Bamboo tea and preparation method thereof

Abstract

The invention relates to the field of tea preparation methods, and particularly discloses bamboo tea and a preparation method thereof.The bamboo tea is obtained by selecting bamboo materials, chopping the bamboo materials, naturally fermenting the bamboo materials, rolling, heating and distilling the bamboo materials at 180-200 DEG C, deactivating enzymes at 220-250 DEG C, drying the bamboo materials at 55-65 DEG C until the moisture content of the bamboo materials is lower than 7%, and baking the bamboo materials to be fragrant. The prepared bamboo tea is high in sugar content and rich in sugar flavor, and the content of aromatic alcohol, aromatic aldehyde and ketone which are aroma characteristic components is remarkably increased.

Description

Technical Field

[0001] The invention relates to the field of tea preparation methods, in particular to bamboo tea and a preparation method thereof. Background Art

[0002] As living standards continue to improve, people are increasingly demanding a healthier diet, and naturally sourced ingredients are becoming increasingly popular. The widespread use of additives in canned beverages has led to a growing dislike for them, creating a market for natural and healthy drinks. The rise of Traditional Chinese Medicine (TCM) is driving the development of dual-purpose medicinal and edible ingredients into health-conscious products. Bamboo, a dual-purpose medicinal and edible plant, is rich in bamboo leaf polysaccharides. Bamboo shoots and bamboo shavings have been used by humans since ancient times and are considered safe and healthy.

[0003] Bamboo tea, as the name suggests, is a type of tea made primarily from bamboo. Bamboo tea has a long history of consumption and medicinal use in my country. Zhu Xi, a renowned Neo-Confucianist of the Southern Song Dynasty, was deeply acquainted with bamboo tea and even called himself the "Tea Immortal." He particularly favored bitter bamboo tea, saying, "Bitter bamboo, bitter at first, then sweet, like the beginning of worry and diligence, ending in leisure and joy, reason and then harmony." Using tea to discuss the Dao and spread principles, cultivate virtue, clarify ethics, and convey principles—tea shares similarities with Neo-Confucianism, a lesson Zhu Xi learned from bitter bamboo tea. Bamboo tea contains a wealth of flavonoids, lactones, polysaccharides, chlorophyll, amino acids, vitamins, and trace elements. Among these, bamboo leaf flavonoids can effectively regulate blood lipids and reduce blood viscosity, thus lowering blood lipids and serum cholesterol. Furthermore, bamboo leaf flavonoids can slow heart rate, reduce myocardial oxygen consumption during ischemia, and lower blood pressure, offering cardiovascular and cerebrovascular protection. Bamboo leaf flavonoids have a strong function of inhibiting platelet aggregation. It can also significantly prolong coagulation time, inhibit the conversion of fibrinogen to fibrin, thereby inhibiting the formation of arterial thrombosis, and has the function of reducing platelet aggregation and anti-thrombotic function.

[0004] Bamboo tea also boasts powerful health benefits. Bamboo leaf flavonoids, upon entering the human body, reduce protein breakdown and glycogen depletion, significantly improving athletic endurance and vitality, combating fatigue and providing a refreshing effect. Furthermore, bamboo leaf flavonoids possess excellent antioxidant and free radical resistance, making drinking bamboo tea in daily life potentially beneficial for delaying aging. Furthermore, bamboo leaf flavonoids also possess antibacterial, anti-inflammatory, antiviral, and immune-boosting properties.

[0005] Bamboo tea has garnered widespread attention and popularity as a health-promoting tea. However, the preparation process significantly impacts the taste and aroma of the resulting tea. As a beverage, the drinking experience and efficacy are equally important. Different preparation processes yield tea leaves with varying polysaccharide contents and states, resulting in significant variations in the taste and aroma of the resulting tea. Therefore, there is a need to develop a bamboo tea rich in sugar aroma. Summary of the Invention

[0006] In order to develop a bamboo tea rich in sugar aroma, the present invention provides a bamboo tea and a preparation method thereof. The bamboo tea prepared by the present invention has high sugar content, overflowing sugar aroma, and significantly improved aroma characteristic components such as aromatic alcohols, aromatic aldehydes and ketones.

[0007] The present invention provides a method for preparing bamboo tea, comprising the following steps:

[0008] Select high-quality bamboo materials, remove impurities and clean them, chop them and let them stand for 30-50 minutes for natural fermentation. During the standing period, after the bamboo materials are chopped, the destroyed cellulose, hemicellulose and wood fiber tissues, as well as the polysaccharides contained therein, come into contact with the air to produce natural oxidation and enzymatic reactions. The bamboo materials are allowed to slowly heat up at room temperature (25°C) to produce natural fermentation. During the fermentation process, the sugars are loosened and softened, and the sugary aroma overflows.

[0009] The fermented bamboo material is then subjected to rolling heating and distillation at 180-200°C for 120-180 minutes until the water content of the bamboo material is 30-50%, thereby obtaining a bamboo material coated with sugar. The distillation and heating process causes the sugar in the bamboo material to expand and overflow along with the water contained in the bamboo material itself when heated. Since the material is chopped and easily permeable, the release rate of the sugar in the material is increased. The sugar then penetrates the surface of the bamboo material due to the power of the rolling pot. Under the action of heat, the water forms water vapor and leaves the material, leaving the sugar coated on the surface of the material, thereby obtaining a bamboo material coated with sugar.

