A processing method of yak milk coffee

Abstract

The application provides a processing method of yak milk coffee and belongs to the technical field of food processing. The processing method mixes semi-skimmed yak milk, coffee extract and water to obtain yak milk coffee. The coffee extract is obtained by filtering coffee water extract three times and centrifuging once in sequence, and the coffee extract is deeply decontaminated and has no visible particles. The semi-skimmed yak milk is subjected to homogenization treatment, so that the semi-skimmed yak milk has excellent solubility. Through the improvement of the processing method, the yak milk coffee of the application still has good stability without adding stabilizers, and no obvious fat floating and bottom precipitation phenomenon occurs in the shelf life.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, and in particular relates to a method for processing yak milk coffee. Background Technology

[0002] Milk coffee is a neutral milk-containing coffee beverage made primarily from coffee extract or instant coffee powder, with the addition of milk powder or milk, white sugar, stabilizers, and other auxiliary materials, and then effectively sterilized. It has poor product stability during its shelf life, easily leading to fat floating, protein flocculation, and sedimentation, which seriously affects product quality. Summary of the Invention

[0003] The purpose of this invention is to provide a processing method for yak milk coffee. The yak milk coffee product prepared by the method of this invention has good stability and will not exhibit fat floating, protein flocculation, or precipitation during its shelf life.

[0004] This invention provides a method for processing yak milk coffee, comprising the following steps: mixing coffee powder and water, extracting the mixture to obtain an aqueous extract; filtering the aqueous extract sequentially and collecting the filtrate; centrifuging the filtrate and collecting the supernatant to obtain a coffee extract; homogenizing semi-skimmed yak milk to obtain homogenized semi-skimmed yak milk; mixing the homogenized semi-skimmed yak milk, the coffee extract, and water to obtain yak milk coffee; the filtration includes a first filtration, a second filtration, and a third filtration; the third filtration uses a filter with a mesh size greater than that used in the second filtration; the second filtration uses a filter with a mesh size greater than that used in the first filtration; the third filtration uses a filter with a mesh size of 300 mesh.

[0005] Preferably, the coffee powder is obtained by grinding medium-dark roasted coffee beans; the particle size of the coffee powder is 0.5~0.85mm.

[0006] Preferably, the fat volume content of the semi-skimmed yak milk is 1.7% to 2%.

[0007] Preferably, the volume ratio of the homogenized semi-skimmed yak milk, coffee extract, and water is 3:1:4.

[0008] Preferably, the extraction temperature is 90~93℃.

[0009] Preferably, the first filter uses a 50-mesh filter, and the second filter uses a 100-mesh filter.

[0010] Preferably, the temperature for homogenizing the semi-skimmed yak milk is 70-75°C; and the pressure for homogenizing the semi-skimmed yak milk is 200-250 bar.

[0011] Preferably, before mixing the homogenized semi-skimmed yak milk and coffee extract, the semi-skimmed yak milk is further heated; the heating temperature is 60~70℃; and the heating time is 20~30s.

[0012] Preferably, after mixing the homogenized semi-skimmed yak milk and coffee extract, the mixture further includes adding a sweetener to the mixture; the sweetener includes white sugar.

[0013] Preferably, no stabilizers are added to the yak milk coffee.

[0014] This invention provides a processing method for yak milk coffee. The method involves mixing semi-skimmed yak milk, coffee extract, and water to obtain yak milk coffee. The coffee extract is obtained by sequentially filtering an aqueous coffee extract three times and centrifuging once, resulting in thorough impurity removal and the absence of visible particles. The semi-skimmed yak milk is homogenized to improve its solubility. Through this improved processing method, without the addition of stabilizers, the yak milk coffee of this invention maintains good temperature stability and does not exhibit significant fat bubbling or bottom sedimentation during its shelf life. Detailed Implementation

[0015] This invention provides a method for processing yak milk coffee, comprising the following steps: mixing coffee powder and water, extracting the mixture to obtain an aqueous extract; filtering the aqueous extract sequentially and collecting the filtrate; centrifuging the filtrate and collecting the supernatant to obtain a coffee extract; homogenizing semi-skimmed yak milk to obtain homogenized semi-skimmed yak milk; mixing the homogenized semi-skimmed yak milk, the coffee extract, and water to obtain yak milk coffee; the filtration includes a first filtration, a second filtration, and a third filtration; the third filtration uses a filter with a mesh size greater than that used in the second filtration; the second filtration uses a filter with a mesh size greater than that used in the first filtration; the third filtration uses a filter with a mesh size of 300 mesh.

