Preparation method of aromatic vinegar brewed with oranges

Abstract

The invention provides a preparation method of orange aromatic vinegar. The preparation method comprises the following steps: debitterizing green orange juice, preparing green orange wine mash, preparing orange vinegar fermentation liquor, clarifying the orange vinegar fermentation liquor, and ageing the orange vinegar fermentation liquor. In the green orange juice debitterizing step, a debitterizing agent composed of limonin dehydrogenase, limonin epoxidase and modified activated carbon according to the mass ratio of (3-5): (1-3): (10-15) is added, limonin is effectively removed, and the taste of the orange aromatic vinegar is improved. In the step of preparing the orange vinegar fermentation liquor, the immobilized acetobacter aceti is added, so that the acetobacter aceti is not easy to lose along with the fermentation liquor, the utilization rate of thalli and the fermentation stability are improved, relatively high thalli concentration and activity can be kept, and the fermentation period is shortened. In the step of ageing the orange vinegar fermentation liquor, a bamboo barrel is used for ageing, and the bamboo barrel has good air permeability, so that trace oxygen exchange of the orange vinegar fermentation liquor in the ageing process is facilitated, further fusion and development of flavor components in vinegar are promoted, and the flavor of the orange vinegar is more mellow and harmonious.

Description

Technical Field

[0001] The invention belongs to the field of edible vinegar brewing, and particularly relates to a method for preparing orange-brewed aromatic vinegar. Background Art

[0002] As people's living standards improve and scientific research further reveals the functional properties of vinegar, the use of vinegar is becoming more and more extensive, and the demand for vinegar and its derivatives is increasing. The use of vinegar is no longer limited to traditional cooking, but is becoming more and more popular as a nutritional drink and health product.

[0003] Vinegar has rich and varied functions: First, it can digest fat and sugar. Eating it in moderation can not only help you lose weight, but also promote the burning of nutrients in the body and improve the utilization rate of heat energy, thereby promoting physical health; second, it can inhibit and reduce the formation of lipid peroxides during the aging process of the human body, reduce age spots, and delay aging; third, it has a diuretic effect, which can prevent urinary retention, constipation, and various stone diseases, as well as lower blood pressure, soften blood vessels, reduce the accumulation of cholesterol, and reduce urine sugar content, thereby preventing cardiovascular diseases and diabetes; fourth, it is rich in alkaline earth metal elements such as K, Na, Ca, and Mg, which can regulate the acid-base balance of the blood, maintain the relative balance of the human body's internal environment, and reduce various diseases such as arteriosclerosis, hyperlipidemia, hyperglycemia, and hyperuricemia induced by acidification of body fluids.

[0004] Orange-brewed balsamic vinegar is a type of balsamic vinegar brewed with green orange as the main raw material. Orange-brewed balsamic vinegar retains the natural aroma of green orange, making the taste of vinegar more refreshing and pleasant, adding a new flavor dimension to traditional vinegar products. At the same time, orange-brewed balsamic vinegar is rich in vitamin C, flavonoids, organic acids, and amino acids. It is not only rich in nutritional value, but also has significant health benefits. During the juicing process of orange-brewed balsamic vinegar, the fruit is mechanically damaged, and the limonin A-ring lactone in the fruit is dissolved. Under acidic conditions, limonin A-ring lactone is catalyzed by limonin D-ring lactone hydrolase to be converted into limonin with a strong bitter taste, which greatly affects the edible taste of orange-brewed balsamic vinegar. Summary of the invention

[0005] In view of this, the present invention proposes a method for preparing orange-brewed aromatic vinegar to solve the above problems.

[0006] The technical solution of the present invention is achieved as follows: a method for preparing orange-brewed fragrant vinegar, comprising the following steps:

[0007] S1. Debittering green orange juice: washing and draining fresh green oranges free of pests and mildew, removing the peel and taking out the pulp, squeezing the pulp to obtain green orange juice; adding a debittering agent to the green orange juice for debittering treatment, wherein the amount of the debittering agent added is 1-2% of the volume of the orange juice; the debittering agent is composed of limonin dehydrogenase, limonin epoxidase, and modified activated carbon in a mass ratio of (3-5):(1-3):(10-15), and the particle size of the modified activated carbon is 0.5-1.5 mm;

[0008] S2, preparing green orange wine mash: after the debittering treatment is completed, filtering with a filter screen to obtain a filtrate; adding sugar to the filtrate to adjust the sugar content, and adding brewer's yeast and saccharifying enzyme to ferment orange wine to obtain green orange wine mash;

[0009] S3, preparing orange vinegar fermentation liquid: adding immobilized acetic acid bacteria and acid protease to green orange wine mash to carry out orange vinegar fermentation to obtain orange vinegar fermentation liquid;

[0010] S4, clarification of orange vinegar fermentation liquid: adding a clarifier to the orange vinegar fermentation liquid for clarification treatment, wherein the amount of the clarifier added is 0.4-0.6% of the volume of the orange vinegar fermentation liquid, and the clarifier is composed of chitosan and diatomaceous earth;

[0011] S5. Aging of orange vinegar fermented liquid: placing the clarified orange vinegar fermented liquid into bamboo barrels and aging it in stages under controlled temperature; after the aging, sterilizing it with a high-voltage pulse electric field to obtain orange vinegar.

