Biomass straw and method for preparing the same

Abstract

The present application relates to a kind of biomass drinking straw and its multiple composite modification preparation method.The multiple composite modification preparation method of the biomass drinking straw, specifically includes the following steps:S1, enzyme denatured starch preparation:S2, malic esterification modified bamboo powder preparation:S3, enzyme denatured starch and malic esterification modified bamboo powder are mixed to obtain mixture A, wherein enzyme denatured starch accounts for 30%-70%, and composite plasticizer is added to mix, then put into self-sealing bag and balanced at room temperature, then extruded;Balanced mixture is extruded using extrusion equipment, and is cooled and dried to obtain drinking straw.The multiple composite modification preparation method of the biomass drinking straw, molecular structure modification is carried out on starch using composite enzyme method, crosslinking esterification modification is carried out on bamboo powder using green organic acid malic acid, and enzyme modified starch and acid modified bamboo powder are compounded to prepare a kind of biomass drinking straw with low price, high strength, high toughness, can be completely natural degradation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of modified composite materials, and particularly relates to a biomass straw and a multi-element composite modification preparation method thereof. BACKGROUND

[0002] Non-degradable plastic straws are considered to be a kind of garbage with relatively great harm due to small volume, light weight and difficulty in recycling. Food and beverage industries all over the country actively seek to use degradable straws to replace traditional plastic straws. At present, there are mainly two kinds of paper straws and polylactic acid (PLA) straws on the market. The service performance of paper straws is poor, which is easy to soften and rot in hot drinks. Although the service performance of PLA straws is close to that of traditional plastic straws, in terms of raw material cost, the cost of PLA straws (about 0.05 yuan per straw) is much higher than that of plastic straws (about 0.01 yuan per straw) and paper straws (about 0.03 yuan per straw), which limits its application. In addition, other degradable straws on the market also have problems such as poor service performance, high cost, and difficulty in mass production, such as bamboo straws (not durable, easy to break, prone to mold, limited resources, complex processing, and need to be washed by hand and polished by hand), glass straws (fragile, difficult to store, high price, etc.), metal straws (not easy to clean, metal taste, etc.), and wheat straw straws (not solid, easy to break, etc.). Therefore, it is an urgent task to develop a degradable straw that can completely replace traditional plastic straws, with low production cost, good product performance, and complete degradation.

[0003] Starch is a kind of natural polymer compound, which has the advantages of wide raw material, multiple varieties, high yield, low price, and complete degradation in natural environment (product is CO2 and H2O), and has broad market development prospects. Especially, starch is widely favored by the food packaging industry due to its green, safe and edible nature. However, although there are starch straw products on the market at present, almost all of them have problems such as easy brittle fracture of the straw, easy swelling, breaking and flocculent dissolution in hot drinks, which seriously restricts the large-scale production and application of starch straws. Modified starch is a kind of starch that is treated by physical, chemical or enzymatic method to improve the performance of starch and expand its application range. New functional groups are introduced into the starch molecules or the size and particle properties of the starch molecules are changed, so that the natural properties of the starch are changed to make it more suitable for certain applications. The ordered and compact arrangement of the molecules of the original starch after modification will significantly improve the mechanical, barrier and hydrophobic properties of the starch straw.

[0004] Bamboo flour, a natural polymer material, offers advantages such as low cost, high strength, low density, good mechanical properties, and complete biodegradability. However, because bamboo flour is rich in cellulose, hemicellulose, and lignin, it is incompatible with starch. The resulting composite material exhibits poor mechanical properties, such as low strength, brittleness, difficulty bending, and a lack of toughness. Consequently, the combination of bamboo flour and starch to create biomass straws is rare in existing technologies. Summary of the Invention

[0005] The purpose of the present invention is to provide a biomass straw and a multi-component composite modification preparation method thereof in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] A biomass straw and a multi-component composite modification preparation method thereof, characterized by comprising the following steps:

[0008] S1. Preparation of enzyme-modified starch:

[0009] S101, mixing plant starch with phosphate buffer, gelatinizing in boiling water, and then adjusting to a suitable temperature;

[0010] S102, performing enzymatic hydrolysis on the mixture;

[0011] S103, after the enzymatic hydrolysis treatment, an enzyme inactivation operation is performed, followed by an aging and retrogradation treatment, washing with water, centrifugation, and drying to obtain enzyme-modified starch;

[0012] S2. Preparation of malic acid esterified modified bamboo powder:

[0013] S201, mixing bamboo powder with sulfuric acid solution in a certain proportion, and after the reaction is completed, terminating the acid hydrolysis reaction with deionized water and removing the sulfuric acid;

[0014] S202, dialyzing with deionized water to obtain a suspension with a neutral pH, and concentrating the suspension to adjust the pH of the concentrate;

[0015] S203, mixing a certain proportion of malic acid into the concentrate, and performing a malic acid esterification reaction at a certain temperature;

[0016] S204, drying at 45°C, grinding, and sieving to obtain malic acid esterified modified bamboo powder;

[0017] S3. Preparation of biomass straws:

[0018] S301, mixing enzyme-modified starch and malic acid esterified modified bamboo powder to obtain a mixture A, wherein the enzyme-modified starch accounts for 30%-70%, adding a composite plasticizer, and mixing, then placing the mixture in a ziplock bag, equilibrating at room temperature, and then extruding;

[0019] S302: The balanced mixture is extruded using an extrusion device and cooled and dried.

[0020] Furthermore, in step S101, the plant starch is corn starch, the volume of the phosphate buffer is 100 mL, and the boiling water gelatinization time is 1 h.

[0021] Furthermore, in step S102, the specific steps are:

[0022] The gelatinized mixture was placed in a 50°C water bath and allowed to stabilize for 10 minutes. 4 U / g α-amylase (based on dry starch) was added and allowed to react for 30 minutes. The mixture was inactivated in a boiling water bath for 20 minutes, cooled to 65°C, and then 500 U / g branching enzyme (based on dry starch) was added and allowed to react for 20 minutes. After inactivating the enzyme in a boiling water bath for 20 minutes, the mixture was placed in a 47°C water bath and 40 U / g pullulanase (based on dry starch) was added and allowed to react for 24 hours.

[0023] Furthermore, in step S103, the specific steps are: inactivating the enzyme in the mixture by boiling water for 20 minutes, aging at 4°C for 24 hours, washing with water and centrifuging, washing the starch with anhydrous ethanol, centrifuging and drying to obtain enzyme-modified starch.

[0024] Furthermore, in step S201, the concentration of the sulfuric acid solution is 60%, the ratio of the bamboo powder to the sulfuric acid solution is 1:5, the unit is w / v, the reaction time is 50 minutes, the deionized water is 15 times the product, and a high-speed centrifuge is used to remove sulfuric acid through water exchange / centrifugal circulation.

[0025] Furthermore, in step S202, the specific steps are as follows: dialyzing the suspension with deionized water to obtain a suspension with a neutral pH, concentrating the suspension to a concentration of 8% using a rotary evaporator, and then adjusting the pH of the concentrate to 3-4 using 0.1 mol / L hydrochloric acid.

[0026] Furthermore, in step S203, the ratio of the concentrate to malic acid is 3:1, the unit is w / w, the mixing time is 10 minutes, the reaction temperature is 140° C., and the reaction time is 1 hour.

[0027] Furthermore, in step S301, the composite plasticizer accounts for 20% of the mixture A, and the composite plasticizer is a mixture of 5 parts of water, 3 parts of glycerol and 2 parts of erythritol.

[0028] Furthermore, in step S302, the extrusion equipment is a three-screw extruder, and the extrusion temperature is divided into three temperature-controlled zones from the extrusion outlet to the extrusion inlet: zone 1 temperature is 90°C, zone 2 temperature is 95°C, and zone 3 temperature is 85°C. The sample is extruded from the die head and cooled at room temperature for 48 hours. The straws are then dried at 40°C to a moisture content of 7.0%.

[0029] As a further optimization solution of the present invention, the present invention also provides a biomass straw, which is prepared according to the above-mentioned biomass straw and the multi-component composite modification preparation method thereof.

[0030] The beneficial effects of the present invention are as follows: the present invention utilizes a composite enzyme method to modify the molecular structure of starch, utilizes green organic acid malic acid to perform cross-linking esterification modification on bamboo powder, and composites the enzyme-modified starch and acid-modified bamboo powder to prepare a biomass straw that is low in price, high in strength, high in toughness, and can be completely naturally degraded. The straw has high toughness, is not prone to deformation and deterioration, and has a long storage time, reducing failure or safety issues caused by material deterioration. The straw is more stable at high temperatures, is not prone to deformation, and can better resist corrosion from chemical substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart for preparing the biomass straws of the present invention;

[0032] Figure 2 This is an appearance diagram of the biomass straw of the present invention;