[0016] This invention involves mixing coffee powder and water, then extracting the mixture to obtain an aqueous extract.

[0017] In this invention, the coffee powder is preferably obtained by grinding medium-dark roast coffee beans. Medium-dark roast coffee beans fall between light and dark roasts, resulting in a flavor that is neither too bitter nor too acidic. This level of roasting retains a certain degree of acidity, making the coffee more vibrant and allowing for a more natural blend with yak milk. The preferred grinding degree is medium-coarse, meaning that 65% to 70% of the coffee powder passes through a No. 20 standard sieve. During the specific implementation of this invention, it is crucial to ensure uniform grinding of the coffee beans, avoiding excessively coarse or fine particles. This ensures a more stable and balanced taste and flavor during brewing. The preferred particle size of the coffee powder is 0.5 to 0.85 mm to facilitate better extraction of the coffee's essence during brewing. The preferred extraction temperature is 90 to 93°C, which improves extraction efficiency. Medium-dark roast coffee beans have a moderate hardness, ensuring that soluble substances in the coffee are neither too easily nor too difficult to extract. Using water that is too hot or too cold may result in over- or under-extraction.

[0018] In this invention, the preferred method for preparing medium-dark roasted coffee beans includes the following steps: roasting coffee beans to a medium-dark level to obtain medium-dark roasted coffee beans.

[0019] In this invention, the coffee beans are preferably of superior quality and have a unique flavor; the preferred variety is Arabica; the preferred brand is illy; and the preferred origin is Brazil. Prior to roasting, the coffee beans are preferably sun-dried, with the moisture content of the sun-dried beans preferably being 11%–12%, which helps maintain the quality and flavor of the beans. In this invention, the medium-dark roasting temperature is preferably 180–225°C, more preferably 190–195°C. The roasting process of coffee beans is a complex chemical change, with temperature and time being the most critical roasting conditions. The roasting is carried out in a roasting machine; the medium-dark roasting time is preferably 15–25 minutes; and the moisture content of the medium-dark roasted coffee beans is preferably ≤5%. Medium-dark roasting of the coffee beans allows for a balance of oil production, bitterness, and acidity on the surface of the beans, resulting in a rich aroma and flavor.

[0020] The main roasting conditions for coffee beans include temperature and time. Roasting begins at a temperature between 190 and 195°C. After the green beans are placed in the roaster, the internal temperature temporarily drops to 90-95°C. The roaster then enters a warm-up phase, with the internal temperature rising again. Between 2 minutes and 30 seconds and 2 minutes and 45 seconds into the warm-up, the coffee beans begin to turn yellow, a crucial point. Afterward, the beans rapidly dehydrate and enter the caramelization stage. As the roasting intensity increases, the color of the beans changes from yellow to brown. Further dehydration causes the fibers to break, producing a crackling sound – this is known as the "first crack." The roasting time and temperature after the first crack directly affect the flavor and taste of the coffee. Shorter roasting times and lower temperatures result in more fruity and acidic notes; longer roasting times and higher temperatures produce a more intense and bitter flavor. In the specific implementation of this invention, the baking temperature after the "first explosion" is 180~200℃; the baking time after the "first explosion" is 10~15min.

