Preparation of purple corn anthocyanin dyed cigarette paper

Abstract

The invention belongs to the technical field of cigarette additives, and particularly relates to a preparation method of purple corn anthocyanin dyed cigarette paper, which comprises the following steps: by using purple corn seeds and corncobs as raw materials, cleaning, drying at controlled temperature, crushing and screening, and then carrying out ultrasonic-assisted extraction by using 70-75% ethanol or methanol to obtain a natural anthocyanin crude extract; and loading the crude extract into an AB-8 macroporous resin column, washing with pure water to remove impurities, eluting with ethanol, carrying out rotary evaporation concentration, and freeze-drying to obtain anthocyanin powder. And uniformly mixing the powder with deionized water and a proper amount of mordant, complexing to form a dye, and finally applying the dye to cigarette paper in a dipping or coating manner and drying. According to the process, the color value of anthocyanin is increased, miscellaneous gas components in smoke after combustion of the dyed cigarette paper are remarkably reduced, and dual optimization of color expression and smoking quality is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of cigarette additives, and particularly relates to the preparation of a purple corn anthocyanin-dyed cigarette paper. Background Art

[0002] With the continuous innovation in the global tobacco industry, cigarette paper, as an important part of tobacco products, not only directly affects the consumer experience in terms of appearance, but also plays a key role in enhancing product differentiation, meeting diversified needs and increasing added value. At present, the main process for preparing colored cigarette paper is to impregnate pigments on blank cigarette paper, and the selection of pigments directly determines the quality of the final colored cigarette paper.

[0003] Existing pigments are mainly divided into two categories: natural pigments and synthetic pigments. Although synthetic pigments have the characteristics of uniform coloring and good stability, their potential health risks have been confirmed by many studies. In addition, their artificial synthesis sources often arouse consumers' concerns about safety and are also difficult to meet the current market demand for natural and healthy products. Therefore, natural pigments are gradually becoming the mainstream raw materials for preparing colored cigarette paper. However, compared with synthetic pigments, natural pigments have more complex components, and they are easily affected by high temperature during the combustion process and undergo oxidation, decomposition and other reactions, generating other unwanted by-products. These by-products appear as "off-flavors" in the smoke, which not only reduces the purity of tobacco combustion, but also may have an adverse impact on the taste and smoking experience.

[0004] Therefore, at the stage of preparing natural pigments, how to remove impurities while retaining as much as possible the effective components that play a decisive role in the coloring effect is the key bottleneck faced by the current development of colored cigarette paper technology. Purple is often associated with mystery, nobility and luxury, and can give products a high-end and unique impression. Using purple on cigarette paper helps to enhance the brand image and product grade. However, natural purple pigments (such as anthocyanins) are easily oxidized, and their loss is inevitable in the existing extraction process, ultimately affecting the color value of cigarette paper. In addition, in traditional processes, in order to retain more anthocyanins, it is often difficult to effectively separate anthocyanins from impurities such as polysaccharides and proteins, which affects the smoking experience of cigarettes.

[0005] To solve the above problems, the present invention is proposed. Summary of the Invention

[0006] Aiming at the problem that the color value of natural pigments and the smoke quality cannot be taken into account simultaneously in the prior art, the present invention provides a method for preparing a purple corn anthocyanin-dyed cigarette paper, specifically selecting the seeds and corn cobs of purple corn as raw materials, and through a process of directional extraction, gradient purification and synergistic regulation with a mordant, while improving the color value of anthocyanins, significantly reducing the off-flavor components in the smoke after combustion of the dyed cigarette paper, and achieving double optimization of color performance and smoking quality.

[0007] The technical solution adopted by the present invention is as follows:

[0008] In the first aspect of the present invention, a method for preparing purple corn anthocyanin - dyed cigarette paper is provided, and the preparation includes the following steps:

[0009] Step (1): Wash the seeds and cobs of purple corn thoroughly, dry them under temperature control, then crush them. After screening, obtain uniform raw material powder.

[0010] Step (2): According to a predetermined mass ratio, fully mix the raw material powder obtained in step (1) with ethanol or methanol with a concentration of 70% - 75%. Adopt ultrasonic - assisted extraction technology, and perform extraction 2 - 3 times under specified conditions. Combine the filtrates obtained each time to obtain a crude extract of natural anthocyanin.

