Yoghourt and preparation method thereof

Abstract

The invention provides yoghourt and a preparation method thereof, and belongs to the technical field of food processing. The yoghourt comprises the following raw materials for preparation: a fermentation raw material and a leavening agent, wherein the fermentation raw material comprises the following raw materials in parts by mass: raw milk, a sweetening agent and lactase; the sweetening agent comprises sugar substitutes and does not comprise cane sugar. According to the yoghourt disclosed by the invention, sugar substitutes are adopted to replace sucrose, and lactase is added to hydrolyze lactose in the raw milk, so that the taste loss caused by no addition of sucrose is made up, and on the basis of ensuring the appropriate sour and sweet taste of the yoghourt, the intake energy when the yoghourt is eaten is reduced, and the health requirements of consumers can be further met.

Description

Technical Field

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

[0002] Ordinary yogurt has a suitable sweet and sour taste, and the sweetness usually comes from sucrose. Many consumers worry about consuming too much energy when eating foods containing sucrose. At present, it is urgent to develop a yogurt with zero sucrose and a suitable sweet and sour taste to meet the health needs of consumers. Summary of the invention

[0003] The object of the present invention is to provide a yogurt and a preparation method thereof. The yogurt of the present application is zero-sucrose and has appropriate sweetness and sourness, which can meet the health needs of consumers.

[0004] The present invention provides a yogurt, comprising the following raw materials for preparation: fermentation raw materials and a starter, wherein the fermentation raw materials comprise the following raw materials in parts by weight: 94.99 to 98.47 parts of raw cow's milk, 2.01 to 5.03 parts of a sweetener and 0.01 to 0.05 parts of lactase; the sweetener comprises a sugar substitute but does not include sucrose.

[0005] Preferably, the sugar substitute is a complex sugar substitute; the complex sugar substitute includes xylitol and steviol glycoside.

[0006] Preferably, the mass ratio of xylitol to steviol glycoside is (1.5-5): (0.01-0.03).

[0007] Preferably, the dosage of the leavening agent is 0.1-0.3 DCU / kg yogurt.

[0008] Preferably, the starter culture contains Streptococcus salivarius subspecies thermophilic and Lactobacillus delbrueckii subspecies bulgaricus.

[0009] The present invention also provides a method for preparing the yogurt described in the above scheme, comprising the following steps: pasteurizing raw cow milk to obtain pasteurized milk; first mixing the pasteurized milk and a sweetener to obtain a first mixture; ultra-high temperature instantaneous sterilization of the first mixture to obtain a sterilized liquid; first cooling the sterilized liquid, and then second mixing it with a starter and lactase to ferment to obtain a fermentation product; second cooling and post-ripening the fermentation product to obtain yogurt.

[0010] Preferably, after the first mixing, the method further includes subjecting the first mixed materials to high shear stirring.

[0011] Preferably, the temperature of the ultra-high temperature instantaneous sterilization is 95° C.; the time of the ultra-high temperature instantaneous sterilization is 300 s.

[0012] Preferably, the fermentation temperature is 37-45°C; the acidity of the fermentation product is 90-115°T.

[0013] Preferably, the temperature after the second cooling is 10° C.; the temperature of the post-ripening is 2-6° C.; and the time of the post-ripening is ≥24 h.

[0014] The present invention provides a yogurt, comprising the following raw materials for preparation: fermentation raw materials and a fermentation agent, wherein the fermentation raw materials include the following raw materials by weight: raw milk, a sweetener and lactase; the sweetener includes a sugar substitute, but does not include sucrose. The yogurt of the present invention uses a sugar substitute to replace the addition of sucrose, and lactase is added to hydrolyze the lactose in the raw milk to make up for the taste loss caused by not adding sucrose, and on the basis of ensuring the sweet and sour taste of the yogurt, the energy intake when eating the yogurt is reduced, and the health needs of consumers can be further met. DETAILED DESCRIPTION

[0015] The present invention provides a yogurt, comprising the following raw materials for preparation: fermentation raw materials and a starter, wherein the fermentation raw materials comprise the following raw materials in parts by weight: 94.99 to 98.47 parts of raw cow's milk, 2.01 to 5.03 parts of a sweetener and 0.01 to 0.05 parts of lactase; the sweetener comprises a sugar substitute but does not include sucrose.