[0021] In addition, the control of heat, oven temperature, and exhaust during the roasting process are also key factors. During the roasting stage, the quality of heat control, oven temperature, and exhaust control directly affects the flavor development of the coffee beans. In the specific implementation of this invention, the heat control conditions are as follows: 1) Preheating stage: time 6-8 minutes, temperature 120-150℃; 2) Dehydration stage: when the beans turn white and surface moisture appears, the drying and dehydration process begins, with the heat adjusted to medium, the entire process lasting 4-5 minutes; 3) Roasting stage: starting temperature ≥180℃. In the specific implementation of this invention, the temperature conditions of the furnace are as follows: 1) Preheating stage: After the furnace body is preheated to 200℃, it is cooled to 150℃ and then ignited for heating; after reaching 200℃, heating is stopped, the furnace body is cooled again, and after reaching 150℃, it is heated again to 180~200℃; 2) Dehydration stage: The temperature is 120~150℃; 3) Baking stage: The starting temperature is ≥180℃, and after the "first explosion", the furnace temperature is maintained between 180~225℃, and the baking time is 12~20 min; the initial firepower is small, and the firepower gradually increases as the baking process proceeds. In the specific implementation of this invention, the temperature conditions for exhaust control are as follows: 1) Preheating stage: Exhaust control is at medium to low level; 2) Dehydration stage: Exhaust control in the furnace is at medium level; 3) Baking stage: The amount of smoke generated in the furnace is large, so the exhaust volume must be increased, and the exhaust control is at high level. In the specific implementation of this invention, medium heat is maintained before and at the beginning of the first crack. As baking progresses, the heat is appropriately reduced 10-20 seconds before the second crack. After the second crack is completed, the heat level is determined according to the desired degree of baking for medium-dark baking. In the specific implementation of this invention, the sound of the first crack is relatively loud, while the sound of the second crack is relatively faint.

[0022] During coffee bean roasting, the Maillard and caramelization reactions occur. The main Maillard reaction phase generally refers to the period from when the coffee beans turn yellow to the first crack. During this reaction, large molecules like melanin are continuously produced, resulting in over 600 volatile organic compounds in the roasted coffee beans. Therefore, the Maillard reaction contributes to the coffee's flavor, mouthfeel, color, and complexity. The caramelization reaction produces two main products: dehydration products of sugars, which are caramel or browning, and cracking products, primarily volatile aldehydes and ketones. Caramelization generates the roasted aroma, caramel color, and other aromatic compounds such as maltol. Over-caramelization during roasting is detrimental, causing carbonization and resulting in a harsh, bitter taste. Insufficient caramelization leads to a monotonous and unlayered aroma. Therefore, the caramelization reaction primarily contributes to aroma and mouthfeel. Generally speaking, the longer the total roasting time, the less acidity remains in the end. Conversely, the bitterness becomes stronger with longer roasting time, and the darker the roast, the more bitter the coffee will be. Therefore, by roasting at a temperature of 225℃ for 25 minutes, the taste of coffee gradually changes from astringent to smooth and then to mellow.

[0023] In the specific implementation of this invention, the coffee beans do not include substandard beans; the uneven beans include insect beans, fermented beans, and shell beans.

[0024] In one embodiment of the present invention, the preparation method of the medium-dark roasted coffee beans includes the following steps: 1. Drying: Removing moisture from the coffee beans, the color of the beans changes from green to white, at a temperature of 135℃; 2. Dehydration: The coffee beans will slowly turn yellow, and finally become light brown, at a temperature of 160℃; 3. First Crack: The coffee beans begin to crack and expand, turning dark brown, at a temperature ≥185℃; 4. Flavor Development Stage: The aroma of the coffee beans becomes more pronounced, and the color deepens further; 5. Second Crack: The beans crack violently, and the color quickly turns black, at a temperature of 225℃; 6. Stop Roasting: When the temperature reaches the desired roasting level, roasting ends.

[0025] After obtaining the aqueous extract, the present invention filters the aqueous extract sequentially and collects the filtrate.

[0026] In this invention, the filtration includes a first filter, a second filter, and a third filter; the third filter uses a filter with a larger mesh size than the second filter; the second filter uses a filter with a larger mesh size than the first filter; the third filter uses a filter with a mesh size of 300 mesh. Preferably, the first filter uses a filter with a mesh size of 50 mesh; preferably, the second filter uses a filter with a mesh size of 100 mesh.

[0027] After obtaining the filtrate, the present invention centrifuges the filtrate, collects the supernatant, and obtains coffee extract.

[0028] In this invention, the centrifugation speed is preferably 6800~7500 rpm; the centrifugation time is preferably 5 min.

[0029] Following centrifugation, the present invention preferably further includes sterilizing and cooling the supernatant sequentially. In this invention, the temperature of the cooled material is preferably ≤10°C, more preferably ≤5°C.

