Fermented milk containing prebiotics and preparation method thereof

Abstract

The invention provides fermented milk containing prebiotics and a preparation method of the fermented milk. On one hand, the invention provides the fermented milk containing the prebiotics. The raw materials for preparing the fermented milk containing the prebiotics comprise a milk-based raw material, probiotics and the prebiotics; the prebiotics comprise galactooligosaccharide, fructo-oligosaccharide and isomalto-oligosaccharide, the mass of the galactooligosaccharide is 40%-50% of the total mass of the prebiotics, the mass of the fructo-oligosaccharide is 30%-40% of the total mass of the prebiotics, and the mass of the isomalto-oligosaccharide is 10%-30% of the total mass of the prebiotics; the prebiotics are added after the fermentation of the milk-based raw materials is completed. The fermented milk containing prebiotics provided by the invention has the characteristics of high viable count and good stability during storage.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to fermented milk containing prebiotics and a preparation method thereof. Background Art

[0002] Prebiotics are a dietary supplement that is not easily digested and absorbed by the human body, but can serve as a nutrient source for beneficial bacteria in the body. Beneficial bacteria in the intestines can decompose, digest and absorb them, promoting their own growth and reproduction. Prebiotics and probiotics can regulate the balance of intestinal microecology and improve the body's immune function. The mass consumer demand for related food products is increasing year by year.

[0003] At present, fermented milk is considered to be the most effective carrier for transporting prebiotics and probiotics into the body. After adding prebiotics and probiotics, the health benefits of prebiotics and probiotics can be perfectly combined with the health benefits of fermented milk. Fermented milk is nutritious and unique in flavor. It is easier to be absorbed and utilized by the human body than cow's milk. Fermented milk has many effects on the human body, such as inhibiting the growth and reproduction of putrefactive bacteria in the intestines, and preventing and treating constipation and bacterial diarrhea; the organic acids produced in fermented milk can promote gastrointestinal motility and gastric juice secretion. Patients with gastric acid deficiency can drink fermented milk in moderation every day to restore their health; it can overcome lactose intolerance, etc.

[0004] However, the existing fermented milk containing prebiotics has problems such as low viable probiotic count and poor stability during storage. Therefore, how to obtain fermented milk containing prebiotics with high viable count and good stability is the focus of technical personnel in this field. Summary of the invention

[0005] The invention provides a fermented milk containing prebiotics, and solves the problem of low viable bacteria count and poor stability of the fermented milk containing prebiotics during storage by optimizing the type and addition amount of the prebiotics and the adding process of the prebiotics.

[0006] The present invention also provides a method for preparing the fermented milk containing prebiotics.

[0007] The present invention provides a fermented milk containing prebiotics, and the raw materials for preparing the fermented milk containing prebiotics include milk-based raw materials, probiotics and prebiotics;

[0008] The prebiotics include galacto-oligosaccharides, fructo-oligosaccharides and isomalto-oligosaccharides, wherein the mass of the galacto-oligosaccharides is 40% to 50% of the total mass of the prebiotics, the mass of the fructo-oligosaccharides is 30% to 40% of the total mass of the prebiotics, and the mass of the isomalto-oligosaccharides is 10% to 30% of the total mass of the prebiotics;

[0009] The prebiotics are added after the fermentation of the milk-based raw material is completed.

[0010] The fermented milk containing prebiotics as described above, the milk-based raw materials include one or more of raw cow milk that has undergone or has not undergone the Maillard reaction, skimmed milk, skimmed milk powder reconstituted milk, and whole milk powder reconstituted milk.

[0011] In the fermented milk containing prebiotics as described above, the probiotics include one or more of Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus paracasei, Bifidobacterium, Bifidobacterium longum, Bifidobacterium animalis, Leuconostoc mesenteroides, Lactobacillus rhamnosus, and Lactobacillus reuteri.

[0012] As for the fermented milk containing prebiotics as described above, the raw materials for preparing the fermented milk further include food additives, and the food additives include one or more of stabilizers, sweetness regulators, and acidity regulators.

[0013] The fermented milk containing prebiotics as described above, wherein the stabilizer comprises one or more of pectin, carboxymethyl cellulose, gellan gum, propylene glycol alginate, soluble soybean polysaccharide, citrus fiber, and xanthan gum;

[0014] And / or, the sweetness regulator includes one or more of sucrose, fructose, sucralose, acesulfame potassium, steviol glycosides, xylitol, maltitol, erythritol, and mogroside;

[0015] And / or, the acidity regulator includes one or more of lactic acid, citric acid, malic acid, tartaric acid, phosphoric acid, and NaOH.

