Solidified yoghurt and preparation method thereof

Abstract

The invention provides set yoghurt and a preparation method thereof, and the preparation method comprises the following steps: squeezing ginger to obtain ginger juice to be fermented; fermenting the to-be-fermented ginger juice at a first fermentation temperature in the presence of a first fermentation agent until the pH value reaches 5.2 or below to obtain fermented ginger juice; wherein the first fermentation agent comprises lactobacillus plantarum, and the first fermentation temperature is less than or equal to 32 DEG C; and fermenting a mixed system containing animal milk and the fermented ginger juice in the presence of a second leavening agent to prepare the set yogurt. The preparation method can weaken the spicy taste of the ginger and improve the flavor, taste and other qualities of the set yoghurt.

Description

Technical Field

[0001] The invention relates to the technical field of dairy products, and in particular to a coagulated yogurt and a preparation method thereof. Background Art

[0002] Ginger has nutritional and health functions. Combining dairy products with ginger can further improve the nutritional value of dairy products. However, ginger has a strong spicy taste. Adding it to dairy products is not conducive to the flavor and taste of dairy products. Summary of the invention

[0003] The invention provides a set-type yogurt and a preparation method thereof, which can reduce the pungent taste of ginger, improve the flavor and taste of the set-type yogurt, and effectively overcome the defects of the prior art.

[0004] One aspect of the present invention provides a method for preparing a coagulated yogurt, comprising the following steps: squeezing ginger juice to obtain ginger juice to be fermented; fermenting the ginger juice to be fermented at a first fermentation temperature in the presence of a first fermentation agent until the pH reaches below 5.2 to obtain fermented ginger juice; wherein the first fermentation agent comprises one or more of Lactobacillus plantarum, Lactobacillus casei and Lactobacillus helveticus, and the first fermentation temperature is less than or equal to 32°C; fermenting a mixed system containing animal milk and the fermented ginger juice in the presence of a second fermentation agent to obtain a coagulated yogurt.

[0005] According to one embodiment of the present invention, the process of squeezing ginger to obtain ginger juice includes: squeezing peeled and washed ginger to obtain initial ginger juice; filtering, first homogenizing and sterilizing the initial ginger juice in sequence to obtain the ginger juice to be fermented; wherein the filtration process includes: filtering the initial ginger juice through a first filter membrane with a pore size of 70 to 80 meshes, and then filtering through a second filter membrane with a pore size of 180 to 200 meshes; and / or, the pressure of the first homogenization is 180 to 200 bar; and / or, the sterilization is performed using a microfiltration membrane.

[0006] According to one embodiment of the present invention, the first fermentation temperature is 28-32°C.

[0007] According to one embodiment of the present invention, the process of fermenting the ginger juice to be fermented in the presence of a first fermentation agent at a first fermentation temperature until the pH reaches below 5.2 comprises: heating the ginger juice to be fermented to the first fermentation temperature, adding the first fermentation agent thereto for fermentation until the pH reaches below 5.2, and then cooling to 4°C to obtain the fermented ginger juice.

[0008] According to one embodiment of the present invention, the process of fermenting the mixed system containing animal milk and the fermented ginger juice in the presence of a second fermentation agent includes: fermenting the mixed system in the presence of the second fermentation agent at a second fermentation temperature until the acidity reaches above 67°T or the pH reaches below 4.7, and then cooling to below 20°C to obtain the coagulated yogurt; wherein the second fermentation temperature is 40-45°C.

[0009] According to one embodiment of the present invention, the method further includes: after subjecting the mixed system to a second homogenization and sterilization, controlling the temperature of the mixed system to a second fermentation temperature, adding the second leavening agent thereto, and fermenting at the second fermentation temperature; wherein the second homogenization is performed using a homogenizer, and during the second homogenization process, the first-level pressure of the homogenizer is controlled to be 30-40 bar, and the second-level pressure is controlled to be 160-180 bar; and / or, the sterilization temperature is 74-76°C, and the time is 14-16s; and / or, the second fermentation temperature is 40-45°C.

[0010] According to one embodiment of the present invention, the second fermentation agent includes Streptococcus thermophilus and / or Lactobacillus delbrueckii subsp. bulgaricus.

[0011] According to one embodiment of the present invention, in the mixed system, the mass ratio of the animal milk to the fermented ginger juice is (4-9):1.

[0012] According to one embodiment of the present invention, the mixed system further comprises a sweetener, a thickener, a starch and an emulsifier; wherein, in the mixed system, by weight, the sweetener is 40-60 parts, the thickener is 3-5 parts, the starch is 3-5 parts, the emulsifier is 1-1.5 parts, and the balance is the animal milk and the fermented ginger juice; and / or, the sweetener comprises white sugar; and / or, the thickener comprises gelatin, carrageenan, konjac gum, gellan gum, xanthan gum, starch, pectin, agar, citrus fiber, thorn One or more of locust bean gum and guar gum; and / or, the starch includes acetylated distarch phosphate and / or hydroxypropyl distarch phosphate; and / or, the emulsifier includes one or more of sodium carboxymethyl cellulose, diacetyl tartaric acid mono- and diglycerides and mono-fatty acid glycerides; and / or, the preparation process of the mixed system includes: mixing the animal milk and the fermented ginger juice, heating to 50-55° C., adding the sweetener, thickener, starch and emulsifier thereto, and stirring evenly to obtain the mixed system.