[0030] In this invention, the coffee extract is preferably preserved by quick-freezing at -20 to -18°C.

[0031] This invention homogenizes semi-skimmed yak milk to obtain homogenized semi-skimmed yak milk.

[0032] In this invention, the preferred method for preparing semi-skimmed milk includes the following steps: defatting fresh yak milk to obtain skimmed yak milk; and injecting fat into the skimmed yak milk to obtain semi-skimmed yak milk.

[0033] In this invention, the fresh yak milk refers to high-quality yak milk that has undergone rigorous inspection to ensure that the raw milk is odorless, free of impurities, and has a rich milky aroma and abundant nutritional value. In the specific implementation of this invention, the fresh yak milk is preferably Lanyi yak milk. In this invention, before defatting the fresh yak milk, it is preferable to further filter it; the filter screen used for filtering preferably has a pore size of 80-200 mesh; the purpose of filtering is to remove impurities. In this invention, defatting is preferably carried out by high-speed rotation. This process of defatting followed by fat injection achieves standardized processing of the defatted yak milk, ensuring that the fat content of the semi-defatted yak milk meets the semi-defatted standard.

[0034] In this invention, the preferred temperature for homogenizing semi-skimmed yak milk is 70-75°C; the preferred pressure for homogenizing semi-skimmed yak milk is 200-250 bar. This invention, through homogenization of semi-skimmed yak milk, reduces the size of fat globules, increases the surface area of ​​fat molecules by approximately 4-6 times, and achieves a uniform distribution of fat globules with a diameter of about 1 μm. This prevents fat aggregation and stratification, resulting in a smoother texture and a more uniform and stable emulsion. Therefore, a more delicate and silky mouthfeel is achieved. Improper homogenization time and pressure can lead to fat floating and stratification, uneven distribution of nutrients, and shortened shelf life. This invention uses high-speed centrifugal rotation for homogenization of yak milk.

[0035] After homogenizing the semi-skimmed yak milk, the present invention preferably further includes sterilizing and cooling the homogenized semi-skimmed yak milk sequentially; the sterilization preferably includes high-temperature short-time sterilization or ultra-high-temperature pasteurization; the temperature of the high-temperature short-time sterilization is preferably 75~85℃; the time of the high-temperature short-time sterilization is preferably 15~20s; the temperature of the ultra-high-temperature pasteurization is preferably 125~138℃; the time of the ultra-high-temperature pasteurization is preferably 2~4s; after sterilization, the milk is rapidly cooled, and the temperature of the cooled semi-skimmed yak milk is preferably 4~5℃. Rapid cooling helps maintain the freshness and quality of the semi-skimmed yak milk. After cooling, the present invention preferably further includes aseptic packaging of the cooled semi-skimmed yak milk.

[0036] The semi-skimmed yak milk of this invention provides consumers with a more balanced nutritional choice, reducing fat intake while retaining some of the flavor and taste of yak milk. In this invention, the fat volume content of the semi-skimmed yak milk is preferably 1.7% to 2%, a moderate fat content that prevents it from being too rich as whole yak milk or too bland as skimmed yak milk. In this invention, the fat volume content of the semi-skimmed yak milk is adjusted using ghee extracted from yak milk; the ghee extracted from yak milk is preferably Lanyi brand yak milk butter.

[0037] Before mixing the homogenized semi-skimmed yak milk and coffee extract, the present invention preferably further includes heating the semi-skimmed yak milk; the heating temperature is preferably 60~70℃, which ensures that the semi-skimmed yak milk is fully heated without destroying its nutrients, and also maintains the smooth taste of the semi-skimmed yak milk; the heating time is preferably 20~30s.

[0038] After obtaining coffee extract and homogenized semi-skimmed yak milk, the present invention mixes the homogenized semi-skimmed yak milk, coffee extract and water to obtain yak milk coffee.

[0039] In this invention, the preferred volume ratio of the homogenized semi-skimmed yak milk, coffee extract, and water is 3:1:4. In this invention, the mixing is preferably performed by stirring or high-speed shear mixing; the high-speed shearing time is preferably 20 minutes; the mixing is performed to ensure that the homogenized semi-skimmed yak milk and coffee extract are fully integrated.

