Stabilizing compositions and their use in improving the stability of milk-containing coffee drinks, and milk-containing coffee drinks made thereby

Abstract

This invention relates to the field of coffee beverage processing technology, and particularly to a stabilizing composition and its application in improving the stability of milk-containing coffee beverages, as well as the resulting milk-containing coffee beverage. Due to the high coffee concentration and milk solids content, the product is prone to casein aggregation and decreased fluidity after high-temperature sterilization. This invention effectively solves these problems, and the product can be stored at room temperature for up to 9 months, while also increasing the logistics and distribution radius.

Description

Technical Field

[0001] This invention relates to the field of coffee beverage processing technology, and particularly to stabilizing compositions and their application in improving the stability of milk-containing coffee beverages, as well as the resulting milk-containing coffee beverages. Background Technology

[0002] The coffee market is growing rapidly at a compound annual growth rate of 10%, and the number of coffee products on the market is increasing. However, the growth rate of instant coffee has dropped to around 2%, mainly because 3-in-1 instant coffee requires hot water to prepare, greatly reducing its convenience. This invention can be prepared with cold water, effectively solving the above problems. Moreover, compared to pure espresso, espresso with milk has a richer and smoother flavor, making it more palatable. This invention can not only be drunk directly, but can also be mixed with water, milk, or ice, providing more application scenarios. Due to the high coffee concentration and milk solids content, the product is prone to casein aggregation after high-temperature sterilization, resulting in poor fluidity. This invention effectively solves the above difficulties, and it can be stored at room temperature for up to 9 months, while also increasing the logistics and distribution radius.

[0003] Because espresso has high acidity and undergoes significant acidification during its shelf life, when mixed with dairy products, substances such as caffeic acid, tannic acid, and chlorogenic acid in the coffee easily bind and flocculate with milk proteins. This increases the instability of the two components, making the proteins highly prone to flocculation and clumping during high-temperature sterilization and throughout the shelf life, affecting product stability and taste. Therefore, most espresso products on the market currently contain almost no milk, and ordinary milk-containing coffee beverages often have a protein content of less than 3%.

[0004] Therefore, providing a milk-based espresso beverage with high caffeine concentration and its preparation method is of significant practical importance. Summary of the Invention

[0005] In view of this, the present invention provides a stabilizing composition and its application in improving the stability of milk-containing coffee beverages, as well as the resulting milk-containing coffee beverage.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a stable composition comprising, by weight, the following components:

[0008]

[0009] In some specific embodiments of the present invention, the stable composition comprises, by weight, the following components:

[0010]

[0011]

[0012] or

[0013]

[0014] or

[0015]

[0016]

[0017] The present invention also provides a stabilizing formulation comprising the aforementioned stabilizing composition and water.

[0018] In some specific embodiments of the present invention, the stable formulation comprises, by weight percentage, the following components:

[0019]

[0020] The remainder is water.

[0021] In some specific embodiments of the present invention, the stable formulation comprises, by weight percentage, the following components:

[0022]

[0023] The remainder is water;

[0024] or

[0025]

[0026]

[0027] The remainder is water;

[0028] or

[0029]

[0030] The remainder is water.

[0031] Based on the above research, the present invention also provides the following applications in improving the stability of milk-containing coffee beverages;

[0032] (I) the stable composition described above; or

[0033] (II) The stabilized formulation.

[0034] More importantly, the present invention also provides milk-containing coffee beverages, including any of the following:

[0035] (I) the stable composition described above; or

[0036] (II) The stabilized formulation.

[0037] In some specific embodiments of the present invention, the milk-containing coffee beverage further includes dairy products and coffee solids;

[0038] The weight ratio of the dairy product, the coffee solids, and any of the following is (4.7–20): (4–10): (0.625–2.045);

[0039] (I) The stable composition as described in claim 1 or 2; or

[0040] (II) The stable formulation as described in any one of claims 3 to 5.

[0041] In addition, the present invention also provides a method for preparing the milk-containing coffee beverage, wherein the dairy product, the coffee solids and any of the following are mixed;

[0042] (I) the stable composition described above; or

[0043] (II) The stabilized formulation.

