Preparation method and application of soybean-dried orange peel fermented milk

Abstract

The invention discloses a preparation method and application of soybean-dried orange peel fermented milk. The preparation method comprises the following steps: soaking soybeans, cooking, mixing with dried orange peel, grinding into thick liquid, performing ultrasonic treatment, and sterilizing to obtain a fermentation base material; mixing the fermentation base material with a leavening agent, and fermenting to obtain a fermented product; and carrying out after-ripening treatment on the fermented product to obtain the soybean-dried orange peel fermented milk. Through formula optimization, the dried orange peel and the soybeans are added for mixed fermentation, so that the flavor of the soybean milk is improved; the dissolution rate of soybean protein can be effectively improved and the molecular structure and aggregation state of the protein can be changed through a treatment mode of combining a damp-heat method and a hot grinding method, and milk droplets can be effectively formed by adding vegetable fat before fermentation and then carrying out ultrasonic treatment, so that the texture of the fermented milk is improved, the retention rate of flavor substances is increased, and the quality of the fermented milk is improved. And a relatively good micro-network structure can be formed, so that the hardness, the gel structure and the water binding capacity of the product are improved, and the taste and the quality of the product are improved.

Description

Technical Field

[0001] The present invention relates to the field of soybean processing, and in particular to a preparation method and application of soybean-tangerine peel fermented milk. Background Art

[0002] Lactic acid bacteria fermented soy milk is a new type of plant-based milk product, which can enrich the nutritional value of original soy milk, improve the unpleasant beany smell in soy milk, and improve the functional value of soy milk. However, there are still problems affecting the quality of fermented soy milk in terms of flavor and texture. For example, it still has a beany smell, the texture is not smooth and delicate enough, and it is easy to precipitate water. These have seriously affected the sensory quality of the product, reduced consumer acceptance, and brought resistance to the development of fermented soy milk. For the texture problem, the current solution is mainly to adopt formula design to add polysaccharides to improve the texture, and how to improve the texture and sensory quality of fermented soy milk through process technology innovation is still a key common problem faced by related industries.

[0003] At present, the research on the process technology to regulate the quality of fermented soy milk is mainly concentrated in three directions: one is to improve the starter formula of fermented soy milk; the second is to use processing technology to change the structural characteristics of soy protein such as depolymerization, unfolding, polymerization and cross-linking to improve the solubility and emulsification of protein, and reduce the size of emulsion droplets during processing to make them evenly distributed in the fermented milk system, which is conducive to the formation of a dense and uniform gel network by lactic acid bacteria fermentation, thereby making the fermented milk delicate in texture, high in water retention and smooth in taste; the third is to change the fermentation method to increase the network cross-linking of soy protein or produce special aromatic substances to achieve the effect of improving texture and flavor. However, these methods also have their own limitations. Therefore, it is necessary to use a variety of control technologies to jointly treat to make up for the lack of a single method in optimizing the quality of fermented soy milk. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for preparing soybean-tangerine peel fermented milk, aiming to overcome the problems existing in the prior art of soybean fermented milk having a strong beany smell, a texture that is not smooth and delicate enough, poor product stability and insufficient product quality.

[0005] To achieve the above object, the present invention provides a method for preparing soybean-tangerine peel fermented milk, comprising the following steps:

[0006] Providing soybeans, soaking and steaming the soybeans to obtain pre-treated soybeans;

[0007] The pretreated soybeans and tangerine peels are mixed and ground to obtain a mixed solution, and the mixed solution is mixed with vegetable oil and subjected to ultrasonic treatment for sterilization to obtain a fermentation base;

[0008] Mixing the fermentation base with a fermentation agent to obtain a fermentation product;

[0009] The fermentation base material is mixed with a starter and fermented to obtain soybean-tangerine peel fermented milk.

[0010] Optionally, in the step of soaking and steaming the soybeans:

[0011] The soaking time is 8 to 12 hours; and / or,

[0012] The steaming time is 20 to 40 minutes.

[0013] Optionally, in the step of mixing and grinding the soybeans and tangerine peel to obtain a mixed solution, mixing the mixed solution with vegetable oil and performing ultrasonic treatment to sterilize the mixture, and obtaining a fermentation base material:

[0014] The mass ratio of soybean to tangerine peel is: (1-5): 100; and / or,

[0015] The vegetable oil comprises at least one of soybean oil, tea seed oil, walnut oil and grape seed oil; and / or,

[0016] The amount of vegetable oil added is 1-5% of the mass of the mixed liquid; and / or,

[0017] The power of ultrasonic treatment is 200-400W; and / or,

[0018] The ultrasonic treatment time is 5 to 10 minutes; and / or,

[0019] The sterilization time is 10 to 15 minutes.