[0012] Furthermore, the modified activated carbon in the S1 debittering agent is prepared by the following method: taking the activated carbon and placing it in a beaker, adding deionized water, stirring for 5-10 minutes, the mass volume ratio of the activated carbon to the deionized water is (1.0-1.2): (50.0-100.0); using a vacuum pump to filter, the activated carbon is separated, and washed with deionized water until the filtrate is clear; placing the washed activated carbon in a drying oven, drying at 100-110°C to constant weight, and set aside; weighing glycine, adding deionized water, stirring to dissolve, the glycine and deionized water are The mass volume ratio of ionized water is g / L (65-75):1 to obtain a glycine solution; the treated activated carbon is added into a reactor, the glycine solution is slowly added, and the mixture is reacted at 80-100°C with stirring at 200-300r / min for 2.5-3.5h; after the reaction is completed, the mixture is cooled to room temperature, and a vacuum pump is used to filter to separate the modified activated carbon, and the modified activated carbon is washed with deionized water for 2-3 times, and the washed modified activated carbon is placed in a drying oven and dried at 100-110°C to constant weight to obtain the modified activated carbon.

[0013] Furthermore, the S1 debittering treatment is carried out in a constant temperature water bath at 38-45°C for 20-30 min.

[0014] Furthermore, the amount of sugar added in S2 is 25-35 g / L, the amount of brewer's yeast added is 4-8% of the volume of the filtrate, and the amount of saccharifying enzyme added is 0.06-0.10% of the volume of the filtrate; and the orange wine fermentation is performed at 28-32° C. for 5-8 days.

[0015] Furthermore, the amount of immobilized Acetobacter added in S3 is 4-6% of the volume of the green orange wine mash, and the amount of acid protease added is 0.1-0.3% of the volume of the green orange wine mash; the immobilized Acetobacter is prepared by the following method: inoculating Acetobacter into a culture medium, culturing to a logarithmic growth phase, harvesting the cultured Acetobacter, washing with deionized water and centrifuging at 3000-4000 rpm to collect the Acetobacter cells, resuspending the Acetobacter cells in deionized water to obtain an Acetobacter suspension, and the number of live bacteria in the Acetobacter suspension is ≥1×10 8 CFU / mL; adding gluten protein powder to deionized water in an amount of 20-30 g / L, stirring until dissolved to obtain a gluten protein solution, heating the gluten protein solution to 60-80°C, and then cooling it to 30-35°C, and slowly adding an Acetobacter suspension to the gluten protein solution, the volume ratio of the Acetobacter suspension to the gluten protein solution is (1.0-1.5):(1.0-2.5), stirring evenly to obtain a mixed solution; injecting the mixed solution into a corn cob and standing at room temperature for 1-2 hours to obtain immobilized Acetobacter.

[0016] Furthermore, in S3, orange vinegar fermentation is carried out at 30-35° C., stirring is performed every 4-6 hours during the fermentation process, and fermentation is carried out for 6-8 days to obtain orange vinegar fermentation liquid.

[0017] Furthermore, the clarification treatment in S4 is carried out for 2-3 days, the mass ratio of chitosan to diatomaceous earth in the clarifier is (1-3):(1-2), and the suspended matter is filtered out after the clarification treatment is completed.

[0018] Furthermore, the staged temperature-controlled aging in S5 is as follows: aging at 15-20°C for 10-20 days; heating to 25-30°C and aging for 20-30 days; and cooling to 10-15°C and aging for 10-15 days.

[0019] Furthermore, during the S5 high voltage pulse electric field sterilization treatment, the electric field strength is 20-30 kV / cm, the frequency is 150-250 Hz, the pulse width is 1-3 μs, and the treatment time is 200-450 μs.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The orange vinegar obtained by fermenting green orange juice has a richer taste, and the vinegar aroma also contains green orange aroma. In addition, the orange vinegar contains rich amino acids, which can improve the body's metabolism, prevent fat accumulation, and promote fat decomposition in the body. In addition, it can also regulate acid-base balance, eliminate fatigue, and contribute to the normal progress of the human tricarboxylic acid cycle, thereby making aerobic metabolism smooth.