[0010] The distillation time can be determined according to the color of the polysaccharide water seeping out of the pot, with the standard being dark yellow in color of the distilled polysaccharide water.

[0011] The sugar-coated bamboo material is then heated to 220-250°C for 20-30 minutes to reduce its moisture content to 25-45%. The material is then cooled to obtain the finished bamboo material. During the process, the temperature inside the pot reaches 250°C, causing water vapor to rise with the temperature, forming high-temperature gas that both removes the bamboo material and ripens the alkaloids within it, removing its bitterness. The duration of the process varies depending on the weight and moisture content of the bamboo material, continuing until the bamboo material is fully ripe and the desired results are achieved.

[0012] Then place the bamboo material in a temperature of 55-65℃ and dry it until the moisture content of the bamboo material is 4-7%. The temperature setting of 55-65℃ only separates the moisture from the material and sugar without destroying the original sugar aroma.

[0013] The dried bamboo material is roasted to obtain bamboo tea.

[0014] Furthermore, the bamboo material is bamboo stems or bamboo shoots. Choosing bamboo stems or bamboo shoots can effectively avoid the generation of fishy smell during the withering and fermentation processes. Bamboo stems or bamboo shoots are rich in nutrients and are beneficial for detoxification.

[0015] Furthermore, the chopping process is flaking or shredding, which expands the contact area with the air, promotes natural oxidation and enzyme reaction, and realizes natural fermentation.

[0016] Furthermore, the roasting method is thermal reaction roasting or sultry roasting. Roasting is used to enhance the aroma of bamboo tea (the polysaccharides produced produce aroma under heating). Thermal reaction roasting leaves the aroma on the surface, while sultry roasting allows the aroma to penetrate deep into the bamboo tea, making the aroma last longer when brewing.

[0017] Furthermore, the muggy roasting process is as follows: the dried bamboo material is placed in a roasting machine, roasted at a bottom temperature of 50-60°C and a room temperature of 90-100°C, and a closed high-muffled temperature internal transmission method is used for roasting the aroma. The roasting time is 50-60 minutes, and a muggy-aroma bamboo tea material is obtained, which has a longer-lasting aroma when brewed.

[0018] Furthermore, the thermal reaction roasting process is as follows: the dried dry bamboo material is placed into a roasting machine, with an indoor air flow temperature of 70-80°C and a roasting time of 50-60 minutes to obtain an external fragrant bamboo tea material, in which the fragrance is mainly retained on the surface of the bamboo tea, and the fragrance is more intense when brewed.

[0019] The present invention also provides bamboo tea prepared by the preparation method, wherein the sugar yield of the bamboo tea is significantly improved.

[0020] Furthermore, the characteristic aroma components of the bamboo tea are significantly improved.

[0021] Furthermore, the characteristic aroma components include aromatic alcohols, aromatic aldehydes and ketones.

[0022] Furthermore, the aromatic alcohols include benzyl alcohol, phenylethyl alcohol, phenylpropanol and 1-decanol;

[0023] The aromatic aldehydes include vanillin and neral;

[0024] The ketones include ionone, geranylacetone, β-ionone and hexahydrofarnesylacetone.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention improves the sugar yield by pretreating bamboo stems and then naturally fermenting them, increasing the sugar yield by 76.9%. The combination of pretreatment and natural fermentation of bamboo stems and a preparation process significantly increases the content of aroma-characterizing substances in bamboo tea, adding benzyl alcohol and phenylpropanol. The content of ketones such as ionone, β-ionone, and hexahydrofarnesyl acetone is also increased. This results in a richer, more refreshing bamboo tea.

[0027] 2. In the method provided by the present invention, after the bamboo material is chopped and allowed to stand for a while, the destroyed cellulose, hemicellulose, and wood fiber tissue, as well as the polysaccharides contained therein, come into contact with air and undergo natural oxidation and enzymatic reactions. The bamboo material is then allowed to slowly heat up at room temperature (25°C), leading to natural fermentation. During the fermentation process, the sugars in the bamboo material are softened and released, releasing a sweet aroma. The distillation heating process causes the sugars in the bamboo material to expand and release as the moisture contained in the bamboo material expands upon heating. Since the chopped material is easily permeable, this helps increase the sugar release rate within the material. The tumbling motion of the pot then seeps into the bamboo material's surface. Under the influence of heat, the moisture forms vapor and escapes, leaving the sugars coated on the surface, thus obtaining a sugar-coated bamboo material. The experimental process in this application detected that the polysaccharide dissolution temperature range is 180-200°C, so this range was selected for distillation. During the degumming process, the pot temperature reaches 250°C, causing the water vapor within the pot to rise as the pot temperature rises, forming high-temperature gas that degummes the bamboo material and ripens the alkaloids within the material, removing the bitterness of the material. The duration of withering depends on the weight and moisture content of the materials, until the withering and ripening are achieved, with the material being fully ripe as the standard. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can be obtained from commercial sources unless otherwise specified.

[0029] The invention provides a bamboo tea and a preparation method thereof. The prepared bamboo tea has high sugar content, overflowing sugar fragrance, and significantly improved aroma characteristic components such as aromatic alcohols, aromatic aldehydes and ketones.