[0016] The fermented milk containing prebiotics as described above, wherein the number of viable bacteria in the fermented milk containing prebiotics is not less than 1×10 8 CFU / ml, the centrifugal sedimentation rate is not higher than 2%.

[0017] The fermented milk as described above, wherein the fermented milk containing prebiotics is prepared by the following preparation method:

[0018] The milk-based raw material is homogenized and sterilized in sequence; the probiotics are inoculated into the sterilized milk-based raw material for fermentation to obtain fermented milk;

[0019] The prebiotics are sterilized, and the sterilized prebiotics are mixed and homogenized with the fermented milk to obtain the fermented milk containing the prebiotics.

[0020] The present invention also provides a method for preparing the fermented milk containing prebiotics, comprising the following steps:

[0021] The milk-based raw material is homogenized and sterilized in sequence; the probiotics are inoculated into the sterilized milk-based raw material for fermentation to obtain fermented milk;

[0022] The prebiotics are sterilized, and the sterilized prebiotics are mixed and homogenized with the fermented milk to obtain the fermented milk containing the prebiotics.

[0023] In the preparation method as described above, when the milk-based raw material is one or more of raw milk that has not undergone the Maillard reaction, skimmed milk, skimmed milk powder reconstituted milk, and whole milk powder reconstituted milk, during the fermentation process, when the pH of the milk-based raw material drops below 4.7, or the titrated acidity is 80-100°T, the fermentation is stopped;

[0024] When the milk-based raw material is one or more of raw milk, skimmed milk, skimmed milk powder reconstituted milk, and whole milk powder reconstituted milk that have undergone the Maillard reaction, during the fermentation process, when the pH of the milk-based raw material drops below 4.7, or the titrated acidity is 180-200°T, the fermentation is stopped.

[0025] The preparation method as described above further comprises: mixing the prebiotics with food additives, and sterilizing the mixture of the prebiotics and food additives.

[0026] The present invention optimizes the type, proportion and addition process of prebiotics so that the number of viable bacteria in fermented milk containing prebiotics is not less than 1×10 8 CFU / ml, the centrifugal sedimentation rate is not higher than 2%, and it has the characteristics of high viable bacteria count and good stability during storage.

[0027] The present invention also provides a method for preparing the fermented milk containing prebiotics. The fermented milk containing prebiotics prepared by the preparation method has a high number of viable bacteria and good stability during storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flow chart of a method for preparing fermented milk containing prebiotics provided by one embodiment of the present invention;

[0029] Figure 2 The present invention provides a flowchart of a method for preparing fermented milk containing prebiotics according to another embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The first aspect of the present invention provides a fermented milk containing prebiotics, wherein the raw materials for preparing the fermented milk containing prebiotics include milk-based raw materials, probiotics and prebiotics;

[0032] The prebiotics include galacto-oligosaccharides, fructo-oligosaccharides and isomalto-oligosaccharides, wherein the mass of the galacto-oligosaccharides is 40% to 50% of the total mass of the prebiotics, the mass of the fructo-oligosaccharides is 30% to 40% of the total mass of the prebiotics, and the mass of the isomalto-oligosaccharides is 10% to 30% of the total mass of the prebiotics;

[0033] The prebiotics are added after the fermentation of the milk-based raw material is completed.

[0034] The fermented milk in the present invention refers to a dairy product prepared by adding probiotics to a milk-based raw material and fermenting the milk with the probiotics, and the finished product contains corresponding active microorganisms.

[0035] The present invention optimizes the type, proportion and addition process of prebiotics so that the number of viable bacteria in fermented milk containing prebiotics is not less than 1×10 8 CFU / ml, the centrifugal sedimentation rate is not higher than 2%, and it has the characteristics of high viable bacteria count and good stability during storage.

[0036] In a specific embodiment, prebiotics, as a dietary supplement, can promote the growth and proliferation of probiotics in fermented milk. The prebiotics provided by the present invention include galacto-oligosaccharides, oligofructose and oligoisomaltose. Specifically, galacto-oligosaccharides (GOS) are made from lactose in milk, and the galactoside bond is hydrolyzed by β-galactosidase to generate galactose and glucose, and the hydrolyzed galactoside is transferred to the lactose molecule through the action of galactoside to generate galacto-oligosaccharides; its mass is 40% to 50% of the total mass of the prebiotics, and can be specifically 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50% or within the range of any two of them.

[0037] Furthermore, in galacto-oligosaccharides, the galacto-oligosaccharides content (on a dry basis) is greater than 50%, the anhydrous lactose content (on a dry basis) is less than 25%, and the anhydrous glucose content (on a dry basis) is less than 25%.

