Preparation method of kumquat flower tea

Abstract

The invention relates to the technical field of tea processing, in particular to a making method of kumquat flower tea. The method comprises the following steps of raw material pretreatment, directional bitterness removal, gradient scenting and fragrance extraction, specifically, the raw material pretreatment comprises the steps of spreading and airing kumquat flowers, steam inactivation treatment and cold air cooling, and the directional bitterness removal comprises the steps of spraying a citric acid buffer solution; the gradient scenting comprises the steps of mixing the pretreated kumquat flowers and tea leaves according to a certain weight ratio, and then carrying out open scenting pile and closed scenting under the conditions of specific temperature and humidity; and the aroma increasing comprises the steps of screening the kumquat flowers, and then carrying out hot air drying, Maillard reaction induction treatment, aroma fixation and drying on the tea leaves. According to the making method of the kumquat flower tea, efficient utilization of kumquat flower resources is achieved, meanwhile, bitter and astringent substances in the kumquat flower processing process are effectively removed, unique aroma components of the kumquat flowers are fully released and reserved, and the high-quality kumquat flower tea which is rich in aroma, mellow in taste, sweet after taste and free of obvious bitter and astringent taste is made.

Description

Technical field

[0001] The invention relates to the technical field of tea processing, and in particular to a method for making kumquat flower tea. [Background Technology]

[0002] Kumquat, known for its unique flavor and rich nutritional profile, has a long history of cultivation in my country and is widely cultivated. From Guangdong and Guangxi to Fujian and Zhejiang, kumquats are popular with consumers for their excellent taste and medicinal and edible properties, and the cultivated area is expanding year by year. However, in the practice of kumquat cultivation and management, kumquat flowers are often considered an unnecessary part. Because kumquat flowers bloom multiple times each year, their large number often competes with the growing fruit for nutrients. To ensure the yield and quality of kumquat fruit, growers must repeatedly shake the flowers to remove the excess flowers. These shaken-off flowers, along with those that haven't fully opened or are partially opened, are often discarded in the fields, becoming waste. According to incomplete statistics, in areas with dense kumquat cultivation, up to 10,000 tons of kumquat flowers are discarded each year due to flower shaking, which is undoubtedly a huge waste of resources.

[0003] Although kumquat flowers are largely discarded during cultivation, they possess a unique aroma. The fragrance of kumquat flowers is fresh and elegant, with the characteristic fruity aroma of kumquats. This aroma is primarily composed of a variety of volatile compounds, such as linalool and limonene. These aroma components not only impart a unique flavor to foods and beverages but also possess health benefits. For example, they can soothe nerves, relieve stress, and have antioxidant and antibacterial properties.

[0004] However, the application and development of kumquat flowers is still in its infancy. Although kumquat fruit has been widely used to make foods such as jam, juice, and preserves, there are very few reports on systematic research and industrial applications of kumquat flowers. This is mainly because in addition to containing beneficial aroma components, kumquat flowers also contain certain bitter substances, such as limonoid compounds and naringin. The presence of these bitter components makes the taste of kumquat flowers poor when directly used in food or beverage processing, making them difficult to be accepted by consumers. In addition, the volatile components of kumquat flowers have a low boiling point, and the aroma is easily lost during processing, making their utilization difficult.

[0005] Therefore, the prior art lacks a method for effectively utilizing kumquat flowers, resulting in an extremely low utilization rate of kumquat flowers. [Summary of the invention]

[0006] The purpose of the invention is to provide a method for preparing kumquat flower tea to address the problem of lack of a method for effectively utilizing kumquat flowers, so as to achieve efficient utilization of kumquat flower resources, effectively remove bitter substances produced during the processing of kumquat flowers, fully release and retain their unique aroma components, and produce high-quality kumquat flower tea with rich aroma, mellow taste and sweet aftertaste, and no obvious bitterness.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing kumquat flower tea comprises the following steps:

[0009] Raw material pretreatment: After the kumquat buds or flowers that have not fully opened or are half-opened are air-dried to a moisture content of ≤25%, they are subjected to steam inactivation treatment to inactivate the oxidase activity. The steam inactivation temperature is 95-100°C for 30-60 seconds. After steam inactivation, they are immediately cooled to room temperature with cold air at 5-10°C.

[0010] Targeted debittering: spray kumquat flowers with pH 4.5-5.5 citric acid buffer and soak for 10-20 minutes;

[0011] Gradient scenting: Pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:3-6. The flower-tea mixture is scented at a temperature of 20-25°C and a relative humidity of 65-75%. The first 4-8 hours of scenting are open to promote the release of volatile aroma. The pile height is ≤50cm. The pile is turned every 1-2 hours and sprayed with tea polyphenol-arabic gum composite film liquid. The temperature is then adjusted to below 20°C and the humidity to 55-65%. The mixture is sealed and scented for 8-12 hours to promote aroma absorption. The internal temperature of the mixture is kept below 30°C during the scenting process.

[0012] Fragrance enhancement: After screening the kumquat flowers, the tea leaves are first dried with hot air at a temperature of 85-100°C to a moisture content of 15-20%, then cooled to 60-70°C for Maillard reaction induction treatment, the tea leaves are cooled to a moisture content of 8-10%, then cooled to 40-50°C to fix the aroma, and finally dried to a moisture content of ≤5%.