[0030] After the bamboo is chopped and left to stand for a while, the destroyed cellulose, hemicellulose, and wood fiber tissues, as well as the polysaccharides contained therein, come into contact with air and undergo natural oxidation and enzymatic reactions. The bamboo material is then slowly heated at room temperature (25°C), producing natural fermentation. During the fermentation process, the sugars soften and release their sweet aroma. The distillation and heating process causes the sugars in the bamboo material to expand and release as the moisture contained in the bamboo material expands upon exposure to heat. Since the material is chopped and easily permeable, this helps increase the sugar release rate within the material. The resulting sugars are then absorbed into the surface of the bamboo material by the rotating pot's power. Under the action of heat, the moisture forms vapor and leaves the material, leaving the sugars coated on the surface. This results in a sugar-coated bamboo material. The experimental process in this application detected that the polysaccharide dissolution temperature range is 180-200°C, so this range was selected for distillation. During the withering process, the pot temperature reaches 250°C, causing the water vapor within the pot to rise as the pot temperature rises, forming high-temperature gas that completes the withering process of the bamboo material and the ripening process of the alkaloids within the material, removing the bitterness of the material. The duration of withering depends on the weight and moisture content of the materials, until the withering and ripening are achieved, with the material being fully ripe as the standard.

[0031] Example 1: A bamboo tea and a preparation method thereof.

[0032] 1. Experimental Methods

[0033] 1. Preparation method of bamboo tea

[0034] (1) Select fresh high-quality green bamboo and milk bamboo stems, remove impurities and wash them, and obtain 50 kg of bamboo tea raw materials with a moisture content of 70% and a net weight. Use a mechanical shredder and let it stand for natural fermentation for 40 minutes;

[0035] During the static process, after the bamboo material is shredded, the destroyed cellulose, hemicellulose and wood fiber tissues, as well as the polysaccharides contained therein, come into contact with air and undergo natural oxidation and enzymatic reactions. The bamboo material is then slowly heated up at room temperature (25°C) to produce natural fermentation. During the fermentation process, the sugars are loosened and softened, releasing a sweet aroma.

[0036] (2) Place the fermented bamboo strips in a rolling pot and heat them with an electric rolling method until the pot temperature reaches 200°C for 120 minutes (distillation);

[0037] The heating process causes the sugar in the bamboo material to expand and overflow as the moisture contained in the bamboo material itself is heated. Since the material is shaved into thin strips, it is easy to penetrate, which helps to increase the release rate of the sugar in the material. Later, with the power of the rolling pot, it seeps into the surface of the bamboo material. Under the action of heat, the moisture forms water vapor and leaves the material, leaving the sugar wrapped on the surface of the material, thus obtaining a bamboo material coated with sugar.

[0038] (3) Seal the original pot of bamboo material coated with sugar, increase the temperature in the pot to 250℃ and kill the bamboo for 30 minutes, then remove from the pot and let it cool for later use;

[0039] During the withering process, the temperature inside the pot reaches 250℃, causing the water vapor in the pot to rise as the pot temperature rises, forming high-temperature gas to achieve the withering process of the bamboo material and the ripening process of the plant alkaloids in the material, removing the bitter taste of the material.

[0040] (4) The bamboo material after withering is placed in a hot air circulation dryer, and the drying temperature is set to 60°C (the purpose of this temperature is to only remove moisture from the material and sugar without destroying the original sugar aroma). The hot air circulation dehydration and drying is carried out until the moisture content of the bamboo material is 5%. The dry material is taken out for use, and the dried bamboo material is obtained.

[0041] (5) Stuffy roasting: put the dried bamboo material into a roasting machine (model: GB 4706.52-2008GB4706.1-2005), roast it at a bottom temperature of 60℃ and a room temperature of 100℃, use a closed high-stuffy temperature internal transmission to roast the aroma, and roast it for 60 minutes to obtain a stuffy aroma bamboo tea.

[0042] Example 2: A bamboo tea and a preparation method thereof.

[0043] 1. Experimental Methods

[0044] 1. Preparation method of bamboo tea

[0045] (1) Select fresh high-quality green bamboo and milk bamboo stems, remove impurities and wash them, and obtain 50 kg of bamboo tea raw materials with a moisture content of 70% and a net weight. Use a mechanical shredder and let it stand for natural fermentation for 40 minutes;

[0046] During the static process, after the bamboo material is shredded, the destroyed cellulose, hemicellulose and wood fiber tissues, as well as the polysaccharides contained therein, come into contact with air and undergo natural oxidation and enzymatic reactions. The bamboo material is then slowly heated up at room temperature (25°C) to produce natural fermentation. During the fermentation process, the polysaccharides are loosened and softened, and the sugary aroma overflows.

[0047] (2) Place the fermented bamboo strips in a rolling pot and heat them with an electric rolling method until the pot temperature reaches 200°C for 120 minutes (distillation);

[0048] The heating process causes the sugar in the bamboo material to expand and overflow as the moisture contained in the bamboo material itself is heated. Since the material is shaved into thin strips, it is easy to penetrate, which helps to increase the release rate of the sugar in the material. Later, with the power of the rolling pot, it seeps into the surface of the bamboo material. Under the action of heat, the moisture forms water vapor and leaves the material, leaving the sugar wrapped on the surface of the material, thus obtaining a bamboo material coated with sugar.