[0044] In some specific embodiments of the present invention, the preparation method includes the following steps:

[0045] Step 1: Pre-dissolve 4.7% to 20% of milk powder (condensed milk, concentrated milk) in water at 60 to 70°C, stir in a water bath at 60 to 70°C for 30 to 60 minutes to obtain liquid A, and cool it to 10 to 15°C for later use.

[0046] Step 2: Add mono- and diglycerides of fatty acids, sucrose fatty acid esters, phospholipids, carrageenan, microcrystalline cellulose, and gellan gum to hot water at 70-85℃ to disperse them, and then cool the solution to 10-15℃ for later use.

[0047] Step 3: Dissolve instant coffee powder or coffee concentrate in water at 15-35℃ (powder to water ratio 1:3, 90℃ hot water, 0-5 bar to obtain extract), coffee solids account for 4%-10% of the total mass of the finished product, add 0.15-0.4% sodium carbonate, filter, centrifuge (disc centrifuge, speed 4500-5500 rpm, turbidity less than 40 NTU) to obtain liquid C, cool to 10-15℃ for later use;

[0048] Step 4: After mixing solution A and solution B evenly, add sodium citrate (potassium) and sodium tripolyphosphate and stir for 5-10 minutes. Then slowly add solution C and mix evenly. Add 0.05-0.1% sodium carbonate again and use room temperature water to make up to 100% to obtain solution D.

[0049] Step 5: Heat the liquid material D to 70-75℃ and homogenize at 200 bar; after instantaneous sterilization at 130-140℃ for 3-5 seconds, homogenize again at 160 bar, aseptically fill or cool to 25-90℃ for filling, and sterilize at 100-130℃ for 10-20 minutes to obtain the milk-containing coffee beverage.

[0050] Because of the high coffee concentration and milk solids content, the product is prone to casein aggregation and poor flowability after high-temperature sterilization. This invention solves the above problems well, and can be stored at room temperature for up to 9 months, and can also increase the logistics circulation radius. Detailed Implementation

[0051] This invention discloses a stabilizing composition and its application in improving the stability of milk-containing coffee beverages, as well as the resulting milk-containing coffee beverage. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0052] The technical solution of the present invention includes:

[0053]

[0054]

[0055] The preparation method includes the following steps:

[0056] Step 1: Predissolve 4.7% to 20% of milk powder (condensed milk, concentrated milk) in water at 60 to 70°C, stir in a water bath at 60 to 70°C for 30 to 60 minutes to obtain liquid A, and cool it to 10 to 15°C for later use.

[0057] Step 2: Add mono- and diglycerides of fatty acids, sucrose fatty acid esters, phospholipids, carrageenan, microcrystalline cellulose, and gellan gum to hot water at 70-85℃ to disperse them, and then cool the solution to 10-15℃ for later use.

[0058] Step 3: Dissolve instant coffee powder or coffee concentrate in water at 15-35℃ (powder to water ratio 1:3, 90℃ hot water, 0-5 bar to obtain extract), coffee solids account for 4%-10% of the total mass of the finished product, add 0.15-0.4% sodium carbonate, filter, centrifuge (disc centrifuge, speed 4500-5500 rpm, turbidity less than 40 NTU) to obtain liquid C, cool to 10-15℃ for later use;

[0059] Both instant coffee powder and coffee concentrate are derived from coffee bean extraction (the difference is that instant coffee powder is more than 95% coffee solids, while coffee concentrate contains 4-60% coffee solids).

[0060] Step 4: After mixing solution A and solution B evenly, add sodium citrate (potassium) and sodium tripolyphosphate and stir for 5-10 minutes. Then slowly add solution C and mix evenly. Add 0.05-0.1% sodium carbonate again and use room temperature water to make up to 100% to obtain solution D.

[0061] Step 5: Heat the liquid material D to 70-75℃ and homogenize at 200 bar. After instantaneous sterilization at 130-140℃ for 3-5 seconds, homogenize again at 160 bar, and aseptically fill or cool to 25-90℃ for filling. After sterilization at 100-130℃ for 10-20 minutes, the finished product is obtained.