[0013] Further optimization is to carry out enzymatic hydrolysis treatment before spreading and airing, and the enzymatic hydrolysis treatment uses a composite enzyme preparation to be sprayed onto the surface of the kumquat flowers, and the composite enzyme preparation contains cellulase, pectinase and β-glucosidase in a mass ratio of 2:1-1.2:0.5-0.8, and the concentration of the composite enzyme preparation is 0.1%-0.3% of the total weight of the kumquat flowers.

[0014] Before spreading out to air, the kumquat flowers were enzymatically treated, and a composite enzyme preparation with a specific ratio was used to further enhance the targeted debittering effect. Cellulase, pectinase, and β-glucosidase were compounded in a mass ratio of 2:1-1.2:0.5-0.8, synergistically decomposing the cell walls of the kumquat flowers, facilitating the release of aroma components while making bitter substances more easily removed by subsequent citric acid buffer treatment. Compared with no enzymatic treatment or treatment with a single enzyme, the kumquat flowers treated with this composite enzyme preparation significantly increased the adsorption rate of aroma components by tea leaves under the same scenting conditions, further reduced the content of bitter substances, and significantly improved the quality and taste of kumquat flower tea.

[0015] Further optimized, the complex enzyme preparation also contains naringinase extract, with a concentration of 0.03%-0.1% of the total weight of kumquat flowers.

[0016] The addition of naringinase extract to the complex enzyme preparation specifically targets naringin, a component found in high concentrations in kumquat flowers. The synergistic effect of naringinase and the complex enzyme preparation effectively reduces the naringin content in kumquat flowers, further reducing the bitterness and astringency, resulting in a richer, more sweet taste for kumquat flower tea.

[0017] Further optimized, the citric acid buffer solution is composed of citric acid and sodium citrate, and the dosage of the citric acid buffer solution is 1:5-10 based on the kumquat material-liquid ratio; the ratio of tea polyphenols to gum arabic in the tea polyphenol-gum arabic composite membrane liquid is 1:2.5-4, and the dosage is 0.5%-1.0% of the mass of the flower-tea mixture.

[0018] Citric acid buffer is prepared at a kumquat material-liquid ratio of 1:5-10, which can accurately control the pH value of kumquat flowers and promote the dissolution and removal of bitter substances. Tea polyphenols are combined with gum arabic to not only exert the antioxidant effect of tea polyphenols to protect the aroma components, but also form a uniform and stable membrane structure on the surface of the flower-tea mixture to reduce the loss of aroma. Compared with the simple bittering or aroma preservation measures in the prior art, the combination scheme of the present invention increases the aroma retention rate of kumquat flower tea by at least 20%-25%, while ensuring the richness of the aroma, it improves the stability and shelf life of the product.

[0019] In a further optimized gradient scenting method, the flower-tea mixture is stacked in 3-5 layers, with each layer being ≤15 cm thick.

[0020] Further optimized, during the Maillard reaction induction treatment stage, a mixed gas of nitrogen and carbon dioxide with a volume concentration of 0.5-1.0% is introduced into the baking environment, and the volume ratio of nitrogen to carbon dioxide in the mixed gas is 2-3:1.

[0021] During the Maillard reaction induction stage, a mixture of nitrogen and carbon dioxide is introduced into the baking environment to effectively control the baking atmosphere. This gas combination promotes the targeted progress of the Maillard reaction, imparting a unique roasted aroma to the tea while suppressing the formation of other undesirable flavor compounds. Compared to conventional hot air drying or baking methods, kumquat flower tea treated with this mixed gas treatment exhibits a richer aroma, a more intense and long-lasting roasted aroma, and a significantly improved flavor quality.

[0022] Further optimized, the tea is tea leaves that have been dried after withering, and the tea leaves are green tea.

[0023] Further optimized, a dynamic aroma recovery system is provided in the gradient scenting system, and the system comprises:

[0024] a) Condensation recovery unit: The temperature is controlled at -5°C to 5°C to collect volatile aroma components;

[0025] b) Adsorption and desorption unit: Modified activated carbon fiber is used as the adsorption medium, and thermal desorption is carried out at 120-150°C. The aroma components after thermal desorption are sequentially condensed, recovered, purified and filtered, and then mixed with the microencapsulated aroma components in a ratio of 1:1-2;

[0026] c) Microencapsulation unit: The recovered aroma components and β-cyclodextrin are mixed in a mass ratio of 1:5-8 to prepare microcapsules, and the particle size of the microcapsules is controlled to be 5-15 μm.

[0027] Further optimized, the microencapsulated aroma components are sprayed onto the tea leaves by atomization spraying during the low-temperature aroma stage of the aroma process, with an atomization pressure of 0.2-0.3 MPa and a spraying amount accounting for 0.5-1.0% of the mass of the tea leaves.

[0028] A dynamic aroma recovery system is set up, including condensation recovery, adsorption analysis and microencapsulation units, to achieve efficient recovery and reuse of aroma components. The condensation recovery unit collects volatile aroma components, and the microencapsulation unit prepares microcapsules with the recovered aroma components and β-cyclodextrin. The stability of the aroma components after microencapsulation is improved, and after backfilling into the tea leaves, the aroma release is uniform and long-lasting. Compared with the existing technology that does not adopt an aroma recovery system, the present invention not only reduces the loss of aroma components, but also significantly improves the aroma intensity and persistence of kumquat flower tea, enhancing the market competitiveness of the product.

