Production process of frozen yoghourt

Abstract

The invention discloses a production process of frozen yoghurt, which belongs to the field of food processing and comprises the following steps: pretreatment: performing centrifugal separation on raw milk at low temperature, dissolving and filtering a sweetening agent, performing low-temperature freeze-drying treatment on fruits, and crushing the fruits into granules; fermenting: uniformly mixing the pretreated milk, sweetening agent solution and fruit particles, heating, inoculating a probiotic fermenting agent, and fermenting in a fermentation tank; cooling: after fermentation is completed, cooling the yoghourt; congelation: sending the cooled yoghourt into a congelation machine, stirring and congelating at low temperature, and simultaneously filling a proper amount of nitrogen, so that the texture of the yoghourt is more fluffy and fine; and packaging and storing: immediately carrying out aseptic packaging on the frozen yogurt. According to the production process of the frozen yoghourt, due to the high-quality raw materials and the unique fermentation and congelation process, the frozen yoghourt has rich and mellow taste and fluffy and fine texture, and rich taste levels are added due to the addition of the fruit particles.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and particularly to a production process of frozen yogurt. Background Art

[0002] Frozen yogurt is a frozen dessert made from yogurt through freezing technology. It combines the health benefits and special flavors of yogurt, as well as the cool feeling and delicate texture of ice cream, so it is loved by consumers. Frozen yogurt retains the basic nutrients of yogurt, such as protein, calcium, and vitamins. Although some water-soluble vitamins and probiotics may be reduced during the freezing process, the overall nutritional value is still relatively high. At the same time, the probiotics in frozen yogurt help regulate the balance of intestinal flora and promote the digestion and absorption of food.

[0003] Currently, there are many deficiencies in the production process of frozen yogurt on the market. Common production processes are relatively traditional in raw material selection, using ordinary milk, conventional probiotic combinations, a large amount of granulated sugar, and concentrated fruit juice or jam, etc., resulting in products being difficult to meet the increasingly diverse needs of consumers in terms of taste, nutrition, and health attributes. At the same time, in the existing production steps, the fermentation process is not precise enough, and there is a lack of innovative technologies in the cooling and freezing steps, making the quality and stability of products uneven. Summary of the Invention

[0004] The purpose of the present invention is to propose a production process of frozen yogurt in order to solve the problem that the existing frozen yogurt is difficult to meet the increasingly diverse needs of consumers in terms of taste, nutrition, and health attributes.

[0005] In order to achieve the above purpose, the present invention adopts the following technology: A production process of frozen yogurt, comprising the following steps:

[0006] S1. Pretreatment: Centrifuge raw milk at low temperature, dissolve and filter the sweetener, and freeze-dry the fruit at low temperature and then crush it into granular form;

[0007] S2. Fermentation: Mix the pretreated milk, sweetener solution, and fruit granules evenly, heat them, then inoculate with probiotic starter, and then ferment in a fermentation tank;

[0008] S3. Cooling: After fermentation is completed, cool the yogurt to below 10°C;

[0009] S4. Freezing: Feed the cooled yogurt into a freezer, stir and freeze it at low temperature, and at the same time inject an appropriate amount of nitrogen to make the texture of the yogurt more fluffy and delicate;

[0010] S5. Packaging and Storage: Immediately perform aseptic packaging on the frozen yogurt after freezing, and store the packaged product in a cold storage.

[0011] As a further description of the above technical solution: In step S1, the raw milk is selected as fresh and high-quality raw milk from a specific ranch, without antibiotic residues and with a fat content between 3.5% and 4.5%. The sweetener is a compound of natural low-calorie steviol glycoside and erythritol, and the fruit is selected as fresh fruit of the current season.

[0012] As a further description of the above technical solution: In step S2, the mixed milk, sweetener solution and fruit particles are inoculated with probiotic starters after being heated to 42°C - 45°C.

[0013] As a further description of the above technical solution: In step S2, the fermentation temperature of the fermentation tank is maintained at 42°C, the fermentation time is 4 - 6 hours, and during the fermentation process, low-speed intermittent stirring is carried out by a stirring mechanism.

[0014] As a further description of the above technical solution: In step S3, cooling is carried out by a plate heat exchanger. During the cooling process, the temperature of the coolant in the plate heat exchanger is controlled at 2°C - 5°C, and the flow rate is dynamically adjusted according to the flow rate of the yogurt to ensure that the yogurt is cooled from the fermentation temperature to below 10°C within 5 - 8 minutes.

[0015] As a further description of the above technical solution: In step S4, during the freezing process of the freezer, the stirring speed is controlled at 100 - 150 revolutions per minute, the freezing time is 20 - 30 minutes, and the pressure of the nitrogen gas charged is 0.2 - 0.3 MPa.

[0016] As a further description of the above technical solution: In step S1, the particle size range of the fruit particles is between 2 - 5 mm.

[0017] As a further description of the above technical solution: In step S5, the packaging material is a degradable and environmentally friendly packaging material, and the packaged product is stored in a cold storage at a temperature below -18°C.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] High-quality raw materials and unique fermentation and freezing processes make the frozen yogurt have a rich and mellow taste, a fluffy and delicate texture. The addition of fruit particles adds rich taste levels. The new probiotic combination is helpful for intestinal health. The use of low-calorie sweeteners meets the needs of a healthy diet. The fruit particles retain more nutrients. The use of a new type of degradable and environmentally friendly packaging material conforms to the environmental protection concept and reduces environmental pollution. Specific embodiments

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] A production process of frozen yogurt provided in this embodiment includes the following steps:

[0022] S1. Pretreatment: Centrifuge raw milk at low temperature, dissolve and filter the sweetener, and freeze-dry the fruit at low temperature and then crush it into granular form;

[0023] S2. Fermentation: Mix the pretreated milk, sweetener solution and fruit granules evenly, heat them and then inoculate with probiotic starter, and then ferment in a fermentation tank;

[0024] S3. Cooling: After fermentation is completed, cool the yogurt to below 10°C;

[0025] S4. Freezing: Feed the cooled yogurt into a freezer, stir and freeze it at low temperature, and at the same time fill in an appropriate amount of nitrogen to make the texture of the yogurt more fluffy and delicate;

[0026] S5. Packaging and storage: Immediately aseptically package the frozen yogurt after freezing, and store the packaged product in a cold storage.