[0022] 2. The present invention effectively removes limonin by adding a debittering agent composed of a specific ratio of limonin dehydrogenase, limonin epoxidase, and modified activated carbon, thereby improving the taste of orange-brewed balsamic vinegar. Among them, limonin dehydrogenase can convert limonin into non-bitter limonin glycosides or 17-dehydrolimonin A-ring lactones, thereby achieving the purpose of debittering. Limonin epoxidase can convert limonin into non-bitter deoxylimonin, thereby effectively debittering. Activated carbon is modified to introduce nitrogen-containing groups. When the nitrogen-modified activated carbon contacts limonin, the functional groups on the limonin molecules hydrogen bond with the nitrogen-containing functional groups on the surface of the activated carbon, thereby enhancing the adsorption strength of the activated carbon to limonin, thereby effectively removing limonin.

[0023] 3. The present invention performs orange vinegar fermentation by adding immobilized acetobacter. The immobilization technology makes it difficult for acetobacter to be lost with the fermentation liquid, thereby improving the utilization rate of the thalli and the stability of the fermentation, and being able to maintain a high concentration and activity of the thalli. In the orange vinegar fermentation process of orange vinegar, the fermentation can be started faster and the fermentation cycle can be shortened. In addition, during the immobilization process, acetobacter is embedded in gluten protein, and a protective barrier is formed on the surface of acetobacter, thereby reducing the adverse effects of the external environment on the thalli, thereby improving the stability and activity of the thalli. The structural characteristics of gluten protein also contribute to the attachment and growth of the thalli, further promoting the performance of the thalli activity. By injecting the mixed solution into the corn cob, the porous structure of the corn cob provides a broad attachment surface for acetobacter, which helps the thalli to be evenly distributed on the carrier, improves the contact efficiency between the thalli and the substrate, and is conducive to the synthesis of acetic acid and ester compounds.

[0024] 4. The present invention places the orange fermented liquid into a bamboo barrel for aging. The natural bamboo fragrance contained in the bamboo barrel can penetrate into the orange fermented liquid, adding a unique natural fragrance to it. This fragrance is combined with the original flavor of orange vinegar to form a more complex and layered taste. The bamboo barrel has good air permeability, which helps the orange fermented liquid to exchange trace amounts of oxygen during the aging process, thereby promoting the further fusion and development of the flavor components in the vinegar liquid, making the flavor of the orange vinegar more mellow and coordinated. In addition, bamboo contains some trace elements and minerals that are beneficial to the human body. These components penetrate into the orange vinegar during the aging process, increasing its nutritional value. DETAILED DESCRIPTION

[0025] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0026] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0027] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0028] Example 1

[0029] A method for preparing orange-brewed aromatic vinegar comprises the following steps:

[0030] S1. Debittering green orange juice: Wash and drain fresh green oranges that are free of insect pests and mildew, remove the peel and take the pulp, squeeze the pulp to obtain green orange juice. Add a debittering agent to the green orange juice and perform a debittering treatment in a 38°C constant temperature water bath for 30 minutes. The amount of the debittering agent added is 1% of the volume of the orange juice, and the debittering agent is composed of limonin dehydrogenase, limonin epoxidase, and modified activated carbon in a mass ratio of 3:1:10. The modified activated carbon has a particle size of 0.5 mm and is prepared by the following method: taking activated carbon and placing it in a beaker, adding deionized water, stirring for 5 minutes, the mass volume ratio of the activated carbon to the deionized water is 1.0:50.0 g / mL; using a vacuum pump to filter, separate the activated carbon, and wash it with deionized water until the filtrate is clear; placing the washed activated carbon in a drying oven, drying it to constant weight at 100°C for standby use; weighing glycine, adding deionized water, stirring and dissolving, the mass volume ratio of glycine to deionized water is 65:1 glycine solution; adding the treated activated carbon to a reactor, slowly adding the glycine solution, stirring and reacting at 80°C at 2000r / min for 3.5h; cooling to room temperature after the reaction, using a vacuum pump to filter, separating the modified activated carbon, and washing it twice with deionized water, and placing the washed modified activated carbon in a drying oven, drying it to constant weight at 100°C to obtain modified activated carbon.

[0031] S2. Preparation of green orange wine mash: After the debittering treatment is completed, filter with a filter to obtain the filtrate. Sugar is added to the filtrate to adjust the sugar content, and brewer's yeast and saccharifying enzyme are added to ferment orange wine at 28°C for 8 days to obtain green orange wine mash. Among them, the amount of sugar added is 25g / L, the amount of brewer's yeast added is 4% of the volume of the filtrate, and the amount of saccharifying enzyme added is 0.06% of the volume of the filtrate.

