Coffee concentrated solution and preparation process thereof

Abstract

The invention relates to the technical field of food and beverage, in particular to a preparation process of coffee concentrate, which comprises the following steps: S1, putting raw coffee beans into raw bean processing equipment provided with a magnetic rod, and removing metal impurities mixed in the raw coffee beans; s2, baking the raw coffee beans by adopting coffee baking equipment to obtain cooked coffee beans; s3, crushing the cooked coffee beans by adopting grinding equipment; s4, adding water into the cooked coffee beans, carrying out ultrasonic extraction, and filtering to obtain a coffee extracting solution and coffee grounds; s5, adding the coffee grounds into an ethanol solution for extraction, and then carrying out vacuum concentration to remove ethanol so as to obtain coffee oil; s6, uniformly mixing coffee oil with the coffee extract, cooling, and standing to obtain a coffee oil layer and a coffee liquid layer; s7, concentrating the coffee liquid layer, and uniformly mixing the concentrated coffee liquid layer with the coffee oil layer to obtain a coffee concentrated solution; coffee concentrate obtained through an RO membrane concentration mode has a rich and real taste.

Description

Technical Field

[0001] The invention relates to the technical field of food and beverage, and in particular to a coffee concentrate and a preparation process thereof. Background Art

[0002] In recent years, with the accelerated pace of life and the growing demand of consumers for convenient and high-quality beverages, the market demand for ready-to-drink coffee products has been increasing. Traditional ready-to-drink coffee is mostly canned or bottled liquid coffee, which has problems such as short shelf life and the need for refrigerated storage, which limits its application scenarios.

[0003] At present, some ready-to-drink coffee products on the market use coffee beans from a single source and lack diversified taste blending; at the same time, in the process of coffee bean screening, modern scientific and technological means are often not fully utilized to remove impurities, affecting the quality of the final product; many manufacturers lack scientific basis for coffee bean blending, and simply mix based on experience, which makes it difficult to achieve the best flavor combination; traditional roasting methods usually adopt a unified standard and cannot customize roasting according to the characteristics of different types of coffee beans, resulting in a large loss of flavor; existing extraction technologies are mostly based on room temperature or low temperature conditions, with low extraction efficiency, and cannot fully extract the flavor substances in coffee, affecting the taste of the finished product; although some concentration methods can increase the solid content, they are often accompanied by a large loss of flavor, affecting product quality; traditional pasteurization or other medium and low temperature sterilization methods are difficult to ensure the safety and stability of the product, while high temperature and long-term sterilization will seriously damage the original flavor of the coffee. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a coffee concentrate and a preparation process thereof.

[0005] In a first aspect, the present invention provides a process for preparing a coffee concentrate, comprising the following steps:

[0006] S1. Selecting green coffee beans, and putting the green coffee beans into a green bean processing device equipped with a magnetic bar to remove metal impurities mixed in the green coffee beans;

[0007] S2, roasting green coffee beans using coffee roasting equipment, roasting them according to a corresponding green coffee bean roasting curve to obtain cooked coffee beans;

[0008] S3, using grinding equipment to crush the cooked coffee beans;

[0009] S4, adding cooked coffee beans to water for ultrasonic extraction, filtering, and obtaining coffee extract and coffee grounds;

[0010] S5, adding coffee grounds to an ethanol solution for extraction, and then concentrating under reduced pressure to remove the ethanol to obtain coffee oil;

[0011] S6, uniformly mixing the coffee oil and the coffee extract, cooling, and standing to obtain a coffee oil layer and a coffee liquid layer;

[0012] S7, concentrating the coffee liquid layer and mixing it with the coffee oil layer to obtain the coffee concentrated liquid.

[0013] Preferably, in step S2, the roasting degree is controlled by a color measuring instrument to have an L value between 90 and 100, and the roasted coffee beans are placed in a roasting bean bin for more than 24 hours.

[0014] In the present invention, the green coffee beans are blended in a ratio of 80% Yunnan small-grain coffee, 10% Uganda coffee and 10% Brazilian coffee.