[0011] Step (3): Load the crude extract of natural purple pigment obtained in the previous step onto an AB - 8 macroporous resin column for adsorption. First, wash with pure water to remove water - soluble impurities. Then, elute with ethanol at a certain concentration, and gradually collect the eluate rich in purple components. After rotary evaporation and concentration of the collected eluate, perform vacuum freeze - drying to obtain natural anthocyanin powder.

[0012] Step (4): Uniformly mix the natural anthocyanin powder obtained in step (3) with deionized water according to a predetermined ratio to form a homogeneous solution. On this basis, add an appropriate amount of mordant, and stir to make the mordant fully dispersed and complex with anthocyanin, thereby preparing purple corn anthocyanin dye.

[0013] Step (5): Apply the purple corn anthocyanin dye to the cigarette paper by impregnation or coating, and dry it naturally or under temperature control to obtain the purple corn anthocyanin - dyed cigarette paper.

[0014] Preferably, in step (1), the mass ratio of the seeds to the cobs of purple corn is 5:1 - 3:1.

[0015] Preferably, in step (2), the raw material powder made from crushed purple corn seeds and cobs is fully mixed with ethanol or methanol with a concentration of 70% - 75% according to a mass ratio of 1:2 - 1:10, and ultrasonic - assisted extraction is carried out at 40°C for 1 - 2 hours. This preferred solution uses ultrasonic technology to effectively break the cell structure at a lower temperature, accelerate the full contact between the solvent and anthocyanin in the purple corn raw material, thereby significantly increasing the dissolution rate of anthocyanin. At the same time, the extraction temperature of 40°C and the treatment time of 1 - 2 hours can effectively avoid the damage of active ingredients caused by long - term high temperature, and ensure the quality and activity of the crude natural pigment.

[0016] Preferably, in step (3), the ethanol elution concentration is 70% - 75%, and the elution flow rate is 3BV.

[0017] Preferably, in the step (4), the mordant is a dry extract of natural sour papaya, and the addition amount is 2%-5% of the mass of the natural anthocyanin powder.

[0018] Preferably, in the step (4), the natural anthocyanin powder is mixed with deionized water at a ratio of 1 g:10 ml - 1 g:50 ml.

[0019] Preferably, in the step (5), when dyeing by the coating method, the dosage of anthocyanin is 2.4 - 4 kg per ton of cigarette paper.

[0020] In the second aspect of the present invention, there is provided a purple corn anthocyanin - dyed cigarette paper prepared by the method described in the first aspect. The purple corn anthocyanin - dyed cigarette paper uses the natural anthocyanin powder prepared by the preparation method of the first aspect as a dye. After the natural anthocyanin powder is configured into an aqueous solution, the DPPH free - radical scavenging rate is ≥65% at a concentration of 25 μg / mL.

[0021] In the third aspect of the present invention, there is provided an application of the purple corn anthocyanin - dyed cigarette paper described in the second aspect in cigarettes. The characteristic is that when the purple corn anthocyanin - dyed cigarette paper is used in cigarettes, the oral residues during the combustion process are significantly reduced. At the same time, the smoke is pure and smooth during suction, no obvious miscellaneous gas is generated, and the suction quality is significantly improved.

[0022] The present invention has the following beneficial effects:

[0023] 1. The present invention uses purple corn seeds and corn cobs as raw materials, and the extracted anthocyanins show higher chromaticity when applied to cigarette paper. The colored cigarette paper made from the extracted natural pigment can endow the cigarette paper with natural and personalized colors, and at the same time meet the needs of consumers for safe products. The cigarette made by rolling the colored cigarette paper prepared by the present invention has no bad smell, high safety, bright and beautiful colors, and is suitable for developing various personalized cigarette products.

[0024] 2. The present invention uses the AB - 8 macroporous resin gradient elution technology as the purification process, and at the same time combines the pre - extraction process of purple corn seeds and corn cobs, realizing the effective retention of its antioxidant activity (DPPH scavenging rate ≥65%) while maintaining the high color value of anthocyanins. After the extracted anthocyanins are applied to cigarettes, the antioxidant effect of anthocyanins can significantly reduce the green and miscellaneous gas and dry and burnt gas in the smoke, and improve the suction quality of cigarettes.

[0025] 3. The present invention selects the dry extract of sour papaya as a mordant to be compounded with anthocyanins, solves the problem of color fastness of natural pigments on cigarette paper, and does not affect the combustion performance of cigarettes. Description of the Drawings

[0026] Figure 1This is a physical picture of a purple corn anthocyanin - dyed cigarette paper in the specific embodiment of the present invention;

[0027] Figure 2 This is the ultraviolet - visible absorption spectrogram of natural anthocyanin in the specific embodiment of the present invention; Specific Embodiment

[0028] The following further elaborates on the present invention in conjunction with the attached drawings and embodiments, but the attached drawings and embodiments do not limit the technical solution of the present invention.