[0032] S3. Preparation of orange vinegar fermentation liquid: Add immobilized Acetobacter and acid protease to green orange wine mash, ferment orange vinegar at 30°C for 8 days, stir every 6 hours during the fermentation process, and obtain orange vinegar fermentation liquid. The amount of immobilized Acetobacter added is 4% of the volume of green orange wine mash, and the amount of acid protease added is 0.1% of the volume of green orange wine mash. The immobilized Acetobacter is prepared by the following method: inoculate Acetobacter into a culture medium, culture to the logarithmic growth phase, harvest the cultured Acetobacter, wash with deionized water, and collect the Acetobacter cells by centrifugation at 30,000 rpm, resuspend the Acetobacter cells in deionized water to obtain an Acetobacter suspension, and the number of active bacteria in the Acetobacter suspension is 1×10 8 CFU / mL. Add gluten protein powder to deionized water in an amount of 20g / L, stir until dissolved to obtain a gluten protein solution. Heat the gluten protein solution to 60°C, then cool to 30°C, and slowly add the Acetobacter suspension to the gluten protein solution in a volume ratio of Acetobacter suspension to gluten protein solution of 1.0:1.0, stir evenly, and obtain a mixed solution. Inject the above mixed solution into corn cobs and let stand at room temperature for 1h to obtain immobilized Acetobacter.

[0033] S4, clarification of orange vinegar fermentation liquid: adding a clarifier to the orange vinegar fermentation liquid for clarification treatment for 3 days, the amount of the clarifier added is 0.4% of the volume of the orange vinegar fermentation liquid, and the clarifier is composed of chitosan and diatomaceous earth in a mass ratio of 1:1. After the clarification treatment is completed, the suspended matter is filtered out.

[0034] S5. Aging of orange vinegar fermented liquid: The clarified orange vinegar fermented liquid was placed in a bamboo barrel and aged in stages under controlled temperature, specifically: aged at 15°C for 10 days; raised to 25°C for 20 days; and then cooled to 10°C for 10 days. After aging, a high-voltage pulse electric field was used for sterilization, and the treatment lasted for 200 μs under the conditions of an electric field strength of 20 kV / cm, a frequency of 150-Hz, and a pulse width of 1 μs, to obtain orange vinegar.

[0035] Example 2

[0036] A method for preparing orange-brewed aromatic vinegar comprises the following steps:

[0037] S1. Debittering green orange juice: Wash and drain fresh green oranges that are free of pests and mildew, remove the peel and take the pulp, squeeze the pulp to obtain green orange juice. Add a debittering agent to the green orange juice and perform a debittering treatment in a 32°C constant temperature water bath for 25 minutes. The amount of the debittering agent added is 1.5% of the volume of the orange juice, and the debittering agent is composed of limonin dehydrogenase, limonin epoxidase, and modified activated carbon in a mass ratio of 4:2:12.5. The modified activated carbon has a particle size of 1.0 mm and is prepared by the following method: taking activated carbon and placing it in a beaker, adding deionized water, stirring for 5-10 minutes, and the mass volume ratio of the activated carbon to the deionized water is 1.1:75.0 g / mL; using a vacuum pump to filter, separating the activated carbon, and washing with deionized water until the filtrate is clear; placing the washed activated carbon in a drying oven, drying it to constant weight at 105°C for standby use; weighing glycine, adding deionized water, stirring and dissolving, and the mass volume ratio of glycine to deionized water is 70:1 glycine solution; adding the treated activated carbon to a reactor, slowly adding the glycine solution, stirring and reacting at 90°C at 250r / min for 3.0 hours; cooling to room temperature after the reaction, using a vacuum pump to filter, separating the modified activated carbon, and washing it with deionized water 3 times, and placing the washed modified activated carbon in a drying oven, drying it to constant weight at 105°C to obtain modified activated carbon.

[0038] S2. Preparation of green orange wine mash: After the debittering treatment is completed, filter with a filter to obtain the filtrate. Sugar is added to the filtrate to adjust the sugar content, and brewer's yeast and saccharifying enzyme are added to ferment orange wine at 30°C for 6 days to obtain green orange wine mash. Among them, the amount of sugar added is 30g / L, the amount of brewer's yeast added is 6% of the volume of the filtrate, and the amount of saccharifying enzyme added is 0.08% of the volume of the filtrate.