[0020] Optionally, in the step of mixing the fermentation base with a fermentation agent and fermenting to obtain a fermented product:

[0021] The fermentation temperature is 41-43°C; and / or,

[0022] The fermentation time is 5 to 7 hours.

[0023] Optionally, in the step of mixing the fermentation base with a starter and fermenting to obtain a fermented product, the starter includes at least one of Lactobacillus delbrueckii subsp. bulgaricus and Lactococcus lactis subsp. lactis.

[0024] Optionally, the mass concentration of the leavening agent in the fermentation base is 0.08-0.15% (w / v).

[0025] Optionally, the step of subjecting the fermented product to post-ripening treatment to obtain soybean-tangerine peel fermented milk includes: refrigerating the fermented product to obtain soybean-tangerine peel fermented milk.

[0026] Optionally, in the step of refrigerating the fermented product to obtain soybean-tangerine peel fermented milk:

[0027] Refrigeration time is 10 to 14 hours; and / or,

[0028] The refrigeration temperature is 2-5℃.

[0029] The present invention also provides a soybean-tangerine peel fermented milk, which is prepared by the above-mentioned soybean-tangerine peel fermented milk preparation method.

[0030] The invention discloses a preparation method of soybean-tangerine peel fermented milk, comprising the following steps: firstly, treating the soybeans by a combination of a wet heat method and a hot grinding method to effectively improve the dissolution rate of soybean protein and change the molecular structure and aggregation state of the protein, then mixing the soybeans with tangerine peel, optimizing the formula, adding tangerine peel and soybeans for mixed fermentation to improve the flavor of the soybean milk, and adding vegetable oil before fermentation to significantly improve the taste, flavor characteristics and system stability of the plant-based fermented milk. Then, vegetable oil is added to the slurry for ultrasonic treatment and sterilization steps to prepare a base material for fermentation, and vegetable oil is added to the slurry and then ultrasonically treated to prepare a fermentation base material. The soybean-tangerine peel slurry can be treated with ultrasonic technology to reduce the size of fat globules formed after adding vegetable oil. Smaller fat globules can promote the interaction between protein and fat globules and between fat globules during the fermentation process, which is conducive to forming a better microscopic network structure, thereby improving the hardness, gel structure and water holding capacity of the product. Then, the fermentation base material is mixed with the fermentation agent and fermented to obtain a fermentation product. Finally, the fermentation product is post-ripened to improve the texture of the fermented milk and obtain soybean-tangerine peel fermented milk. The plant-based fermented milk obtained after fermentation can be significantly improved in taste and sensory quality of the product, thereby better meeting people's needs for food and nutritional health, and is conducive to promoting the high-quality development of the plant-based fermented food industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is the soybean-tangerine peel fermented milk prepared in Examples 1 to 3. DETAILED DESCRIPTION

[0033] To make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme in the embodiment of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiment, it is carried out according to the normal conditions or the conditions recommended by the manufacturer. If the reagents or instruments used do not specify the manufacturer, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes, taking "A and / or B" as an example, including scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical schemes between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in the field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist, and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention.

[0034] Lactic acid bacteria fermented soy milk is a new type of plant-based milk product, which can enrich the nutritional value of original soy milk, improve the unpleasant bean smell in soy milk, and enhance the functional value of soy milk. However, there are still some problems affecting the quality of fermented soy milk in terms of flavor and texture. For example, it still has a bean smell, the texture is not smooth and delicate enough, and the stability is poor. These have seriously affected the sensory quality of the product, reduced consumer acceptance, and brought resistance to the development of fermented soy milk.

[0035] In view of this, the present invention proposes a method for preparing soybean-tangerine peel fermented milk, aiming to overcome the problems of soybean fermented milk in the prior art, such as beany smell, insufficiently smooth and delicate texture, poor stability and insufficient product quality.