[0062] The resulting espresso has good fluidity, can be stored at room temperature for 9 months, and can be drunk directly or with water, milk, alcohol, or ice.

[0063] This product has a total solids content of approximately 20% or more, including over 10% total milk solids and approximately 4-10% coffee solids. However, it may or may not contain sodium carbonate (potassium), sodium bicarbonate (potassium), disodium hydrogen phosphate (potassium), sodium tripolyphosphate, sodium citrate (potassium), carrageenan, microcrystalline cellulose, or gellan gum. The coffee solids are provided by instant coffee powder, concentrate, or roasted coffee beans. The milk solids are provided by milk powder, condensed milk (sweetened or unsweetened), concentrated milk, anhydrous butter, or light cream.

[0064] The stable composition provided by this invention and its application in improving the stability of milk-containing coffee beverages, as well as the raw materials and reagents used in the prepared milk-containing coffee beverages, are all commercially available.

[0065] The present invention will be further illustrated below with reference to the embodiments:

[0066] Example 1

[0067] The formula contains 4% coffee solids, 16% concentrated milk, 0.09% mono- and diglycerides of fatty acids and sucrose fatty acids in a 2:1 ratio, 0.01% phospholipids, 0.2% sodium carbonate (added twice, 0.15% the first time and 0.05% the second time), 0.06% disodium hydrogen phosphate, 0.8% sodium citrate, 0.015% carrageenan, 0.2% microcrystalline cellulose, 0.005% gellan gum, and 0.01% sodium tripolyphosphate.

[0068] Preparation method:

[0069] Predissolve 16% of concentrated milk in water at 60℃, stir in a water bath at 60℃ for 30 minutes to obtain liquid A, and cool to 15℃ for later use.

[0070] Add mono- and diglycerides of fatty acids, sucrose fatty acid esters, phospholipids, carrageenan, microcrystalline cellulose, and gellan gum to hot water at 70°C to disperse them, and then cool the solution to 15°C for later use.

[0071] Dissolve instant coffee powder or coffee concentrate in 15℃ water (powder to water ratio 1:3, 90℃ hot water, 0 bar to obtain extract), coffee solids account for 4% of the total mass of the finished product, add 0.15% sodium carbonate, filter, centrifuge (disc centrifuge, speed 4500rpm, turbidity less than 40NTU) to obtain liquid C, cool to 15℃ for later use.

[0072] After mixing solution A and solution B evenly, add sodium citrate (potassium) and sodium tripolyphosphate and stir for 5 minutes. Then slowly add solution C and mix evenly. Finally, add 0.05% sodium carbonate and dilute to 100% with water to obtain solution D.

[0073] Heat liquid D to 70°C and homogenize at 200 bar. After instantaneous sterilization at 130°C for 5 seconds, homogenize again at 160 bar, aseptically fill or cool to 25°C for filling, and sterilize at 100°C for 20 minutes to obtain the finished product.

[0074] Example 2

[0075] The formula contains 7% coffee solids, 20% sweetened condensed milk, 0.06% mono- and diglycerides of fatty acids in a 2:1 ratio with a total addition of 0.06%, 0.03% phospholipids, 0.35% sodium carbonate (added twice, 0.28% the first time and 0.07% the second time), 0.1% disodium hydrogen phosphate, 0.4% sodium citrate, 0.01% carrageenan, 0.3% microcrystalline cellulose, 0.015% gellan gum, and 0.02% sodium tripolyphosphate.

[0076] Preparation method:

[0077] Predissolve 20% of condensed milk in water at 65℃, stir in a water bath at 65℃ for 45 minutes to obtain liquid A, and cool to 13℃ for later use.

[0078] Add mono- and diglycerides of fatty acids, sucrose fatty acid esters, phospholipids, carrageenan, microcrystalline cellulose, and gellan gum to hot water at 80°C to disperse them, and then cool the solution to 13°C for later use.

[0079] Dissolve instant coffee powder or coffee concentrate in water at 25℃ (powder to water ratio 1:3, 90℃ hot water, 3 bar to obtain extract), coffee solids account for 7% of the total mass of the finished product, add 0.28% sodium carbonate, filter, centrifuge (disc centrifuge, speed 5000rpm, turbidity less than 40NTU) to obtain liquid C, cool to 13℃ for later use.