[0039] S3. Preparation of orange vinegar fermentation liquid: Add immobilized Acetobacter and acid protease to green orange wine mash, ferment orange vinegar at 32.5°C for 7 days, stir every 5 hours during the fermentation process, and obtain orange vinegar fermentation liquid. The amount of immobilized Acetobacter added is 5% of the volume of green orange wine mash, and the amount of acid protease added is 0.2% of the volume of green orange wine mash. The immobilized Acetobacter is prepared by the following method: inoculate Acetobacter into the culture medium, culture to the logarithmic growth phase, harvest the cultured Acetobacter, wash with deionized water and collect the Acetobacter cells by centrifugation at 3500rpm, resuspend the Acetobacter cells in deionized water to obtain an Acetobacter suspension, and the number of active bacteria in the Acetobacter suspension is 5×10 8CFU / mL. Add gluten protein powder to deionized water in an amount of 25g / L, stir until dissolved to obtain a gluten protein solution. Heat the gluten protein solution to 70°C, then cool it to 32.5°C, and slowly add the Acetobacter suspension to the gluten protein solution in a volume ratio of Acetobacter suspension to gluten protein solution of 1.0:1.0, stir evenly, and obtain a mixed solution. Inject the above mixed solution into corn cobs and let stand at room temperature for 1.5h to obtain immobilized Acetobacter.

[0040] S4, clarification of orange vinegar fermentation liquid: add a clarifier to the orange vinegar fermentation liquid for clarification treatment for 3 days, the amount of the clarifier added is 0.45% of the volume of the orange vinegar fermentation liquid, and the clarifier is composed of chitosan and diatomaceous earth in a mass ratio of 2:1.5. After the clarification treatment is completed, filter out the suspended matter.

[0041] S5. Aging of orange vinegar fermentation liquid: The clarified orange vinegar fermentation liquid is placed in a bamboo barrel and aged in stages under controlled temperature, specifically: aging at 17.5°C for 15 days; heating to 27.5°C for 25 days; and cooling to 12.5°C for 13 days. After aging, a high-voltage pulse electric field is used for sterilization, and the treatment is carried out for 300 μs under the conditions of an electric field strength of 25 kV / cm, a frequency of 200 Hz, and a pulse width of 2 μs to obtain orange vinegar.

[0042] Example 3

[0043] A method for preparing orange-brewed aromatic vinegar comprises the following steps:

[0044] S1. Debittering green orange juice: Wash and drain fresh green oranges that are free of insect pests and mildew, remove the peel and take the pulp, squeeze the pulp to obtain green orange juice. Add a debittering agent to the green orange juice and perform a debittering treatment in a 45°C constant temperature water bath for 20 minutes. The amount of the debittering agent added is 2% of the volume of the orange juice, and the debittering agent is composed of limonin dehydrogenase, limonin epoxidase, and modified activated carbon in a mass ratio of 5:3:15. The modified activated carbon has a particle size of 1.5 mm and is prepared by the following method: taking activated carbon and placing it in a beaker, adding deionized water, stirring for 10 minutes, the mass volume ratio of the activated carbon to the deionized water is g / mL of 1.2:50.0; using a vacuum pump to filter, separating the activated carbon, and washing with deionized water until the filtrate is clear; placing the washed activated carbon in a drying oven, drying it to constant weight at 110°C for standby use; weighing glycine, adding deionized water, stirring and dissolving, the mass volume ratio of glycine to deionized water is g / L of 75:1, and obtaining a glycine solution; adding the treated activated carbon to a reactor, slowly adding the glycine solution, stirring and reacting at 100°C at 300r / min for 2.5h; cooling to room temperature after the reaction, using a vacuum pump to filter, separating the modified activated carbon, and washing it with deionized water 3 times, and placing the washed modified activated carbon in a drying oven, drying it to constant weight at 110°C to obtain the modified activated carbon.

[0045] S2. Preparation of green orange wine mash: After the debittering treatment is completed, filter with a filter to obtain the filtrate. Sugar is added to the filtrate to adjust the sugar content, and brewer's yeast and saccharifying enzyme are added to ferment orange wine at 32°C for 5 days to obtain green orange wine mash. Among them, the amount of sugar added is 35g / L, the amount of brewer's yeast added is 8% of the volume of the filtrate, and the amount of saccharifying enzyme added is 0.10% of the volume of the filtrate.

[0046] S3. Preparation of orange vinegar fermentation liquid: Add immobilized Acetobacter and acid protease to green orange wine mash, ferment orange vinegar at 35°C for 6 days, stir every 4 hours during the fermentation process, and obtain orange vinegar fermentation liquid. The amount of immobilized Acetobacter added is 6% of the volume of green orange wine mash, and the amount of acid protease added is 0.3% of the volume of green orange wine mash. The immobilized Acetobacter is prepared by the following method: inoculate Acetobacter into the culture medium, culture to the logarithmic growth phase, harvest the cultured Acetobacter, wash with deionized water and collect the Acetobacter cells by centrifugation at 4000rpm, resuspend the Acetobacter cells in deionized water to obtain an Acetobacter suspension, and the number of active bacteria in the Acetobacter suspension is 9×10 8CFU / mL. Add gluten protein powder to deionized water in an amount of 30g / L, stir until dissolved to obtain a gluten protein solution. Heat the gluten protein solution to 80°C, then cool to 35°C, and slowly add the Acetobacter suspension to the gluten protein solution in a volume ratio of Acetobacter suspension to gluten protein solution of 1.5:2.5, stir evenly to obtain a mixed solution. Inject the above mixed solution into corn cobs and let stand at room temperature for 2h to obtain immobilized Acetobacter.