[0016] In the present invention, the fermentation raw material comprises 94.99-98.47 parts of raw milk, preferably 95.986 parts, by mass. In the present invention, the mass percentage of raw milk in the yogurt is preferably 94.99%-98.47%, more preferably 94.99%, 95.986%, 96.983%, 97.48% or 97.978%.

[0017] In the present invention, the fermentation raw material includes 0.01 to 0.05 parts of lactase by mass, preferably 0.02, 0.03 or 0.04 parts.

[0018] In the present invention, the fermentation raw material includes 2.01 to 5.03 parts of sweetener, preferably 4.014 parts, by mass. In the present invention, the mass percentage of the sweetener in the yogurt is preferably 2.01% to 5.03%, more preferably 4.014%. In the present invention, the sweetener is preferably a sugar substitute; the sugar substitute is preferably a composite sugar substitute; the composite sugar substitute preferably includes xylitol and steviol glycoside, more preferably, the composite sugar substitute is composed of xylitol and steviol glycoside; the mass ratio of xylitol to steviol glycoside is preferably (1.5 to 5): (0.01 to 0.03), and more preferably 4: 0.014. In the present invention, the mass percentage of xylitol in the yogurt is preferably 1.5% to 5%, more preferably 2%, 2.5%, 3% or 4%. In the present invention, the mass percentage of steviol glycoside in the yogurt is preferably 0.01% to 0.03%, more preferably 0.01%, 0.014%, 0.017%, 0.02%, 0.022% or 0.03%. The present invention uses a specific type and ratio of high-intensity sweeteners, which greatly reduces the amount of sugar alcohol used compared to commercial products, thereby avoiding the problem of sugar alcohol intolerance.

[0019] The invention uses lactase to hydrolyze lactose in raw milk to increase sweetness, and uses sugar substitutes to reduce the energy of yogurt and ensure the taste of the yogurt. The sweetness of the yogurt is close to that of conventional yogurt with 8% sucrose content.

[0020] In the present invention, the dosage of the starter is 0.1-0.3 DCU / kg yogurt; the starter preferably contains thermophilic Streptococcus salivarius subsp. and Lactobacillus delbrueckii subsp. bulgaricus. The present invention has no special restrictions on the source and proportion of the thermophilic Streptococcus salivarius subsp. and Lactobacillus delbrueckii subsp. bulgaricus, and conventional thermophilic Streptococcus salivarius subsp. and Lactobacillus delbrueckii subsp. bulgaricus in the art and conventional proportions can be used.

[0021] In the present invention, the yogurt does not contain a stabilizer.

[0022] In the present invention, the effective live bacteria count in the yogurt is preferably ≥ 60 billion CFU / 100g.

[0023] The present invention also provides a method for preparing the yogurt described in the above scheme, comprising the following steps:

[0024] Raw milk is pasteurized to obtain pasteurized milk; the pasteurized milk and a sweetener are first mixed to obtain a first mixture; the first mixture is ultra-high temperature instantaneous sterilized to obtain a sterilized liquid; the sterilized liquid is first cooled, and then mixed with a starter and lactase for a second time to ferment to obtain a fermentation product; the fermentation product is second cooled and post-ripened to obtain yogurt.

[0025] The invention first pasteurizes raw cow milk to obtain pasteurized milk.

[0026] After obtaining the pasteurized milk, the present invention first mixes the pasteurized milk and a sweetener to obtain a first mixture.

[0027] Before the first mixing of the pasteurized milk and the sweetener, the present invention preferably further comprises heating the pasteurized milk to 50-60°C, more preferably 55°C; the heating is performed by a plate heat exchanger. In the present invention, the first mixing is preferably performed in a material tank.

[0028] After the first mixing, the present invention preferably further comprises high shear stirring of the first mixed material. During the high shear stirring, a material tank is used to circulate the material; the high shear stirring time is preferably 10 to 20 minutes, more preferably 15 minutes.

[0029] After obtaining the first mixture, the present invention performs ultra-high temperature instantaneous sterilization on the first mixture to obtain a sterilized liquid.