[0049] The distillation time can be determined according to the color of the polysaccharide water seeping out of the pot, with the standard being dark yellow in color of the distilled polysaccharide water.

[0050] (3) Seal the original pot of bamboo material coated with sugar, increase the temperature in the pot to 250℃ and kill the bamboo for 30 minutes, then remove from the pot and let it cool for later use;

[0051] During the withering process, the temperature inside the pot reaches 250℃, causing the water vapor in the pot to rise as the pot temperature rises, forming high-temperature gas to achieve the withering process of the bamboo material and the ripening process of the plant alkaloids in the material, removing the bitter taste of the material.

[0052] The duration of withering depends on the weight and moisture content of the materials, until the withering and ripening are achieved, with the material being fully ripe as the standard.

[0053] (4) The bamboo material is placed in a hot air circulation dryer, and the drying temperature is set to 60°C (the purpose of this temperature is to only remove moisture from the material and sugar, without destroying the original sugar aroma). The hot air circulation dehydration and drying is carried out until the moisture content of the bamboo material is 5%. The dry material is taken out for use, and the dried bamboo material is obtained.

[0054] (5) Thermal reaction roasting: put the dried bamboo material into an airflow roasting machine (YJ-6CHG-6 / YJ-6CHG-8 tea roasting machine), set the indoor airflow temperature at 80℃ and the roasting time for 60 minutes to obtain the external fragrance bamboo tea.

[0055] Example 3: A bamboo tea and a preparation method thereof.

[0056] 1. Experimental Methods

[0057] 1. Preparation method of bamboo tea

[0058] (1) Select fresh high-quality green bamboo and milk bamboo stems, remove impurities and wash them, and obtain 50 kg of bamboo tea raw materials with a moisture content of 70%, shaving them mechanically, and letting them stand for natural fermentation for 50 minutes;

[0059] During the static process, after the bamboo material is flaked, the destroyed cellulose, hemicellulose and wood fiber tissues, as well as the polysaccharides contained therein, come into contact with the air and undergo natural oxidation and enzymatic reactions. The bamboo material is then slowly heated up at room temperature (25°C) to produce natural fermentation. During the fermentation process, the polysaccharides are loosened and softened, and the sugary aroma overflows.

[0060] (2) Place the fermented bamboo strips in a rolling pot and heat them with an electric rolling method until the pot temperature reaches 180°C for 180 minutes (distillation);

[0061] The heating process causes the sugar in the bamboo material to expand and overflow as the moisture contained in the bamboo material itself is heated. Since the material is planed into thin slices, it is easy to penetrate, which helps to increase the release rate of the sugar in the material. Later, with the power of the rolling pot, it seeps into the surface of the bamboo material. Under the action of heat, the moisture forms water vapor and leaves the material, leaving the sugar wrapped on the surface of the material, thus obtaining a bamboo material coated with sugar.

[0062] The distillation time can be determined according to the color of the polysaccharide water seeping out of the pot, with the standard being dark yellow in color of the distilled polysaccharide water.

[0063] (3) Seal the original pot of bamboo material coated with sugar, increase the temperature in the pot to 220℃ and kill the bamboo for 30 minutes, then remove from the pot and let it cool for later use;

[0064] During the withering process, the temperature in the pot reaches 220℃, causing the water vapor in the pot to rise as the pot temperature rises, forming high-temperature gas to achieve the withering process of the bamboo material and the ripening process of the plant alkaloids in the material, removing the bitter taste of the material.

[0065] The duration of withering depends on the weight and moisture content of the materials, until the withering and ripening are achieved, with the material being fully ripe as the standard.

[0066] (4) The bamboo material is placed in a hot air circulation dryer, and the drying temperature is set to 55°C (the purpose of this temperature is to only remove moisture from the material and sugar without destroying the original sugar aroma). The hot air circulation dehydration and drying is carried out until the moisture content of the bamboo material is 7%. The dry material is taken out for use, and the dried bamboo material is obtained.

[0067] (5) Stuffy roasting: put the dried bamboo material into the roasting machine, roast it at a bottom temperature of 60℃ and a room temperature of 100℃, use a closed high-stuffy temperature internal transmission to roast the aroma, and roast it for 60 minutes to obtain a stuffy aroma bamboo tea.

[0068] Example 4: A bamboo tea and a preparation method thereof.

[0069] 1. Experimental Methods

[0070] 1. Bamboo tea preparation method

[0071] (1) Select fresh high-quality green bamboo and milk bamboo stems, remove impurities and wash them, and obtain 50 kg of bamboo tea raw materials with a moisture content of 70% and a net weight. Use a mechanical shredder and let it stand for natural fermentation for 30 minutes;

[0072] During the static process, after the bamboo material is shredded, the destroyed cellulose, hemicellulose and wood fiber tissues, as well as the polysaccharides contained therein, come into contact with air and undergo natural oxidation and enzymatic reactions. The bamboo material is then slowly heated up at room temperature (25°C) to produce natural fermentation. During the fermentation process, the polysaccharides are loosened and softened, and the sugary aroma overflows.