[0029] Further optimized, the number of times of gradient scenting is 1-6 times, the tea leaves and kumquat flowers are separated after each scenting, and fresh kumquat flowers are replaced each time.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] 1. The present invention addresses the prior art issues of insufficient aroma retention and a bitter taste in kumquat flower tea by utilizing key technical approaches such as raw material pretreatment, targeted bitter removal, gradient scenting, and aroma enhancement. Raw material pretreatment, including airing, steam inactivation, and cold air cooling of the kumquat flowers, effectively inactivates oxidase activity, preventing oxidative loss of aroma components during subsequent processing and laying a solid foundation for subsequent processes. Spraying the kumquat flowers with a citric acid buffer solution at a specific pH significantly reduces the content of bitter substances in the flowers, resulting in a mellower, sweeter taste and improved product quality. By controlling temperature and humidity conditions and turning the pile, the release and adsorption of aroma components are optimized. Open scenting promotes the release of volatile aroma, while closed scenting facilitates full aroma absorption by the tea leaves. Maintaining the internal temperature of the mixture below 30°C prevents the destruction of aroma components, thereby improving aroma retention and the tea leaves' aroma adsorption efficiency. After hot air drying, Maillard reaction induction treatment and subsequent aroma fixation and drying steps, the aroma intensity and stability of the tea are further enhanced, giving the final product a more excellent aroma quality.

[0032] Compared with the prior art, the kumquat flower tea produced by the present invention has a rich and pure aroma, a mellow and sweet taste, and no obvious bitterness; it effectively avoids the transfer of bitter and astringent substances into tea leaves, significantly improves the quality and taste of the kumquat flower tea, provides consumers with a new taste experience, and at the same time realizes the efficient utilization of kumquat flower resources and increases the economic income of kumquat growers. [Specific implementation method]

[0033] The present invention will be further described below with reference to the embodiments.

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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 efforts are within the scope of protection of the present invention.

[0035] Application Overview

[0036] In view of the low utilization rate of kumquat flowers, which have excellent special aroma components and efficacy, and the characteristics that bitter components are difficult to control and easily remain during processing, affecting the taste, and aroma components are easily lost, and considering that our company is a tea production company with a long history, in order to solve the above technical problems, this application provides a method for preparing kumquat flower tea. The overall idea of the technical solution provided by this application is as follows:

[0037] A management method for a non-standard conveying equipment manufacturing enterprise.

[0038] A method for preparing kumquat flower tea comprises the following steps:

[0039] Raw material pretreatment: After the kumquat buds or flowers that are not fully opened or half opened are spread out to dry until the moisture content is ≤25%, steam inactivation treatment is used to passivate the oxidase activity. The steam inactivation temperature is 95-100°C and the time is 30-60 seconds. After steam inactivation, the kumquat flowers are immediately cooled to room temperature with cold air at 5-10°C; directional debittering: the kumquat flowers are sprayed with a pH 4.5-5.5 citric acid buffer solution and soaked for 10-20 minutes; gradient scenting: the pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:3-6, and the flower-tea mixture is scented at a temperature of 20-25°C and a relative humidity of 65-75%. The first 4-8 hours of the scenting process are open for stacking. To promote the release of volatile aroma, the pile height should be ≤50cm, the pile should be turned over every 1-2 hours and tea polyphenol-gum arabic composite film liquid should be sprayed; then the temperature should be adjusted to below 20℃ and the humidity should be adjusted to 55-65%, and the mixture should be sealed and scented for 8-12 hours to promote aroma adsorption. During the scenting process, the internal temperature of the mixture should be kept below 30℃; aroma enhancement: after screening the kumquat flowers, the tea leaves should be first dried with hot air at a temperature of 85-100℃ to a moisture content of 15-20%, then cooled to 60-70℃ for Maillard reaction induction treatment, the tea leaves should be reduced to a moisture content of 8-10%, and then cooled to 40-50℃ to fix the aroma, and finally dried to a moisture content of ≤5%.

[0040] After introducing the basic principles of the present application, various non-limiting implementation methods of the present application will be specifically introduced below.

[0041] Example 1

[0042] A method for preparing kumquat flower tea comprises the following steps:

[0043] Raw material pretreatment: After the kumquat buds or flowers that have not fully opened or are half-opened are air-dried to a moisture content of ≤25%, they are steam-inactivated to inactivate the oxidase activity at a temperature of 95°C for 60 seconds. After steam inactivation, they are immediately cooled to room temperature with a 5°C air stream.

[0044] Targeted debittering: spray kumquat flowers with pH 4.5 citric acid buffer and soak for 10 minutes;

[0045] Gradient scenting: Pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:3. The flower-tea mixture is scented at a temperature of 20°C and a relative humidity of 65%. The scenting pile is opened for the first 4 hours to promote the release of volatile aroma. The pile height is ≤50cm. The pile is turned every 2 hours and sprayed with tea polyphenol-gum arabic composite film liquid. The temperature is then adjusted to below 20°C and the humidity to 55%. The mixture is sealed and scented for 8 hours to promote aroma absorption. The internal temperature of the mixture is kept below 30°C during the scenting process.

