Method for preparing konjak filter stick by using gradient alkalization technology

Abstract

The invention belongs to the technical field of cigarette filter stick manufacturing, and particularly relates to a method for preparing a konjak filter stick through a gradient alkalization technology. According to the method, konjac fine powder sol is sequentially subjected to gradient alkalization treatment through coagulating baths with different alkali concentrations, and an extrusion forming process is combined, so that the konjac filter stick with a pore structure and performance is prepared. According to the invention, step-by-step gelation of the konjac powder is realized by using gradient alkali concentration, the crosslinking degree and the pore structure of the filter stick are effectively regulated and controlled, and the mechanical strength, the adsorption performance and the filtering efficiency of the filter stick are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cigarette filter rod manufacturing, and particularly relates to a method for preparing a konjac filter rod by using a gradient alkali treatment technology. BACKGROUND

[0002] Konjac is an important characteristic agricultural product, and its main component is konjac glucomannan. Konjac glucomannan is a natural high molecular polysaccharide, has good water solubility, gelation, thickening and biocompatibility, and has a wide application in the fields of food, medicine, chemical industry, environmental protection and the like. The cigarette filter rod material prepared by using the gelation property of konjac glucomannan has a potential application value in the field of filtration and separation due to its porous structure, large specific surface area and good adsorption performance.

[0003] The traditional konjac gel preparation method usually adopts a single concentration of alkali solution for coagulation, and the alkali concentration and treatment time are key factors affecting the gel performance. However, the single high-concentration alkali solution is easy to cause rapid cross-linking of the glucomannan molecules, and the formed gel structure is dense and uneven, and the internal stress is large, thereby affecting the mechanical strength and pore connectivity of the filter rod; and the single low-concentration alkali solution has a slow cross-linking reaction, low production efficiency, and insufficient gel strength.

[0004] In order to solve the above problems, the present application is proposed. SUMMARY

[0005] The present application aims at overcoming the deficiencies of the prior art, and provides a method for preparing a konjac filter rod by using a gradient alkali treatment technology. The method realizes step-by-step gelation of konjac glucomannan by gradient alkali concentration treatment, can effectively regulate the pore structure and performance of the filter rod, and improves the mechanical strength, adsorption performance and filtration efficiency thereof.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The first aspect of the present application provides a method for preparing a konjac filter rod by using a gradient alkali treatment technology, comprising the following steps:

[0008] (1) Preparation of konjac powder sol: according to the mass ratio of konjac powder to water being 1:5-1:20, the konjac powder is dispersed in water, uniformly stirred, and then heated at 60-95℃ for 10-60 minutes to obtain a uniform konjac powder sol.

[0009] The ratio of konjac powder to water directly affects the concentration of the sol and the subsequent forming performance, and a too high ratio is not conducive to extrusion due to too large viscosity of the sol, and a too low ratio is insufficient in gel strength.

[0010] Preferably, the konjac powder is konjac fine powder.

[0011] The purpose of heating gelatinization is to make konjac glucomannan molecules fully hydrated and swollen and form a uniform sol system. Temperature and time are key parameters. Preferably, heating is performed at 75-90°C for 20-40 minutes. Under this condition, gelatinization is ensured, and polysaccharide degradation caused by long time and high temperature is avoided.

[0012] (2) Configuration of gradient alkali concentration coagulation bath: at least two stages of coagulation baths with different alkali concentrations are configured, and the alkali concentration of each stage of coagulation bath is sequentially increased.

[0013] The setting of alkali concentration gradient is the core of the present application. The initial low alkali concentration can slowly crosslink the surface layer of the extruded sol strip to form a preliminary "shell", which is beneficial to maintaining its shape and preventing subsequent excessive swelling or deformation in high concentration alkali. The subsequent gradually increasing alkali concentration can promote further crosslinking inside the gel, thereby improving the overall crosslinking density and structural stability. The type of alkali is selected from common alkalis such as sodium hydroxide, potassium hydroxide or calcium hydroxide, which can effectively induce the deacetylation and crosslinking reaction of konjac glucomannan. The alkali concentration of the first stage coagulation bath is controlled at 0.5-2.0wt%, and the alkali concentration of the last stage coagulation bath is controlled at 2.5-6.0wt%. The number of stages of the coagulation bath is preferably 2-4 stages. Too many stages will increase the complexity of the equipment and the operation cost, and too few stages will not have obvious gradient effect. For example, when using three-stage coagulation bath, the alkali concentration of each stage can be set as 0.8-1.5wt%, 2.0-3.5wt%, and 4.0-5.5wt%, respectively, to form a reasonable gradient increase.