[0036] A method for preparing soybean-tangerine peel fermented milk comprises the following steps:

[0037] S10, providing soybeans, and soaking and steaming the soybeans to obtain pretreated soybeans;

[0038] S20, mixing and grinding the pretreated soybeans and tangerine peel to obtain a mixed solution, mixing the mixed solution with vegetable oil and performing ultrasonic treatment for sterilization to obtain a fermentation base;

[0039] S30, mixing the fermentation base material with the fermentation agent and fermenting to obtain a fermentation product;

[0040] S40, performing post-ripening treatment on the fermented product to obtain soybean-tangerine peel fermented milk.

[0041] In the preparation method of the present invention, first, the soybeans are mixed with tangerine peel, and tangerine peel and soybeans are added for mixed fermentation through formula optimization to improve the flavor of soy milk, and vegetable oil is added before fermentation to significantly improve the taste, flavor characteristics and stability of the plant-based fermented milk, and then the vegetable oil is added to the slurry for ultrasonic treatment and sterilization steps to prepare a base material for fermentation, and the vegetable oil is added to the slurry and then ultrasonically treated to prepare a fermentation base material, and the soybean-tangerine peel slurry can be treated with ultrasonic technology to reduce the size of fat globules formed after the vegetable oil is added, and smaller fat globules can be To promote the interaction between protein and fat globules and between fat globules during the fermentation process, it is beneficial to form a better micro-network structure, thereby improving the hardness, gel structure and water holding capacity of the product. Then, the fermentation base is mixed with the starter and fermented to obtain a fermented product. Finally, the fermented product is post-ripened to improve the texture of the fermented milk to obtain soybean-tangerine peel fermented milk. The plant-based fermented milk obtained after fermentation can be significantly improved in taste and sensory quality of the product, thereby better meeting people's needs for food and nutritional health, and is conducive to promoting the high-quality development of the plant-based fermented food industry.

[0042] It should be noted that tangerine peel is one of the traditional Chinese medicines of "medicine and food homology" in my country, rich in multiple active ingredients such as flavonoids, phenolic acids, volatile oils, and has strong antioxidant, anticancer and antibacterial physiological activities. Mixing tangerine peel with soybean for fermentation can improve the functional characteristics and nutritional value of fermented soy milk. In addition, flavor substances such as limonene, carvone, and pineneol in tangerine peel can be fully released after fermentation to bring fruity, floral, sweet, sour, green, medicinal and citrus aromas, partially covering up the beany smell, thereby improving the flavor of fermented soy milk. The tangerine peel of the present invention can be directly purchased on the market.

[0043] In the technical scheme of the present invention, through formula optimization, tangerine peel and soybean, which are both medicinal and edible substances, are added for mixed fermentation to improve the flavor of soy milk, and the citrus aromatic substances in tangerine peel help to effectively cover up the beany smell. By adding vegetable oils and fats before fermentation, not only can the texture and mouthfeel of fermented milk be improved, but also the retention rate of flavor substances in tangerine peel be beneficial. And the soybean-tangerine peel slurry and vegetable oil mixture are processed by ultrasonic technology, and ultrasound is not only conducive to the formation of emulsion droplets by vegetable oil and protein, but also helps to reduce the particle size of fat globules, so that more small fat globules are wrapped in the protein mesh structure formed by fermentation, and smaller fat globules can promote the interaction between protein and fat globules and between fat globules during fermentation, which is conducive to forming a better microscopic network structure, thereby improving the hardness, gel structure and water holding capacity of the product, increasing the surface area of ​​the gel, preventing water loss, and reducing whey precipitation.

[0044] This application improves the taste and quality of the product by combining formula optimization and processing technology, better meets people's needs for food and nutritional health, and promotes the development of the plant-based fermented food industry.

[0045] In any embodiment of the present invention, step S10 is to provide soybeans, soak and steam the soybeans to obtain pretreated soybeans.