[0040] After mixing the homogenized semi-skimmed yak milk and coffee extract, the present invention preferably further includes adding a sweetener to the mixed material; the sweetener preferably includes granulated sugar. In the present invention, the purpose of adding the sweetener is to enhance the richness of the flavor of the yak milk coffee.

[0041] In one embodiment of the present invention, semi-skimmed yak milk and coffee extract are used as the main ingredients, and white sugar is used as an auxiliary ingredient.

[0042] After adding sweetener to the mixed material, the present invention preferably further includes homogenizing the material after adding sweetener; the homogenization includes a primary homogenization and a secondary homogenization performed sequentially; the homogenization temperature is 70~75℃; the pressure of the primary homogenization is preferably 180~200 bar; the pressure of the secondary homogenization is preferably 40~50 bar; the primary homogenization breaks down large particles into smaller particles; the secondary homogenization prevents the small particles from re-aggregating, ensuring better homogenization effect.

[0043] After homogenizing the material with added sweetener, the present invention preferably further includes sterilizing and cooling the homogenized material sequentially. In the present invention, the sterilization temperature is preferably 125~130℃; the sterilization time is preferably 2~4s, more preferably 3s; the temperature of the cooled material is preferably ≤9℃, more preferably 5~9℃, and most preferably 5~7℃.

[0044] After cooling, the present invention preferably further includes filling the cooled material; the filling temperature is preferably ≤9°C.

[0045] In this invention, the yak milk coffee preferably does not contain any stabilizers.

[0046] To further illustrate the present invention, the following detailed description of a yak milk coffee processing method provided by the present invention is provided in conjunction with embodiments, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0047] The yak milk used in this embodiment of the invention is Blue Yi yak milk; the coffee bean variety used is Arabica, the brand is illy, and the origin is Brazil.

[0048] Example 1 1. A method for preparing semi-skimmed yak milk, comprising the following steps: 1) Raw material acceptance: High-quality Lanyi yak milk is selected as the raw material and is subject to strict acceptance to ensure the quality and safety of the raw milk.

[0049] 2) Pretreatment: The raw yak milk is filtered and impurities are removed using a 60-200 mesh filter to obtain pretreated yak milk.

[0050] 3) Defatting: The pre-treated yak milk is defat-free by high-speed rotation to obtain defatted yak milk.

[0051] 4) Standardization: Through machine control, 1.7% fat (butter extracted from yak milk) is injected into skim yak milk to obtain semi-skim yak milk.

[0052] 5) The semi-skimmed yak milk was homogenized at a temperature of 70°C and a pressure of 250 bar to obtain homogenized semi-skimmed yak milk.

[0053] 6) Sterilization and cooling: The homogenized semi-skimmed yak milk is sterilized using a high-temperature short-time sterilization method at a temperature of 75-85℃ for 15-20 seconds. After sterilization, the semi-skimmed yak milk is quickly cooled to 4-5℃.

[0054] 7) Packaging: The cooled semi-skimmed yak milk is aseptically packaged.

[0055] 2. A method for preparing coffee extract, comprising the following steps: 1) Bean selection: Select Arabica beans from Brazil and sun-dry them. The moisture content of the sun-dried coffee beans is controlled at 11%~12%.

[0056] 2) Roasting: The processed coffee beans are roasted to a medium-dark temperature of 225℃ for 25 minutes. The moisture content of the roasted coffee beans is controlled to be below 5%.

[0057] 3) Grinding: Grind the roasted coffee beans to a medium-coarse grind.

[0058] 4) Extract the ground coffee powder to obtain an extract. The temperature of the water used for extraction is 90℃.

[0059] 5) The extract was filtered three times to obtain the filtrate; the first filter had a mesh size of 50, the second filter had a mesh size of 100, and the third filter had a mesh size of 300.

[0060] 6) Centrifugation: Centrifuge the filtrate and collect the supernatant; the centrifugation speed is 6800 rpm and the centrifugation time is 5 min.

[0061] 7) Sterilization: Sterilize the supernatant by heating it to 135°C and holding it for 8 seconds, then rapidly cooling it to 30~40°C.