[0030] In the specific implementation of the present invention, the temperature of the ultra-high temperature instantaneous sterilization is 95°C; the time of the ultra-high temperature instantaneous sterilization is 300s. In the present invention, the ultra-high temperature instantaneous sterilization is preferably carried out using a UHT system.

[0031] After obtaining the sterilized liquid, the present invention performs a first cooling on the sterilized liquid, and then performs a second mixing with a fermentation agent and lactase to perform fermentation to obtain a fermentation product.

[0032] In the present invention, the temperature after the first cooling is preferably less than 10° C. In the present invention, a fermentation agent and lactase are added to the material after the first cooling in sequence. In the present invention, the fermentation agent is preferably added through a strain adder; and the lactase is preferably added through a sterile adder.

[0033] The lactase of the present invention is added after ultra-high temperature instantaneous sterilization, and lactose hydrolysis and lactic acid bacteria fermentation are carried out simultaneously, thereby avoiding the problem that lactose is hydrolyzed into glucose and galactose when lactase is added before high temperature sterilization, glucose and galactose undergo Maillard reaction during high temperature sterilization, and the final product exhibits browning and color aggravation. During the fermentation process, the lactase maintains activity and plays a role, and when the pH of the yogurt is fermented to less than 4.6 (high acid system), the lactase loses activity.

[0034] In the present invention, the fermentation temperature is preferably 37-45°C, more preferably 41 or 43°C. The fermentation temperature of the present invention makes the product have better flavor, taste and texture, and more active lactic acid bacteria reproduce; the fermentation time is preferably based on the fermentation to a suitable target acidity; the acidity of the fermentation product is preferably 90-115°T, more preferably 105°T.

[0035] After obtaining the fermentation product, the present invention performs a second cooling and post-ripening on the fermentation product to obtain yogurt.

[0036] In the present invention, the temperature after the second cooling is preferably 10° C.; the temperature of the post-ripening is preferably 2-6° C.; and the time of the post-ripening is preferably ≥ 24 h.

[0037] The yogurt of the present invention is preferably fermented by a coagulation type yogurt fermentation process. Even without adding an additional stabilizer, the viscosity and taste of the yogurt product can remain normal.

[0038] In order to further illustrate the present invention, a yogurt and a preparation method thereof provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1

[0040] A method for preparing yogurt, comprising the following steps:

[0041] 1. Pasteurize raw milk to obtain pasteurized milk;

[0042] 2. Heat the pasteurized milk with a product mass percentage of 94.99% to about 55°C through a plate heat exchanger, add 5% xylitol and 0.01% stevioside into the material tank, and circulate the material in the material tank for about 15 minutes while stirring with high shear;

[0043] 3. After the materials are processed, they are sterilized by UHT system at 95℃ and 300 seconds;

[0044] 4. After the sterilization, the liquid is cooled to less than 10°C before being canned. 0.3DCU / kg of yogurt product bacteria is added through the bacteria adder and stirred evenly.

[0045] 5. Add 0.01% lactase online through a sterile adder;

[0046] 6. Heat the liquid with added bacteria to the fermentation temperature of 45°C, fill it into packaging containers, and pack it;

[0047] 7. The packed products are moved to the fermentation room for constant temperature fermentation;

[0048] 8. Cooling and post-ripening: After fermentation to the appropriate acidity of 90°Τ, move the product to a quick cold storage, quickly cool it to <10°C, and post-ripen it in a cold storage at 2-6°C for more than 24 hours.

[0049] Example 2

[0050] A kind of preparation method of yogurt

[0051] The specific operation method is shown in Example 1, wherein in step 2, the pasteurized milk with a product mass percentage of 95.986% is heated to about 55° C. through a plate heat exchanger, and 4% of xylitol and 0.014% of stevioside are added to the material tank, and high shear stirring is performed while circulating the material in the material tank for about 15 minutes;

[0052] In step 4, the sterilized liquid is cooled to less than 10°C before being canned, and 0.3DCU / kg of the yogurt product bacteria is added through a bacteria adder and stirred evenly;

[0053] In step 5, lactase having a mass percentage of 0.02% is added online through a sterile adder;

[0054] In step 6, the liquid with added bacteria is heated to a fermentation temperature of 41°C, filled into packaging containers, and packed;

[0055] Step 8, cooling and ripening: after fermentation to the appropriate acidity of 105°T, move the product to a quick cold storage, quickly cool it to <10°C, and ripen it in a cold storage at 2-6°C for more than 24 hours.