[0013] Another aspect of the present invention provides a set-type yogurt prepared according to the above preparation method.

[0014] The preparation method of the coagulated yogurt provided by the present invention adopts a first fermentation agent and performs low-temperature fermentation (the first fermentation temperature is less than or equal to 32°C) on the ginger juice to be fermented, which can reduce the strong bitter and spicy taste of the ginger juice, while retaining the nutritional components of the ginger juice and the sweet and spicy flavor thereof, thereby improving the flavor of the fermented ginger juice, and in conjunction with the subsequent fermentation process of a mixed system containing animal milk and fermented ginger juice, the nutritional properties of ginger are combined with yogurt to prepare coagulated yogurt, and the flavor and mouthfeel of the prepared coagulated yogurt can be improved, for example, the bitter and spicy taste of the coagulated yogurt can be reduced, and at the same time, the coagulated yogurt can have the characteristics of fine texture, rich nutrition, and health preservation, thereby satisfying consumers' pursuit of the taste and nutrition of yogurt products.

[0015] In addition, the coagulated yogurt of the embodiment of the present invention also has good uniformity, and its state is uniform, the texture is uniform, and basically no water is separated (the water and the base are basically not separated).

[0016] In addition, the present invention can also ensure the texture of the coagulated yogurt, so that it has suitable hardness, viscosity, elasticity and thixotropy, and has good stability. Specifically, as the storage time increases, the acidity and pH change of the coagulated yogurt are low. For example, after the coagulated yogurt is placed for 7 days, the acidity change rate is less than 10%, and the pH change rate is less than 5.3%; after being placed for 14 days, the acidity change rate is less than 20%, and the pH change rate is less than 9.6%. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the description of the present invention, terms such as "first" and "second" are used only for descriptive purposes, such as distinguishing between components to more clearly illustrate / explain the technical solution, and cannot be understood as indicating or implying the number of the indicated technical features or the order with substantial significance.

[0019] In recent years, people's living standards have continued to improve, consumers' health awareness has increased, healthy nutrition and health preservation have gradually become the focus of people's attention, and products with both medicinal and edible properties have been continuously produced.

[0020] Ginger is rich in nutritional value, and also has certain anti-aging, anti-inflammatory and antibacterial pharmaceutical effects. For example, the zingiberene contained in ginger can stimulate the gastric mucosa to synthesize and release endogenous pepsinogen with cell-protective effects, thereby protecting the gastric mucosa and preventing damage to the gastric mucosa; in addition, ginger can act on the sympathetic and vagus nervous systems, inhibiting gastric function and directly stimulating gastric smooth muscle; in addition, the gingerol in ginger can produce an anti-aging superoxide dismutase after being digested and absorbed by the human body, thereby inhibiting the production and deposition of lipofuscin pigments in the body and delaying cell aging.

[0021] Dairy products have nutritional and health benefits. Combining dairy products with ginger can further improve the nutritional value of dairy products. However, ginger has a strong bitter and spicy taste. If it is added to dairy products, it is not conducive to the flavor and taste of dairy products.

[0022] In view of this, an embodiment of the present invention provides a method for preparing a coagulable yogurt, comprising the following steps: squeezing ginger juice to obtain ginger juice to be fermented; fermenting the ginger juice to be fermented at a first fermentation temperature in the presence of a first fermentation agent until the pH reaches below 5.2 to obtain fermented ginger juice; wherein the first fermentation agent includes one or more of Lactobacillus plantarum, Lactobacillus casei and Lactobacillus helveticus, and the first fermentation temperature is less than or equal to 32°C; fermenting a mixed system containing animal milk and fermented ginger juice in the presence of a second fermentation agent to obtain a coagulable yogurt.

[0023] In the above preparation process, a first fermentation agent is used, and the ginger juice to be fermented is fermented at a low temperature (the first fermentation temperature is less than or equal to 32°C), which can reduce the strong bitter and spicy taste of the ginger juice, while retaining the nutritional components of the ginger juice and its sweet and spicy flavor, making it moderately spicy, thereby improving the flavor of the fermented ginger juice, and cooperating with the subsequent fermentation process of a mixed system containing animal milk and fermented ginger juice to combine the nutritional properties of ginger with yogurt to obtain a solidified yogurt, and can improve the flavor and taste of the solidified yogurt obtained. For example, the solidified yogurt can have the characteristics of coordinated aroma, moderate sweet and sour, fine texture, rich nutrition, health and nourishing, healthy, natural, etc., to meet consumers' pursuit of taste and nutrition for yogurt products.

[0024] Specifically, in the above preparation process, the process of squeezing ginger to obtain ginger juice may include: squeezing peeled and washed ginger to obtain initial ginger juice; filtering, first homogenizing and sterilizing the initial ginger juice in sequence to obtain ginger juice to be fermented.

[0025] In specific implementation, fresh ginger can be selected, and the ginger can be peeled and cleaned using equipment such as a hair roller peeling machine, and then squeezed using a juicer to obtain initial ginger juice.