[0080] After mixing solution A and solution B evenly, add sodium citrate (potassium) and sodium tripolyphosphate and stir for 7 minutes. Then slowly add solution C and mix evenly. Finally, add 0.07% sodium carbonate and dilute to 100% with water to obtain solution D.

[0081] The feed solution D is heated to 72°C and homogenized at 200 bar. After instantaneous sterilization at 135°C for 3 seconds, it is homogenized again at 160 bar. It is then aseptically filled or cooled to 55°C for filling, and sterilized at 121°C for 15 minutes to obtain the finished product.

[0082] Example 3

[0083] The composition includes 10% coffee solids, 4.7% milk powder, 0.03% mono- and diglycerides of fatty acids and sucrose fatty acids in a 2:1 ratio, 0.05% phospholipids, 0.5% sodium carbonate (added twice, 0.4% the first time and 0.1% the second time), 0.14% disodium hydrogen phosphate, 0.1% sodium citrate, 0.02% carrageenan, 0.4% microcrystalline cellulose, 0.01% gellan gum, and 0.03% sodium tripolyphosphate.

[0084] Preparation method:

[0085] 4.7% of the milk powder was pre-dissolved in water at 70°C, and stirred in a water bath at 70°C for 60 minutes to obtain liquid A, which was then cooled to 10°C for later use.

[0086] Add mono- and diglycerides of fatty acids, sucrose fatty acid esters, phospholipids, carrageenan, microcrystalline cellulose, and gellan gum to hot water at 85°C to disperse them, and then cool the solution to 10°C for later use.

[0087] Dissolve instant coffee powder or coffee concentrate in water at 35℃ (powder to water ratio 1:3, 90℃ hot water, 5 bar to obtain extract), coffee solids account for 10% of the total mass of the finished product, add 0.4% sodium carbonate, filter, centrifuge (disc centrifuge, speed 5500rpm, turbidity less than 40NTU) to obtain liquid C, cool to 10℃ for later use.

[0088] After mixing solution A and solution B evenly, add sodium citrate (potassium) and sodium tripolyphosphate and stir for 10 minutes. Then slowly add solution C and mix evenly. Finally, add 0.1% sodium carbonate and dilute to 100% with water to obtain solution D.

[0089] Heat liquid D to 75°C and homogenize at 200 bar. After instantaneous sterilization at 140°C for 4 seconds, homogenize again at 160 bar, aseptically fill or cool to 90°C for filling, and sterilize at 130°C for 10 minutes to obtain the finished product.

[0090] Compare with Example 1

[0091] The coffee solids were 7%, the sweetened condensed milk was 20%, the mono- and diglycerides of fatty acids were 0.1%, the sucrose fatty acid esters were 0.1%, and the rest of the operation was the same as in Example 2.

[0092] Compare with Example 2

[0093] The coffee solids content is 7%, the sugared condensed milk content is 20%, no phospholipids are added, and the rest of the operation is the same as in Example 2.

[0094] Compare with Example 3

[0095] The coffee solids content was 7%, the sweetened condensed milk was 20%, the sodium carbonate content was 0.6%, and the rest of the operation was the same as in Example 2.

[0096] Compare with Example 4

[0097] The coffee solids content was 7%, the sweetened condensed milk was 20%, the disodium hydrogen phosphate content was 0.2%, and the rest of the operation was the same as in Example 2.

[0098] Compare with Example 5

[0099] The coffee solids content was 7%, the sweetened condensed milk was 20%, the sodium citrate was 1.0%, and the rest of the operation was the same as in Example 2.

[0100] Compare with Example 6

[0101] The coffee solids content was 7%, the sweetened condensed milk was 20%, the sodium tripolyphosphate was 0.05%, and the rest of the operation was the same as in Example 2.

[0102] Compare with Example 7

[0103] The coffee solids content was 7%, the sweetened condensed milk was 20%, the carrageenan was 0.05%, and the rest of the operation was the same as in Example 2.