[0073] (2) Place the fermented bamboo strips in a rolling pot and heat them with an electric rolling method until the pot temperature reaches 200°C for 150 minutes (distillation);

[0074] The heating process causes the sugar in the bamboo material to expand and overflow as the moisture contained in the bamboo material itself is heated. Since the material is shaved into thin strips, it is easy to penetrate, which helps to increase the release rate of the sugar in the material. Later, with the power of the rolling pot, it seeps into the surface of the bamboo material. Under the action of heat, the moisture forms water vapor and leaves the material, leaving the sugar wrapped on the surface of the material, thus obtaining a bamboo material coated with sugar.

[0075] The distillation time can be determined according to the color of the polysaccharide water seeping out of the pot, with the standard being dark yellow in color of the distilled polysaccharide water.

[0076] (3) Seal the original pot of bamboo material coated with sugar, increase the temperature in the pot to 220℃ and kill the bamboo for 20 minutes, then remove from the pot and let it cool for later use;

[0077] During the withering process, the temperature in the pot reaches 220℃, causing the water vapor in the pot to rise as the pot temperature rises, forming high-temperature gas to achieve the withering process of the bamboo material and the ripening process of the plant alkaloids in the material, removing the bitter taste of the material.

[0078] The duration of withering depends on the weight and moisture content of the materials, until the withering and ripening are achieved, with the material being fully ripe as the standard.

[0079] (4) The bamboo material is placed in a hot air circulation dryer, and the drying temperature is set to 55°C (the purpose of this temperature is to only remove moisture from the material and sugar without destroying the original sugar aroma). The hot air circulation dehydration and drying is carried out until the moisture content of the bamboo material is 5%. The dry material is taken out for use, and the dried bamboo material is obtained.

[0080] (5) Stuffy roasting: put the dried bamboo material into the roasting machine, roast it at a bottom temperature of 50℃ and a room temperature of 90℃, use a closed high-stuffy temperature internal transmission to roast the aroma, and roast it for 50 minutes to obtain a stuffy aroma bamboo tea.

[0081] Example 5: A bamboo tea and a preparation method thereof.

[0082] 1. Experimental Methods

[0083] 1. Bamboo tea preparation method

[0084] (1) Select fresh high-quality green bamboo and milk bamboo stems, remove impurities and wash them, and obtain 50 kg of bamboo tea raw materials with a moisture content of 70% and a net weight. Use a mechanical shredder and let it stand for natural fermentation for 30 minutes;

[0085] During the static process, after the bamboo material is shredded, the destroyed cellulose, hemicellulose and wood fiber tissues, as well as the polysaccharides contained therein, come into contact with air and undergo natural oxidation and enzymatic reactions. The bamboo material is then slowly heated up at room temperature (25°C) to produce natural fermentation. During the fermentation process, the polysaccharides are loosened and softened, and the sugary aroma overflows.

[0086] (2) Place the fermented bamboo strips in a rolling pot and heat them with an electric rolling method until the pot temperature reaches 200°C for 120 minutes (distillation);

[0087] The heating process causes the sugar in the bamboo material to expand and overflow as the moisture contained in the bamboo material itself is heated. Since the material is shaved into thin strips, it is easy to penetrate, which helps to increase the release rate of the sugar in the material. Later, with the power of the rolling pot, it seeps into the surface of the bamboo material. Under the action of heat, the moisture forms water vapor and leaves the material, leaving the sugar wrapped on the surface of the material, thus obtaining a bamboo material coated with sugar.

[0088] The distillation time can be determined according to the color of the polysaccharide water seeping out of the pot, with the standard being dark yellow in color of the distilled polysaccharide water.

[0089] (3) Seal the original pot of bamboo material coated with sugar, increase the temperature in the pot to 240℃ and kill the bamboo for 25 minutes, then remove from the pot and let it cool for later use;

[0090] During the withering process, the temperature in the pot reaches 240℃, causing the water vapor in the pot to rise as the pot temperature rises, forming high-temperature gas to achieve the withering process of the bamboo material and the ripening process of the plant alkaloids in the material, removing the bitter taste of the material.

[0091] The duration of withering depends on the weight and moisture content of the materials, until the withering and ripening are achieved, with the material being fully ripe as the standard.

[0092] (4) The bamboo material is placed in a hot air circulation dryer, and the drying temperature is set to 65°C (the purpose of this temperature is to only remove moisture from the material and sugar without destroying the original sugar aroma). The hot air circulation dehydration and drying is carried out until the moisture content of the bamboo material is 4%. The dry material is taken out for use, and the dried bamboo material is obtained.

[0093] (5) Stuffy roasting: put the dried bamboo material into the roasting machine, roast it at a bottom temperature of 55℃ and a room temperature of 95℃, use a closed high-stuffy temperature internal transmission to roast the aroma, and the roasting time is 60 minutes to obtain a stuffy aroma bamboo tea.

[0094] Example 6: A bamboo tea and a preparation method thereof.

[0095] 1. Experimental Methods

[0096] 1. Bamboo tea preparation method

[0097] (1) Select fresh high-quality green bamboo and milk bamboo stems, remove impurities and wash them, and obtain 50 kg of bamboo tea raw materials with a moisture content of 70% and a net weight. Use a mechanical shredder and let it stand for natural fermentation for 30 minutes;

[0098] During the static process, after the bamboo material is shredded, the destroyed cellulose, hemicellulose and wood fiber tissues, as well as the polysaccharides contained therein, come into contact with air and undergo natural oxidation and enzymatic reactions. The bamboo material is then slowly heated up at room temperature (25°C) to produce natural fermentation. During the fermentation process, the polysaccharides are loosened and softened, and the sugary aroma overflows.