[0014] (3) Gradient alkalinization extrusion molding: the konjac glucomannan sol is continuously extruded into a strip shape through an extrusion device with a specific pore size mold (pore size 10-20mm, selected according to the required filter rod diameter). The extruded strip-shaped sol needs to be sequentially treated in each stage of coagulation bath. In each stage of coagulation bath, the alkali penetrates into the interior of the sol and reacts with the glucomannan molecules to form a gel. The treatment time in each stage of coagulation bath is 5-30 minutes, and the bath temperature is 20-50°C. Too short treatment time will not fully alkalinize, and too long treatment time will be inefficient. Higher bath temperature can accelerate the reaction rate, but too high bath temperature may cause rough gel structure. The present application can accurately control the crosslinking degree of each stage by controlling the treatment time and bath temperature of each stage.

[0015] (4) Post-treatment: the strip-shaped gel after gradient alkalinization already has a basic structure and shape. After being taken out, it is washed with water to remove residual alkali and unreacted small molecules. The washing liquid is neutral until the washing liquid is neutral, which is crucial to ensure the stability of the filter rod in subsequent application and to avoid pollution to the filtered material.

[0016] The washed wet gel is dried, and the drying method is selected as freeze-drying, which can better maintain the original porous structure of the gel, and the filter rod has certain strength and necessary porosity at this time.

[0017] Preferably, the dried rod is cut into a length of 5-200 mm as needed to obtain the final konjac filter rod product.

[0018] The second aspect of the present application provides a konjac filter rod prepared by any of the above-mentioned methods.

[0019] The third aspect of the present application provides the use of the above-mentioned konjac filter rod in a heated cigarette.

[0020] In use, the konjac filter rod is wrapped with paper, and then, as a filter rod segment, it is rolled with other segments such as a smoking segment, a hollow cooling segment, etc. to obtain a heated cigarette.

[0021] The beneficial effects of the present application are:

[0022] 1. The gradient alkali concentration extrusion molding technology is adopted to realize step-by-step and gradual cross-linking gelation of konjac glucomannan. Compared with the traditional single high-concentration alkali one-time solidification, the problem of rapid excessive cross-linking on the surface and insufficient cross-linking inside is effectively avoided, so that the cross-linking degree and structure distribution of the prepared filter rod from the surface to the inside are more uniform and reasonable, thereby significantly improving the overall mechanical strength and structural stability of the filter rod and reducing the damage during use.

[0023] 2. By adjusting the alkali concentration gradient, solidification time and temperature and other parameters, the micro-pore structure (such as pore size, distribution, porosity, etc.) of the konjac filter rod can be accurately controlled. This controllability enables the filter rod to adapt to different filtration needs, such as obtaining a filter rod with a specific pore size distribution by adjusting the process parameters to improve the adsorption and filtration efficiency of specific particle size materials.

[0024] 3. The method of the present application is simple, uses continuous extrusion and gradient coagulation bath treatment, is easy to realize industrialized continuous production, and has low production cost. The prepared konjac filter rod uses natural konjac glucomannan as raw material, has good biocompatibility and degradability, and belongs to an environmentally friendly material.

[0025] 4. The prepared konjac filter rod combines the inherent properties of konjac glucomannan gel (such as high water absorption, certain ion exchange capacity and adsorption performance) and the optimized microstructure. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The photo is of the konjac filter rod of Example 1.

[0027] Figure 2 The photo is of the konjac filter rod of Example 3.

[0028] Figure 3 A konjac filter rod photo of Comparative Example 1. DETAILED DESCRIPTION

[0029] The present application will be further described in conjunction with the following examples.

[0030] It will be appreciated by those skilled in the art that the following examples are given by way of illustration only and not as limitations of the present application. In the examples, unless specifically indicated otherwise, the technical or conditions are as described in the literature or as per the product manual. In the examples, unless specifically indicated otherwise, the materials or apparatuses used are commercially available.

[0031] As will be understood by those familiar with the art, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. In this disclosure, "multiple" means two or more, unless otherwise specifically indicated.