[0104] Compare with Example 8

[0105] The coffee solids content was 7%, the sweetened condensed milk was 20%, the microcrystalline cellulose was 0.1%, and the remaining operations were the same as in Example 2.

[0106] Compare with Example 9

[0107] The coffee solids content was 7%, the sweetened condensed milk was 20%, the microcrystalline cellulose content was 0.6%, and the rest of the operation was the same as in Example 2.

[0108] Compare with Example 10

[0109] The coffee solids content was 7%, the sweetened condensed milk was 20%, the gellan gum was 0.025%, and the remaining operations were the same as in Example 2.

[0110] Compare with Example 11

[0111] The difference from Example 2 is that the sodium carbonate added in step 4 is added to the feed solution C in advance, while the rest of the operation is the same as in Example 2.

[0112] Compare with Example 12

[0113] The difference from Example 2 is that sodium citrate and sodium tripolyphosphate are added to the feed solution C in advance, while the rest of the operation is the same as in Example 2.

[0114] Compare with Example 13

[0115] The difference from Example 2 is that step 5 does not involve the 130-140 degree 3-5 second process. The remaining operations are the same as in Example 2.

[0116] Compare with Example 14

[0117] The difference from Example 2 is that step 5 does not involve secondary homogenization.

[0118] Compare with Example 15

[0119] The difference from Example 2 is that the secondary homogenization pressure in step 5 is 200 bar.

[0120] Example 1: [Physicochemical Index Testing]

[0121] The caffeine detection method refers to GB 5009.139-2014 "Determination and Evaluation of Caffeine in Beverages". The protein content detection method refers to the Kjeldahl method in GB 5009.5-2016.

[0122] Table 1. Common milk-containing coffee beverages and their physicochemical properties in this invention

[0123]

[0124] Example 2 [Performance Testing Method]

[0125] Caffeine detection was performed according to GB 5009.139-2014, "Determination and Evaluation of Caffeine in Beverages". Protein content detection was performed according to the Kjeldahl method in GB 5009.5-2016. Particle size was measured using a laser particle size analyzer. The sample material was polystyrene latex (refractive index 1.596). Background sampling time was 10 s, single sampling time was 10 s, sampling interval was 1 s, and three samples were taken, with the average value taken.

[0126] [Performance Analysis and Discussion]

[0127] The results of the examples and control examples are summarized in Table 2:

[0128] Table 2

[0129]

[0130]

[0131]

[0132] As can be seen from Examples 1-3, the particle size distribution in Example 1 is superior to that in Example 2, which is superior to that in Example 3. This indicates that Example 1 has the best stability, Example 2 has the second best stability, and Example 3 has the third best stability. The main reason for this is the increased coffee content in the beverage. This also suggests that high caffeine and high protein concentrations are prone to protein aggregation, leading to decreased stability. However, due to the combined effects of the stable system formulation of this invention, the specific order of inorganic salt addition, the instantaneous high-temperature sterilization before secondary sterilization, and the secondary homogenization process, the milk-containing coffee beverage of this application, although having a much higher coffee content than commercially available milk-containing coffee beverages, still maintains a better particle size distribution and a more suitable average particle size. In other words, the product is less prone to aggregation and has excellent stability, indicating that the milk-containing espresso of this application can achieve a longer shelf life.

[0133] Compared to Example 2, Comparative Example 1 had the same coffee and protein content and the same processing technology, but the ratio of mono- and diglyceride fatty acid esters to sucrose fatty acid esters was 1:1 and the amount added was higher. From particle size analysis, in Comparative Example 1, d10 decreased, indicating more small-diameter particles, but d90 increased significantly, resulting in a wider overall particle size distribution. This indicates an increase in small-diameter components and a significant increase in large-diameter components, leading to uneven particle size distribution and a tendency for oil to rise and protein to aggregate during shelf life. The main reason for this is that the emulsifier failed to achieve a suitable HLB value and the dosage was too high. When the emulsifier ratio and dosage are appropriate, it is easier to form a suitable three-dimensional spatial distribution, effectively and appropriately coating the milk fat and binding the protein. Combining Example 2 and Comparative Example 1, it can be demonstrated that at the ratio and dosage of diglyceride fatty acid esters to sucrose fatty acid esters proposed in this invention, the formulation has a good stabilizing effect on the milk-containing espresso system.