[0047] S4, clarification of orange vinegar fermentation liquid: adding a clarifier to the orange vinegar fermentation liquid for clarification treatment for 3 days, the amount of the clarifier added is 0.6% of the volume of the orange vinegar fermentation liquid, and the clarifier is composed of chitosan and diatomaceous earth in a mass ratio of 3:2. After the clarification treatment is completed, the suspended matter is filtered out.

[0048] S5. Aging of orange vinegar fermented liquid: The clarified orange vinegar fermented liquid was placed in a bamboo barrel and aged in stages under controlled temperature, specifically: aged at 20°C for 10 days; raised to 30°C for 20 days; and then cooled to 15°C for 10 days. After aging, a high-voltage pulse electric field was used for sterilization, and the treatment lasted for 450 μs under the conditions of an electric field strength of 30 kV / cm, a frequency of 250 Hz, and a pulse width of 3 μs to obtain orange vinegar.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 2 is that no debittering agent is added to S1 for debittering treatment.

[0051] Comparative Example 2

[0052] Compared with Example 2, the difference between this comparative example and Example 2 is that the debittering agent in S1 is composed of limonin dehydrogenase and limonin epoxidase in a mass ratio of 4:2.

[0053] Comparative Example 3

[0054] The difference between this comparative example and Example 2 is that an equal mass of Acetobacter is used in S3 to replace the immobilized Acetobacter, that is, the Acetobacter is not immobilized.

[0055] Comparative Example 4

[0056] The difference between this comparative example and Example 2 is that a metal bucket is used instead of a bamboo bucket in S5.

[0057] Comparative Example 5

[0058] The difference between this comparative example and Example 2 is that no stage-by-stage temperature-controlled aging is performed in S5, and the entire aging process is performed at 17.5° C. for 53 days.

[0059] 1. Determination of limonin content

[0060] The limonin content in the debittered green orange juice in S1 was determined by high performance liquid chromatography with reference to NY / 2011-2011 "Determination of limonin content in citrus fruits and products". The green orange juices prepared by the preparation methods of Examples 1-3 and Comparative Examples 1-5 were measured three times respectively, and the average value was taken. The results are shown in Table 1.

[0061] Table 1

[0062]

[0063] It can be seen from Comparative Example 1 compared with Examples 1-3 that by adding a debittering agent composed of a specific ratio of limonin dehydrogenase, limonin epoxidase, and modified activated carbon, limonin in green orange juice can be effectively removed. This is because limonin dehydrogenase can convert limonin into non-bitter limonin glycosides or 17-dehydrolimonin A-ring lactones, thereby achieving the purpose of debittering. Limonin epoxidase can convert limonin into non-bitter deoxylimonin, thereby effectively debittering. Activated carbon is modified to introduce nitrogen-containing groups, and the hydrogen atoms in the hydroxyl and carboxyl functional groups on the limonin form hydrogen bonds with the nitrogen atoms or oxygen atoms in the nitrogen-containing functional groups on the surface of the activated carbon, thereby significantly enhancing the adsorption strength of activated carbon to limonin, thereby effectively removing limonin. From Example 2 compared with Comparative Example 2, it can be seen that the lack of modified activated carbon in the debittering agent greatly weakens its removal effect on limonin. It can be seen that the debittering agent can only achieve the best limonin removal effect under the synergistic effect of limonin dehydrogenase, limonin epoxidase and modified activated carbon in a specific proportion.

[0064] 2. Determination of total acid content and total ester content

[0065] The total acid content was determined with reference to GB12456-2021 "Determination of total acid content in food", and the total acid content was calculated as acetic acid. The total ester content was determined with reference to GB / T19777-2013 "Geographical Indication Product Shanxi Old Mature Vinegar". The total acid content and total ester content in the orange-brewed fragrant vinegar prepared in Examples 1-3 and Comparative Examples 1-5 were determined respectively, and each group was measured 3 times, and the average value was taken. The results are shown in Table 2.

[0066] Table 2

[0067]

[0068]

[0069] It can be seen from Table 2 that the total acid content and total ester content of the orange vinegar prepared in Examples 1-3 are higher than those in Comparative Examples 3-5, among which the content in Example 2 is the highest.