[0046] It should be noted that the present invention is the first to study the use of wet heat method and grinding method to compositely treat soybeans, which can reduce the content of anti-nutritional factors in soybeans, such as trypsin inhibitors and urease, and inhibit the activity of soybean lipoxygenase, prevent linoleic acid and linolenic acid from being converted into hydroperoxides, and reduce the generation of beany odor substances. At the same time, after the composite treatment of wet heat method and hot grinding method, the molecular structure and intermolecular interaction force of protein in soybeans have changed, which can affect the aggregation state, solubility, emulsification characteristics of protein and the cross-linking effect between protein molecules and emulsion droplets in the subsequent fermentation process, which will be beneficial to improve the sensory texture of fermented milk. After ultrasonic treatment, the secondary and tertiary structures of soybean protein can be further significantly changed, its solubility can be improved and the particle size can be reduced, thereby increasing the interaction between protein and water, promoting the formation of a stable homogenized product, and making the texture of fermented soy milk smoother and more delicate. In any embodiment of the present invention, in the step of soaking and steaming soybeans: the soaking time is 8 to 12 hours; and / or the steaming time is 10 to 40 minutes. By using a wet heat method in the soybean pulping process, that is, steaming soybeans, the soybean lipoxygenase can be fully passivated and the generation of beany odor substances can be reduced. At the same time, the soybean tissue structure can be effectively softened and the molecular conformation of the soybean protein can be changed, laying a foundation for the subsequent hot grinding treatment to increase the solubility rate of the soybean protein and change the structure and aggregation state of the soybean protein.

[0047] Specifically, the operation steps include: selecting soybeans with good maturity, removing impurities and moldy particles, soaking the washed soybeans and pure water at 4°C for 8 to 12 hours according to a certain mass ratio, draining the water and steaming for 10 to 40 minutes.

[0048] In any embodiment of the present invention, in step S20, the pretreated soybean and tangerine peel are mixed and ground to obtain a mixed liquid, and the mixed liquid is mixed with vegetable oil and fat and ultrasonically treated to sterilize, to obtain a fermentation base material: the vegetable oil includes at least one of soybean oil, tea seed oil, walnut oil and grape seed oil; the vegetable oil is mixed and then ultrasonically treated to effectively form emulsion droplets, which is beneficial to improve the texture and increase the retention rate of flavor substances.

[0049] Furthermore, the added amount of the vegetable oil accounts for 1-5% of the mass of the mixed liquid. Within this mass range, the texture improvement effect on the fermented milk is better.

[0050] In any embodiment of the present invention, the power of ultrasonic treatment is 200-400W; and / or, the time of ultrasonic treatment is 5-10min, the cavitation force, microjet and turbulent force generated by ultrasonic treatment can change the secondary and tertiary structures of soybean protein, and this structural change leads to a decrease in protein particle size and an increase in solubility, while increasing the number of hydrophobic residues and free sulfhydryl groups, and these changes are conducive to forming a dense and uniform acid gel network during the fermentation process, giving soybean-tangerine peel fermented milk a mellow taste and delicate texture, and the sterilization time is 10-15min, and here, grinding is adding 80-90°C water grinding, that is, hot grinding, hot grinding can reduce or even inactivate the activity of lipoxygenase in soybeans, reduce the enzymatic reaction rate, and reduce the content of intermediate hydroperoxide (13- or 9-hydroxy peroxide), which effectively plays a role in reducing the content of beany smell compounds. In addition, hot grinding is also conducive to the dissolution of soybean protein, accelerates the denaturation of protein, and provides a good protein structure and protein concentration for subsequent ultrasonic emulsification treatment. At the same time, within this ultrasonic range, the texture of the fermented milk is improved and its water holding capacity is increased.

[0051] Specifically, the operation steps include: adding 80-90°C hot water to grind the pretreated soybeans and tangerine peel at a soybean-water mass ratio of 1:5-1:9, and then sieving to obtain a soybean milk and tangerine peel mixed liquid; adding 4%-7% sucrose to the mixed liquid to provide a carbon source for lactic acid bacteria, accelerate the fermentation process, increase the sweetness of yogurt and improve the taste; then treating for 5-10 minutes at an ultrasonic frequency of 20KHz and an ultrasonic power of 200-400W, with the working time and the interval time both being 6s; placing the sample in an ice water bath during the ultrasonic process to control the ultrasonic temperature; sterilizing the mixed liquid at 85°C for 10-15 minutes, and cooling it for use after sterilization.

[0052] In any embodiment of the present invention, in step S30, the fermentation base is mixed with the fermentation agent and fermented to further increase the nutritional and health-care effects of soybeans, and the fermentation temperature is set to 41-43°C; and / or the fermentation time is 5-7h. Within this fermentation range, the fermentation efficiency can be improved. In any embodiment of the present invention, in the step of mixing the fermentation base with the fermentation agent and fermenting to obtain a fermented product, the fermentation agent includes at least one of Streptococcus salivarius thermophilus subspecies, Lactobacillus delbrueckii subspecies bulgaricus, Lactococcus lactis lactis subspecies and Bifidobacterium animalis lactis subspecies, wherein the fermentation agent is purchased from Angel Yeast Co., Ltd., purchase number 520655306414.