[0026] In addition, by filtering the initial ginger juice, the residue and larger fibers and other components in the initial ginger juice can be filtered out. In some embodiments, the filtering process includes: filtering the initial ginger juice through a first filter membrane and then filtering it through a second filter membrane, wherein the pore size of the second filter membrane is smaller than the pore size of the first filter membrane, and the residue in the initial ginger juice can be mainly removed through the first filter membrane, and the larger fibers and other components in the initial ginger juice can be mainly removed through the second filter membrane.

[0027] Specifically, the pore size of the first filter membrane may be 70-80 meshes, for example, 70 meshes, 73 meshes, 75 meshes, 78 meshes, 80 meshes or a range consisting of any two thereof.

[0028] Specifically, the pore size of the second filter membrane can be 180-200 mesh, for example, 180 mesh, 183 mesh, 185 mesh, 188 mesh, 190 mesh, 193 mesh, 195 mesh, 198 mesh, 200 mesh or a range consisting of any two thereof.

[0029] By performing a first homogenization on the filtered initial ginger juice, the system of the initial ginger juice can be made more uniform. In some embodiments, the pressure of the first homogenization can be 180-200 bar (i.e., the filtered initial ginger juice is homogenized at a pressure of 180-200 bar), for example, 180 bar, 183 bar, 185 bar, 188 bar, 190 bar, 193 bar, 195 bar, 198 bar, 200 bar or a range consisting of any two of them.

[0030] In addition, a sterilization membrane can be used to sterilize the initial ginger juice after the first homogenization, that is, the sterilization membrane is used to filter the initial ginger juice after the first homogenization, so that all microorganisms in the initial ginger juice are trapped on the sterilization membrane, thereby achieving sterilization. Among them, the sterilization membrane used can specifically include a microfiltration membrane (MF), that is, the microfiltration membrane (MF) can be used to sterilize the initial ginger juice after the first homogenization.

[0031] Specifically, the above-mentioned coagulated yogurt (or ginger curd) is in a gelatinous state, specifically in the state of old yogurt. According to the research and analysis of the inventor, the first fermentation agent is used, and the ginger juice to be fermented is fermented at a low temperature. While reducing the strong bitter and spicy taste of ginger, it can also make the ginger juice have a certain amount of ginger protease and maintain the enzyme activity. In the subsequent fermentation process of the mixed system containing animal milk and fermented ginger juice, the presence of the enzyme can promote protein cross-linking gel, which is conducive to the preparation of coagulated yogurt. Studies have shown that if the first fermentation temperature is too high (greater than 32°C), the flavor and morphology of the prepared yogurt product will be poor, and it will not meet the requirements of coagulated yogurt products.

[0032] Generally speaking, within the range of the first fermentation temperature being less than or equal to 32°C, when the first fermentation temperature is higher, the fermentation time can be shortened (i.e., the target pH (pH reaches below 5.2) can be fermented in a shorter time), thereby improving the fermentation efficiency. Conversely, when the first fermentation temperature is lower, the fermentation time will be relatively longer.

[0033] Therefore, in some preferred embodiments, the first fermentation temperature can be 28-32°C, for example, 28°C, 29°C, 30°C, 31°C, 32°C or a range composed of any two of them, which is conducive to improving the fermentation efficiency of ginger juice while improving the flavor and texture of the prepared solidified yogurt.

[0034] The fermentation endpoint of the fermented ginger juice is when the pH of the fermented ginger juice reaches below 5.2, that is, the fermentation is stopped when the pH of the ginger juice reaches below 5.2. Specifically, during the low-temperature fermentation of the fermented ginger juice, before reaching the fermentation endpoint, the pH value of the system is relatively high. As the fermentation proceeds (that is, as the fermentation time increases), the pH value of the system gradually decreases. When the pH of the system reaches below 5.2 (the pH just reaches 5.2 or is slightly below 5.2), the fermentation is stopped.

[0035] According to the research and analysis of the inventors, during the low-temperature fermentation process of the above-mentioned ginger juice to be fermented, if the pH value at the fermentation end point is too high (i.e., the pH of the fermented ginger juice>5.2), the ginger juice will not be fully fermented, and the prepared coagulated yogurt will have a heavier spicy taste, poor flavor and taste. If the pH value at the fermentation end point is too low, it will also affect the subsequent fermentation process of the mixed system to a certain extent.

[0036] In a specific implementation, the pH value of the fermentation system can be detected, and the fermentation is stopped when the pH reaches below 5.2, and the fermentation can be stopped when the pH value of the fermentation system is 5.1-5.2 to obtain fermented ginger juice (the pH of the fermented ginger juice is 5.1-5.2). When the fermentation end point is reached (the ginger juice is fermented until the pH reaches below 5.2), the fermentation system can be cooled to a temperature lower than the first fermentation temperature, and can be cooled to about 4°C to stop the fermentation.

[0037] Specifically, the ginger juice to be fermented can be heated to a first fermentation temperature, and a first fermentation agent is added thereto for fermentation until the pH value reaches below 5.2, and then the fermentation is stopped to obtain the fermented ginger juice.

[0038] In some embodiments, the process of fermenting the ginger juice to be fermented in the presence of a first fermentation agent at a first fermentation temperature until the pH reaches below 5.2 may include: heating the ginger juice to be fermented to the first fermentation temperature, adding the first fermentation agent thereto for fermentation until the pH reaches below 5.2, and then cooling to 2-6°C (i.e., terminating the fermentation), for example, 2°C, 3°C, 4°C, 5°C, 6°C or a range composed of any two thereof, to obtain fermented ginger juice.