[0029] Embodiment 1

[0030] This embodiment provides a preparation method of purple corn anthocyanin - dyed cigarette paper, including the following steps:

[0031] (1) Extraction of purple corn anthocyanin

[0032] a. Pretreatment of raw materials

[0033] Take purple corn seeds and purple corn cobs. After thorough washing, dry them at 40°C, then mix them in a predetermined mass ratio of 3:1. Crush and screen the mixed raw materials to obtain a powder with a particle size below 90 mesh, which is the uniform raw material powder;

[0034] b. Ultrasonic - assisted extraction

[0035] Mix the raw material powder obtained in step (a) with methanol at a concentration of 70% in a mass ratio of 1:2 of solid to liquid. After sufficient soaking, perform ultrasonic - assisted extraction at 40°C for 1 hour; then, filter the primary extract with gauze, add an appropriate amount of extract to the filter residue for ultrasonic extraction again, collect the two filtrates and combine them. The combined filtrate is first centrifuged, the supernatant is collected, and then filtered with filter paper; finally, rotate and evaporate the obtained filtrate at 40°C until it has basically no alcohol smell to obtain the extract for standby;

[0036] c. Separation and purification

[0037] Pre - treat the AB - 8 macroporous adsorption resin in advance: soak the resin in high - concentration absolute ethanol and let it stand for 24 hours, then repeatedly rinse it with deionized water until all alcohol - soluble impurities are completely removed. Load the rotary evaporation liquid obtained in step (b) into the pre - treated resin column by wet packing (the height of the AB - 8 macroporous resin after packing is 20 cm, and the flow rate is about 3 BV), and let it stand for adsorption for 30 minutes; then rinse the column with pure water to remove water - soluble impurities, and then elute it with ethanol at a concentration of 70%, and collect the eluate with a darker purple color. The collected eluate is concentrated by rotary evaporation until it has no alcohol smell, and then natural anthocyanin powder is prepared by vacuum freeze - drying technology.

[0038] (2) Preparation of the dye solution

[0039] The anthocyanin powder obtained in step (1) is uniformly mixed with deionized water at a mass ratio of 1 g:10 ml to form a homogeneous dye solution, and 3% of the natural acid papaya extract by the mass of the anthocyanin powder is added as a mordant to enhance the dyeing fastness.

[0040] The preparation method of the natural acid papaya extract is as follows: Weigh a certain mass of dried acid papaya, cut it into small pieces, then mix it with distilled water at a ratio of 3 g:100 ml, and then perform ultrasonic treatment for 1 h under the temperature control condition of 50 °C, and collect the solution part to obtain the natural acid papaya extract.

[0041] (3) Cigarette paper dyeing

[0042] The dipping method is adopted: Immerse the blank cigarette paper into the dye solution prepared in step (2), take it out after soaking for about 20 seconds, and squeeze it appropriately to remove the excess dye solution; Subsequently, it can be naturally dried or dried at 50 °C, and finally the purple corn anthocyanin-dyed cigarette paper is obtained, as Figure 1 shown.

[0043] (4) Cigarette rolling experiment

[0044] Manually process the dyed cigarette paper into a cigarette sample, and mark this sample as sample No. 1.

[0045] Example 2

[0046] This example provides a preparation method of purple corn anthocyanin-dyed cigarette paper, including the following steps:

[0047] (1) Purple corn anthocyanin extraction

[0048] a. Raw material pretreatment

[0049] Take purple corn seeds and purple corn cobs, after thorough cleaning, dry them under temperature control at 40 °C, then mix them in a predetermined mass ratio of 4:1, crush and screen the mixed raw materials, and obtain the powder with a mesh size below 90 to get a uniform raw material powder;

[0050] b. Ultrasonic-assisted extraction

[0051] Mix the raw material powder obtained in step (a) with methanol at a concentration of 70% at a solid-liquid mass ratio of 1:10, fully soak it, and then perform ultrasonic-assisted extraction for 1 hour at 40 °C; Subsequently, filter the primary extract with gauze, take the filter residue, add an appropriate amount of extract, and perform ultrasonic extraction again, collect the two filtrates and combine them. The combined filtrate is first centrifuged, the supernatant is collected, and then filtered with filter paper; Finally, the obtained filtrate is rotary evaporated at 40 °C until there is basically no alcohol smell, and the extract is obtained for standby;