[0062] 8) Bottling: Cool the sterilized extract to below 10°C for bottling.

[0063] 9) Storage: Quick-freeze at -18℃.

[0064] 3. A method for preparing yak milk coffee, the steps of which are as follows: 1) Heat the semi-skimmed yak milk obtained in step 1 at 60℃ for 30 seconds to obtain hot semi-skimmed yak milk; 2) Mix hot semi-skimmed yak milk, coffee extract obtained in step 2, and water in a volume ratio of 3:1:4, and shear at 14000 rpm for 20 minutes to obtain the mixture.

[0065] 3) Add white sugar to the mixture obtained in step 2) and stir well.

[0066] 4) Homogenize the material that was mixed evenly in step 3) at a first pressure of 180 bar and a second pressure of 40 bar.

[0067] 5) Sterilize the homogenized liquid from step 4) at a temperature of 125°C for 4 seconds, and then cool it to below 7°C.

[0068] 6) The sterilized material is canned at a temperature below 9°C.

[0069] The yak milk coffee of this embodiment has a unique milky aroma and nutritional value. What makes this coffee unique is that it uses yak milk from high-altitude yaks (above 3200m). This milk is naturally fragrant and rich in nutrients, with each box containing 270mg of naturally occurring calcium, making the brewed coffee exceptionally sweet.

[0070] Example 2: 1. A method for preparing semi-skimmed yak milk, comprising the following steps: 1) Raw material acceptance: High-quality Lanyi yak milk is selected as the raw material and is subject to strict acceptance to ensure the quality and safety of the raw milk.

[0071] 2) Pretreatment: The raw yak milk is filtered and impurities are removed using an 80-200 mesh filter to obtain pretreated yak milk.

[0072] 3) Defatting: The pre-treated yak milk is defat-free by high-speed rotation to obtain defatted yak milk.

[0073] 4) Standardization: Through machine control, 2% fat (yak butter extracted from yak milk) is injected into skimmed yak milk to obtain semi-skimmed yak milk.

[0074] 5) The semi-skimmed yak milk was homogenized at a temperature of 70-75℃ and a pressure of 250 bar to obtain homogenized semi-skimmed yak milk.

[0075] 6) Sterilization and cooling: The homogenized semi-skimmed yak milk is sterilized using ultra-high temperature pasteurization at a temperature of 125℃~138℃ for 2~4 seconds. After sterilization, the yak milk is rapidly cooled to 4~5℃.

[0076] 7) Packaging: The cooled semi-skimmed yak milk is aseptically packaged.

[0077] 2. A method for preparing coffee extract, comprising the following steps: 1) Bean selection: Select Arabica beans from Brazil and sun-dry them. The moisture content of the sun-dried coffee beans is controlled at 11%~12%.

[0078] 2) Roasting: The processed coffee beans are roasted to a medium-dark temperature of 250℃ for 20 minutes. The moisture content of the roasted coffee beans is controlled to be below 5%.

[0079] 3) Grinding: Grind the roasted coffee beans to a medium-coarse grind.

[0080] 4) Extract the ground coffee powder to obtain an extract. The temperature of the water used for extraction is 93℃.

[0081] 5) The extract was filtered three times to obtain the filtrate; the first filter had a mesh size of 50, the second filter had a mesh size of 100, and the third filter had a mesh size of 300.

[0082] 6) Centrifugation: Centrifuge the filtrate and collect the supernatant; the centrifugation speed is 7500 rpm and the centrifugation time is 5 min.

[0083] 7) Sterilization: Sterilize the supernatant by heating it to 150°C and holding it for 4 seconds, then rapidly cooling it to 30~40°C.

[0084] 8) Bottling: Cool the sterilized extract to below 5°C for bottling.

[0085] 9) Storage: Quick-freeze at -20℃.

[0086] 3. A method for preparing yak milk coffee, the steps of which are as follows: 1) Heat the semi-skimmed yak milk obtained in step 1 at 70℃ for 20 seconds to obtain hot semi-skimmed yak milk; 2) Mix hot semi-skimmed yak milk, coffee extract obtained in step 2, and water in a volume ratio of 3:1:4, and shear at 11000 rpm for 20 minutes to obtain the mixture.