[0070] Compared with Comparative Example 3 by Example 2, the immobilization technology of Example 2 makes it difficult for Acetobacter to be lost with the fermentation liquid, thereby improving the utilization rate of the cell and the stability of the fermentation, and being able to maintain a high cell concentration and activity. In the orange vinegar fermentation process of orange vinegar, the fermentation can be started faster and the fermentation cycle can be shortened. In addition, during the immobilization process, Acetobacter is embedded in gluten protein, and a protective barrier is formed on the surface of Acetobacter, thereby reducing the adverse effects of the external environment on the cell, thereby improving the stability and activity of the cell. The structural characteristics of gluten protein also contribute to the attachment and growth of the cell, further promoting the performance of the cell activity. By injecting the mixed solution into the corn cob, the porous structure of the corn cob provides a broad attachment surface for Acetobacter, which helps the cell to be evenly distributed on the carrier, improves the contact efficiency of the cell with the substrate, and is conducive to the synthesis of acetic acid and ester compounds, so the immobilized Acetobacter is used for fermentation to harvest a higher total acid content and total ester content.

[0071] By comparing Example 2 with Comparative Example 4, the bamboo barrel in Example 2 is made of natural bamboo, and its material has air permeability and adsorption properties. This property enables the bamboo barrel to exchange substances with the orange vinegar fermentation liquid to a certain extent during the aging process, which is helpful for the generation and conversion of flavor substances in the vinegar liquid, thereby facilitating the synthesis of acetic acid and ester compounds.

[0072] By comparing Example 2 with Comparative Example 5, the generation of acetic acid and the esterification reaction are two important reaction processes in the aging process of orange-brewed balsamic vinegar. Example 2 can set the optimum temperature for different reaction stages by staged temperature control, thereby promoting the progress of these chemical reactions, which is beneficial to the further generation of acetic acid and ester compounds.

[0073] 3. Sensory Evaluation

[0074] 10 professional sensory evaluation personnel were selected to evaluate the orange vinegar prepared in Examples 1-3 and Comparative Examples 1-5 from the three aspects of color, taste and aroma, and the average score was taken as the evaluation score. The evaluation criteria are shown in Table 3, and the evaluation results are shown in Table 4.

[0075] Table 3

[0076]

[0077] Table 4

[0078] Color score Taste score Aroma score Total score Example 1 17 38 37 91 Example 2 19 38 39 96 Example 3 18 36 38 92 Comparative Example 1 18 37 36 91 Comparative Example 2 17 36 38 91 Comparative Example 3 13 29 28 70 Comparative Example 4 17 32 31 80 Comparative Example 5 12 25 29 66

[0079] As can be seen from Table 4, the orange-brewed fragrant vinegar obtained in Examples 1-3 of the present invention has excellent performance in color, taste and aroma. The present invention places the orange-brewed fermented liquid into a bamboo barrel for aging, and the natural bamboo fragrance contained in the bamboo barrel can penetrate into the orange-brewed fermented liquid, adding a unique natural aroma to it. This aroma is combined with the original flavor of orange vinegar to form a more complex and layered taste. In addition, the material of the bamboo barrel has good air permeability, which helps the orange-brewed fermented liquid to exchange a small amount of oxygen during the aging process, thereby promoting the further fusion and development of the flavor components in the vinegar liquid, making the flavor of the orange-brewed fragrant vinegar more mellow and coordinated. In addition, the present invention uses staged temperature-controlled aging. In the early stage of aging, a lower temperature is used to promote the stability of vinegar and the initial fusion of flavors; then the temperature is gradually raised to 25-30°C to accelerate the interaction of flavor substances; finally, the temperature is lowered to 10-15°C for aging to make the aroma more mellow, so that the taste and aroma of the prepared orange-brewed fragrant vinegar are more outstanding.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing orange-brewed fragrant vinegar, characterized in that: The following steps are involved: S1. Debittering green orange juice: washing and draining fresh green oranges free of pests and mildew, removing the peel and taking out the pulp, squeezing the pulp to obtain green orange juice; adding a debittering agent to the green orange juice for debittering treatment, wherein the amount of the debittering agent added is 1-2% of the volume of the orange juice; the debittering agent is composed of limonin dehydrogenase, limonin epoxidase, and modified activated carbon in a mass ratio of (3-5):(1-3):(10-15), and the particle size of the modified activated carbon is 0.5-1.5 mm; S2, preparing green orange wine mash: after the debittering treatment is completed, filtering with a filter screen to obtain a filtrate; adding sugar to the filtrate to adjust the sugar content, and adding brewer's yeast and saccharifying enzyme to ferment orange wine to obtain green orange wine mash; S3, preparing orange vinegar fermentation liquid: adding immobilized acetic acid bacteria and acid protease to green orange wine mash to carry out orange vinegar fermentation to obtain orange vinegar fermentation liquid; S4, clarification of orange vinegar fermentation liquid: adding a clarifier to the orange vinegar fermentation liquid for clarification treatment, wherein the amount of the clarifier added is 0.4-0.6% of the volume of the orange vinegar fermentation liquid, and the clarifier is composed of chitosan and diatomaceous earth; S5. Aging of orange vinegar fermented liquid: placing the clarified orange vinegar fermented liquid into bamboo barrels and aging it in stages under controlled temperature; after the aging, sterilizing it with a high-voltage pulse electric field to obtain orange vinegar.