[0052] c. Separation and purification

[0053] Pre-treat the AB-8 macroporous adsorption resin in advance: soak the resin in high-concentration absolute ethanol and let it stand for 24 hours, then repeatedly rinse it with deionized water until all alcohol-soluble impurities are completely removed. Load the rotary evaporation liquid obtained in step (b) into the pre-treated resin column by wet packing (the height of the AB-8 macroporous resin after packing is 20 cm, and the flow rate is about 3 BV), and let it stand for adsorption for 30 minutes; then rinse the column with pure water to remove water-soluble impurities, and then elute with 70% ethanol, and collect the eluate with a darker purple color. After the collected eluate is concentrated by rotary evaporation until there is no alcohol smell, natural anthocyanin powder is prepared by vacuum freeze-drying technology.

[0054] (4) Preparation of dye solution

[0055] Mix the anthocyanin powder obtained in step (1) and deionized water evenly at a mass ratio of 1:25 to form a homogeneous dye solution, and add 2% of the natural dry extract of papaya acid by the mass of the anthocyanin powder as a mordant to enhance the dyeing fastness.

[0056] The preparation method of the natural papaya acid extract is as follows: weigh a certain mass of dried papaya, cut it into small pieces, then mix it according to the ratio of 3 g of dried papaya to 100 ml of distilled water, and then ultrasonically treat it for 1 h under the temperature control condition of 50 °C, and collect the solution part to obtain the natural papaya acid extract.

[0057] (5) Cigarette paper dyeing

[0058] Prepare purple corn anthocyanin-dyed cigarette paper by the coating method: the cigarette paper production workshop machine produces dyed cigarette paper, and the coating amount is 100 kg of liquid per ton of consumption (3 kg of purple corn anthocyanin per ton of consumption), and the production process adopts the existing conventional process for producing colored cigarette paper.

[0059] (4) Cigarette rolling experiment

[0060] Use the cigarette making and tipping equipment of the cigarette factory to roll the purple corn anthocyanin-dyed cigarette paper sample, and mark this sample as the 2# sample.

[0061] Example 3

[0062] This example provides a method for preparing purple corn anthocyanin-dyed cigarette paper, which includes the following steps:

[0063] (1) Extraction of purple corn anthocyanin

[0064] a. Raw material pre-treatment

[0065] Take purple corn seeds and purple corn cobs, after thorough cleaning, dry them at a controlled temperature of 40 °C, mix them according to a predetermined mass ratio of 3:1, crush and screen the mixed raw materials, and obtain a powder with a mesh size below 90 to obtain a uniform raw material powder;

[0066] b. Ultrasonic-assisted extraction

[0067] Mix the raw material powder obtained in step (a) with methanol at a concentration of 75% at a solid-liquid mass ratio of 1:5. After sufficient soaking, perform ultrasonic-assisted extraction at 40 °C for 1 hour; then, filter the primary extract with gauze, add an appropriate amount of extract to the filter residue and perform ultrasonic extraction again. After collecting the two filtrates and combining them, centrifuge the combined filtrate, collect the supernatant, and then filter it with filter paper; finally, rotate-evaporate the obtained filtrate at 40 °C until it is basically odorless of alcohol to obtain the extract for standby;

[0068] c. Separation and purification

[0069] Pre-treat the AB-8 macroporous adsorption resin in advance: soak the resin in high-concentration absolute ethanol and let it stand for 24 hours, then repeatedly rinse it with deionized water until all alcohol-soluble impurities are completely removed. Load the rotary evaporation solution obtained in step (b) into the pre-treated resin column by wet packing (the height of the AB-8 macroporous resin after packing is 20 cm, and the flow rate is about 2 BV), and let it stand for adsorption for 30 minutes; then rinse the column with pure water to remove water-soluble impurities, and then elute it successively with ethanol at a gradient concentration of 75%. Collect the eluate with a darker purple color. After the collected eluate is rotary-evaporated and concentrated until it is odorless of alcohol, use vacuum freeze-drying technology to obtain natural anthocyanin powder.

[0070] (2) Preparation of dye solution

[0071] Uniformly mix the anthocyanin powder obtained in step (1) with deionized water at a mass ratio of 1:50 to form a homogeneous dye solution, and add 3% of the natural dried extract of sour papaya by the mass of the anthocyanin powder as a mordant to enhance the dyeing fastness.