[0046] Fragrance enhancement: After screening the kumquat flowers, the tea leaves are first dried with hot air at a temperature of 85°C to a moisture content of 20%, then cooled to 60°C for Maillard reaction induction treatment, the tea leaves are cooled to a moisture content of 10%, then cooled to 40°C to fix the aroma, and finally dried to a moisture content of ≤5%.

[0047] Before spreading and airing, enzymatic hydrolysis treatment is carried out, wherein a composite enzyme preparation is sprayed onto the surface of the kumquat flowers. The composite enzyme preparation comprises cellulase, pectinase and beta-glucosidase in a mass ratio of 2:1:0.5, and the concentration of the composite enzyme preparation is 0.1% of the total weight of the kumquat flowers.

[0048] The complex enzyme preparation also contains naringinase extract, with a concentration of 0.03% of the total weight of kumquat flowers.

[0049] The citric acid buffer solution is composed of citric acid and sodium citrate, and the dosage of the citric acid buffer solution is 1:5 based on the kumquat material-liquid ratio; the ratio of tea polyphenols to gum arabic in the tea polyphenol-gum arabic composite membrane liquid is 1:2.5, and the dosage is 0.5% of the mass of the flower-tea mixture.

[0050] In the gradient scenting method, the flower-tea mixture is stacked in three layers, with each layer ≤15cm thick.

[0051] During the Maillard reaction induction treatment stage, a mixed gas of nitrogen and carbon dioxide with a volume concentration of 0.5% is introduced into the baking environment, and the volume ratio of nitrogen to carbon dioxide in the mixed gas is 2:1.

[0052] The tea is tea leaves that have been dried after being withered, and the tea leaves are green tea.

[0053] A dynamic aroma recovery system is provided in the gradient scenting process, and the system comprises:

[0054] a) Condensation recovery unit: The temperature is controlled at -5°C to collect volatile aroma components;

[0055] b) Adsorption and desorption unit: Modified activated carbon fiber is used as the adsorption medium, and thermal desorption is carried out at 120°C. The aroma components after thermal desorption are sequentially condensed, recovered, purified and filtered, and then mixed with the microencapsulated aroma components in a 1:1 ratio;

[0056] c) Microencapsulation unit: The recovered aroma components and β-cyclodextrin are mixed in a mass ratio of 1:5 to prepare microcapsules, and the particle size of the microcapsules is controlled to be 5-15 μm.

[0057] The microencapsulated aroma component is sprayed onto the tea leaves in an atomizing spraying manner during the low-temperature aroma enhancement stage of the aroma enhancement process, with an atomizing pressure of 0.2 MPa and a spraying amount accounting for 0.5% of the mass of the tea leaves.

[0058] The gradient scenting is performed twice, and the tea leaves and kumquat flowers are separated after each scenting, and fresh kumquat flowers are replaced each time.

[0059] Example 2

[0060] A method for preparing kumquat flower tea comprises the following steps:

[0061] Raw material pretreatment: After the kumquat buds or flowers that have not fully opened or are half-opened are air-dried to a moisture content of ≤25%, they are subjected to steam inactivation treatment to inactivate the oxidase activity at a temperature of 100°C for 30 seconds. After steam inactivation, they are immediately cooled to room temperature with cold air at 10°C.

[0062] Targeted debittering: spray kumquat flowers with pH 5.5 citric acid buffer and soak for 10 minutes;

[0063] Gradient scenting: Pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:6. The flower-tea mixture is scented at a temperature of 25°C and a relative humidity of 75%. The first 8 hours of scenting are open to promote the release of volatile aroma. The pile height is ≤50cm. The pile is turned every hour and sprayed with tea polyphenol-arabic gum composite film liquid. Then, the temperature is adjusted to below 20°C and the humidity is adjusted to 65%. The mixture is sealed and scented for 12 hours to promote aroma absorption. The internal temperature of the mixture is kept below 30°C during the scenting process.

[0064] Fragrance enhancement: After screening the kumquat flowers, the tea leaves are first dried with hot air at a temperature of 100°C to a moisture content of 15%, then cooled to 70°C for Maillard reaction induction treatment, the tea leaves are cooled to a moisture content of 8%, then cooled to 50°C to fix the aroma, and finally dried to a moisture content of ≤5%.

[0065] Before spreading and airing, enzymatic hydrolysis treatment is carried out, wherein a composite enzyme preparation is sprayed onto the surface of the kumquat flowers. The composite enzyme preparation comprises cellulase, pectinase and β-glucosidase in a mass ratio of 2:1.2:0.8, and the concentration of the composite enzyme preparation is 0.3% of the total weight of the kumquat flowers.

[0066] The complex enzyme preparation also contains naringinase extract, with a concentration of 0.1% of the total weight of kumquat flowers.

[0067] The citric acid buffer solution is composed of citric acid and sodium citrate, and the dosage of the citric acid buffer solution is 1:10 based on the kumquat material-liquid ratio; the ratio of tea polyphenols to gum arabic in the tea polyphenol-gum arabic composite membrane liquid is 1:4, and the dosage is 1.0% of the mass of the flower-tea mixture.