[0038] Fructooligosaccharide (FOS) refers to a functional oligosaccharide formed by fructose groups connected by β (2→1) glycosidic bonds and having a degree of polymerization of 2 to 9, and its mass is 30% to 40% of the total mass of the prebiotics, specifically 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40% or within the range of any two thereof.

[0039] Furthermore, in the oligofructose, the dry matter content is not less than 70%, the total content of oligofructose (in dry matter) is not less than 50%, and the total content of glucose+fructose+sucrose (in dry matter) is not higher than 10%.

[0040] Isomaltooligosaccharide (IMO) is a starch sugar product made from starch or starchy raw materials through enzymatic conversion, refining, concentration and other processes. Its main components are oligosaccharides such as isomaltose, panose, isomaltotriose and isomaltotetraose (including tetrasaccharides) bonded by α-1,6-glycosidic bonds, and its mass is 10% to 30% of the total mass of the prebiotics, specifically 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% or within the range of any two thereof.

[0041] Furthermore, in the isomaltooligosaccharide, the dry matter (round matter) content is not less than 75%, and the IMO content (accounting for dry matter) is not less than 90%.

[0042] Furthermore, the prebiotics provided by the present invention are composed of galacto-oligosaccharides, fructo-oligosaccharides and isomaltooligosaccharides, and the contents of galacto-oligosaccharides, fructo-oligosaccharides and isomaltooligosaccharides are as shown above.

[0043] In a specific embodiment, the milk-based raw material includes one or more of raw cow milk that has not undergone or has undergone the Maillard reaction, skimmed cow milk, whole milk powder reconstituted milk, and skimmed milk powder reconstituted milk.

[0044] Specifically, raw milk refers to unprocessed milk.

[0045] Skim milk is made by removing fat from raw milk through centrifugal separation and other techniques. The fat content is generally below 0.5%, or even fat-free.

[0046] Whole milk powder reconstituted milk refers to the process of concentrating and drying raw milk into concentrated milk or milk powder, and then adding an appropriate amount of water to make an emulsion with a water-to-solid ratio equivalent to that of the original milk.

[0047] Skim milk powder reconstituted milk refers to skim milk that is concentrated and dried into concentrated milk or milk powder, and then an appropriate amount of water is added to make an emulsion with a water-to-solid ratio equivalent to that in skim milk.

[0048] One or more milk-based ingredients among the above raw milk, skimmed milk, whole milk powder reconstituted milk and skimmed milk powder reconstituted milk are mixed, and the milk-based raw material can be obtained after or without the Maillard reaction. The milk-based raw material that has not undergone the Maillard reaction is a white milk base, which is often used to prepare white or light-colored fermented milk; the milk-based raw material that has undergone the Maillard reaction is a brown milk base, which is used to prepare brown fermented milk.

[0049] When the milk-based components include at least two of raw cow's milk, skimmed milk, whole milk powder reconstituted milk, and skimmed milk powder reconstituted milk, the present invention does not impose any further restrictions on the ratio of the two.

[0050] The present invention does not specifically limit the process and conditions of the Maillard reaction, which can be carried out according to conventional technical means in the art; for example, the temperature of the Maillard reaction is 115-120° C., and the reaction time is 5-10 minutes to obtain a brown milk base; or one or more milk-based components in raw milk, skimmed milk, whole milk powder reconstituted milk, and skimmed milk powder reconstituted milk can be immersed in a water bath above 90° C. and reacted for 2-4 hours to obtain a brown milk base.

[0051] Furthermore, during the Maillard reaction, reducing sugars may be added to one or more milk-based components in raw milk, skimmed milk, whole milk powder reconstituted milk, or skimmed milk powder reconstituted milk.

[0052] Specifically, the reducing sugar includes one or more of glucose, galactose, fructose, and high fructose corn syrup.

[0053] Furthermore, the amount of reducing sugar added is 2.5% to 4% of the total mass of the milk-based components.

[0054] When producing low-lactose or lactose-free fermented milk, the milk-based components also need to be subjected to lactose hydrolysis treatment. Specifically, the lactose hydrolysis treatment can be performed first, and then the Maillard reaction can be performed.

[0055] In a specific embodiment, the probiotics include one or more of Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus paracasei, Bifidobacterium, Bifidobacterium longum, Bifidobacterium animalis, Leuconostoc mesenteroides, Lactobacillus rhamnosus, and Lactobacillus reuteri.

[0056] The types and inoculation amounts of the probiotics in the present invention can be determined according to conventional techniques in the art. When there are at least two types of probiotics inoculated, the present invention does not limit the specific ratio of the inoculation amounts.

[0057] In a specific embodiment, the raw materials for preparing the fermented milk further include food additives, and the food additives include one or more of stabilizers, sweetness regulators, and acidity regulators.