[0056] Example 3

[0057] A kind of preparation method of yogurt

[0058] The specific operation method is shown in Example 1, wherein in step 2, the pasteurized milk with a product mass percentage of 96.983% is heated to about 55° C. through a plate heat exchanger, 3% of xylitol and 0.017% of stevioside are added to the material tank, and high shear stirring is performed while circulating the material in the material tank for about 15 minutes;

[0059] In step 4, the sterilized liquid is cooled to less than 10°C before being canned, and 0.2DCU / kg of yogurt product bacteria is added through a bacteria adder and stirred evenly;

[0060] In step 5, 0.03% lactase by mass percentage is added online through a sterile adder;

[0061] In step 6, the liquid with added bacteria is heated to a fermentation temperature of 43°C, filled into packaging containers, and packed;

[0062] Step 8, cooling and ripening: after fermentation to the appropriate acidity of 115°T, move the product to a quick cold storage, quickly cool it to <10°C, and ripen it in a cold storage at 2-6°C for more than 24 hours.

[0063] Example 4

[0064] A kind of preparation method of yogurt

[0065] The specific operation method is shown in Example 1, wherein in step 2, the pasteurized milk with a product mass percentage of 97.48% is heated to about 55° C. through a plate heat exchanger, and 2.5% of xylitol and 0.02% of stevioside are added to the material tank, and high shear stirring is performed while circulating the material in the material tank for about 15 minutes;

[0066] In step 4, the sterilized liquid is cooled to less than 10°C before being canned, and 0.2DCU / kg of yogurt product bacteria is added through a bacteria adder and stirred evenly;

[0067] In step 5, lactase having a mass percentage of 0.04% is added online through a sterile adding device;

[0068] In step 6, the liquid with added bacteria is heated to a fermentation temperature of 40° C., filled into packaging containers, and packed;

[0069] Step 8, cooling and ripening: after fermentation to the appropriate acidity of 110°T, move the product to a quick cold storage, quickly cool it to <10°C, and ripen it in a cold storage at 2-6°C for more than 24 hours.

[0070] Example 5

[0071] A kind of preparation method of yogurt

[0072] The specific operation method is shown in Example 1, wherein in step 2, the pasteurized milk with a product mass percentage of 97.978% is heated to about 55° C. through a plate heat exchanger, and 2.0% of xylitol and 0.022% of stevioside are added to the material tank, and high shear stirring is performed while circulating the material in the material tank for about 15 minutes;

[0073] In step 4, the sterilized liquid is cooled to less than 10°C before being canned, and 0.1 DCU / kg of yogurt product bacteria is added through a bacteria adder and stirred evenly;

[0074] In step 5, 0.05% lactase by weight is added online through a sterile adder;

[0075] In step 6, the liquid containing the added bacteria is heated to a fermentation temperature of 39° C., filled into packaging containers, and packed;

[0076] Step 8, cooling and ripening: after fermentation to the appropriate acidity of 100°T, move the product to a quick cold storage, quickly cool it to <10°C, and ripen it in a cold storage at 2-6°C for more than 24 hours.

[0077] Example 6

[0078] A kind of preparation method of yogurt

[0079] The specific operation method is shown in Example 1, wherein in step 2, the pasteurized milk with a product mass percentage of 98.47% is heated to about 55° C. through a plate heat exchanger, and 1.5% of xylitol and 0.03% of stevioside are added to the material tank, and high shear stirring is performed while circulating the material in the material tank for about 15 minutes;

[0080] In step 4, the sterilized liquid is cooled to less than 10°C before being canned, and 0.1 DCU / kg of yogurt product bacteria is added through a bacteria adder and stirred evenly;

[0081] In step 5, 0.02% lactase by mass percentage is added online through a sterile adding device;

[0082] In step 6, the liquid with added bacteria is heated to a fermentation temperature of 37° C., filled into packaging containers, and packed;

[0083] Step 8, cooling and ripening: after fermentation to the appropriate acidity of 95°T, move the product to a quick cold storage, quickly cool it to <10°C, and ripen it in a cold storage at 2-6°C for more than 24 hours.