[0027] Among them, in step S1, the raw milk is selected as fresh and high-quality raw milk from a specific ranch without antibiotic residues and with a fat content between 3.5% and 4.5%. Compared with ordinary milk, its protein and fat have higher quality, which can endow the yogurt with a more rich and mellow taste. The sweetener is selected as a compound of natural low-calorie stevioside and erythritol, which can not only meet the consumers' demand for sweetness, but also reduce the calorie content of the product, meeting the current trend of healthy diet. The fruit is selected as fresh fruit of the current season, directly freeze-dried at low temperature and then crushed into granular form. The particle size range of the fruit granules is between 2-5 mm. Compared with using concentrated fruit juice or jam, it can retain the nutritional components and original flavor of the fruit to the greatest extent.

[0028] Specifically, in step S2, the mixed milk, sweetener solution and fruit granules are inoculated with probiotic starter after being heated to 42°C - 45°C. The fermentation temperature of the fermentation tank is maintained at 42°C, and the fermentation time is 4 - 6 hours. And during the fermentation process, low-speed intermittent stirring is carried out through a stirring mechanism. The low-speed intermittent stirring frequency during the fermentation process is to stir for 3 - 5 minutes every 10 - 15 minutes. Through intermittent stirring, the fermentation can be promoted to proceed evenly, generating a unique flavor and texture.

[0029] Specifically, in step S3, cooling is performed using a plate heat exchanger. During the cooling process, the temperature of the coolant in the plate heat exchanger is controlled at 2°C - 5°C, and the flow rate is dynamically adjusted according to the flow rate of the yogurt to ensure that the yogurt is cooled from the fermentation temperature to below 10°C within 5 - 8 minutes, thereby inhibiting the continued fermentation of probiotics, maintaining the flavor and acidity stability, and avoiding affecting the quality due to uneven temperature changes.

[0030] Specifically, in the said step S4, during the freezing process of the freezer, the stirring speed is controlled at 100 - 150 revolutions per minute, the freezing time is 20 - 30 minutes, and the pressure of the nitrogen gas charged is 0.2 - 0.3 MPa. The charging of nitrogen gas makes the texture of the yogurt more fluffy and delicate, and the taste more rich. Strictly controlling the stirring speed and time ensures the formation of a uniform and delicate ice crystal structure.

[0031] Specifically, in step S5, the packaging material uses a degradable and environmentally friendly packaging material. The packaged product is stored in a cold storage at a temperature below -18°C. Using the new degradable and environmentally friendly packaging material conforms to the environmental protection concept and reduces environmental pollution.

[0032] As mentioned above, the above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent replacements or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A production process for frozen yogurt, characterized in that: The following steps are involved: S1. Pretreatment: centrifuge the raw milk at low temperature, dissolve and filter the sweetener, freeze-dry the fruit and crush it into particles; S2, fermentation: the pretreated milk, sweetener solution and fruit particles are mixed evenly, and after heating, a probiotic fermentation agent is added, and then fermented in a fermentation tank; S3, cooling: after fermentation is completed, cool the yogurt to below 10°C; S4, freezing: the cooled yogurt is sent to a freezing machine, stirred and frozen at low temperature, and a proper amount of nitrogen is charged at the same time to make the yogurt more fluffy and delicate; S5. Packaging and storage: The frozen yogurt is immediately aseptically packaged and the packaged products are stored in a cold storage.

2. The production process of frozen yogurt according to claim 1, characterized in that: In step S1, the raw milk is fresh high-quality raw milk from a specific pasture, has no antibiotic residues and has a fat content between 3.5% and 4.5%, the sweetener is a natural low-calorie combination of stevioside and erythritol, and the fruit is fresh fruit of the season.

3. The production process of frozen yogurt according to claim 1, characterized in that: In step S2, the mixed milk, sweetener solution and fruit particles are heated to 42° C.-45° C. and then added with a probiotic fermentation agent.

4. The production process of frozen yogurt according to claim 3, characterized in that: In step S2, the fermentation temperature of the fermentation tank is maintained at 42°C, the fermentation time is 4-6 hours, and low-speed intermittent stirring is performed by a stirring mechanism during the fermentation process.

5. The production process of frozen yogurt according to claim 1, characterized in that: In step S3, cooling is performed using a plate heat exchanger. During the cooling process, the temperature of the coolant is controlled at 2°C-5°C, and the flow rate is dynamically adjusted according to the yogurt flow rate to ensure that the yogurt is cooled from the fermentation temperature to below 10°C within 5-8 minutes.

6. The production process of frozen yogurt according to claim 1, characterized in that: In step S4, during the freezing process, the stirring speed of the freezer is controlled at 100-150 rpm, the freezing time is 20-30 minutes, and the pressure of the nitrogen filled is 0.2-0.3 MPa.

7. The production process of frozen yogurt according to claim 1, characterized in that: In step S1, the particle size of the fruit particles ranges from 2 to 5 mm.

8. The production process of frozen yogurt according to claim 1, characterized in that: In step S5, the packaging material is a degradable and environmentally friendly packaging material, and the packaged product is stored in a cold storage below -18°C.