:1, and the sensory quality score is the lowest (79.6 points) when the ratio is 1:3:1. In summary, the fermented milk has the best quality when the strain ratio is 3:1:1.

[0072] like Figure 3 As shown in the figure, the final pH of fermented milk decreases with the increase of bacterial inoculation amount, and the acidity increases sharply first and then increases slowly. The sensory quality score of fermented milk is the highest (85.0 points) when the inoculation amount is 0.15%. When the inoculation amount is low, there are fewer lactic acid bacteria in Pueraria fermented milk, the acid production capacity is weak, the substrate is not fully utilized, and the fermented milk texture is uneven. When the inoculation amount is too large, more whey is precipitated, which may be due to the excessive fermentation of the fermented milk by lactic acid bacteria. When the inoculation amount is 0.15%, the fermented milk has a unique aroma of Pueraria and less whey precipitation. At this time, the quality of Pueraria fermented milk is the best.

[0073] like Figure 4 As shown in the figure, with the increase of the amount of kudzu powder added, the acidity of the fermented milk gradually increased, reaching the maximum value (82.6°T) when the addition amount was 5%, and the pH decreased from 4.7 at the beginning to 4.53. The sensory quality score of the fermented milk first increased, reaching the highest value (84.6 points) when the addition amount of kudzu powder was 4%, and then the sensory quality decreased. During the fermentation process, Lactobacillus bulgaricus, Lactobacillus thermophilus and Lactobacillus plantarum proliferated rapidly, converting lactose into lactic acid, resulting in a decrease in pH. The reason for the decrease in pH after adding kudzu powder may be that the polysaccharides in kudzu enhance the activity of lactic acid bacteria and make the fermentation more thorough. The addition of kudzu powder can make the fermented milk have a unique kudzu flavor. When too much kudzu powder is added, the astringency of the fermented milk increases, affecting the final sensory quality.

[0074] like Figure 5As shown in the figure, when the amount of white sugar added is 5-8%, the pH of fermented milk decreases, and the lowest value is 4.62 when the addition amount is 8%, and then the pH increases; the acidity first increases rapidly, reaches the highest point (82.3°T) at the addition amount of 8%, and then the acidity decreases. The sensory quality of fermented milk increases slowly when the amount of white sugar added is 5-7%, reaches the highest value (83.6 points) at the addition amount of 7%, and decreases when the sensory quality is greater than 7%. This phenomenon is explained as follows: the addition of white sugar promotes the growth of lactic acid bacteria, the fermentation is more thorough, the pH decreases, and the acidity increases; however, when the amount of white sugar added is too much, it will lead to an increase in osmotic pressure, which will inhibit the growth of lactic acid bacteria, and the excessive addition of white sugar makes the fermented milk too sweet and greasy, affecting the sensory quality.

[0075] As shown in Table 1, based on the single factor experiment, sensory quality was used as an indicator to conduct L 9 (3 4 ) orthogonal test to determine the best formula of Pueraria lobata fermented milk. From the range analysis in Table 1, it can be seen that the order of influence of each factor on sensory quality is: C>A>B>D. The main factor affecting the quality of fermented milk is C (the amount of Pueraria lobata powder added), followed by A (the proportion of bacteria). Combining the k value and R value, as well as intuitive comparison, the optimal combination is A 1 B 3 C 2 D 1 , but this combination did not appear in any of the 9 test numbers. The highest sensory score in the 9 test numbers was A 3 B 3 C 2 D 1 , so for A 1 B 3 C 2 D 1 and A 3 B 3 C 2 D 1 2 groups conducted verification tests and obtained A 1 B 3 C 2 D 1 The sensory quality score is 84.62, A 3 B 3 C 2 D 1 The sensory quality score is 83.73, A 1 B 3 C 2 D 1 Sensory score higher than A 3 B 3 C 2 D 1 , so determine A 1 B 3 C2 D 1 The best formula combination is that the ratio of bacteria is thermophilic streptococcus: bulgaricus lactobacillus: plantarum lactobacillus = 1:1:1, the inoculation amount is 0.25%, the addition amount of kudzu root powder is 4%, and the addition amount of white sugar is 7%.

[0076]

[0077] The above description is only used to explain the preferred embodiments of the present invention, and is not intended to limit the present invention in any form. Therefore, any modifications or changes made to the present invention under the same inventive spirit should still be included in the scope of protection intended by the present invention.

Claims

1. A kudzu root fermented milk, characterized in that: The raw material formula of the Pueraria root fermented milk comprises the following raw materials in percentage by weight: 3-5% of puffed Pueraria root powder, 5-9% of white sugar, 5-9% of milk powder and 0.15-0.25% of mixed bacterial powder.

2. A method for preparing Pueraria fermented milk, characterized in that: The following steps are involved: Step 1: Pueraria root pretreatment Rinse the kudzu root with clean water, dry until the moisture content is less than or equal to 5%, and grind to obtain kudzu root powder; Step 2: Extrusion and expansion of Pueraria root Extruding and puffing the kudzu root powder; Step 3: Ultrafine grinding of Pueraria root The expanded kudzu root powder is taken out, first crushed to an average particle size of 20-60 mesh, and then crushed to an average particle size of 200-400 mesh using a vibrating superfine grinder to obtain expanded kudzu root powder; Step 4: Deployment 3-5% puffed kudzu root powder, 5-9% white sugar, 5-9% milk powder; Step 5: Filling and sterilization After the materials in step 4 are prepared, they are put into glass beverage bottles and sterilized at 90-98° C. for 20-40 minutes to obtain fermentation raw materials; Step 6: Inoculation and fermentation The fermentation raw material is cooled to 40-44°C, mixed with fermentation bacterial powder, and fermented at 435-45°C for 7-8h to obtain Pueraria fermented milk.

3. The method for preparing Pueraria fermented milk according to claim 2, characterized in that: In step 1, the drying temperature is 80-120°C.

4. The method for preparing Pueraria fermented milk according to claim 2, characterized in that: In step 2, the process parameters are: controlling the moisture content at 17-21%, the screw speed at 100-150 r / min, the extrusion temperature at 160-180° C., and the feed rate at 12-16 kg / h.

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