[0032] In the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are used only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0033] In addition, the terms "first", "second", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can include one or more of the features explicitly or implicitly. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0034] In the present application, unless specifically defined otherwise or limited in context, the terms "mount", "connect", "connection", "fixed", and like terms are used generally and exemplarily, for example, can be a connection, or detachable connection, or integrated; can be a mechanical connection, or electrical connection; can be a direct connection, or indirect connection via an intermediate medium, or internal communication of two elements, or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In the present application, unless specifically defined otherwise or limited in context, the terms "mount", "connect", "connection", "fixed", and like terms are used generally and exemplarily, for example, can be a connection, or detachable connection, or integrated; can be a mechanical connection, or electrical connection; can be a direct connection, or indirect connection via an intermediate medium, or internal communication of two elements, or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present application.

[0037] Those skilled in the art can understand that, unless otherwise defined, all terms used herein, including technical terms and scientific terms, have the same meaning as that generally understood by those skilled in the art to which the present application belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have meanings consistent with those in the context of the prior art, and should not be interpreted with idealized or overly formal meanings unless defined as such.

[0038] Embodiment 1

[0039] (1) Preparation of konjac glucomannan sol: 10 g of konjac powder was dispersed in 100 g of deionized water, and after stirring uniformly, it was heated in a water bath at 85°C for 30 minutes to obtain konjac glucomannan sol.

[0040] (2) Configuration of the gradient alkali concentration coagulation bath: three-stage coagulation bath was configured. First stage: sodium hydroxide concentration 1.0wt%, bath temperature 30℃; second stage: sodium hydroxide concentration 3.0wt%, bath temperature 30℃; third stage: sodium hydroxide concentration 5.0wt%, bath temperature 30℃.

[0041] (3) Gradient alkalinization extrusion molding: the sol was extruded into a strip through an extrusion die with a pore size of 20mm, and sequentially entered the above-mentioned three-stage coagulation bath, and the treatment time of each stage was 15 minutes.

[0042] (4) Post-treatment: the strip-shaped gel was taken out, washed with deionized water until pH=7, and then freeze-dried at -60℃ to a moisture content of about 10wt%, and cut into konjac filter rods with a length of 260mm.

[0043] Example 2

[0044] (1) Preparation of konjac glucmannan sol: 15g konjac powder was dispersed in 225g deionized water (mass ratio 1:15), and after uniform stirring, it was heated and gelatinized at 90℃ for 25 minutes to obtain a konjac glucmannan sol.

[0045] (2) Configuration of the gradient alkali concentration coagulation bath: two-stage coagulation bath was configured. First stage: potassium hydroxide concentration 0.8wt%, bath temperature 25℃; second stage: potassium hydroxide concentration 4.5wt%, bath temperature 25℃.

[0046] (3) Gradient alkalinization extrusion molding: the sol was extruded into a strip through an extrusion die with a pore size of 20mm, and sequentially entered the two-stage coagulation bath, with a treatment time of 20 minutes in the first stage and 10 minutes in the second stage.

[0047] (4) Post-treatment: the strip-shaped gel was taken out, washed with deionized water until neutral, and then freeze-dried at -60℃ to a moisture content of about 8wt%, and cut into konjac filter rods with a length of 260mm.

[0048] Subsequently, the konjac filter rods can be dyed according to customer requirements.

[0049] Example 3

[0050] (1) Preparation of konjac glucmannan sol: 8g konjac powder was dispersed in 120g deionized water (mass ratio 1:15), and after uniform stirring, it was heated and gelatinized at 75℃ for 40 minutes to obtain a konjac glucmannan sol.

[0051] (2) Configuration of the gradient alkali concentration coagulation bath: configure four-stage coagulation bath. First stage: mixed alkali of sodium hydroxide and calcium hydroxide (mass ratio 1:1) concentration 0.5wt%, bath temperature 40℃; second stage: mixed alkali concentration 1.8wt%, bath temperature 40℃; third stage: mixed alkali concentration 3.5wt%, bath temperature 40℃; fourth stage: mixed alkali concentration 5.5wt%, bath temperature 40℃.

[0052] (3) Gradient alkalinization extrusion molding: extrude the sol into a strip through an extrusion die with a pore size of 20mm, and sequentially enter the four-stage coagulation bath, each stage processing time being 10 minutes.

[0053] (4) Post-treatment: take out the strip-shaped gel, wash with deionized water until neutral, freeze-dry (-60℃, vacuum degree 10Pa, sublimation drying for 24 hours), and cut into konjac filter rods with a length of 260mm.

[0054] Comparative Example 1

[0055] (1) Preparation of konjac glucmannan sol: disperse 10g konjac powder in 100g deionized water, uniformly stir, and then heat in a water bath at 85℃ for 30 minutes to obtain konjac glucmannan sol.