[0053] In any embodiment of the present invention, the mass concentration ratio of the fermentation agent to the fermentation base is 0.08-0.15% w / v. Within this ratio range, the biological activity of the fermentation agent and the substrate utilization rate can be effectively exerted.

[0054] In any embodiment of the present invention, in step S40, the fermented product is subjected to a post-ripening treatment so that the fermented product is further fermented, which can improve the texture of the soybean-tangerine peel fermented milk.

[0055] Specifically, the step of post-ripening the fermented product to obtain soybean-tangerine peel fermented milk includes: refrigerating the fermented product to obtain soybean-tangerine peel fermented milk.

[0056] In any embodiment of the present invention, in the step of refrigerating the fermented product to obtain soybean-tangerine peel fermented milk: the refrigeration time is 10 to 14 hours; and / or the refrigeration temperature is 2 to 5°C. Within this refrigeration range, the fermented product has a better ripening effect and can improve the texture of the fermented milk.

[0057] Specifically, the operation steps of step S40 include: refrigerating the fermented product at 2-5° C. for 10-14 hours, and performing post-ripening treatment to obtain soybean-tangerine peel fermented milk.

[0058] The present invention also proposes a soybean-tangerine peel fermented milk, which is prepared by the preparation method of the soybean-tangerine peel fermented milk. The soybean-tangerine peel fermented milk has all the technical solutions of the preparation method of the soybean-tangerine peel fermented milk, and thus has all the beneficial effects of the preparation method of the soybean-tangerine peel fermented milk, which will not be described in detail in the present invention.

[0059] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention. The following embodiments are used as examples for description.

[0060] Example 1

[0061] Purchase soybeans and pre-treat them: select soybeans with good maturity, remove impurities and moldy particles, soak 30g of washed soybeans in pure water (bean-water ratio 1:3) at 4°C for 10h, drain the water and steam for 30min to obtain pre-treated soybeans;

[0062] The pretreated soybeans and tangerine peels were mixed in a mass ratio of 100:2, and 85°C hot water was added for grinding, and then sieved to obtain a soybean milk and tangerine peel mixed solution, 6% sucrose and 1% walnut oil were added to the mixed solution, and then the mixed solution was treated for 8 minutes under the conditions of ultrasonic frequency of 20KHz and ultrasonic power of 300W, with the working time and intermittent time being 6s. During the ultrasonic process, the sample was placed in an ice water bath to control the ultrasonic temperature, and sterilized for 12 minutes to obtain a fermentation base material;

[0063] The fermentation base material and the lactic acid bacteria starter are mixed at 0.1% w / v, and fermented at 42° C. for 6 hours to obtain a fermentation product;

[0064] The fermented product was placed in a refrigerator at 4° C. and refrigerated for 12 hours to obtain soybean-tangerine peel fermented milk.

[0065] Example 2

[0066] Purchase soybeans and pre-treat them: select soybeans with good maturity, remove impurities and moldy particles, soak 30g of washed soybeans in pure water (bean-water ratio 1:3) at 4℃ for 8h, drain the water and steam for 20min;

[0067] The pretreated soybeans and tangerine peels are mixed in a mass ratio of 100:2, and 85°C hot water is added for grinding, and then sieved to obtain a soybean milk and tangerine peel mixed solution, 6% sucrose and 1% walnut oil are added to the mixed solution, and then the mixed solution is treated for 5 minutes under the conditions of an ultrasonic frequency of 20KHz and an ultrasonic power of 200W, with the working time and the interval time being 6s. During the ultrasonic process, the sample is placed in an ice water bath to control the ultrasonic temperature, and sterilized for 10 minutes to obtain a fermentation base material;

[0068] The fermentation base material and the lactic acid bacteria starter are mixed at 0.1% w / v, and fermented at 43° C. for 7 hours to obtain a fermentation product;

[0069] The fermented product was placed in a refrigerator at 2° C. and refrigerated for 10 hours to obtain soybean-tangerine peel fermented milk.