[0087] 3) Add white sugar to the mixture obtained in step 2) and stir well.

[0088] 4) Homogenize the material that was mixed evenly in step 3) at a first pressure of 180 bar and a second pressure of 40 bar.

[0089] 5) Sterilize the homogenized liquid from step 4) at a temperature of 130°C for 3 seconds, and then cool it to below 9°C.

[0090] 6) The sterilized material is canned at a temperature below 9°C.

[0091] Experimental Example 1 The yak milk coffee samples prepared in Examples 1 and 2 were kept at 6°C for 3 days, and the presence of fat floating on the surface and sedimentation at the bottom was observed by the naked eye.

[0092] The yak milk coffee prepared in Examples 1 and 2 differed mainly in the top and bottom portions from three commercially available milk coffee samples with added stabilizers (Hengyu Cheese Latte Coffee Milk Beverage, Nestlé, and Fino Thick Coconut Milk, which respectively added milk beverage stabilizers, milk stabilizers, sodium caseinate, etc.). The commercially available milk coffee samples had a larger top slope (some properties of the top of the sample, such as concentration, particle distribution, and instability index, changed more rapidly), indicating that the top tissue state of the commercially available milk coffee samples was not very stable. The difference in the middle portion was very small, indicating that there may be a risk of fat floating during the shelf life. There were no abnormalities in the bottom and middle stratification.

[0093] However, observations showed that the yak milk coffee prepared in Examples 1 and 2 did not exhibit significant fat floating or bottom sedimentation during the shelf life, indicating that the product has good stability and achieves the effect of ensuring the stability of coffee milk products without adding stabilizers.

[0094] The yak milk coffee prepared in Examples 1 and 2 after homogenization and high-temperature sterilization has a shelf life of up to 12 months.

[0095] Comparative Example 1 The semi-skimmed yak milk was replaced with semi-skimmed milk with a fat volume content of 1% to 1.5%, and the rest was the same as in Example 1. Compared with the yak milk coffee of Example 1, the yak milk coffee obtained in Comparative Example 1 had a milder taste and a lighter milky aroma.

[0096] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for processing yak milk coffee, characterized in that, Includes the following steps: Coffee powder and water are mixed and extracted to obtain an aqueous extract; The aqueous extract was filtered sequentially, and the filtrate was collected. The filtrate was centrifuged, and the supernatant was collected to obtain coffee extract; The semi-skimmed yak milk was homogenized to obtain homogenized semi-skimmed yak milk; The homogenized semi-skimmed yak milk, coffee extract, and water are mixed to obtain yak milk coffee. The filtration includes a first filter, a second filter, and a third filter; the third filter uses a filter with a larger mesh size than the second filter; the second filter uses a filter with a larger mesh size than the first filter; the third filter uses a filter with a mesh size of 300.

2. The processing method according to claim 1, characterized in that, The coffee powder is obtained by grinding medium-dark roasted coffee beans; the particle size of the coffee powder is 0.5~0.85mm.

3. The processing method according to claim 1, characterized in that, The semi-skimmed yak milk has a fat volume content of 1.7% to 2%.

4. The processing method according to claim 1, characterized in that, The volume ratio of the homogenized semi-skimmed yak milk, coffee extract, and water is 3:1:

4.

5. The processing method according to claim 1, characterized in that, The extraction temperature is 90~93℃.

6. The processing method according to claim 1, characterized in that, The first filter uses a 50-mesh filter; the second filter uses a 100-mesh filter.

7. The processing method according to claim 1, characterized in that, The temperature for homogenizing the semi-skimmed yak milk is 70-75℃; the pressure for homogenizing the semi-skimmed yak milk is 200-250 bar.

8. The processing method according to claim 1, characterized in that, Before mixing the homogenized semi-skimmed yak milk and coffee extract, the semi-skimmed yak milk is further heated; the heating temperature is 60~70℃; and the heating time is 20~30s.

9. The processing method according to claim 1, characterized in that, After mixing the homogenized semi-skimmed yak milk and coffee extract, the mixture also includes adding a sweetener, which includes white sugar.

10. The processing method according to claim 9, characterized in that, No stabilizers are added to the yak milk coffee.