[0039] Relatively speaking, when the fermented ginger juice is too little (the mass ratio of animal milk to fermented ginger juice is greater than 9:1), the characteristic ginger flavor of the coagulated yogurt is weaker; when the animal milk is too little (the mass ratio of animal milk to fermented ginger juice is less than 4:1), it will affect the texture stability of the coagulated yogurt to a certain extent, making the coagulated yogurt have poor locking ability for components such as whey and water, resulting in the phenomenon of water base separation, and at the same time, the locking ability for spicy flavors is weak, making the spicy flavor release stronger, affecting the properties of the coagulated yogurt such as flavor and aroma coordination. Therefore, considering these factors comprehensively, in the above-mentioned mixed system, the mass ratio of animal milk to fermented ginger juice is preferably (4 to 9): 1, such as 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1 or any two of them, which is more conducive to the preparation of coagulated yogurt and optimizes the properties such as flavor and morphology of coagulated yogurt.

[0040] Specifically, the animal milk used may include cow's milk, and conventional cow's milk in the art may be used.

[0041] In addition, the above-mentioned mixed system can also include sweeteners, thickeners, starch and emulsifiers, among which the sweeteners can improve the taste of the coagulated yogurt, the thickeners can be used as stabilizers, and the thickeners and starches can be used as thickeners at the same time. The emulsifiers can improve the compatibility between the components and make the components better integrated, thereby facilitating the formation of coagulated yogurt, and can further improve the texture and other properties of the coagulated yogurt.

[0042] Specifically, the sweetener may include white sugar; the thickener may include one or more of gelatin, carrageenan, konjac gum, gellan gum, xanthan gum, starch, pectin, agar, citrus fiber, locust bean gum and guar gum; the starch may include acetylated distarch phosphate and / or hydroxypropyl distarch phosphate; the emulsifier may include one or more of sodium carboxymethyl cellulose, diacetyl tartaric acid mono- and diglycerides and mono-fatty acid glycerides.

[0043] Specifically, in the above-mentioned mixed system, by weight, the sweetener can be 40-60 parts, the thickener can be 3-5 parts, the starch can be 3-5 parts, the emulsifier can be 1-1.5 parts, and the remainder is animal milk and fermented ginger juice (i.e., the remaining weight is the sum of the weights of animal milk and fermented ginger juice). Controlling the ingredients such as starch and emulsifier within the above range is beneficial to the texture stability of the prepared coagulated yogurt, avoiding the phenomenon of water base separation, and can enhance the locking ability of flavors such as spicy taste, and further optimize the properties of the coagulated yogurt such as flavor and aroma coordination.

[0044] Exemplarily, the sweetener may be in a range of 40 parts, 43 parts, 45 parts, 48 ​​parts, 50 parts, 53 parts, 55 parts, 58 parts, 60 parts, or any two thereof.

[0045] For example, the thickener may be in a range of 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, or any two of them.

[0046] Exemplarily, the starch may be in a range of 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, or any two thereof.

[0047] Illustratively, the emulsifier may be in a range of 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, or any two thereof.

[0048] It should be noted that, for each of the sweeteners, thickeners, starches and emulsifiers, when there are multiple types in the mixed system, the weight fraction thereof refers to the sum of the weight fractions of these types. Taking the thickener as an example, when the mixed system contains multiple thickeners, the weight fraction of the above-mentioned thickener (3 to 5 parts) is the sum of the weight fractions of these thickeners.

[0049] In a specific implementation, the animal milk and the fermented ginger juice can be mixed first, and then ingredients such as a sweetener, a thickener, starch and an emulsifier are added thereto, and mixed evenly to obtain a mixed system.

[0050] In some embodiments, the preparation process of the mixed system may include: mixing animal milk and fermented ginger juice, heating to 50-55° C., adding sweetener, thickener, starch and emulsifier thereto, stirring evenly (for example, stirring for about 18-22 minutes), to obtain a mixed system.

[0051] Generally, the second fermentation agent may include a high-yield viscous fermentation strain. In some embodiments, the second fermentation agent may include Streptococcus thermophilus and / or Lactobacillus delbrueckii subspecies bulgaricus.

[0052] In addition, the mixed system may be subjected to a second homogenization and sterilization treatment before fermentation. In some specific embodiments, the preparation process may include: after subjecting the mixed system to a second homogenization and sterilization treatment, controlling the temperature of the mixed system to a second fermentation temperature, then adding a second fermentation agent thereto, and fermenting at the second fermentation temperature.

[0053] A homogenizer is used for the second homogenization, and during the second homogenization process, the first-stage pressure of the homogenizer is controlled to be 30-40 bar, and the second-stage pressure is controlled to be 160-180 bar, that is, the mixed system is homogenized under the joint action of the two-stage pressure.

[0054] In specific implementation, a pasteurization process can be used to sterilize the mixed system after the second homogenization.

[0055] Specifically, the sterilization temperature can be 74-76°C, for example 75°C, and the time can be 14-16s, for example 15s. This can reduce the impact on the enzyme activity in the ginger juice during sterilization, ensure the retention of the enzyme activity in the ginger juice, facilitate the gelation of ingredients such as animal milk in the mixed system to form a coagulated yogurt, and improve the texture stability of the coagulated yogurt, avoid phenomena such as water base separation, and optimize the color, flavor, aroma coordination and other properties of the coagulated yogurt.