[0058] Specifically, the stabilizer includes one or more of pectin, carboxymethyl cellulose, gellan gum, propylene glycol alginate, soluble soybean polysaccharide, citrus fiber, and xanthan gum.

[0059] Specifically, the sweetness regulator includes one or more of sucrose, fructose, sucralose, acesulfame potassium, steviol glycosides, xylitol, maltitol, erythritol, and mogroside.

[0060] Specifically, the acidity regulator includes one or more of lactic acid, citric acid, malic acid, tartaric acid, phosphoric acid, and NaOH.

[0061] When the raw materials for preparing the fermented milk include at least two food additives, the present application does not specifically limit their types and proportions, and they can be added according to actual needs.

[0062] In a specific embodiment, the raw materials for preparing fermented milk may also include flavor regulators such as fruit juice and edible flavors to give the fermented milk more abundant nutrition or further improve the product flavor. Those skilled in the art may determine the selection and addition amount of these substances according to actual needs.

[0063] Specifically, the fruit juice includes one or more of apple juice, pomegranate juice, lemon juice, tangerine juice, kumquat juice, grape juice, pear juice, strawberry juice, mango juice, and pineapple juice.

[0064] Furthermore, the particle size of the contents in the juice is required to be at least 100 mesh.

[0065] In a specific embodiment, the fermented milk containing prebiotics of the present invention is prepared by the following preparation method:

[0066] The milk-based raw material is homogenized and sterilized in sequence; probiotics are inoculated into the sterilized milk-based raw material for fermentation to obtain fermented milk;

[0067] The prebiotics are sterilized, and the sterilized prebiotics are mixed and homogenized with the fermented milk to obtain the fermented milk containing the prebiotics.

[0068] Different from the conventional method for preparing fermented milk containing prebiotics, the prebiotics in the present invention are added after the fermented milk is obtained by fermenting the milk-based raw materials, which can reduce the loss of prebiotics during the fermentation of the milk-based raw materials, maintain the added amount of prebiotics at a higher level, and promote the growth and proliferation of probiotics.

[0069] The second aspect of the present invention provides a method for preparing the fermented milk containing prebiotics, comprising the following steps:

[0070] The milk-based raw material is homogenized and sterilized in sequence; probiotics are inoculated into the sterilized milk-based raw material for fermentation to obtain fermented milk;

[0071] The prebiotics are sterilized, and the sterilized prebiotics are mixed and homogenized with the fermented milk to obtain the fermented milk containing the prebiotics.

[0072] In a specific embodiment, Figure 1 A flow chart of a method for preparing a fermented milk containing prebiotics provided by one embodiment of the present invention is shown in FIG. Figure 1 As shown, the preparation method specifically comprises the following steps:

[0073] Step 1: homogenizing and sterilizing the milk-based raw material in sequence; inoculating probiotics into the sterilized milk-based raw material for fermentation to obtain fermented milk.

[0074] As mentioned above, the selection of milk-based raw materials is firstly to be homogenized. Homogenization means to disperse the fat globules in milk more evenly in the milk through mechanical action, so as to achieve the purpose of making it less likely to separate, better taste, uniform quality, stable quality, longer shelf life, etc. For example, the milk-based raw materials can be input into a homogenizer and homogenized at a temperature of 50℃ to 60℃ and a homogenization pressure of 20 to 30MPa.

[0075] Next, the homogenized milk-based raw materials are sterilized to eliminate pathogens and harmful bacteria to ensure food safety. The sterilization temperature is 90-98°C and the sterilization time is 5-10 minutes.

[0076] Finally, probiotics are inoculated into the sterilized milk-based raw material. The types of probiotics are as described above. The present invention does not impose too many restrictions on the method of inoculating probiotics into the sterilized milk-based raw material and fermenting it to obtain fermented milk.

[0077] In order to ensure the acidity of fermented milk, it is necessary to control the end time of fermentation. Specifically, when the milk-based raw material is a white milk-based raw material that has not undergone the Maillard reaction, the fermentation is carried out at 42°C to 44°C, and the fermentation ends when the pH is below 4.7 or the titrated acidity is 80-100°T. When the milk-based raw material is a brown milk-based raw material that has undergone the Maillard reaction, the fermentation is carried out at 42°C to 44°C, and the fermentation ends when the pH is below 4.7 or the titrated acidity is 180-200°T.

[0078] Step 2: sterilize the prebiotics, and mix and homogenize the sterilized prebiotics with the fermented milk to obtain the fermented milk containing the prebiotics.

[0079] Prebiotics are dispersed in pure water according to a proportion and sterilized at a temperature of 90 to 98° C. for 5 to 10 minutes.