[0099] (2) Place the fermented bamboo strips in a rolling pot and heat them with an electric rolling method until the pot temperature reaches 200°C for 120 minutes (distillation);

[0100] The heating process causes the polysaccharides in the bamboo material to expand and overflow as the water contained in the bamboo material itself is heated. Since the material is planed into thin strips, it is easy to penetrate, which helps to increase the release rate of polysaccharides in the material. Later, with the power of the rolling pot, it penetrates into the surface of the bamboo material. Under the action of heat, the water forms water vapor and leaves the material, leaving the sugar wrapped on the surface of the material, thus obtaining a bamboo material coated with sugar.

[0101] The distillation time can be determined according to the color of the polysaccharide water seeping out of the pot, with the standard being dark yellow in color of the distilled polysaccharide water.

[0102] (3) Seal the original pot of bamboo material coated with sugar, increase the temperature in the pot to 240℃ and kill the bamboo for 25 minutes, then remove from the pot and let it cool for later use;

[0103] During the withering process, the temperature in the pot reaches 240℃, causing the water vapor in the pot to rise as the pot temperature rises, forming high-temperature gas to achieve the withering process of the bamboo material and the ripening process of the plant alkaloids in the material, removing the bitter taste of the material.

[0104] The duration of withering depends on the weight and moisture content of the materials, until the withering and ripening are achieved, with the material being fully ripe as the standard.

[0105] (4) The bamboo material is placed in a hot air circulation dryer, and the drying temperature is set to 65°C (the purpose of this temperature is to only remove moisture from the material and sugar without destroying the original sugar aroma). The hot air circulation dehydration and drying is carried out until the moisture content of the bamboo material is 4%. The dry material is taken out for use, and the dried bamboo material is obtained.

[0106] (5) Thermal reaction roasting: put the dried bamboo material into an airflow roasting machine, set the indoor airflow temperature at 80℃ and the roasting time at 60 minutes to obtain the external fragrance bamboo tea.

[0107] Comparative Example 1: A bamboo tea and a preparation method thereof.

[0108] Fresh, high-quality green bamboo stems are carefully selected, cleaned, and washed to obtain 50 kg of bamboo tea raw material with a moisture content of 70%. The raw material is then placed directly into a rolling boiler and heated using an electric rolling method until the pot temperature reaches 200°C and the temperature is maintained for 120 minutes (distillation) to obtain the bamboo material coated with sugar.

[0109] Seal the original pot of bamboo material wrapped with sugar, increase the temperature in the pot to 250℃ and kill the bamboo for 30 minutes, then remove from the pot and let it cool for later use;

[0110] The bamboo material after the fixation is placed in a hot air circulation dryer, the drying temperature is set to 60 ° C, and the hot air circulation dehydration and drying is carried out until the moisture content of the bamboo material is 5% and the dry material is taken out for use, that is, the dried bamboo material is obtained;

[0111] Stuffy roasting: put the dried bamboo material into the roasting machine, roast it at a bottom temperature of 60℃ and a room temperature of 100℃, use a closed high-stuffy temperature internal transmission to roast the aroma, the roasting time is 60 minutes, and you will get a stuffy fragrant bamboo tea.

[0112] Comparative Example 2: A bamboo tea and a preparation method thereof.

[0113] 1. Experimental Methods

[0114] 1. Bamboo tea preparation method

[0115] (1) Select fresh high-quality green bamboo and milk bamboo stems, remove impurities and wash them, and obtain 50 kg of bamboo tea raw materials with a moisture content of 70% and a net weight. Use a mechanical shredder and let it stand for natural fermentation for 40 minutes;

[0116] (2) Place the fermented bamboo strips in a rolling pot and heat them with an electric rolling method until the pot temperature reaches 130°C for 120 minutes (distillation);

[0117] (3) Seal the original pot of bamboo material coated with sugar, raise the temperature in the pot to 120℃ and kill the bamboo for 30 minutes, then remove from the pot and let it cool for later use;

[0118] (4) The bamboo material is placed in a hot air circulation dryer, and the drying temperature is set to 60°C (the purpose of this temperature is to only remove moisture from the material and sugar, without destroying the original sugar aroma). The hot air circulation dehydration and drying is carried out until the moisture content of the bamboo material is 5%. The dry material is taken out for use, and the dried bamboo material is obtained.

[0119] (5) Stuffy roasting: put the dried bamboo material into the roasting machine, roast it at a bottom temperature of 60℃ and a room temperature of 100℃, use a closed high-stuffy temperature internal transmission to roast the aroma, and roast it for 60 minutes to obtain a stuffy aroma bamboo tea.

[0120] Taking Examples 1-3 above as an example, the sugar yield and aroma characteristics of the bamboo tea obtained in the preparation examples and comparative examples were tested; the specific testing methods are as follows. The test results are recorded in Tables 1-3.