[0070] Example 3

[0071] Purchase soybeans and pre-treat them: select soybeans with good maturity, remove impurities and moldy particles, soak 30g of washed soybeans in pure water (bean-water ratio 1:3) at 4℃ for 12h, drain the water and steam for 40min;

[0072] The pretreated soybeans and tangerine peels are mixed in a mass ratio of 100:5, and 80°C hot water is added to grind the mixture, and then sieved to obtain a soybean milk and tangerine peel mixed solution, 6% sucrose and 1% walnut oil are added to the mixed solution, and then the mixture is treated for 10 minutes under the conditions of an ultrasonic frequency of 20KHz and an ultrasonic power of 400W, with the working time and the interval time being 6s. During the ultrasonic process, the sample is placed in an ice water bath to control the ultrasonic temperature, and sterilized for 15 minutes to obtain a fermentation base material;

[0073] The fermentation base material and the lactic acid bacteria starter are mixed at 0.1% w / v, and fermented at 41° C. for 5 hours to obtain a fermentation product;

[0074] The fermented product was placed in a refrigerator at 5° C. and refrigerated for 14 hours to obtain soybean-tangerine peel fermented milk.

[0075] Example 4

[0076] Purchase soybeans and pre-treat them: select soybeans with good maturity, remove impurities and moldy particles, soak 30g of washed soybeans in pure water (bean-water ratio 1:3) at 4℃ for 6h, drain the water and steam for 50min;

[0077] The pretreated soybeans and tangerine peels are mixed in a mass ratio of 100:1, and 80°C hot water is added to grind the mixture, and then sieved to obtain a soybean milk and tangerine peel mixed solution, 6% sucrose and 1% walnut oil are added to the mixed solution, and then the mixture is treated for 15 minutes under the conditions of an ultrasonic frequency of 20KHz and an ultrasonic power of 500W, with the working time and the interval time being 6s. During the ultrasonic process, the sample is placed in an ice water bath to control the ultrasonic temperature, and sterilized for 20 minutes to obtain a fermentation base material;

[0078] The fermentation base material and the lactic acid bacteria starter are mixed at 0.1% w / v, and fermented at 45° C. for 8 hours to obtain a fermentation product;

[0079] The fermented product was placed in a refrigerator at 6° C. and refrigerated for 8 hours to obtain soybean-tangerine peel fermented milk.

[0080] Comparative Example 1

[0081] The preparation method of the soybean-tangerine peel fermented milk of Comparative Example 1 is the same as that of Example 1 except that there is no "tangerine peel".

[0082] Comparative Example 2

[0083] The preparation method of soybean-tangerine peel fermented milk in Comparative Example 2 is the same as that of Example 1 except that there is no "ultrasonic treatment".

[0084] Comparative Example 3

[0085] The preparation method of soybean-tangerine peel fermented milk in Comparative Example 2 is the same as that in Example 1 except that "adding 85° C. hot water for grinding" is replaced by "grinding at room temperature".

[0086] Comparative Example 4

[0087] The preparation method of soybean-tangerine peel fermented milk of Comparative Example 4 is the same as that of Example 1 except that the step of steaming soybeans after draining the water is omitted.

[0088] Comparative Example 5

[0089] The preparation method of soybean-tangerine peel fermented milk of Comparative Example 5 is the same as that of Example 1 except that “tangerine peel and vegetable oil” are not included.

[0090] Performance Testing

[0091] The soybean-tangerine peel fermented milk prepared in the above examples 1 to 3 is as follows Figure 1 As shown, other performance tests were performed on the above embodiments, and the test results are as follows:

[0092] 1. Water holding capacity test of soybean-tangerine peel fermented milk

[0093] Water holding capacity (WHC) determination: 15 g of the soybean-tangerine peel fermented milk prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were tested, and cultured at a constant temperature of 41 to 43° C. in a centrifuge tube until the end of fermentation. After refrigeration at 4° C., the sample was centrifuged at a rate of 3000 r / min for 10 min at 20° C., and weighed after removing the whey. The soybean-tangerine peel fermented milk prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were respectively measured in parallel 3 times, and the water holding capacity was calculated according to the following formula: Water holding capacity (%) = m1 / m2, wherein,

[0094] m1 is the mass of the sample after centrifugation (g), m2 is the mass of the sample before centrifugation (g), and the measurement results are shown in Table 1 below.

[0095] 2. Texture determination of soybean-tangerine peel fermented milk

[0096] Determination method: The fermented soy milk was tested using the TMS-Pro texture analyzer produced by FTC Company of the United States, using a cylindrical probe P10; the probe test speed was 1 mm / s; the trigger force was 5.0 g; and the strain degree was 30%.