[0056] In addition, the second fermentation temperature may be 40-45°C, for example, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C or a range consisting of any two thereof.

[0057] Specifically, the mixed system can be fermented at the second fermentation temperature in the presence of the second fermentation agent until the acidity reaches 67°T or above or the pH reaches 4.7 or below, that is, the fermentation end point is when the system acidity reaches 67°T or above or the pH reaches 4.7 or below. Specifically, during the fermentation process of the mixed system, before reaching the fermentation end point, the acidity of the system is relatively low and the pH value is relatively high. As the fermentation proceeds (i.e., as the fermentation time increases), the acidity of the system gradually increases and the pH value gradually decreases. When the acidity of the system reaches 67°T or above (the acidity just reaches 4.7 or is slightly lower than 4.7) or the pH reaches below 4.7 (the pH just reaches 4.7 or is slightly lower than 4.7), the fermentation is stopped.

[0058] In specific implementation, the pH value of the fermentation system can be detected, and the fermentation is stopped when the acidity reaches 67°T or above or the pH reaches 4.7 or below. Specifically, the fermentation can be stopped when the acidity of the fermentation system is 67-72°T or the pH value is 4.6-4.7 to obtain a coagulated yogurt. When the fermentation end point is reached (the system is fermented until the acidity reaches 67°T or above or the pH reaches 4.7 or below), the fermentation system can be cooled to a temperature lower than the second fermentation temperature, specifically, it can be cooled to below 20°C (i.e., the system temperature is cooled to less than or equal to 20°C) to stop the fermentation and obtain a coagulated yogurt.

[0059] In some specific embodiments, the process of fermenting a mixed system containing animal milk and fermented ginger juice in the presence of a second fermentation agent includes: fermenting the mixed system in the presence of the second fermentation agent at a second fermentation temperature until the acidity reaches above 67°T or the pH reaches below 4.7, and then cooling to below 20°C to stop the fermentation to obtain a coagulated yogurt.

[0060] In specific implementation, after the mixed system is subjected to the second homogenization and sterilization treatment, the mixed system can be cooled to the second fermentation temperature and then inoculated with the second fermentation agent. Specifically, the second fermentation agent can be added thereto and then filled into a packaging container. The packaging container is then placed in a fermentation room and kept warm and fermented at the second fermentation temperature until the acidity reaches above 67°T or the pH reaches below 4.7. The fermentation time is generally 4 to 10 hours, for example, 5 to 8 hours. The system is then cooled to below 20°C to stop the fermentation.

[0061] Generally, after the fermentation of the mixed system is completed (i.e., the fermentation is stopped), the obtained solidified fermentation product can also be post-ripened. The embodiment of the present invention can adopt the conventional post-ripening process in the field, for example, the solidified fermentation product is refrigerated at 4 to 8°C for 3 to 5 hours to be post-ripened to obtain solidified yogurt, and then the obtained solidified yogurt can be refrigerated at 2 to 6°C.

[0062] In the embodiment of the present invention, ginger is used, peeled and cleaned, and then ginger juice (initial ginger juice) is obtained by crushing and squeezing. After screening (filtration), it is sterilized by filtering and sterilizing equipment such as a microfiltration membrane, and then homogenized. Then, a fermentation strain (a first fermentation agent) is added thereto, and low-temperature fermentation is carried out under the aforementioned specific conditions, so as to improve the flavor of the ginger juice, reduce the strong bitter and spicy taste of the ginger juice, and retain the nutrition and rich ginger smell of the ginger juice; through the fermentation process of the subsequent mixing system, the fermented ginger juice is introduced into the coagulated yogurt product, which can improve the flavor and taste of the coagulated yogurt. Specifically, the coagulated yogurt can have the characteristics of full color, uniform state, uniform texture, no water analysis, strong ginger flavor but significantly reduced ginger spiciness, coordinated aroma, delicate taste, and moderate sweetness and sourness.

[0063] The set yogurt provided by the embodiment of the present invention is prepared according to the above preparation method. The embodiment of the present invention combines the nutritional properties of ginger with yogurt, so that the set yogurt has the nutritional and health functions of ginger and yogurt, and has both the smell of ginger and the flavor of yogurt, and can reduce the spicy taste of ginger, so that the set yogurt has a unique flavor and taste.

[0064] In addition, the embodiments of the present invention can not only give the set yogurt unique health attributes and flavor, but also ensure the texture of the set yogurt, so that it has suitable hardness, viscosity, elasticity and thixotropy. Studies have shown that the hardness of the set yogurt prepared by the embodiments of the present invention can be 170-175g, the viscosity can be 30-32g, the elasticity can be 0.17-0.19 (for example, 0.18-0.185), and the thixotropy can be 2500-2650Pa / s (for example, 2510-2610Pa / s).

[0065] In addition, the coagulated yogurt of the embodiment of the present invention has good uniformity, a uniform state, a uniform texture, and a stable texture, and substantially no water is separated (water and the coagulated yogurt base are substantially not separated).