[0015] Preferably, in step S3, the particle size distribution range of the roasted coffee beans is as follows: particles above 20 mesh account for 10%-20%; particles below 20 mesh and above 30 mesh account for 30%-40%; particles below 30 mesh and above 40 mesh account for 15%-30%; particles below 40 mesh account for 15%-25%.

[0016] Preferably, in step S4, the temperature of the ultrasonic extraction is 5-25° C. and the time is 10-60 min.

[0017] Preferably, in step S5, the ethanol solution is an ethanol aqueous solution with a volume concentration of 80%-95%.

[0018] Preferably, in step S5, the temperature of the reduced pressure concentration to remove ethanol is 30-70°C.

[0019] Preferably, in step S6, the standing time is 8-14 hours.

[0020] Preferably, in step S7, the coffee liquid layer is filtered through a ceramic membrane and concentrated through a RO reverse osmosis membrane to a mass concentration of 5%-25%.

[0021] Preferably, in step S7, after the coffee liquid layer is concentrated and mixed with the coffee oil layer, the steps of degassing, nitrogen filling and packaging are also included; after the packaging, the step of sterilizing at 100-150° C. for 1-3 minutes is also included.

[0022] In a second aspect, the present invention provides a coffee concentrate prepared by the coffee concentrate preparation process described in the first aspect.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Through a series of screening steps such as washing, metal detection, color sorting, and screening, only first-grade coffee beans with full grains and uniform size enter the subsequent processing links. This strict raw material selection not only improves the quality of the final product, but also provides consumers with a more consistent and reliable taste experience.

[0025] (2) Based on research on the characteristics of coffee beans from different origins, a blend of 80% Yunnan small-grain coffee, 10% Ugandan coffee, and 10% Brazilian coffee was used to achieve the best balance of acidity, bitterness, and concentration. This carefully designed formula can satisfy a wider range of taste preferences and give the product a unique flavor profile.

[0026] (3) The roasting curve customized by professional roasters according to the characteristics of different coffee beans ensures that each bean can complete the roasting process under its most suitable conditions. This not only helps to preserve the original aroma of the coffee, but also maximizes its potential flavor, laying a solid sensory foundation for the final product.

[0027] (4) The roasted beans are placed in a bean ripening bin for more than 24 hours. This process allows the internal gas to be fully released, further enhancing the aroma and taste complexity of the coffee.

[0028] (5) Extraction is performed at 90°C and 2 atmospheres of pressure, ensuring that the flavor substances in the coffee beans are extracted to the greatest extent possible. Compared with traditional methods, this method can achieve a higher extraction rate and better flavor performance.

[0029] (6) The solid content is increased from 2-3% to 10% through RO membrane concentration, and then low-temperature vacuum concentration technology is used to increase the solid content to 15%; this staged concentration method not only ensures efficiency but also minimizes flavor loss, so that the final coffee concentrate has a rich and authentic taste.

[0030] (7) By extracting coffee grounds with ethanol solution and recovering the oil components therein, not only the resource utilization rate is improved, but also natural oil is added to the coffee concentrate, enriching the taste level of the product.

[0031] (8) Ultra-high temperature instantaneous sterilization technology is used to perform low-temperature filling under aseptic conditions. This sterilization method can greatly reduce the impact on the flavor of the coffee, while ensuring that the product can be stored for a long time at room temperature, greatly reducing logistics costs and storage requirements. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0033] Example 1

[0034] This embodiment provides a preparation process of coffee concentrate, comprising the following steps:

[0035] S1. Selecting green coffee beans, and putting the green coffee beans into a green bean processing device equipped with a magnetic bar to remove metal impurities mixed in the green coffee beans;

[0036] S2. Roasting green coffee beans with coffee roasting equipment according to the corresponding green coffee bean roasting curve to obtain cooked coffee beans; the roasting degree is controlled at an L value of 95 using a color measuring instrument, and the roasted coffee beans are placed in a roasting bean warehouse for 26 hours;

[0037] S3. Use grinding equipment to crush the roasted coffee beans; the particle size distribution range of the roasted coffee beans is: above 20 mesh accounts for 15%; below 20 mesh and above 30 mesh accounts for 35%, below 30 mesh and above 40 mesh accounts for 30%, and below 40 mesh accounts for 20%.