[0084] Test Example 1 Sensory Evaluation of Zero Sucrose Yogurt

[0085] The sensory evaluation of the product is carried out with a full score of 100. The evaluation panel consists of 10 people with certain sensory evaluation experience. Each person gives a score and the average is taken. The evaluation is mainly based on the color, smell, taste and texture of the yogurt, with each accounting for 10% of the total score for color, 30% for smell, 30% for taste, and 30% for texture. The sensory evaluation criteria are shown in Table 1.

[0086] Table 1 Yogurt sensory scoring standard

[0087]

[0088] According to the sensory scoring standard, the average sensory scores of the zero-sucrose yogurts of Examples 1 to 6 and some competing products were obtained. The results are shown in Table 2.

[0089] Table 2 Sensory scoring table of various embodiments and related competing products

[0090]

[0091]

[0092] It can be seen from Table 2 that among all the embodiments, Example 2 is the best technical solution. The yogurt obtained in this embodiment has the best color, flavor and state as a whole. Compared with the three market competing products, Examples 1 to 6 also have higher sensory scores.

[0093] Comparative Example 1

[0094] Based on the formula and preparation method of Example 2, without adding lactase, the overall sweet and sour taste of the yogurt prepared without adding lactase is not as good as that of the yogurt with lactase. Therefore, lactase plays a certain role in regulating the taste in the yogurt of the present invention. At the same time, lactase hydrolyzes lactose, and the yogurt of the present invention is also suitable for some people with lactose intolerance.

[0095] It can be seen from the above that the zero-sucrose yogurt prepared in the above embodiment of the present invention has a good texture, a smooth and delicate taste, and its various indicators can meet the technical requirements.

[0096] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A yogurt comprising the following raw materials for preparation: fermentation raw materials and a fermentation agent, characterized in that: The fermentation raw materials include the following raw materials in parts by mass: 94.99-98.47 parts of raw milk, 2.01-5.03 parts of sweeteners and 0.01-0.05 parts of lactase; the sweeteners include sugar substitutes but do not include sucrose.

2. The yogurt according to claim 1, characterized in that The sugar substitute is a complex sugar substitute; the complex sugar substitute comprises xylitol and steviol glycoside.

3. The yogurt according to claim 2, characterized in that The mass ratio of xylitol to steviol glycoside is (1.5-5): (0.01-0.03).

4. The yogurt according to claim 1, characterized in that The dosage of the leavening agent is 0.1-0.3 DCU / kg yogurt.

5. The yogurt according to claim 1 or 4, characterized in that: The fermentation agent contains Streptococcus salivarius subspecies thermophilus and Lactobacillus delbrueckii subspecies bulgaricus.

6. The method for preparing yogurt according to any one of claims 1 to 5, characterized in that: The following steps are involved: Raw milk is pasteurized to obtain pasteurized milk; The pasteurized milk and the sweetener are first mixed to obtain a first mixture; Performing ultra-high temperature instantaneous sterilization on the first mixture to obtain a sterilized liquid; After first cooling the sterilized liquid, the liquid is mixed with a fermentation agent and lactase for second fermentation to obtain a fermentation product; The fermentation product is subjected to a second cooling and post-ripening to obtain yogurt.

7. The preparation method according to claim 6, characterized in that: After the first mixing, the method further includes subjecting the first mixed materials to high shear stirring.

8. The preparation method according to claim 6, characterized in that: The temperature of the ultra-high temperature instantaneous sterilization is 95° C.; the time of the ultra-high temperature instantaneous sterilization is 300 seconds.

9. The preparation method according to claim 6, characterized in that: The fermentation temperature is 37-45°C; the acidity of the fermentation product is 90-115°T.

10. The preparation method according to claim 6, characterized in that: The temperature after the second cooling is 10° C.; the temperature of the post-ripening is 2-6° C.; and the time of the post-ripening is ≥24 hours.

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