[0134] As can be seen from Example 2 and Comparative Example 2, the addition or absence of phospholipids has a significant impact on the product's D(4,3), d10, d50, and d90. When phospholipids are not added, the overall particle size of the product increases, and obvious flocculation and white precipitate are observed. This is mainly because phospholipids, as a natural emulsifier, can better bind proteins and milk fats, forming appropriately sized, neatly arranged, and tightly packed micelles, preventing complexation and precipitation with substances such as chlorogenic acid and caffeine in high-concentration coffee. However, excessive introduction of phospholipids results in an overly oily taste and a beany flavor. Experiments show that in this product formulation, an addition of 0.02% to 0.05% phospholipids ensures the best product stability.

[0135] Combining Example 2 with Comparative Examples 3 and 4, the optimal addition range for the main buffer salt system of this invention can be seen. Due to the influence of high temperature and oxidation conditions on various organic acids such as chlorogenic acid in coffee, the pH will decrease. As the pH decreases and approaches the isoelectric point of proteins, the stability of milk proteins also decreases, making them prone to clumping and flocculation, thus shortening the shelf life of coffee. However, if the amount of buffer salt added is too high, it will competitively bind to the calcium ions already present in milk, forming insoluble or slightly soluble calcium salts. Comparative Example 3 shows that sodium carbonate exceeding the range described in this invention is more likely to cause an overall increase in particle size and a wider particle size distribution. Comparative Example 4 shows that although not as significant as carbonate, an overall increase in particle size still occurs. Therefore, this indicates that within the content range of carbonate and phosphate in this formula, it has a good stabilizing effect on the milk-containing espresso system.

[0136] By combining Example 2 with Comparative Examples 5 and 6, the optimal addition range of sodium citrate and sodium tripolyphosphate in this invention can be observed. In this invention, sodium citrate and sodium tripolyphosphate mainly function as protein stabilizers, chelating metal ions in milk and protecting the protein. Comparative Examples 5 and 6 show that excessive addition can lead to excessively high ion concentrations in the system, inhibiting the charge repulsion between protein micelles and thus reducing protein stability. Therefore, it can be seen that sodium citrate and sodium tripolyphosphate of this invention can ensure optimal performance within this formulation system.

[0137] By combining Example 2 with Comparative Examples 7 and 10, it can be seen that the colloidal system of the present invention has the optimal application range and stabilizing effect. Carrageenan and gellan gum can form a stable network bond with proteins through hydrogen bonds. Too low an addition amount cannot form an effective binding protection, while too high a addition amount will make the product system too viscous, which not only increases the particle size (see Table 2), but also easily forms a paste and has an unsmooth texture.

[0138] Combining Example 2 with Comparative Examples 8 and 9, the significant effect of microcrystalline cellulose within the scope of this invention can be seen. After homogenization, microcrystalline cellulose has a loose structure and can form a three-dimensional network structure distributed throughout the system, thereby ensuring the stability of the product's shelf life. Comparative Example 8 shows that although the d10 value is significantly reduced without the addition of microcrystalline cellulose, the overall particle size distribution becomes more dispersed, the average particle size increases, product stability decreases, and there is increased floating oil during shelf life and significant flocculation after secondary sterilization. Comparative Example 9 shows that although increasing the amount of microcrystalline cellulose can enhance the overall stability of the product and tighten the particle size distribution, exceeding the addition range proposed in this invention will significantly increase the particle size. Since microcrystalline cellulose is mainly an insoluble component, excessive addition will result in a high product particle size, making it prone to clumping during secondary sterilization, and increasing viscosity during production, which can easily lead to tube blockage.