[0066] In addition, the coagulated yogurt of the embodiment of the present invention also has good stability, which can be specifically manifested in that its acidity and pH are stable, that is, as the storage time increases, the degree of change of its acidity and pH is low. For example, after the coagulated yogurt is placed for 7 days, its acidity change rate is less than 10%, and its pH change rate is less than 5.3%; after being placed for 14 days, the acidity change rate is less than 20%, and the pH change rate is less than 9.6%.

[0067] The acidity change rate of the solidified yogurt after it has been placed for n days (such as 7 days and 14 days mentioned above) refers to the acidity change rate on the nth day of placement, starting from the day when the solidified yogurt is just made as the first day, that is, the acidity on the first day is A0, and the acidity on the nth day is A n , the acidity change rate after n days w1=(A n -A0) / A0; pH change rate refers to the pH change rate on the nth day of storage, starting from the day when the coagulated yogurt is just made, that is, the pH on the first day is pH0, and the acidity on the nth day is pH n , pH change rate after n days w2 = (pH0-pH n ) / pH0.

[0068] The present invention is further described below through specific embodiments.

[0069] 1. Examples and Comparative Examples

[0070] Example 1

[0071] The preparation process of the ginger curd in Example 1 of the present invention is as follows:

[0072] 1. Preparation of ginger juice

[0073] (1-1) Ginger processing: Take fresh ginger and use a roller peeling machine to peel and clean it;

[0074] (1-2) Crushing and squeezing: using a juicer to squeeze the peeled and washed ginger to obtain initial ginger juice;

[0075] (1-3) Filtration: The initial ginger juice is filtered through a first filter membrane with a pore size of 70 to 80 mesh, and then filtered through a second filter membrane with a pore size of 180 to 200 mesh;

[0076] (1-4) First homogenization: The filtered initial ginger juice is first homogenized using a pressure of 180 to 200 bar;

[0077] (1-5) Sterilization: The initial ginger juice after the first homogenization is filtered using a MF membrane to sterilize;

[0078] (1-6) Fermentation: The sterilized initial ginger juice is heated to 30° C., Lactobacillus plantarum is added thereto (0.2 g of Lactobacillus plantarum is added to 1 kg of initial ginger juice on average), and fermented at 30° C. until the pH reaches 5.1 to 5.2, and then the system is cooled to 4° C. to terminate the fermentation;

[0079] 2. Preparation of ginger curd

[0080] (2-1) Ingredients

[0081] The milk and the fermented ginger juice were mixed in a mass ratio of 8:2, and the obtained mixture was heated to 50-55° C., and then white sugar, gelatin, acetylated distarch phosphate and diacetyl tartaric acid mono- and diglycerides were added thereto, and stirred for 20 minutes to prepare a mixed system;

[0082] Among them, based on the total weight of the mixed system, there are 50 parts of white sugar, 4 parts of thickener, 4 parts of starch, 1 part of emulsifier, and the balance is a mixture of milk and ginger juice;

[0083] (2-2) Homogenization and sterilization: The mixed system is subjected to a second homogenization and sterilization. During the second homogenization process, the primary pressure of the homogenizer is 30-40 bar, and the secondary pressure is 160-180 bar. A pasteurization process is adopted, the sterilization temperature is 75°C, and the time is 15 seconds.

[0084] (2-3) Inoculation: The homogenized and sterilized mixed system is cooled to about 43° C., a second fermentation agent is added thereto (the mass ratio of the second fermentation agent to the mixed system is about 0.02%, and the second fermentation agent includes thermophilic Streptococcus and Lactobacillus delbrueckii subspecies bulgaricus), and then the mixture is filled into a packaging container;

[0085] (2-4) Fermentation: The packaging container is placed in a fermentation room and fermented at a temperature of about 43°C. When the acidity of the fermentation system reaches about 67-70°T (pH reaches below 4.7), the system is cooled to below 20°C to stop the fermentation and obtain a solidified type;

[0086] (2-5) Post-ripening: The coagulation-type fermentation product is refrigerated at about 4 to 8°C for 4 hours to obtain coagulation-type fermented yogurt.

[0087] Example 2 to Example 3: The difference from Example 1 is that the ingredients used in preparing ginger curd are different, as shown in Table 1. Except for the differences shown in Table 1, the other conditions are the same.

[0088] Comparative Example 1: The difference from Example 1 is that (1) the ginger juice is not fermented (that is, in the ginger juice preparation process, only steps (1-1) to (1-5) are performed, and step (1-6) is not performed); (2) the ingredients for preparing ginger curd are different, see Table 1 for details; the other conditions are the same.

[0089] Example 4: The difference from Example 1 is that the ingredients used in preparing ginger curd are different, as shown in Table 1. Except for the differences shown in Table 1, the other conditions are the same.

[0090] Example 5: The difference from Example 1 is that the ingredients used in preparing ginger curd are different, as shown in Table 1. Except for the differences shown in Table 1, the other conditions are the same.

[0091] Example 6: The difference from Example 1 is that the sterilization temperature in step (2-2) is 95°C, the sterilization time is 300s, and the other conditions are the same.

[0092] Table 1

[0093]

[0094] 2. Product Evaluation

[0095] 1. The fresh ginger curd prepared in each embodiment and comparative example was subjected to sensory evaluation in terms of taste and flavor. The main evaluation items included tissue state (whey separation, viscosity, fineness, texture, etc.), color, flavor, mouthfeel, ice crystal morphology, etc. The sensory scoring standard is shown in Table 2. When the ginger curd prepared in each embodiment or comparative example was subjected to sensory evaluation, 35 people participated in the experiment, and the average of the scores of the 35 people was taken as the final scoring result. The experimental record results are shown in Table 3.