[0068] In the gradient scenting method, the flower-tea mixture is stacked in 5 layers, with each layer ≤15cm thick.

[0069] During the Maillard reaction induction treatment stage, a mixed gas of nitrogen and carbon dioxide with a volume concentration of 1.0% is introduced into the baking environment, and the volume ratio of nitrogen to carbon dioxide in the mixed gas is 3:1.

[0070] The tea is tea leaves that have been dried after being withered, and the tea leaves are green tea.

[0071] A dynamic aroma recovery system is provided in the gradient scenting process, and the system comprises:

[0072] a) Condensation recovery unit: The temperature is controlled at 5°C to collect volatile aroma components;

[0073] b) Adsorption and desorption unit: Modified activated carbon fiber is used as the adsorption medium, and thermal desorption is carried out at 150°C. The aroma components after thermal desorption are sequentially condensed, recovered, purified and filtered, and then mixed with microencapsulated aroma components in a ratio of 1:2;

[0074] c) Microencapsulation unit: The recovered aroma components and β-cyclodextrin are mixed in a mass ratio of 1:8 to prepare microcapsules, and the particle size of the microcapsules is controlled to be 5-15 μm.

[0075] The microencapsulated aroma component is sprayed onto the tea leaves in a low-temperature aroma stage of the aroma process through atomization spraying, with an atomization pressure of 0.3 MPa and a spraying amount accounting for 1.0% of the mass of the tea leaves.

[0076] The gradient scenting is performed 4 times, and the tea leaves and kumquat flowers are separated after each scenting, and fresh kumquat flowers are replaced each time.

[0077] Example 3

[0078] A method for preparing kumquat flower tea comprises the following steps:

[0079] Raw material pretreatment: After the kumquat buds or flowers that have not fully opened or are half-opened are air-dried to a moisture content of ≤25%, they are steam-inactivated to inactivate the oxidase activity at a temperature of 98°C for 50 seconds. After steam inactivation, they are immediately cooled to room temperature with cold air at 8°C.

[0080] Targeted debittering: spray kumquat flowers with pH 5.0 citric acid buffer and soak for 16 minutes;

[0081] Gradient scenting: Pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:4.5. The flower-tea mixture is scented at a temperature of 23°C and a relative humidity of 70%. The scenting pile is open for the first 6 hours to promote the release of volatile aroma. The pile height is ≤50cm. The pile is turned every 2 hours and sprayed with tea polyphenol-gum arabic composite film liquid. The temperature is then adjusted to below 20°C and the humidity to 60%. The mixture is sealed and scented for 10 hours to promote aroma absorption. The internal temperature of the mixture is kept below 30°C during the scenting process.

[0082] Fragrance enhancement: After screening the kumquat flowers, the tea leaves are first dried with hot air at a temperature of 95°C to a moisture content of 18%, then cooled to 65°C for Maillard reaction induction treatment, the tea leaves are cooled to a moisture content of 9%, then cooled to 45°C to fix the aroma, and finally dried to a moisture content of ≤5%.

[0083] Before spreading and airing, enzymatic hydrolysis treatment is carried out, wherein a composite enzyme preparation is sprayed onto the surface of the kumquat flowers. The composite enzyme preparation comprises cellulase, pectinase and β-glucosidase in a mass ratio of 2:1.1:0.6, and the concentration of the composite enzyme preparation is 0.2% of the total weight of the kumquat flowers.

[0084] The complex enzyme preparation also contains naringinase extract, with a concentration of 0.06% of the total weight of kumquat flowers.

[0085] The citric acid buffer solution is composed of citric acid and sodium citrate, and the dosage of the citric acid buffer solution is 1:8 based on the kumquat material-liquid ratio; the ratio of tea polyphenols to gum arabic in the tea polyphenol-gum arabic composite membrane liquid is 1:3, and the dosage is 0.7% of the mass of the flower-tea mixture.

[0086] In the gradient scenting method, the flower-tea mixture is stacked in 4 layers, with each layer ≤15cm thick.

[0087] During the Maillard reaction induction treatment stage, a mixed gas of nitrogen and carbon dioxide with a volume concentration of 0.8% is introduced into the baking environment, and the volume ratio of nitrogen to carbon dioxide in the mixed gas is 2.5:1.

[0088] The tea is tea leaves that have been dried after being withered, and the tea leaves are green tea.

[0089] A dynamic aroma recovery system is provided in the gradient scenting process, and the system comprises:

[0090] a) Condensation recovery unit: The temperature is controlled at 2°C to collect volatile aroma components;

[0091] b) Adsorption and desorption unit: Modified activated carbon fiber is used as the adsorption medium, and thermal desorption is carried out at 120°C. The aroma components after thermal desorption are sequentially condensed, recovered, purified and filtered, and then mixed with microencapsulated aroma components at a ratio of 1:1.5;

[0092] c) Microencapsulation unit: The recovered aroma components and β-cyclodextrin are mixed in a mass ratio of 1:7.5 to prepare microcapsules, and the particle size of the microcapsules is controlled to be 5-15 μm.

[0093] The microencapsulated aroma component is sprayed onto the tea leaves in a low-temperature aroma stage of the aroma process through atomization spraying, with an atomization pressure of 0.25 MPa and a spraying amount accounting for 0.8% of the mass of the tea leaves.