[0080] In a specific embodiment, Figure 2 A flow chart of a method for preparing fermented milk containing prebiotics provided by another embodiment of the present invention is as follows: Figure 2 As shown, when food additives such as stabilizers, sweetness regulators, acidity regulators, etc. need to be added to fermented milk, the prebiotics and food additives are first mixed, and then the purified water is heated to 50°C to 60°C, stirring is started and the mixed materials of the prebiotics and food additives are slowly added, and the materials are circulated and stirred in the material system for 15 to 30 minutes, and then sterilized. The sterilization temperature can be 90 to 98°C and the time is 5 to 10 minutes.

[0081] In a specific embodiment, when it is necessary to add a flavor regulator such as fruit juice or edible flavor to the fermented milk, the flavor regulator may be added through a buffer mixing tank during the sterilization process.

[0082] Finally, the fermented milk and the sterilized prebiotics are mixed with a mixture of food additives, flavor regulators, etc., stirred for 20 to 30 minutes and then homogenized at a homogenization pressure of 20 to 30 MPa. After filling, the mixture is refrigerated and stored at 0 to 4°C.

[0083] The fermented milk containing prebiotics prepared in the present invention has a viable bacterial count of not less than 1×10 8 CFU / ml, the centrifugal sedimentation rate is not higher than 2%.

[0084] The present invention adopts the method specified in the national food safety standard food microbiology test lactic acid bacteria test (GB 4789.35-2010) to determine the total number of probiotics in yogurt.

[0085] The centrifugal sedimentation rate refers to the change in radial position of particles in a suspension relative to a centrifuge at a certain speed per unit time, which can reflect the stability of the product. The test method specifically includes: taking a centrifuge tube, weighing its mass, recorded as M0; secondly, weighing the sample into a centrifuge tube, weighing the mass of the centrifuge tube and the sample, recorded as M1; thirdly, continuing to centrifuge the weighed sample, pouring out the liquid in the centrifuge tube after the centrifugation, and then inverting the centrifuge tube for 10 minutes, weighing the mass of the centrifuge tube and the sediment, recorded as M2; the centrifugal sedimentation rate is calculated according to the following formula, each sample is measured three times in parallel, and the results are averaged.

[0086]

[0087] The present invention does not further limit the production equipment and filling process used for fermented milk, and can adopt the well-known equipment and filling process in the field. For example, the equipment used in the production process of the present invention is steam fumigation equipment, a homogenizer for homogenization, a mixing tank for mixing, a fermentation tank for fermentation, and a sterilization equipment, etc. The filling of the liquid dairy product of the present invention can also be carried out according to the existing filling technology of liquid products in the field.

[0088] The following is a detailed description in conjunction with specific examples. In the examples and comparative examples, fructooligosaccharides, galacto-oligosaccharides and isomaltooligosaccharides were purchased from Baolingbao Biological Co., Ltd.

[0089] Example 1

[0090] The raw material formula provided in this embodiment (based on 1000 kg of fermented milk containing prebiotics) is shown in Table 1.

[0091] Table 1 Raw material formula for preparing fermented milk containing prebiotics in Example 1

[0092]

[0093]

[0094] The specific preparation method is as follows:

[0095] 1) Milk-based ingredients: First, dissolve the raw milk at 40-50°C and stir for 30 minutes, then homogenize it at 50-60°C with a homogenization pressure of 20-30 MPa, and sterilize the homogenized milk at 90-98°C for 6 minutes.

[0096] 2) Milk-based inoculation and fermentation: The sterilized milk-based product is inoculated and fermented at 42°C to 44°C until the pH is below 4.7 or the titrated acidity is 100°T. After reaching the end of the fermentation, homogenization and demulsification are performed at a homogenization pressure of 20 to 30 MPa, and fermented milk is obtained after demulsification.

[0097] 3) Sugar solution ingredients: First, dry-mix the white sugar, GOS, FOS, IMO, sweetness regulator, acidity regulator and stabilizer evenly, then raise the temperature of the purified water to 50°C-60°C, start stirring and slowly add the premixed dry materials, and circulate and stir the materials in the chemical system for 20 minutes.

[0098] 4) Sterilization of sugar solution: The mixed sugar solution is sterilized at 90-98° C. for 5-10 minutes. During the sterilization process, concentrated peach juice is added through a buffer mixing tank.

[0099] 5) Mixing the fermented milk base with the sugar solution: Mix the fermented milk after fermentation with the sterilized sugar solution, stir for 20 to 30 minutes and then homogenize at a homogenization pressure of 20 to 30 MPa.

[0100] 6) Filling and storage: After filling, the homogenized lactic acid bacteria beverage is refrigerated and stored at 0-4°C.