[0038] S4, adding cooked coffee beans to water for ultrasonic extraction, filtering, and obtaining coffee extract and coffee grounds;

[0039] The ultrasonic extraction temperature is 20°C and the time is 50 minutes;

[0040] S5, adding coffee grounds to an ethanol solution for extraction, and then concentrating under reduced pressure to remove ethanol to obtain coffee oil; the ethanol solution is an ethanol aqueous solution with a volume concentration of 90%; the temperature for concentrating under reduced pressure to remove ethanol is 60° C.;

[0041] S6, uniformly mixing the coffee oil and the coffee extract, cooling, and standing to obtain a coffee oil layer and a coffee liquid layer; the standing time is 10 hours;

[0042] S7, concentrating the coffee liquid layer and mixing it with the coffee oil layer to obtain the coffee concentrated liquid; filtering the coffee liquid layer through a ceramic membrane and concentrating it through an RO reverse osmosis membrane to a mass concentration of 20%; after concentrating the coffee liquid layer and mixing it with the coffee oil layer, the steps of degassing, nitrogen filling and packaging are also included; after packaging, the step of sterilizing at 138°C for 1 minute is also included.

[0043] This embodiment also provides a coffee concentrate, which is prepared using the above-mentioned preparation process.

[0044] Comparative Example 1

[0045] Compared with Example 1, in step S2, the roasting degree is controlled by a color measuring instrument to have an L value of 80, and the remaining steps are the same as in Example 1.

[0046] Comparative Example 2

[0047] Compared with Example 1, in step S5, the ethanol solution used is an ethanol aqueous solution with a volume concentration of 90%, and the remaining steps are the same as Example 1.

[0048] Comparative Example 3

[0049] Compared with Example 1, in step S7, the RO reverse osmosis membrane is concentrated to a mass concentration of 30%, and the remaining steps are the same as Example 1.

[0050] Comparative Example 4

[0051] Compared with Example 1, in step S7, the RO reverse osmosis membrane is concentrated to a mass concentration of 30%, and the remaining steps are the same as Example 1.

[0052] Comparative Example 5

[0053] Compared with Example 1, water bath sterilization is adopted in step S7, the water bath sterilization temperature is 120° C., and the time is 30 minutes. The remaining steps are the same as Example 1.

[0054] The coffee concentrates prepared in Example 1 and Comparative Examples 1 to 5 were subjected to sensory evaluation.

[0055] The sensory evaluation team consists of 10 people (5 men and 5 women), all of whom are specialty coffee quality graders who can accurately identify the quality of coffee. The sensory evaluation is carried out in accordance with the sensory evaluation standards established by the Specialty Coffee Association of America, and the aroma, acidity, body, consistency, cleanliness, balance, sweetness and other indicators are selected to evaluate and determine the flavor attributes of the samples. All samples are provided at room temperature of 20°C.

[0056] Samples were taken for evaluation by tasters. Tasters rated the intensity of the attribute using a 0-10 point scale, with 0.25 points as an increment (0 = none; 10 = extremely strong). The results are shown in Table 1.

[0057] Table 1

[0058]

[0059] The test results show that Example 1 (7.25) is significantly better than Comparative Example 1 (6.5), indicating that a lighter roasting degree (L=95) helps to retain more aroma substances; Example 1 (7.5) is higher than Comparative Example 1 (6.75), indicating that a proper roasting degree can better balance the sourness and provide a richer taste; Sweetness: The two are equivalent, but Example 1 is slightly higher (8.25>8.25); Aromatic flavor: Example 1 (7.25) is significantly higher than Comparative Example 2 (6), which may be because the volatile components in coffee can be more effectively extracted when the ethanol concentration is moderate; Consistency and cleanliness: Although both scores are 9.5, Example 1 is significantly better in other indicators, indicating that a suitable ethanol concentration is crucial to maintaining the consistency and purity of the overall taste;

[0060] Example 1 vs. Comparative Example 3 and Comparative Example 4: Example 1 (7.5) is better than Comparative Example 3 (6.75) and Comparative Example 4 (7). A higher solid content can increase the body of the coffee.

[0061] Consistency, cleanliness: All samples performed consistently in these aspects, but Example 1 scored higher in other aspects, showing the importance of moderate concentration.