[0094] The gradient scenting is performed three times, and the tea leaves and kumquat flowers are separated after each scenting, and fresh kumquat flowers are replaced each time.

[0095] Comparative Example 1

[0096] A method for preparing kumquat flower tea comprises the following steps:

[0097] Raw material pretreatment: Unopened or half-opened kumquat buds or flowers are spread out to dry until the moisture content is ≤25%;

[0098] Gradient scenting: Pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:4.5. The flower-tea mixture is scented at a temperature of 23°C and a relative humidity of 70%. The pile is left open for the first 6 hours to promote the release of volatile aroma. The pile height is ≤50cm and the pile is turned every 2 hours. The temperature is then adjusted to below 20°C and the humidity to 60%. The mixture is sealed and scented for 10 hours to promote aroma absorption. The internal temperature of the mixture is kept below 30°C during the scenting process.

[0099] Fragrance: After screening the kumquat flowers, dry the tea leaves with hot air at a temperature of 95°C until the moisture content is ≤5%.

[0100] In the gradient scenting method, the flower-tea mixture is stacked in 4 layers, with each layer ≤15cm thick.

[0101] The tea is tea leaves that have been dried after being withered, and the tea leaves are green tea.

[0102] The gradient scenting is performed three times, and the tea leaves and kumquat flowers are separated after each scenting, and fresh kumquat flowers are replaced each time.

[0103] Comparative Example 2

[0104] A method for preparing kumquat flower tea comprises the following steps:

[0105] Raw material pretreatment: After the kumquat buds or flowers that have not fully opened or are half-opened are air-dried to a moisture content of ≤25%, they are steam-inactivated to inactivate the oxidase activity at a temperature of 98°C for 50 seconds. After steam inactivation, they are immediately cooled to room temperature with cold air at 8°C.

[0106] Targeted debittering: spray kumquat flowers with pH 5.0 citric acid buffer and soak for 16 minutes;

[0107] Gradient scenting: Pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:4.5. The flower-tea mixture is scented at a temperature of 23°C and a relative humidity of 70%. The scenting pile is open for the first 6 hours to promote the release of volatile aroma. The pile height is ≤50cm. The pile is turned every 2 hours and sprayed with tea polyphenol-gum arabic composite film liquid. The temperature is then adjusted to below 20°C and the humidity to 60%. The mixture is sealed and scented for 10 hours to promote aroma absorption. The internal temperature of the mixture is kept below 30°C during the scenting process.

[0108] Fragrance enhancement: After screening the kumquat flowers, the tea leaves are first dried with hot air at a temperature of 95°C to a moisture content of 18%, then cooled to 65°C for Maillard reaction induction treatment, the tea leaves are cooled to a moisture content of 9%, then cooled to 45°C to fix the aroma, and finally dried to a moisture content of ≤5%.

[0109] Before spreading and airing, enzymatic hydrolysis treatment is carried out, wherein a composite enzyme preparation is sprayed onto the surface of the kumquat flowers. The composite enzyme preparation comprises cellulase, pectinase and β-glucosidase in a mass ratio of 2:1.1:0.6, and the concentration of the composite enzyme preparation is 0.2% of the total weight of the kumquat flowers.

[0110] The complex enzyme preparation also contains naringinase extract, with a concentration of 0.06% of the total weight of kumquat flowers.

[0111] The citric acid buffer solution is composed of citric acid and sodium citrate, and the dosage of the citric acid buffer solution is 1:8 based on the kumquat material-liquid ratio; the ratio of tea polyphenols to gum arabic in the tea polyphenol-gum arabic composite membrane liquid is 1:3, and the dosage is 0.7% of the mass of the flower-tea mixture.

[0112] In the gradient scenting method, the flower-tea mixture is stacked in 4 layers, with each layer ≤15cm thick.

[0113] During the Maillard reaction induction treatment stage, a mixed gas of nitrogen and carbon dioxide with a volume concentration of 0.8% is introduced into the baking environment, and the volume ratio of nitrogen to carbon dioxide in the mixed gas is 2.5:1.

[0114] The tea is tea leaves that have been dried after being withered, and the tea leaves are green tea.

[0115] The gradient scenting is performed three times, and the tea leaves and kumquat flowers are separated after each scenting, and fresh kumquat flowers are replaced each time.

[0116] Comparative Example 3

[0117] A method for preparing kumquat flower tea comprises the following steps:

[0118] Raw material pretreatment: After the kumquat buds or flowers that have not fully opened or are half-opened are air-dried to a moisture content of ≤25%, they are steam-inactivated to inactivate the oxidase activity at a temperature of 98°C for 50 seconds. After steam inactivation, they are immediately cooled to room temperature with cold air at 8°C.

[0119] Targeted debittering: spray kumquat flowers with pH 5.0 citric acid buffer and soak for 16 minutes;

[0120] Gradient scenting: Pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:4.5. The flower-tea mixture is scented at a temperature of 23°C and a relative humidity of 70%. The scenting pile is open for the first 6 hours to promote the release of volatile aroma. The pile height is ≤50cm. The pile is turned every 2 hours and sprayed with tea polyphenol-gum arabic composite film liquid. The temperature is then adjusted to below 20°C and the humidity to 60%. The mixture is sealed and scented for 10 hours to promote aroma absorption. The internal temperature of the mixture is kept below 30°C during the scenting process.