[0139] Combining Example 2 with Comparative Examples 11 and 12, it can be seen that the overall particle size of Comparative Example 2 is larger, making it more prone to flocculation and sedimentation caused by collision and aggregation of protein particles. The reason for the better state in Example 2 is that adding sodium citrate and sodium tripolyphosphate separately to the milk component in advance allows sodium citrate and sodium tripolyphosphate to better react with free Ca2+. 2+ To form a colloid, preventing carbonates from reacting with Ca. 2+ Preferentially, they bind to form insoluble precipitates, adsorbing onto the protein surface and causing flocculation, which helps improve the stability of high-protein proteins. Compared to adding all the carbonate to coffee at once, the process of adding carbonate in two stages ensures that the solution C reaches a near-neutral pH first, preventing the pH from being too low and denaturing the milk proteins. Then, when the solution volume is close to 100%, the remaining sodium carbonate is added. At this point, because the solution volume has increased and the coffee concentration has decreased, the pH is closer to 7. Therefore, less carbonate can be used to maintain a pH greater than 7.3. Within this pH range, whey proteins no longer bind to casein micelles during heating. In other words, adding carbonate in two stages can meet the pH requirements at different stages while introducing as little as possible that easily denatures calcium. 2+ Precipitated carbonate ions. By adding inorganic salts in a more refined and targeted manner, the stability of milk-containing espresso beverages can be improved, enabling the milk-containing espresso of this application to achieve a longer shelf life.

[0140] Combining Example 2 and Comparative Example 13, it can be seen that the overall particle size of Comparative Example 3 is larger, while that of Example 2 is smaller. The main reason is that during secondary sterilization (100-130 degrees Celsius for 15-20 minutes), the intense high temperature environment accelerates the collision and aggregation of protein micelles and free calcium phosphate micelles, leading to precipitation and a decrease in the stability of the coffee beverage. Pre-treatment with a lower intensity UHT can uniformly heat and "passivate" the protein particles in the beverage, forming particles of a more uniform size, reducing the specific surface area of ​​the protein, and thus improving the thermal stability of the beverage. This ensures that the milk-containing espresso of this application can still maintain a small particle size distribution range after secondary sterilization, preventing both excessively large particle sizes that easily lead to flocculation and excessively large specific surface areas of small particles that can interact with free calcium phosphate. 2+ The formation of sediment allows for longer storage times. Furthermore, secondary sterilization is less expensive to implement than PET filling or Tetra Pak packaging facilities, has lower cleanliness requirements, and helps reduce production costs.

[0141] Combining Example 2 and Comparative Example 14, it can be seen that D(4,3) and D90 increase significantly, indicating a greater number of large-diameter particles. This is mainly because the secondary homogenization under medium pressure after high-temperature instantaneous sterilization makes the particle size distribution within the system more uniform, effectively reducing the presence of large particles without significantly damaging the effects of the preceding processes. This allows the milk-containing espresso to maintain a good state during high-temperature sterilization. However, as seen in Comparative Example 15, exceeding the pressure range proposed in this invention or causing excessively fine particle size dispersion reduces the "passivation" effect of UHT, resulting in some particle sizes increasing and thus decreasing product stability.

[0142] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A stable composition, characterized in that, It consists of the following components in parts by weight: 0.06 parts of mono- and diglycerides of fatty acids 0.03 parts of sucrose fatty acid esters 0.01 parts phospholipids Sodium carbonate 0.2 parts 0.06 parts of disodium hydrogen phosphate Sodium citrate 0.8 parts 0.01 parts of sodium tripolyphosphate 0.015 parts carrageenan 0.2 parts microcrystalline cellulose 0.005 parts gellan gum or 0.04 parts of mono- and diglycerides of fatty acids 0.02 parts of sucrose fatty acid esters 0.03 parts phospholipids Sodium carbonate 0.35 parts 0.1 parts of disodium hydrogen phosphate Sodium citrate 0.4 parts 0.02 parts sodium tripolyphosphate 0.01 parts carrageenan 0.3 parts microcrystalline cellulose 0.015 parts gellan gum or 0.02 parts of mono- and diglycerides of fatty acids 0.01 parts of sucrose fatty acid esters 0.05 parts phospholipids Sodium carbonate 0.5 parts 0.14 parts of disodium hydrogen phosphate Sodium citrate 0.1 parts 0.03 parts sodium tripolyphosphate 0.02 parts carrageenan 0.4 parts microcrystalline cellulose 0.01 parts gellan gum.