[0056] (2) Configuration of alkali concentration coagulation bath: configure coagulation bath: sodium hydroxide concentration 1.0wt%, bath temperature 30℃.

[0057] (3) Gradient alkalinization extrusion molding: extrude the sol into a strip through an extrusion die with a pore size of 20mm, and enter the above coagulation bath, processing time being 45 minutes.

[0058] (4) Post-treatment: take out the strip-shaped gel, wash with deionized water until pH=7, then freeze-dry at -60℃ to a moisture content of about 10wt%, and cut into konjac filter rods with a length of 260mm. Compared with the

[0059] Comparative Example 2

[0060] (1) Preparation of konjac glucmannan sol: disperse 10g konjac powder in 100g deionized water, uniformly stir, and then heat in a water bath at 85℃ for 30 minutes to obtain konjac glucmannan sol.

[0061] (2) Configuration of alkali concentration coagulation bath: configure coagulation bath: sodium hydroxide concentration 5.0wt%, bath temperature 30℃.

[0062] (3) Gradient alkalinization extrusion molding: extrude the sol into a strip through an extrusion die with a pore size of 20mm, and enter the above coagulation bath, processing time being 45 minutes.

[0063] (4) Post-processing: The strip-shaped gel was taken out, washed with deionized water until pH=7, then freeze-dried at -60℃ until the moisture content was about 10wt%, and cut into konjac filter rods with a length of 260mm.

[0064] Performance test:

[0065] The performance of the konjac filter rods obtained from the examples and comparative examples was tested, and the pore size range, porosity, and mechanical strength were tested. The results are shown in Table 1 below. The testing methods for the pore size range, porosity, and mechanical strength were conventional methods in the art.

[0066] Table 1

[0067]

[0068] As can be seen from Table 1:

[0069] Compared with the comparative examples, the gradient alkalization extrusion molding used in the present application can improve the size and uniformity of the pore size of the konjac filter rod, improve the porosity, satisfy the adsorption effect while ensuring the air permeability, and not affect the smoking comfort of the consumer, and improve the mechanical strength so that it meets the requirements of the filter rod forming machine and meets the requirements of mass production applications.

Claims

1. A method for preparing konjac filter rods using gradient alkalization technology, characterized in that, The method includes the following steps: (1) Preparation of konjac powder sol: Disperse konjac powder in water, stir evenly, and heat at 60-95℃ for 10-60 minutes to gelatinize and obtain konjac glucomannan sol; (2) Preparation of gradient alkali concentration coagulation bath: Prepare at least two stages of coagulation bath with different alkali concentrations, with the alkali concentration of each stage of coagulation bath increasing sequentially, wherein the alkali concentration of the first stage coagulation bath is 0.5-2.0wt% and the alkali concentration of the last stage coagulation bath is 2.5-6.0wt%; the alkali is at least one of sodium hydroxide, potassium hydroxide or calcium hydroxide. (3) Gradient alkalization extrusion molding: The konjac powder sol prepared in step (1) is continuously extruded into strips through an extrusion device and sequentially entered into the various stages of coagulation baths prepared in step (2) for gradient alkalization treatment to obtain strip gels; The processing time in each coagulation bath is 5-30 minutes, and the bath temperature is 20-50℃; (4) Post-processing: The strip gel after step (3) gradient alkalization treatment is taken out from the last coagulation bath, washed with water until neutral, and then dried and cut to obtain konjac filter rods.

2. The method according to claim 1, characterized in that, In step (1), the mass ratio of konjac powder to water is 1:5-1:

20.

3. The method according to claim 1, characterized in that, In step (1), the temperature for heating and gelatinization is 75-90℃, and the time is 20-40 minutes.

4. The method according to claim 1, characterized in that, In step (2), the coagulation bath has 2-4 stages.

5. The method according to claim 1, characterized in that, In step (2), when the coagulation bath is three-stage, the alkali concentrations of each coagulation bath are 0.8-1.5wt%, 2.0-3.5wt%, and 4.0-5.5wt%, respectively.

6. The method according to claim 1, characterized in that, In step (3), the diameter of the extrusion die of the extrusion device is 10-20 mm.

7. The method according to claim 1, characterized in that, In step (3), the treatment time in each coagulation bath is 10-20 minutes, and the bath temperature is 25-40℃.

8. The method according to claim 1, characterized in that, In step (4), the drying is freeze drying, and the moisture content is 5-15 wt%.

9. A konjac filter rod prepared by the method according to any one of claims 1-8.

10. The application of the konjac filter rod according to claim 1 in heated cigarettes.

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