[0101] Example 2

[0102] The preparation method of the fermented milk containing prebiotics provided in this embodiment is basically the same as that in Example 1, except that only the addition amount of three prebiotics is adjusted, and the addition amount of other raw materials remains unchanged, specifically, the addition amount of GOS is 5 kg, the addition amount of FOS is 4 kg, and the addition amount of IMO is 1 kg.

[0103] Example 3

[0104] The preparation method of the fermented milk containing prebiotics provided in this embodiment is basically the same as that in Example 1, except that only the addition amount of three prebiotics is adjusted, and the addition amount of other raw materials remains unchanged, specifically, the addition amount of GOS is 4 kg, the addition amount of FOS is 3 kg, and the addition amount of IMO is 3 kg.

[0105] Example 4

[0106] The raw material formula provided in this embodiment (based on 1000 kg of fermented milk containing prebiotics) is shown in Table 2.

[0107] Table 2 Raw material formula for preparing fermented milk containing prebiotics in Example 4

[0108]

[0109] The specific preparation method is as follows:

[0110] 1) Milk-based ingredients: firstly, skim milk powder and glucose are dissolved at 40-50° C. and stirred for 25 minutes; then, homogenization is performed at 50-60° C., and the homogenization pressure is 20-30 MPa. After homogenization, Maillard browning process is performed, and the browning process adopts 115° C. and reacts for 10 minutes.

[0111] 2) Milk-based inoculation and fermentation: The brown milk-based product after browning is inoculated and fermented at 42°C to 44°C until the pH is below 4.7 or the titrated acidity is 180°T. After reaching the end of fermentation, homogenization and demulsification are performed at a homogenization pressure of 20 to 30 MPa, and fermented milk is obtained after demulsification.

[0112] 3) Sugar solution ingredients: First, dry-mix the sweetness regulator, acidity regulator and stabilizer evenly, then raise the temperature of the purified water to 50°C-60°C, start stirring and slowly add the premixed dry materials, and circulate and stir the materials in the chemical system for 30 minutes.

[0113] 4) Sugar solution sterilization: The mixed sugar solution is sterilized at 90-98°C for 5-10 minutes. During the sterilization process, concentrated grape juice is added through a buffer mixing tank.

[0114] 5) Mixing the fermented milk base with the sugar solution: Mix the fermented milk base with the sterilized sugar solution, stir for 20 minutes and then homogenize at a homogenization pressure of 20 to 30 MPa.

[0115] 6) Filling and storage: After filling, the homogenized lactic acid bacteria beverage is refrigerated and stored at 0-4°C.

[0116] Example 5

[0117] The preparation method of the fermented milk containing prebiotics provided in this embodiment is basically the same as that in Example 4, except that only the addition amount of three prebiotics is adjusted, and the addition amount of other raw materials remains unchanged, specifically, the addition amount of GOS is 4 kg, the addition amount of FOS is 4 kg, and the addition amount of IMO is 2 kg.

[0118] Example 6

[0119] The preparation method of the fermented milk containing prebiotics provided in this embodiment is basically the same as that in Example 4, except that only the addition amount of the three prebiotics is adjusted, and the addition amount of other raw materials remains unchanged, specifically, the addition amount of GOS is 5 kg, the addition amount of FOS is 3 kg, and the addition amount of IMO is 2 kg.

[0120] Comparative Example 1

[0121] The preparation method of the fermented milk containing prebiotics provided in this comparative example is basically the same as that in Example 1, except that only the addition amount of the three prebiotics is adjusted, and the addition amount of other raw materials remains unchanged, specifically, the addition amount of GOS is 3 kg, the addition amount of FOS is 5 kg, and the addition amount of IMO is 2 kg.

[0122] Comparative Example 2

[0123] The preparation method of the fermented milk containing prebiotics provided in this comparative example is basically the same as that in Example 1, except that only the addition amount of three prebiotics is adjusted, and the addition amount of other raw materials remains unchanged, specifically, the addition amount of GOS is 2 kg, the addition amount of FOS is 3 kg, and the addition amount of IMO is 5 kg.

[0124] Comparative Example 3

[0125] The preparation method of the fermented milk containing prebiotics in this comparative example is basically the same as that in Example 1, except that only the adding process of prebiotics is changed, that is, the prebiotics are added in the milk-based ingredients process, and other processes remain unchanged, and the specific modifications are as follows:

[0126] Milk-based ingredients: first preheat the raw milk to 40-50°C, then add the prebiotic ingredients and stir for 20-40 minutes, then homogenize at 50-60°C, with a homogenization pressure of 20-30MPa, and sterilize the homogenized milk at 90-98°C for 5-10 minutes.