[0072] The preparation method of the natural dried extract of sour papaya is as follows: weigh a certain mass of dried sour papaya, cut it into small pieces, then mix it with distilled water at a ratio of 3 g:100 ml of dried sour papaya, and then perform ultrasonic treatment at a controlled temperature of 50 °C for 1 h, and collect the solution part to obtain the natural dried extract of sour papaya.

[0073] (3) Cigarette paper dyeing

[0074] Prepare purple corn anthocyanin-dyed cigarette paper by the coating method: The cigarette paper production workshop machine produces dyed cigarette paper, and the coating amount is 120 kg of liquid per ton of consumption (2.4 kg of purple corn anthocyanin per ton of consumption), and the production process adopts the existing conventional process for producing colored cigarette paper.

[0075] (4) Cigarette rolling experiment

[0076] Use the cigarette making and tipping equipment of the cigarette factory to roll the purple corn anthocyanin-dyed cigarette paper sample, and mark this sample as sample No. 3.

[0077] Example 4

[0078] This example provides a method for preparing purple corn anthocyanin-dyed cigarette paper, which includes the following steps:

[0079] (1) Extraction of purple corn anthocyanin

[0080] a. Pretreatment of raw materials

[0081] Take purple corn seeds and purple corn cobs. After thorough cleaning, dry them at 40°C and mix them in a predetermined mass ratio of 5:1. Crush and screen the mixed raw materials to obtain a powder with a mesh size below 90, and obtain a uniform raw material powder;

[0082] b. Ultrasonic-assisted extraction

[0083] Mix the raw material powder obtained in step (a) with methanol at a concentration of 75% in a mass ratio of 1:8 of solid to liquid. After sufficient soaking, perform ultrasonic-assisted extraction at 40°C for 1 hour; then, filter the primary extract with gauze, take the filter residue, add an appropriate amount of extract, and perform ultrasonic extraction again. After collecting the two filtrates and combining them, centrifuge the combined filtrate, collect the supernatant, and then filter it with filter paper; finally, rotate-evaporate the obtained filtrate at 40°C until it is basically odorless of alcohol to obtain an extraction solution for standby;

[0084] c. Separation and purification

[0085] Pre-treat AB-8 macroporous adsorption resin in advance: soak the resin in high-concentration anhydrous ethanol and let it stand for 24 hours, then repeatedly rinse it with deionized water until all alcohol-soluble impurities are completely removed. Load the rotary evaporation solution obtained in step (b) into the pre-treated resin column by wet packing (the height of AB-8 macroporous resin after packing is 20 cm, and the flow rate is about 3 BV), and let it stand for adsorption for 30 minutes; then rinse the column with pure water to remove water-soluble impurities, and then elute it with ethanol at a concentration of 75%, and collect the eluate with a darker purple color. After the collected eluate is rotary-evaporated and concentrated until it is odorless of alcohol, use vacuum freeze-drying technology to prepare natural anthocyanin powder.

[0086] (2) Preparation of dye solution

[0087] Uniformly mix the anthocyanin powder obtained in step (1) with deionized water in a mass ratio of 1:30 to form a homogeneous dye solution, and add 5% of the mass of the anthocyanin powder of natural acid papaya dry extract as a mordant to enhance the dyeing fastness.

[0088] The preparation method of the natural papaya extract is as follows: Weigh a certain mass of dried papaya, cut it into small pieces, and then mix it with distilled water at a ratio of 3g of dried papaya to 100ml of distilled water. Then, under the temperature control condition of 50°C, perform ultrasonic treatment for 1h, and collect the solution part to obtain the natural papaya extract.

[0089] (3) Cigarette paper dyeing

[0090] Preparation of purple corn anthocyanin - dyed cigarette paper by coating method: In the cigarette paper production workshop, the machine produces dyed cigarette paper, with a coating amount of 120 kg of liquid material per ton of consumption (4 kg of purple corn anthocyanin per ton of consumption). The production process adopts the existing conventional process for producing colored cigarette paper.

[0091] (4) Cigarette rolling experiment

[0092] Use the cigarette making and tipping equipment of a cigarette factory to roll the purple corn anthocyanin - dyed cigarette paper sample, and mark this sample as Sample No. 4.