[0121] 1. Sugar yield detection

[0122] 1. Detection method

[0123] Take 20g of bamboo tea sample and put it into the drying container for experiment, put 10g of desiccant, cover it tightly and let it stand for 4 hours, then use the electronic balance with specifications: Max = 100g, e = 0.01g, d = 0.001g to weigh 10g (10g) of dried bamboo tea from the drying container, put it into the special container of the heated electronic constant temperature drying oven, inject 100g of pure water, and soak it in the drying container (material-water ratio 1:10). The total mass in the drying container is 110g. The soaking time is 60 minutes, and then the soaking material is filtered with a 150-mesh sieve to obtain 62 grams of soaking water extract, which is placed in an electronic constant temperature drying oven for drying. The drying temperature is set to 100 and the drying time is 80 minutes. Then the blower system is turned off and the constant temperature is cooled to 30 degrees Celsius. After the cooling alarm sounds, the drying dish containing the water extract in the drying oven is taken out and weighed with an electronic balance with d=0.001. Except for the weight of the drying dish, a light yellow powdery dry matter (i.e., polysaccharide powder) is obtained, which is weighed and recorded.

[0124] 2. Polysaccharide composition analysis

[0125] (1) Weigh 100 mg of the polysaccharide powder from Examples 1-3, add 40 mL of 1.5% H2SO4, and hydrolyze at 100°C for 3 h. After cooling, completely neutralize with BaCO3 and allow to stand overnight. Centrifuge at 4000 rpm for 10 min, and collect the supernatant, which is the hydrolyzate.

[0126] (2) Take about 2 mL of the hydrolyzate in a test tube, dry it in a vacuum oven at 70°C, add 10 mg of hydroxylamine hydrochloride and 0.5 mL of pyridine, shake it, and place it in a water bath at 90°C for 30 min. After cooling it to room temperature, add 0.6 mL of acetic anhydride and acylate it in a water bath at 90°C for 30 min. The obtained product is directly analyzed by GC.

[0127] (3) Polysaccharide determination method:

[0128] Preparation of a Glucose Standard Curve: Prepare sulfuric acid-anthrone solution: Weigh 2g of anthrone Q and dilute to volume with concentrated sulfuric acid in a 100mL volumetric flask. Mix thoroughly and use immediately. Preparation of Standard Glucose Solution: Accurately weigh dry anhydrous glucose to a concentration of 120mg / L and set aside. Plotting a glucose standard curve: Accurately pipette 0, 0.1, 0.2, 0.3, 0.4, 0.6, and 0.8mL of glucose standard solution into a 10mL stoppered test tube. Fill to 1mL with distilled water. Use 1.0mL of distilled water as a blank. Then, add 4mL of sulfuric acid-anthrone solution to each tube. Shake well, cool in ice water, and then boil in boiling water for 10 minutes. Cool to room temperature with tap water and measure the absorbance A at 620nm. Plotting a standard curve: Linearly regress A against glucose concentration (c, mg / mL). The regression equation is A = 58137c-0 00473 (R = Q 9987). The results showed that glucose had a good linear relationship with absorbance in the range of 0-960 mg / L.

[0129] Sample polysaccharide extraction and determination: Take 2g of crushed green bamboo leaf powder and place it in a flask for reflux. The extraction conditions are the same as the solid-liquid ratio of 1:30 (g / mL, the same below), the temperature is 80℃, and the extraction is carried out for 3h. Extract twice, combine the extracts and concentrate, make up the volume in a 25mL volumetric flask, take 1mL respectively in a 10mL stoppered test tube, use 1mL distilled water as a blank control, and then add 4mL of sulfuric acid-anthrone solution to each, shake well, put into ice water to cool, and then put into boiling water for 10min, quickly cool to room temperature, measure A at 620nm, and calculate the mass fraction of polysaccharides by the following formula.

[0130] W=(c×V) / m×100%

[0131] Where: c is the polysaccharide mass concentration calculated by the regression equation based on A, in mg / L;

[0132] V-polysaccharide solution volume, mL; m-sample mass.

[0133] Since the amount of powdered sugar obtained in Comparative Example 1 was small, 30 mg of the sample was used for testing according to the above method.

[0134] 3. Experimental results

[0135] Table 1 Sugar yield of bamboo tea obtained by different processing techniques

[0136] Group Example 1 Example 2 Example 3 Comparative Example 1 Powdered sugar weight (mg) 130mg 100mg 120mg 30mg Sugar yield (%) 1.3％ 1.0％ 1.2％ 0.3％

[0137] As shown in Table 1, Example 1 of the present invention loosens, softens, and overflows the polysaccharide during the fermentation process by shredding and allowing it to ferment naturally. Compared with Comparative Example 1, the sugar yield is significantly improved. Compared with Comparative Example 1 without shredding and natural fermentation, the sugar yield is increased by 76.9%.

[0138] Table 2 Analysis of bamboo tea polysaccharide components obtained in Example 1

[0139]

[0140] As shown in Table 2, although the sugar yields of the bamboo tea prepared in Examples 1-3 of the present invention and Comparative Example 1 are significantly different, the main components of the sugar powder are polysaccharides, arabinose, xylose, glucose and galactose, and there is no significant difference in the proportions.