[0096] Table 2

[0097]

[0098] Table 3

[0099]

[0100] As can be seen from Table 3, the ginger juice of Comparative Example 1 was not fermented, and the ginger curd obtained had a strong spicy taste, poor flavor and taste, and a small amount of water base separation (ie, a small amount of water and whey were precipitated).

[0101] Compared with Comparative Example 1, the ginger juices of Examples 1 to 6 were all fermented, and the fermented ginger juices were introduced into ginger curd, which could reduce the strong spicy taste of ginger and make the ginger curd have the characteristics of rich flavor, harmonious aroma, delicate taste, moderate sweetness and sourness, and uniform taste.

[0102] In addition, compared with Example 4 and Example 5, Examples 1 to 3 can further optimize the organizational morphology and color, as well as the flavor and mouthfeel of the ginger curd by further controlling components such as milk, white sugar, gelatin, starch and emulsifier within an appropriate range. It can be seen that the ginger curds of Examples 1 to 3 have good organizational state, mouthfeel and flavor, and the ginger curds have no water base separation and no whey precipitation.

[0103] In addition, compared with Example 6, Examples 1 to 3 are sterilized under more suitable conditions such as temperature, which can further optimize the texture, color, taste, and texture of the ginger curd.

[0104] 2. Texture test

[0105] 2.1 Texture test

[0106] The texture test of the ginger curd prepared in each embodiment and comparative example was carried out according to the following process: a BROOKFIELD CT3 texture analyzer, a probe TA11, a compression mode, a test target distance of 10 mm, a contact load of 1 g, a forward speed of 1 mm / s, and a backward speed of 1 mm / s were used to test the hardness, viscosity and elasticity of the ginger curd. The results are shown in Table 4.

[0107] Table 4

[0108] Hardness(g) Adhesion(g) elasticity Example 1 173.00 30.25 0.185 Example 2 169.75 31.00 0.185 Example 3 170.25 28.75 0.180 Comparative Example 1 142.55 30.25 0.165 Example 4 195.25 34.00 0.175 Example 5 180.00 33.75 0.180 Example 6 152.13 29.53 0.160

[0109] 2.2 Thixotropy test

[0110] The thixotropy of the ginger curd prepared in each embodiment and comparative example was tested according to the following process: Anton-Paar RST-CC rheometer was used with a CCT-40 probe, and two shear rates were set at 0-300 1 / s and 300-2 1 / s. The product packaged with the ginger curd was shaken for 20 seconds, and then the ginger curd was poured out of the package to test its thixotropy. The results are shown in Table 5.

[0111] Table 5

[0112] Thixotropy (Pa / s) Example 1 2513.579 Example 2 2609.783 Example 3 2540.678 Comparative Example 1 1773.120 Example 4 1897.612 Example 5 2165.436 Example 6 1856.324

[0113] In the texture test, hardness indicates the maximum force required by teeth to compress the product (ginger curd), and this indicator is mainly related to the gel strength of the product; viscosity indicates the force required to overcome the attraction between the product surface and the surfaces of product contact objects such as teeth and tongue, and this indicator is mainly related to the viscosity and viscoelastic properties of the product; elasticity indicates the ability of the product to recover from deformation under force, and this indicator is mainly related to the thixotropic properties of the product; thixotropy test simulates the real-time viscosity change of ginger curd (set yogurt) after being squeezed by teeth and tongue after entering the mouth, and is used to describe the rheological properties of the product after entering the mouth.

[0114] It can be seen from Table 4 and Table 5 that, relative to Comparative Example 1, the hardness, adhesion, elasticity and thixotropy of the ginger curds of Examples 1 to 6 are moderate, especially the ginger curds of Examples 1 to 3 have more suitable hardness, adhesion, elasticity and thixotropy. Combined with the sensory evaluation, the ginger curds of Examples 1 to 3 are smooth and delicate in the mouth, non-sticky, and have better overall performance.

[0115] 3. Stability analysis (monitoring shelf life experiment)

[0116] The acidity and pH of the ginger curd of each embodiment and comparative example were tested on the first day (1d, counting from the day when the ginger curd was just made as the first day), the 7th day (7d) and the 14th day (14d), respectively. The results are shown in Table 6.

[0117] Table 6

[0118]

[0119] It can be seen from the results in Table 6 that the ginger curds of Examples 1 to 6 have good stability, especially Examples 1 to 3, whose pH and acidity can achieve the expected effects within 21 days. In the above-mentioned shelf life monitoring test, the acidity and pH control of Examples 1 to 3 are better, the acidity control is stable, and the quality of the product taste and mouthfeel can remain stable.

[0120] In addition, Lactobacillus casei was used to replace Lactobacillus plantarum in Example 1 (the rest of the conditions were the same as in Example 1) to prepare ginger curd; then the ginger curd was evaluated, texture tested and stability analyzed according to the process in the above-mentioned "II. Product Evaluation" section, and the results were basically equivalent to the effects of Example 1.