[0127] Comparative Example 4

[0128] The preparation method of the fermented milk containing prebiotics provided in this comparative example is basically the same as that in Example 4, except that only the addition amount of the three prebiotics is adjusted, and the addition amount of other raw materials remains unchanged, specifically, the addition amount of GOS is 3 kg, the addition amount of FOS is 4 kg, and the addition amount of IMO is 3 kg.

[0129] Comparative Example 5

[0130] The preparation method of the fermented milk containing prebiotics provided in this comparative example is basically the same as that in Example 4, except that only the addition amount of the three prebiotics is adjusted, and the addition amount of other raw materials remains unchanged, specifically, the addition amount of GOS is 2 kg, the addition amount of FOS is 5 kg, and the addition amount of IMO is 3 kg.

[0131] Comparative Example 6

[0132] The preparation method of the fermented milk containing prebiotics provided in this comparative example is basically the same as that in Example 4, except that only the adding process of the prebiotics is changed, and the prebiotics are added to the milk-based ingredients process, and other processes remain unchanged, and the specific modifications are as follows:

[0133] Milk-based ingredients: firstly, the skim milk powder, glucose and prebiotic raw materials are melted at 40-50°C and stirred for 20-40 minutes; then, they are homogenized at 50-60°C with a homogenization pressure of 20-30MPa. After homogenization, the Maillard browning process is carried out at 115°C for 10 minutes.

[0134] Test example

[0135] 1. Test for determination of viable lactic acid bacteria count during shelf life of products

[0136] In this test example, the total number of lactic acid bacteria in yogurt was determined by the method specified in the National Food Safety Standard Food Microbiology Test Lactic Acid Bacteria Test (GB 4789.35-2010). The experimental results are shown in Table 3.

[0137] Table 3 Results of determination of viable bacteria count during shelf life of fermented milk in Examples and Comparative Examples (cfu / mL)

[0138] Storage time 1 day 14 days 28 days Example 1 8.2E+08 9.3E+08 8.5E+08 Example 2 6.3E+08 1.1E+09 7.4E+08 Example 3 7.2E+08 8.6E+08 8.8E+08 Example 4 4.3E+09 5.3E+09 4.8E+08 Example 5 2.2E+09 4.2E+09 3.1E+08 Example 6 1.3E+09 2.7E+09 1.8E+08 Comparative Example 1 8.6E+07 6.3E+07 7.4E+06 Comparative Example 2 4.3E+07 2.3E+07 7.4E+05 Comparative Example 3 6.2E+06 5.7E+06 6.3E+06 Comparative Example 4 7.4E+07 5.3E+07 3.9E+06 Comparative Example 5 6.2E+08 3.2E+08 5.4E+06 Comparative Example 6 1.1E+08 9.6E+07 6.8E+06

[0139] As shown in Table 3, during the storage period of 1 to 28 days, the number of live bacteria in the fermented milk in the example can be maintained or even higher than the level on the first day, while the number of live bacteria in the fermented milk in the comparative example significantly decreases with the delay of storage time. Comparative Examples 1 to 3 and Comparative Examples 4 to 6 are single factor control experiments based on Example 1 and Example 4, respectively. During the storage period, the number of live bacteria in the fermented milk in Example 1 and Example 4 is higher than the number of live bacteria in the corresponding comparative example products.

[0140] (2) Product shelf life stability test

[0141] Centrifugal sedimentation rate: 1) Take a 50mL centrifuge tube and weigh its mass, record it as M0; 2) Weigh 30.00g (accurate to 0.01g) of sample into a 50mL centrifuge tube, weigh the mass of the centrifuge tube and the sample, record it as M1; 3) Centrifuge the weighed sample at 20℃, 3500r / min for 15min, pour out the liquid in the centrifuge tube after centrifugation, then invert the centrifuge tube for 10min, weigh the mass of the centrifuge tube and the sediment, record it as M2; The centrifugal sedimentation rate is calculated according to the following formula:

[0142]

[0143] Each sample was measured three times in parallel and the results were averaged. The specific results are shown in Table 4.

[0144] Table 4 Experimental results of centrifugal sedimentation rate during shelf life of fermented milk in Examples and Comparative Examples

[0145] Storage time 1 day 14 days 28 days Example 1 1.43％ 1.52％ 1.63％ Example 2 1.42％ 1.78％ 1.82％ Example 3 1.52％ 1.54％ 1.60％ Example 4 1.62％ 1.76％ 1.84％ Example 5 1.53％ 1.6％ 1.66％ Example 6 1.68％ 1.79％ 1.84％ Comparative Example 1 1.83％ 1.97％ 2.82％ Comparative Example 2 1.92％ 2.49％ 3.56％ Comparative Example 3 1.88％ 2.66％ 3.72％ Comparative Example 4 1.87％ 1.99％ 2.76％ Comparative Example 5 1.96％ 2.61％ 3.83％ Comparative Example 6 1.98％ 2.69％ 3.77％