[0141] 2. Detection of aroma characteristic substances

[0142] 1. Instruments used: Agilent 6890 gas chromatograph-5973 mass spectrometer (Agilent Technologies, USA); BP221S electronic balance (Sartorius Electronic Analytical Balance, Germany); MP3002 electronic balance (Shanghai Hengping Scientific Instrument Co., Ltd.); volatile oil extractor (Beijing Glass Instrument Factory); electronic temperature-controlled heating mantle (Beijing Shuiguangming Medical Instrument Factory); EYELAN-1000 rotary evaporator (EYELA, Japan).

[0143] 2. Preprocessing

[0144] The bamboo tea prepared in Examples 1-3 was pulverized and sieved. 50 g of each pulverized bamboo tea sample was weighed and placed in a round-bottom flask. Distilled water was added at a material-to-liquid ratio of 1:10. 5 mL of n-hexane was added to a volatile oil receiver to collect the volatile oil. The round-bottom flask was then gently heated with an electric heating mantle until it reached a slight boil for 7 hours before distillation was terminated. The n-hexane layer was dried over anhydrous sodium sulfate and filtered. The filtrate was then subjected to a rotary evaporator to recover the solvent, yielding fragrant bamboo tea volatile oil. A small amount of the volatile oil was dissolved in n-hexane and analyzed by GC-MS.

[0145] 2. GC-MS conditions

[0146] Chromatographic conditions: chromatographic column: HP-5MS quartz capillary column (30m x 0.25mm x 0.25μm); injection temperature: 220℃, column temperature: 50℃, hold for 1min. -1 The program was raised to 100℃ and maintained for 5min; then the temperature was increased to 5℃.min. -1 Heat to 260°C and maintain for 10 min; the carrier gas is high-purity He, with a flow rate of 1 mL min -1 ; Injection volume 1μL.

[0147] Mass spectrometry conditions: quadrupole temperature 150°C, ion source temperature 230°C, transfer line temperature 280°C, EI ionization mode, electron energy 70 eV. Solvent delay 4 min. Mass scan range: 40–550 amu.

[0148] The NIST 2002 standard mass spectrum was used for data retrieval. Only identification results with a matching degree greater than 80% were confirmed, and the relative percentage of each component was determined using the peak area normalization method.

[0149] Table 3 Effects of different process treatments on characteristic aroma substances of bamboo tea (relative peak area %)

[0150]

[0151]

[0152] As shown in Table 3, the present invention enhances the relative content of characteristic aroma compounds in bamboo tea by pre-treatment with shredded bamboo stems, followed by natural fermentation, high-temperature distillation, and high-temperature fixation, ultimately combining sultry roasting with aroma enhancement, adding benzyl alcohol and phenylpropanol. Shredded bamboo stems and natural fermentation primarily increase the content of ketones such as ionone, β-ionone, and hexahydrofarnesyl acetone. The temperature setting influences the content of all aroma compounds.

[0153] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0154] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing bamboo tea, characterized in that: The steps include: Select high-quality bamboo materials, remove impurities, clean them, chop them, and let them stand for 30-50 minutes for natural fermentation; The fermented bamboo material is then heated and distilled at 180-200° C. for 120-180 minutes until the moisture content of the bamboo material is 30-50%, thereby obtaining a bamboo material coated with sugar; Then, the bamboo material coated with sugar is heated to 220-250° C. for 20-30 minutes to kill the bamboo material until the water content of the bamboo material is 25-45%, and then cooled to obtain the killed bamboo material; Then, the bamboo material is dried at 55-65°C until the moisture content of the bamboo material is 4-7%. The dried bamboo material is roasted to obtain bamboo tea.

2. The method for preparing bamboo tea according to claim 1, wherein: The bamboo material is bamboo stem or bamboo shoot.

3. The method for preparing bamboo tea according to claim 2, wherein: The chopping process is flaking or shredding.

4. The method for preparing bamboo tea according to claim 1, wherein: The roasting method is thermal reaction roasting or stuffy roasting.

5. The method for preparing bamboo tea according to claim 4, wherein: The muggy roasting process is as follows: the dried bamboo material is placed in a roasting machine, roasted at a bottom temperature of 50-60°C and a room temperature of 90-100°C, and roasted in a closed high-stifling temperature internal transmission manner for 50-60 minutes to obtain a muggy-fragrant bamboo tea material.

6. The method for preparing bamboo tea according to claim 4, wherein: The thermal reaction aroma roasting process is as follows: the dried bamboo material is placed in an aroma roasting machine, and the indoor air flow temperature is 70-80° C. and the roasting time is 50-60 minutes to obtain the external aroma bamboo tea material.

7. The bamboo tea prepared by the preparation method according to any one of claims 1 to 6, characterized in that: The sugar yield of the bamboo tea is significantly improved.

8. The bamboo tea according to claim 7, characterized in that The characteristic aroma components of the bamboo tea are significantly improved.

9. The bamboo tea according to claim 8, characterized in that The characteristic aroma components include aromatic alcohols, aromatic aldehydes and ketones.

10. The bamboo tea according to claim 9, characterized in that The aromatic alcohols include benzyl alcohol, phenylethyl alcohol, phenylpropanol and 1-decanol; The aromatic aldehydes include vanillin and neral; The ketones include ionone, geranylacetone, β-ionone and hexahydrofarnesylacetone.

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