2. The method for preparing orange-brewed aromatic vinegar according to claim 1, characterized in that: The modified activated carbon in the S1 debittering agent is prepared by the following method: taking activated carbon and placing it in a beaker, adding deionized water, stirring for 5-10 minutes, and the mass volume ratio of the activated carbon to deionized water is (1.0-1.2): (50.0-100.0); using a vacuum pump to filter, separating the activated carbon, and washing with deionized water until the filtrate is clear; placing the washed activated carbon in a drying oven, drying at 100-110°C to constant weight, and setting aside; weighing glycine, adding deionized water, stirring to dissolve, and the glycine and deionized water are mixed together, and the mixture is stirred for 3 hours. The mass volume ratio of the activated carbon to water is (65-75):1 to obtain a glycine solution; the treated activated carbon is added into the reactor, the glycine solution is slowly added, and the mixture is reacted at 80-100°C with stirring at 200-300r / min for 2.5-3.5h; after the reaction is completed, the mixture is cooled to room temperature, filtered with a vacuum pump, the modified activated carbon is separated, and washed with deionized water for 2-3 times, and the washed modified activated carbon is placed in a drying oven and dried at 100-110°C to constant weight to obtain the modified activated carbon.

3. The method for preparing orange-brewed aromatic vinegar according to claim 1, characterized in that: The debittering treatment of S1 is carried out in a constant temperature water bath at 38-45°C for 20-30 minutes.

4. The method for preparing orange-fermented aromatic vinegar according to claim 1, characterized in that: The amount of sugar added to the S2 is 25-35 g / L, the amount of brewer's yeast added is 4-8% of the volume of the filtrate, and the amount of saccharifying enzyme added is 0.06-0.10% of the volume of the filtrate; the orange wine fermentation is carried out at 28-32° C. for 5-8 days.

5. The method for preparing orange-fermented aromatic vinegar according to claim 1, characterized in that: The amount of immobilized Acetobacter added in S3 is 4-6% of the volume of green orange wine mash, and the amount of acid protease added is 0.1-0.3% of the volume of green orange wine mash; the immobilized Acetobacter is prepared by the following method: inoculating Acetobacter into a culture medium, culturing to a logarithmic growth phase, harvesting the cultured Acetobacter, washing with deionized water and collecting Acetobacter cells by centrifugation at 3000-4000 rpm, and resuspending the Acetobacter cells in deionized water to obtain an Acetobacter suspension, wherein the number of live bacteria in the Acetobacter suspension is ≥1×10 8 CFU / mL; adding gluten protein powder to deionized water in an amount of 20-30 g / L, stirring until dissolved to obtain a gluten protein solution, heating the gluten protein solution to 60-80°C, cooling it to 30-35°C, and slowly adding an acetobacillus suspension to the gluten protein solution, wherein the volume ratio of the acetobacillus suspension to the gluten protein solution is (1.0-1.5):(1.0-2.5), stirring evenly to obtain a mixed solution; injecting the mixed solution into a corn cob and standing at room temperature for 1-2 hours to obtain immobilized acetobacillus.

6. The method for preparing orange-fermented aromatic vinegar according to claim 1, characterized in that: In S3, orange vinegar fermentation is carried out at 30-35° C., stirring is performed every 4-6 hours during the fermentation process, and fermentation is carried out for 6-8 days to obtain orange vinegar fermentation liquid.

7. The method for preparing orange-fermented aromatic vinegar according to claim 1, characterized in that: The clarification treatment in S4 is carried out for 2-3 days, the mass ratio of chitosan to diatomaceous earth in the clarifier is (1-3):(1-2), and the suspended matter is filtered out after the clarification treatment is completed.

8. The method for preparing orange-fermented aromatic vinegar according to claim 1, characterized in that: The staged temperature-controlled aging in S5 is specifically as follows: aging at 15-20° C. for 10-20 days; heating to 25-30° C. for aging for 20-30 days; and cooling to 10-15° C. for aging for 10-15 days.

9. The method for preparing orange-fermented aromatic vinegar according to claim 1, characterized in that: The S5 high-voltage pulse electric field sterilization treatment has an electric field strength of 20-30 kV / cm, a frequency of 150-250 Hz, a pulse width of 1-3 μs, and a treatment time of 200-450 μs.

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