[0097] The texture of the soybean-tangerine peel fermented milk prepared in Examples 1 to 4 and Comparative Examples 1 to 5 was measured, and the results are shown in Table 1:

[0098] Table 1 Texture determination of soybean-tangerine peel fermented milk

[0099]

[0100]

[0101] It can be seen from Table 1 above that the fermented soymilk prepared in Examples 1 to 4 has good stability and texture characteristics. The water holding capacity (WHC) of fermented milk refers to its ability to retain water, which is an important indicator for evaluating its stability. Under the same centrifugal force, Examples 1 to 4 have higher water holding capacity, indicating that their stability is better. The fermented milk of Examples 1 to 4 has a higher hardness, giving it a thicker mouthfeel and higher stability, while the hardness of Comparative Examples 1, 2, 4, and 5 is lower, resulting in the fermented milk being easier to flow and may be lacking in stability. This is because the dietary fiber in tangerine peel can be used as a dispersed particle filler to strengthen the gel structure. Comparative Example 1 lacks tangerine peel, so the hardness is lower. Ultrasonic treatment can destroy fat globules and other large particles in soy milk, making them smaller and more uniform. This change in microstructure helps proteins and other ingredients to be more evenly distributed in the fermented milk, forming a tighter network structure and improving the hardness of the fermented milk. Comparative Example 2 lacks ultrasonic treatment, so the hardness is lower. In comparative example 3, after the soybeans were treated with wet heat, more high molecular weight protein polymers were formed during the water refining process at room temperature. These macromolecules interacted with each other during the fermentation process of fermented milk to form a tight three-dimensional network structure, which increased the hardness of the fermented milk. However, too high a hardness may cause the fermented milk to be difficult to break in the mouth, resulting in difficulty in swallowing. The wet heat treatment partially denatures the protein molecules, exposing more hydrophobic groups, making it easier for these denatured protein molecules to aggregate and cross-link with each other during the fermentation process to form a more stable gel structure, thereby increasing the hardness of the fermented milk. Comparative example 4 lacks wet heat treatment and has a lower hardness. Comparative example 5 lacks vegetable oils and fats, which have a good emulsifying effect and can stabilize the gel structure, making the texture of the fermented milk more uniform. A low fat content may weaken the emulsifying effect, making the fermented milk gel structure relatively unstable and the hardness relatively reduced. The fermented milk of Examples 1 to 4 has a high cohesion, indicating that the internal bonding strength is strong and the fermented milk with high cohesion is not easy to separate or stratify during storage and transportation, maintaining its stable gel structure. The chewiness and stickiness of Comparative Example 3 are too high, indicating that more energy is needed to break the fermented milk into a swallowable state during the chewing process, which makes the taste of the fermented milk too heavy and loses the smoothness it should have.

[0102] 3. Flavor determination: Flavor analysis of soybean-tangerine peel fermented milk using HS-SPME and GC-MS analysis methods

[0103] The soybean-tangerine peel fermented milk prepared in Examples 1 to 4 and Comparative Examples 1 to 5 was analyzed by GC-MS and HS-SPME. The GC-MS test conditions were as follows:

[0104] An HP-5 chromatographic column (30m×0.32mm×0.25μm) was used, and the carrier gas was He. The heating program was as follows: starting temperature 40°C, maintained for 3min; heating to 100°C at 6°C / min, without maintaining; then heating to 140°C at 10°C / min, maintained for 2min; heating to 220°C at 4°C / min, maintained for 3min; heating to 230°C at 10°C / min, maintained for 5min, without split injection.

[0105] Mass spectrometry conditions: ion source EI source, ion source temperature 230°C, interface temperature 250°C, electron energy 70eV, scanning range m / z 33-500. The test results are shown in Table 2.

[0106] Qualitative and quantitative analysis of flavor substances: The NIST mass spectrometry database search results were compared with standard compounds, and the volatile substances with a matching degree greater than 800 were qualitatively identified. The internal standard method was used for quantification, using 2-methyl-3-heptanone as the internal standard substance, and the content of the tested component was calculated according to mg / kg based on the ratio of the chromatographic peak area of ​​the tested compound and the internal standard substance.