2. A stable formulation, characterized in that, Includes the stable composition as described in claim 1 and water.

3. The stable formulation as described in claim 2, characterized in that, On a weight percentage basis, it consists of the following components composition: Mono- and diglycerides of fatty acids 0.06% 0.03% sucrose fatty acid esters Phospholipids 0.01% Sodium carbonate 0.2% Disodium hydrogen phosphate 0.06% Sodium citrate 0.8% Sodium tripolyphosphate 0.01% Carrageenan 0.015% Microcrystalline cellulose 0.2% Gellan gum 0.005% The remainder is water; or Mono- and diglycerides of fatty acids 0.04% 0.02% sucrose fatty acid esters Phospholipids 0.03% Sodium carbonate 0.35% Disodium hydrogen phosphate 0.1% Sodium citrate 0.4% Sodium tripolyphosphate 0.02% Carrageenan 0.01% Microcrystalline cellulose 0.3% Gellan gum 0.015% The remainder is water; or Mono- and diglycerides of fatty acids 0.02% 0.01% sucrose fatty acid esters Phospholipids 0.05% Sodium carbonate 0.5% Disodium hydrogen phosphate 0.14% Sodium citrate 0.1% Sodium tripolyphosphate 0.03% Carrageenan 0.02% Microcrystalline cellulose 0.4% Gellan gum 0.01% The remainder is water.

4. Any of the following applications in improving the stability of milk-containing coffee beverages; (I) The stable composition as described in claim 1; or (II) The stable formulation as described in claim 2 or 3.

5. A milk-containing coffee beverage, characterized in that, Includes any of the following: (I) The stable composition as described in claim 1; or (II) The stable formulation as described in claim 2 or 3.

6. The milk-containing coffee beverage as described in claim 5, characterized in that, It also includes dairy products and coffee solids; The weight ratio of the dairy product, the coffee solids, and any of the following is (4.7~20):(4~10):(0.625~2.045); (I) The stable composition as described in claim 1; or (II) The stable formulation as described in claim 2 or 3.

7. The method for preparing a milk-containing coffee beverage as described in claim 6, characterized in that, Take the dairy product, the coffee solids and mix them with any of the following: (I) The stable composition as described in claim 1; or (II) The stable formulation as described in claim 2 or 3.

8. The preparation method according to claim 7, characterized in that, Including the following steps: Step 1: Predissolve 4.7% to 20% of milk powder, condensed milk or concentrated milk in water at 60 to 70°C, stir in a water bath at 60 to 70°C for 30 to 60 minutes to obtain liquid A, and cool to 10 to 15°C for later use. Step 2: Add mono- and diglycerides of fatty acids, sucrose fatty acid esters, phospholipids, carrageenan, microcrystalline cellulose, and gellan gum to hot water at 70-85℃ to disperse them, and then cool the solution to 10-15℃ for later use. Step 3: Dissolve instant coffee powder or coffee concentrate in water at 15-35℃, with coffee solids accounting for 4%-10% of the total mass of the finished product. Add 0.15-0.4% sodium carbonate, filter, and centrifuge to obtain liquid C. Cool to 10-15℃ for later use. The coffee concentrate has a coffee-to-water ratio of 1:3 and is extracted by heating with hot water at 90°C and at 0-5 bar. The centrifugation is a disc centrifugation with a speed of 4500~5500 rpm and a turbidity of less than 40 NTU; Step 4: After mixing solution A and solution B evenly, add sodium citrate or potassium citrate and sodium tripolyphosphate and stir for 5-10 minutes. During the stirring process, slowly add solution C and mix evenly. Then, add 0.05-0.1% sodium carbonate and use room temperature water to make up to 100% to obtain solution D. Step 5: Heat solution D to 70~75℃ and homogenize at 200 bar; after instantaneous sterilization at 130~140℃ for 3~5 seconds, homogenize again at 160 bar, aseptically fill or cool to 25~90℃ for filling, and sterilize at 100~130℃ for 10min~20min to obtain the milk-containing coffee beverage.

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