[0093] Test Example 1

[0094] This test example organizes an example of the average value of the comparative smoking results of the purple corn anthocyanin - dyed cigarette paper samples and the blank cigarette paper - rolled control samples in Examples 1 to 4 by 7 smoking evaluation experts according to "GB5606.4 - 2005 Cigarettes - Part 4: Sensory Technical Requirements". The results are shown in Table 1 below:

[0095] Table 1 Cigarette smoking evaluation results table

[0096]

[0097] The smoking evaluation results show that when the purple corn anthocyanin - dyed cigarette paper is used for cigarettes, during the combustion process, the oral residues are significantly reduced. At the same time, the smoke is pure and smooth during suction, and no obvious miscellaneous odor is generated.

[0098] (2) Color value test

[0099] As Figure 2 shown, using ultraviolet - visible spectrophotometry with an ultraviolet - visible spectrophotometer, measure the absorption spectra of the natural anthocyanin powders prepared in Examples 1 to 4 between 200 and 800 nm. The characteristic curve of the natural anthocyanin is detected at 515 nm, and its absorbance at 515 nm reaches 2.0.

[0100] As mentioned above, the above are only the specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for preparing purple corn anthocyanin-dyed cigarette paper, characterized in that: The preparation comprises the following steps: Step (1), the purple corn seeds and corn cobs are fully cleaned, temperature-controlled and dried, and then crushed and sieved to obtain a uniform raw material powder; Step (2), according to a predetermined mass ratio, the raw material powder obtained in step (1) is fully mixed with 70%-75% ethanol or methanol, and an ultrasonic-assisted extraction technique is used to perform extraction 2 to 3 times under specified conditions, and the filtrates obtained from each extraction are combined to obtain a crude extract of natural anthocyanins; Step (3), loading the crude extract of natural purple pigment obtained in the previous step into an AB-8 macroporous resin column for adsorption; firstly washing with pure water to remove water-soluble impurities; then eluting with a certain concentration of ethanol, gradually collecting the eluate rich in purple components, concentrating the collected eluate by rotary evaporation, and performing vacuum freeze drying to obtain natural anthocyanin powder; Step (4), uniformly mixing the natural anthocyanin powder obtained in step (3) with deionized water in a predetermined ratio to form a homogeneous solution, adding an appropriate amount of mordant to the solution, and stirring the mordant to fully disperse the mordant and complex it with the anthocyanin, thereby preparing a purple corn anthocyanin dye; Step (5), applying the purple corn anthocyanin dye to cigarette paper by dipping or coating, and drying naturally or by temperature-controlled drying to obtain the purple corn anthocyanin-dyed cigarette paper.

2. The method for preparing cigarette paper dyed with purple corn anthocyanin according to claim 1, characterized in that: In the step (1), the mass ratio of purple corn seeds to corn cobs is 5:1-3:

1.

3. The method for preparing cigarette paper dyed with purple corn anthocyanin according to claim 1, characterized in that: In the step (2), the raw material powder is mixed with 70% to 75% ethanol or methanol in a mass ratio of 1:2 to 1:10, and ultrasonic-assisted extraction is performed at 40° C. for 1 to 2 hours.

4. The method for preparing cigarette paper dyed with purple corn anthocyanin according to claim 1, characterized in that: In the step (3), the ethanol elution concentration is 70%-75%, and the elution flow rate is 3BV.

5. The method for preparing cigarette paper dyed with purple corn anthocyanin according to claim 1, characterized in that: In the step (4), the mordant is a natural acid papaya dry extract, and the added amount is 2%-5% of the mass of the natural anthocyanin powder.

6. The method for preparing cigarette paper dyed with purple corn anthocyanin according to claim 1, characterized in that: In the step (4), the natural anthocyanin powder is mixed with deionized water at a ratio of 1 g:10 ml to 1 g:50 ml.

7. The method for preparing cigarette paper dyed with purple corn anthocyanin according to claim 1, characterized in that: When dyeing by coating method in step (5), the amount of anthocyanin used is 2.4-4 kg / ton of cigarette paper.

8. A purple corn anthocyanin-dyed cigarette paper prepared by any one of claims 1 to 7, characterized in that: The purple corn anthocyanin dyed cigarette paper uses the natural anthocyanin powder prepared by the preparation method of claim 1 as a dye, and the natural anthocyanin powder is configured into an aqueous solution, and the DPPH free radical scavenging rate is ≥65% at a concentration of 25 ug / mL.

9. Use of the purple corn anthocyanin-dyed cigarette paper according to claim 8 in cigarettes, characterized in that: When the purple corn anthocyanin-dyed cigarette paper is used for cigarettes, oral cavity residues are significantly reduced during the combustion process, and smoke is pure and smooth during inhalation without obvious generation of impurities.

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