[0107] Among them, the flavor components of soybean-tangerine peel fermented milk prepared in Example 1, Comparative Example 1 and Comparative Example 4 are shown in Table 2:

[0108] Table 2 Flavor components of soybean-tangerine peel fermented milk prepared in Example 1, Comparative Example 1 and Comparative Example 4

[0109]

[0110] It can be seen from Table 2 that compared with Example 1, Comparative Example 1 lacks tangerine peel, thereby reducing the production of flavor substances and the retention of flavor substances, thereby weakening the flavor. For example, after retaining for 2.439 minutes, Comparative Example 1 contains 0.16 mg / kg of hexanal and grassy flavor substances, and the flavor substances are not pleasant.

[0111] Compared with Example 1, the lack of ultrasonic treatment in Comparative Example 2 indicates that ultrasonic treatment can improve the texture characteristics of the fermented milk in Example 1 and enhance its stability.

[0112] Compared with Example 1, Comparative Example 3 adopts room temperature water grinding, which shows that hot grinding can make the taste of the fermented milk in Example 1 more delicate and reduce its granularity.

[0113] Compared with Example 1, Comparative Example 4 lacks steam treatment of soybeans, that is, wet heat method, indicating that steam treatment of soybeans can significantly improve the flavor of the fermented milk in Example 1 and reduce the beany smell.

[0114] Compared with Example 1, Comparative Example 5 lacks tangerine peel and vegetable oil, thereby reducing the generation of flavor substances and the retention of flavor substances, thereby weakening the flavor.

[0115] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A method for preparing soybean-tangerine peel fermented milk, characterized in that: The following steps are involved: Providing soybeans, soaking and steaming the soybeans to obtain pre-treated soybeans; The pretreated soybeans and tangerine peels are mixed and ground to obtain a mixed solution, and the mixed solution is mixed with vegetable oil and subjected to ultrasonic treatment for sterilization to obtain a fermentation base; The fermentation base material is mixed with a fermentation agent and fermented to obtain a fermentation product; The fermented product is subjected to post-ripening treatment to obtain soybean-tangerine peel fermented milk.

2. The method for preparing soybean-tangerine peel fermented milk according to claim 1, characterized in that: In the step of soaking and steaming soybeans: The soaking time is 8 to 12 hours; and / or, The steaming time is 10 to 40 minutes.

3. The method for preparing soybean-tangerine peel fermented milk according to claim 1, characterized in that: The soybeans and tangerine peels are mixed and ground to obtain a mixed solution, and the mixed solution is mixed with vegetable oil and fat, subjected to ultrasonic treatment, and sterilized to obtain a fermentation base material: The mass ratio of soybean to tangerine peel is: 100:(1-5); and / or, The vegetable oil comprises at least one of soybean oil, camellia oil, walnut oil and grape seed oil; and / or, The amount of vegetable oil added is 1-5% of the mass of the mixed liquid; and / or, The power of ultrasonic treatment is 200-400W; and / or, The ultrasonic treatment time is 5 to 10 minutes; and / or, The sterilization time is 10 to 15 minutes.

4. The method for preparing soybean-tangerine peel fermented milk according to claim 1, characterized in that: In the step of mixing the fermentation base with the fermentation agent and fermenting to obtain the fermented product: The fermentation temperature is 41-43°C; and / or, The fermentation time is 5 to 7 hours.

5. The method for preparing soybean-tangerine peel fermented milk according to claim 1, characterized in that: In the step of mixing the fermentation base with a starter and fermenting to obtain a fermented product, the starter includes at least one of Lactobacillus delbrueckii subsp. bulgaricus and Lactococcus lactis subsp. lactis.

6. The method for preparing soybean-tangerine peel fermented milk according to claim 5, characterized in that: The mass concentration of the leavening agent in the fermentation base material is 0.08-0.15%.

7. The method for preparing soybean-tangerine peel fermented milk according to claim 1, characterized in that: The step of post-ripening the fermented product to obtain soybean-tangerine peel fermented milk includes: refrigerating the fermented product to obtain soybean-tangerine peel fermented milk.

8. The method for preparing soybean-tangerine peel fermented milk according to claim 7, characterized in that: The fermented product is refrigerated to obtain soybean-tangerine peel fermented milk: Refrigeration time is 10 to 14 hours; and / or, The refrigeration temperature is 2-5℃.

9. A soybean-tangerine peel fermented milk, characterized in that: The method for preparing soybean-tangerine peel fermented milk according to any one of claims 1 to 8 is used.

Images