[0062] Sweetness: Example 1 (8.25) is significantly higher than Comparative Example 3 (6.75) and Comparative Example 4 (7.25), indicating that excessive concentration may result in partial loss of sweetness.

[0063] Example 1 vs. Comparative Example 5: aroma, acidity, and body: Example 1 scored higher than Comparative Example 5 in these items, especially body (7.5 vs. 6). Ultra-high temperature instantaneous sterilization (UHT) can better preserve the original flavor of coffee compared to water bath sterilization.

[0064] Sweetness: Example 1 (8.25) is also higher than Comparative Example 5 (7), further demonstrating the advantage of the UHT method.

[0065] Through comparative analysis, it can be seen that the preparation process adopted in Example 1 performs well in all aspects, especially in terms of aroma, flavor, acidity, sweetness, etc. Accurate roasting degree control (L=95) helps to retain the aroma and acidity of coffee, moderate ethanol extraction concentration (90%) ensures effective flavor extraction without destroying the taste, reasonable concentration degree (mass concentration 20%) improves the body without losing sweetness, and sterilization technology (UHT) can minimize the impact on coffee flavor.

[0066] The specific embodiments further describe the present invention, but it should be understood that the specific description here should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the present invention.

Claims

1. A process for preparing coffee concentrate, characterized in that: The following steps are involved: S1. Selecting green coffee beans, and putting the green coffee beans into a green bean processing device equipped with a magnetic bar to remove metal impurities mixed in the green coffee beans; S2, roasting green coffee beans using coffee roasting equipment, roasting them according to a corresponding green coffee bean roasting curve to obtain cooked coffee beans; S3, using grinding equipment to crush the cooked coffee beans; S4, adding cooked coffee beans to water for ultrasonic extraction, filtering, and obtaining coffee extract and coffee grounds; S5, adding coffee grounds to an ethanol solution for extraction, and then concentrating under reduced pressure to remove the ethanol to obtain coffee oil; S6, uniformly mixing the coffee oil and the coffee extract, cooling, and standing to obtain a coffee oil layer and a coffee liquid layer; S7, concentrating the coffee liquid layer and mixing it with the coffee oil layer to obtain the coffee concentrated liquid.

2. The process for preparing a coffee concentrate according to claim 1, characterized in that: In step S2, the roasting degree is controlled by a color measuring instrument to an L value between 90 and 100, and the roasted coffee beans are placed in a roasting bean bin for more than 24 hours.

3. The process for preparing a coffee concentrate according to claim 1, characterized in that: In step S3, the particle size distribution range of the roasted coffee beans is as follows: the proportion of particles above 20 mesh is between 10% and 20%; the proportion of particles below 20 mesh and above 30 mesh is between 30% and 40%; the proportion of particles below 30 mesh and above 40 mesh is between 15% and 30%; and the proportion of particles below 40 mesh is between 15% and 25%.

4. The process for preparing a coffee concentrate according to claim 1, characterized in that: In step S4, the temperature of the ultrasonic extraction is 5-25° C. and the time is 10-60 min.

5. The process for preparing a coffee concentrate according to claim 1, characterized in that: In step S5, the ethanol solution is an ethanol aqueous solution with a volume concentration of 80%-95%.

6. The process for preparing a coffee concentrate according to claim 1, characterized in that: In step S5, the temperature of the reduced pressure concentration to remove ethanol is 30-70°C.

7. The process for preparing a coffee concentrate according to claim 1, characterized in that: In step S6, the standing time is 8-14 hours.

8. The process for preparing a coffee concentrate according to claim 1, characterized in that: In step S7, the coffee liquid layer is filtered through a ceramic membrane and concentrated through a RO reverse osmosis membrane to a mass concentration of 5%-25%.

9. The process for preparing a coffee concentrate according to claim 1, characterized in that: In step S7, after the coffee liquid layer is concentrated and mixed with the coffee oil layer, the steps of degassing, nitrogen filling and packaging are also included; after the packaging, the step of sterilizing at 100-150° C. for 1-3 minutes is also included.

10. A coffee concentrate, characterized in that: The coffee concentrate is prepared using the preparation process of the coffee concentrate as described in claims 1-9.

Images