[0121] Fragrance: After screening the kumquat flowers, dry the tea leaves with hot air at a temperature of 95°C until the moisture content is ≤5%.

[0122] Before spreading and airing, enzymatic hydrolysis treatment is carried out, wherein a composite enzyme preparation is sprayed onto the surface of the kumquat flowers. The composite enzyme preparation comprises cellulase, pectinase and β-glucosidase in a mass ratio of 2:1.1:0.6, and the concentration of the composite enzyme preparation is 0.2% of the total weight of the kumquat flowers.

[0123] The complex enzyme preparation also contains naringinase extract, with a concentration of 0.06% of the total weight of kumquat flowers.

[0124] The citric acid buffer solution is composed of citric acid and sodium citrate, and the dosage of the citric acid buffer solution is 1:8 based on the kumquat material-liquid ratio; the ratio of tea polyphenols to gum arabic in the tea polyphenol-gum arabic composite membrane liquid is 1:3, and the dosage is 0.7% of the mass of the flower-tea mixture.

[0125] In the gradient scenting method, the flower-tea mixture is stacked in 4 layers, with each layer ≤15cm thick.

[0126] The tea is tea leaves that have been dried after being withered, and the tea leaves are green tea.

[0127] A dynamic aroma recovery system is provided in the gradient scenting process, and the system comprises:

[0128] a) Condensation recovery unit: The temperature is controlled at 2°C to collect volatile aroma components;

[0129] b) Adsorption and desorption unit: Modified activated carbon fiber is used as the adsorption medium, and thermal desorption is carried out at 120°C. The aroma components after thermal desorption are sequentially condensed, recovered, purified and filtered, and then mixed with microencapsulated aroma components at a ratio of 1:1.5;

[0130] c) Microencapsulation unit: The recovered aroma components and β-cyclodextrin are mixed in a mass ratio of 1:7.5 to prepare microcapsules, and the particle size of the microcapsules is controlled to be 5-15 μm.

[0131] The microencapsulated aroma component is sprayed onto the tea leaves in a low-temperature aroma stage of the aroma process through atomization spraying, with an atomization pressure of 0.25 MPa and a spraying amount accounting for 0.8% of the mass of the tea leaves.

[0132] The gradient scenting is performed three times, and the tea leaves and kumquat flowers are separated after each scenting, and fresh kumquat flowers are replaced each time.

[0133] Effect Comparison Example 1

[0134] 1. Experimental Design

[0135] Sample preparation: The samples prepared according to Examples 1-3 are marked as experimental samples 1-3.

[0136] Comparative samples: The samples prepared in Comparative Examples 1-3 are marked as Comparative Samples 1-3.

[0137] 2. Sensory evaluation method

[0138] Evaluation team: consists of 12 trained tea assessors (6 men and 6 women), including 5 certified tea assessors (CTC) and 7 ordinary consumers

[0139] Evaluation environment: Sensory analysis laboratory in accordance with ISO8589 standard (temperature 22±2°C, relative humidity 50±5%, no odor interference)

[0140] 3. Evaluation process:

[0141] Sample Coding: Sample numbers were concealed from the evaluation panel. Experimental and comparative samples 1-3 were brewed by three people, using the same water temperature and the same standards. Each sample was brewed by three people, and the evaluation panel scored all samples individually. Statisticians then tallied the scores for each sample and averaged them.

[0142] Evaluation dimension: A 10-point quantitative rating scale is used (Table 1)

[0143] Table 1 Quantitative standards for sensory evaluation

[0144]

[0145]

[0146] 3. Comparison of sensory evaluation and physical and chemical test results

[0147] The sensory evaluation data are shown in Table 2.

[0148] Table 2 Sensory evaluation data

[0149] Group aroma taste Soup color Overall acceptance Experimental sample 1 8.4 8.0 8.6 8.3 Experimental sample 2 9.5 9.2 9.0 9.3 Experimental sample 3 9.2 9.1 9.2 9.2 Comparative Sample 1 2.8 2.1 7.5 2.6 Comparative Sample 2 7.2 6.8 7.8 7.0 Comparative Sample 3 8.1 7.9 8.7 8.3

[0150] As can be seen from the above table, the various indicators of experimental samples 1, 2, and 3 are better than those of the control samples. Among them, Example 3 performs best in terms of aroma richness, taste mellowness, aftertaste and economic benefits, and Example 2 is the best in terms of aroma.

[0151] The reasons why the comparative examples are poor are as follows:

[0152] Comparative Sample 1 (Comparative Example 1): This lacks several key steps, such as steam inactivation, targeted bitter removal, and enzymatic hydrolysis. This fails to effectively remove bitter substances from the kumquat flowers and fails to fully release their aroma, resulting in a low aroma intensity and a strong bitter taste. Furthermore, this results in low production efficiency and poor economic benefits.

[0153] Comparative Sample 2 (Comparative Example 2): Without a dynamic aroma recovery system and atomization spraying step, aroma components could not be effectively recovered and utilized, resulting in significant aroma loss and low aroma intensity. Furthermore, the aroma enhancement process was incomplete, affecting the quality of the final product.