[0146] As shown in Table 4, during the storage period of 1 to 28 days, the centrifugal sedimentation rate of the fermented milk in the examples did not change much, proving that the fermented milk in the examples had good stability during the storage period, while the centrifugal sedimentation rate of the fermented milk in the comparative example increased by more than double at the end of 28 days compared with that on the first day, proving that the stability of the fermented milk in the comparative example deteriorated at the end of the storage period. During the storage period, the centrifugal sedimentation rates of the fermented milk in Examples 1 and 4 were substantially lower than those of the corresponding comparative example products.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fermented milk containing prebiotics, It is characterized in that The raw materials for preparing the fermented milk containing prebiotics include milk-based raw materials, probiotics and prebiotics; The prebiotics include galacto-oligosaccharides, fructo-oligosaccharides and isomalto-oligosaccharides, wherein the mass of the galacto-oligosaccharides is 40% to 50% of the total mass of the prebiotics, the mass of the fructo-oligosaccharides is 30% to 40% of the total mass of the prebiotics, and the mass of the isomalto-oligosaccharides is 10% to 30% of the total mass of the prebiotics; The prebiotics are added after the fermentation of the milk-based raw material is completed.

2. The fermented milk containing prebiotics according to claim 1, It is characterized in that The milk-based raw materials include one or more of raw cow milk that has not undergone or has undergone the Maillard reaction, skimmed cow milk, whole milk powder reconstituted milk, and skimmed milk powder reconstituted milk.

3. The fermented milk containing prebiotics according to claim 1 or 2, It is characterized in that The probiotics include one or more of Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus paracasei, Bifidobacterium breve, Bifidobacterium longum, Bifidobacterium animalis, Leuconostoc mesenteroides, Lactobacillus rhamnosus, and Lactobacillus reuteri.

4. The fermented milk containing prebiotics according to any one of claims 1 to 3, It is characterized in that The raw materials for preparing the fermented milk also include food additives, and the food additives include one or more of stabilizers, sweetness regulators, and acidity regulators.

5. The fermented milk containing prebiotics according to claim 4, It is characterized in that The stabilizer includes one or more of pectin, carboxymethyl cellulose, gellan gum, propylene glycol alginate, soluble soybean polysaccharide, citrus fiber, and xanthan gum; And / or, the sweetness regulator includes one or more of sucrose, fructose, sucralose, acesulfame potassium, steviol glycosides, xylitol, maltitol, erythritol, and mogroside; And / or, the acidity regulator includes one or more of lactic acid, citric acid, malic acid, tartaric acid, phosphoric acid, and NaOH.

6. The fermented milk containing prebiotics according to any one of claims 1 to 5, It is characterized in that After the fermented milk containing prebiotics is placed at 2°C to 10°C for 28 days, the number of viable bacteria is not less than 1×10 8 CFU / ml, the centrifugal sedimentation rate is not higher than 2%.

7. The fermented milk according to any one of claims 1 to 6, It is characterized in that The fermented milk containing prebiotics is prepared by the following preparation method: The milk-based raw material is homogenized and sterilized in sequence; the probiotics are inoculated into the sterilized milk-based raw material for fermentation to obtain fermented milk; The prebiotics are sterilized, and the sterilized prebiotics are mixed and homogenized with the fermented milk to obtain the fermented milk containing the prebiotics.

8. The method for preparing the fermented milk containing prebiotics according to any one of claims 1 to 7, It is characterized in that The steps include: The milk-based raw material is homogenized and sterilized in sequence; the probiotics are inoculated into the sterilized milk-based raw material for fermentation to obtain fermented milk; The prebiotics are sterilized, and the sterilized prebiotics are mixed and homogenized with the fermented milk to obtain the fermented milk containing the prebiotics.

9. The preparation method according to claim 8, It is characterized in that When the milk-based raw material is one or more of raw milk that has not undergone the Maillard reaction, skimmed milk, skimmed milk powder reconstituted milk, and whole milk powder reconstituted milk, during the fermentation process, when the pH of the milk-based raw material drops below 4.7, or the titrated acidity is 80-100°T, the fermentation is stopped; When the milk-based raw material is one or more of raw milk, skimmed milk, skimmed milk powder reconstituted milk, and whole milk powder reconstituted milk that have undergone the Maillard reaction, during the fermentation process, when the pH of the milk-based raw material drops below 4.7, or the titrated acidity is 180-200°T, the fermentation is stopped.

10. The preparation method according to claim 8 or 9, It is characterized in that The preparation method further comprises: mixing the prebiotics with food additives, and sterilizing the mixture of the prebiotics and food additives.

Images