[0121] In addition, Lactobacillus helveticus was used to replace Lactobacillus plantarum in Example 1 (the rest of the conditions were the same as in Example 1) to prepare ginger curd; then the ginger curd was evaluated, texture tested and stability analyzed according to the process in the above-mentioned "II. Product Evaluation" section, and the results were basically equivalent to the effects of Example 1.

[0122] In addition, hydroxypropyl distarch phosphate was used to replace the acetylated distarch phosphate in Example 1 (the rest of the conditions were the same as in Example 1) to prepare ginger curd; then the ginger curd was evaluated, texture tested and stability analyzed according to the process in the above-mentioned "II. Product Evaluation" section, and the results were basically equivalent to the effects of Example 1.

[0123] In addition, sodium carboxymethyl cellulose and monoglycerides were used to replace the diacetyl tartaric acid mono- and diglycerides in Example 1 (other conditions were the same as in Example 1) to prepare ginger curd; then, the ginger curd was evaluated, texture tested and stability analyzed according to the process in the above-mentioned "II. Product Evaluation" section, and the results were basically equivalent to the effects in Example 1.

[0124] 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 method for preparing a coagulated yogurt, characterized in that: The following steps are involved: Squeeze ginger to obtain ginger juice to be fermented; Fermenting the ginger juice to be fermented in the presence of a first fermentation agent at a first fermentation temperature until the pH reaches below 5.2 to obtain fermented ginger juice; wherein the first fermentation agent includes one or more of Lactobacillus plantarum, Lactobacillus casei and Lactobacillus helveticus, and the first fermentation temperature is less than or equal to 32° C.; The mixed system containing the animal milk and the fermented ginger juice is fermented in the presence of a second fermentation agent to prepare a coagulated yogurt.

2. The method for preparing the set yogurt according to claim 1, characterized in that: The process of squeezing ginger to obtain ginger juice comprises: The peeled and washed ginger is squeezed to obtain initial ginger juice; The initial ginger juice is filtered, homogenized and sterilized in sequence to obtain the ginger juice to be fermented; in, The filtering process comprises: filtering the initial ginger juice through a first filter membrane with a pore size of 70 to 80 meshes, and then filtering through a second filter membrane with a pore size of 180 to 200 meshes; And / or, the pressure of the first homogenization is 180-200 bar; And / or, the sterilization is performed using a microfiltration membrane.

3. The method for preparing the set yogurt according to claim 1, characterized in that: The first fermentation temperature is 28-32°C.

4. The method for preparing the set yogurt according to any one of claims 1 to 3, characterized in that: The process of fermenting the ginger juice to be fermented in the presence of a first fermentation agent at a first fermentation temperature until the pH reaches below 5.2 comprises: heating the ginger juice to be fermented to the first fermentation temperature, adding the first fermentation agent thereto for fermentation until the pH reaches below 5.2, and then cooling to 4° C. to obtain the fermented ginger juice.

5. The method for preparing set yogurt according to claim 1, characterized in that: The process of fermenting the mixed system containing animal milk and the fermented ginger juice in the presence of a second fermentation agent comprises: fermenting the mixed system in the presence of the second fermentation agent at a second fermentation temperature until the acidity reaches above 67°T or the pH reaches below 4.7, and then cooling the temperature to below 20°C to obtain the coagulated yogurt; wherein the second fermentation temperature is 40-45°C.

6. The method for preparing set yogurt according to claim 1 or 5, characterized in that: Also includes: After subjecting the mixed system to a second homogenization and sterilization, the temperature of the mixed system is controlled to a second fermentation temperature, and then the second fermentation agent is added thereto, and the fermentation is carried out at the second fermentation temperature; in, A homogenizer is used to perform the second homogenization, and during the second homogenization process, the first-level pressure of the homogenizer is controlled to be 30-40 bar and the second-level pressure is controlled to be 160-180 bar; And / or, the sterilization temperature is 74-76°C and the time is 14-16s; And / or, the second fermentation temperature is 40-45°C.

7. The method for preparing set yogurt according to claim 1 or 5, characterized in that: The second fermentation agent includes Streptococcus thermophilus and / or Lactobacillus delbrueckii subsp. bulgaricus.

8. The method for preparing set yogurt according to claim 1, characterized in that: In the mixed system, the mass ratio of the animal milk to the fermented ginger juice is (4-9):

1.

9. The method for preparing set yogurt according to claim 1 or 8, characterized in that: The mixed system also includes a sweetener, a thickener, a starch and an emulsifier; in, In the mixed system, by weight, the sweetener is 40-60 parts, the thickener is 3-5 parts, the starch is 3-5 parts, the emulsifier is 1-1.5 parts, and the balance is the animal milk and the fermented ginger juice; And / or, the sweetener includes white sugar; and / or, the thickener comprises one or more of gelatin, carrageenan, konjac gum, gellan gum, xanthan gum, starch, pectin, agar, citrus fiber, locust bean gum and guar gum; And / or, the starch comprises acetylated distarch phosphate and / or hydroxypropyl distarch phosphate; And / or, the emulsifier includes one or more of sodium carboxymethyl cellulose, diacetyl tartaric acid mono- and diglycerides, and mono-fatty acid glycerides; And / or, the preparation process of the mixed system includes: mixing the animal milk and the fermented ginger juice, heating to 50-55° C., adding the sweetener, thickener, starch and emulsifier thereto, and stirring evenly to obtain the mixed system.

10. A set yogurt, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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