[0154] Comparative Sample 3 (Comparative Example 3): No enzymatic hydrolysis treatment was performed, and the tea polyphenol-gum arabic composite membrane liquid and atomization spraying steps were used, which failed to fully decompose the bitter substances and protect the aroma components, resulting in a heavier bitter taste, and lower aroma richness and aftertaste.

[0155] In summary, the embodiments of the present invention can significantly improve the quality of kumquat flower tea through scientific and reasonable process design, and have good economic benefits and production efficiency.

[0156] The above description is a detailed description of the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for preparing kumquat flower tea, characterized in that: The following steps are involved: Raw material pretreatment: After the kumquat buds or flowers that have not fully opened or are half-opened are air-dried to a moisture content of ≤25%, they are subjected to steam inactivation treatment to inactivate the oxidase activity. The steam inactivation temperature is 95-100°C for 30-60 seconds. After steam inactivation, they are immediately cooled to room temperature with cold air at 5-10°C. Targeted debittering: spray kumquat flowers with pH 4.5-5.5 citric acid buffer and soak for 10-20 minutes; Gradient scenting: Pretreated kumquat flowers are mixed with tea leaves in a weight ratio of 1:3-6. The flower-tea mixture is scented at a temperature of 20-25°C and a relative humidity of 65-75%. The first 4-8 hours of scenting are open to promote the release of volatile aroma. The pile height is ≤50cm. The pile is turned every 1-2 hours and sprayed with tea polyphenol-arabic gum composite film liquid. The temperature is then adjusted to below 20°C and the humidity to 55-65%. The mixture is sealed and scented for 8-12 hours to promote aroma absorption. The internal temperature of the mixture is kept below 30°C during the scenting process. Fragrance enhancement: After screening the kumquat flowers, the tea leaves are first dried with hot air at a temperature of 85-100°C to a moisture content of 15-20%, then cooled to 60-70°C for Maillard reaction induction treatment, the tea leaves are cooled to a moisture content of 8-10%, then cooled to 40-50°C to fix the aroma, and finally dried to a moisture content of ≤5%.

2. The method for preparing kumquat flower tea according to claim 1, wherein Before spreading and airing, enzymatic hydrolysis treatment is carried out, wherein a composite enzyme preparation is sprayed onto the surface of the kumquat flowers. The composite enzyme preparation comprises cellulase, pectinase and beta-glucosidase in a mass ratio of 2:1-1.2:0.5-0.8, and the concentration of the composite enzyme preparation is 0.1%-0.3% of the total weight of the kumquat flowers.

3. The method for making kumquat flower tea according to claim 2, wherein: The complex enzyme preparation also contains naringinase extract, with a concentration of 0.03% to 0.1% of the total weight of kumquat flowers.

4. The method for making kumquat flower tea according to claim 1, wherein The citric acid buffer solution is composed of citric acid and sodium citrate, and the dosage of the citric acid buffer solution is 1:5-10 based on the kumquat material-liquid ratio; the ratio of tea polyphenols to gum arabic in the tea polyphenol-gum arabic composite membrane liquid is 1:2.5-4, and the dosage is 0.5%-1.0% of the mass of the flower-tea mixture.

5. The method for making kumquat flower tea according to claim 1, wherein: In the gradient scenting method, the flower-tea mixture is stacked in 3-5 layers, with each layer ≤15cm thick.

6. The method for making kumquat flower tea according to claim 1, wherein: During the Maillard reaction induction treatment stage, a mixed gas of nitrogen and carbon dioxide with a volume concentration of 0.5-1.0% is introduced into the baking environment, and the volume ratio of nitrogen to carbon dioxide in the mixed gas is 2-3:

1.

7. The method for making kumquat flower tea according to claim 1, wherein: The tea is tea leaves that have been dried after being withered, and the tea leaves are green tea.

8. The method for making kumquat flower tea according to claim 1, wherein: A dynamic aroma recovery system is provided in the gradient scenting process, and the system comprises: a) Condensation recovery unit: The temperature is controlled at -5°C to 5°C to collect volatile aroma components; b) Adsorption and desorption unit: Modified activated carbon fiber is used as the adsorption medium, and thermal desorption is carried out at 120-150°C. The aroma components after thermal desorption are sequentially condensed, recovered, purified and filtered, and then mixed with the microencapsulated aroma components in a ratio of 1:1-2; c) Microencapsulation unit: The recovered aroma components and β-cyclodextrin are mixed in a mass ratio of 1:5-8 to prepare microcapsules, and the particle size of the microcapsules is controlled to be 5-15 μm.

9. The method for making kumquat flower tea according to claim 8, characterized in that: The microencapsulated aroma component is sprayed onto the tea leaves in an atomizing spraying manner during the low-temperature aroma enhancement stage of the aroma enhancement process, with an atomizing pressure of 0.2-0.3 MPa and a spraying amount accounting for 0.5-1.0% of the mass of the tea leaves.

10. The method for making kumquat flower tea according to claim 1, characterized in that: The gradient scenting is performed 1-6 times, and the tea leaves and kumquat flowers are separated after each scenting, and fresh kumquat flowers are replaced each time.

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