[0033] Figure 3 XRD patterns of the biomass straws of the present invention (a.70:30; b.60:40; c.50:50; d.40:60; e.30:70);

[0034] Figure 4 XRD patterns of aging composite straws with different ratios of enzyme-modified starch / acid-modified bamboo powder after being placed at room temperature for 30 days (a.70:30; b.60:40; c.50:50; d.40:60; e.30:70). DETAILED DESCRIPTION

[0035] The present application is described in further detail below in conjunction with the accompanying drawings. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0036] A biomass straw and its multi-component composite modification preparation method uses corn starch as raw material. First, the starch is enzymatically hydrolyzed using α-amylase, branching enzyme, and pullulanase to prepare enzyme-modified starch with orderly and compact molecular arrangement, significantly improving the starch's crack resistance and hydrophobicity. Second, bamboo powder is esterified with the natural organic acid L-malic acid to improve its viscoelasticity and toughness. The specific steps include:

[0037] Weigh a certain amount of corn starch, add 100mL phosphate buffer, mix thoroughly and gelatinize in a boiling water bath for 1h, cool to room temperature, place in a 50℃ water bath, stabilize for 10min, add 4U / g α-amylase (based on dry starch), and react for 30min. After inactivating the enzyme in a boiling water bath for 20min, cool to 65℃ and then add branching enzyme (500U / g, based on dry starch) and react for 20min. After inactivating the enzyme in a boiling water bath for 20min, place in a 47℃ water bath, add 40U / g pullulanase (based on dry starch), and react for 24h. After inactivating the enzyme in a boiling water bath for 20min, place at 4℃ for aging and regeneration for 24h. Wash the starch with anhydrous ethanol after centrifugation, and dry it after centrifugation to obtain enzyme-modified starch.

[0038] A certain amount of bamboo powder was weighed and added to a 60% sulfuric acid solution at a ratio of 1:5 (w / v), stirring and mixing. The mixture was stirred at room temperature for 50 minutes. After the reaction, the product was poured into 15 times the volume of deionized water to terminate the acidolysis reaction. The sulfuric acid was removed using a high-speed centrifuge through a water exchange / centrifugation cycle. The suspension was then dialyzed against deionized water to obtain a neutral pH suspension. The suspension was concentrated to a concentration of 8% using a rotary evaporator. The pH of the concentrate was then adjusted to 3-4 using 0.1 mol / L hydrochloric acid. Malic acid was then added at a ratio of 3:1 (w / w), stirring and mixing for 10 minutes, and then heated in an oil bath at 140°C for 1 hour. After the reaction, the mixture was removed and washed several times with distilled water to remove excess unreacted malic acid. The filter cake was then dried in an oven at 45°C, ground into a powder in a mortar, and sieved to obtain malic acid-esterified modified bamboo powder.

[0039] Example 1

[0040] The enzyme-modified starch and malic acid-esterified modified bamboo powder were mixed at a ratio of (70:30, w / w) and a composite plasticizer (20%, based on the dry basis of the main ingredients) in a blender at a constant speed for 15 minutes, wherein the plasticizer was a mixture of water: glycerol: erythritol (4:4:2, w / w / w);

[0041] After the mixture is thoroughly mixed, it is placed in a ziplock bag and allowed to equilibrate at room temperature (25°C, RH = 53%) for 24 hours before extrusion. A three-screw extruder is used, and the extrusion temperature is divided into three temperature control zones from the extrusion outlet to the extrusion inlet: zone 1 temperature 85°C, zone 2 temperature 90°C, and zone 3 temperature 90°C;

[0042] The sample was extruded from the die and cooled at room temperature for 24 h, and then the straw was dried at 35° C. to a constant moisture content (7.0%).

[0043] Example 2

[0044] The enzyme-modified starch and malic acid-esterified modified bamboo powder were mixed at a ratio of (60:40, w / w) and a composite plasticizer (20%, based on the dry basis of the main ingredients) in a blender at a constant speed for 15 minutes, wherein the plasticizer was a mixture of water: glycerol: erythritol (6:3:1, w / w / w);

[0045] After the mixture is thoroughly mixed, it is placed in a ziplock bag and allowed to equilibrate at room temperature (25°C, RH = 53%) for 24 hours before extrusion. A three-screw extruder is used, and the extrusion temperature is divided into three temperature control zones from the extrusion outlet to the extrusion inlet: zone 1 temperature 95°C, zone 2 temperature 100°C, and zone 3 temperature 95°C;

[0046] The sample was extruded from the die and cooled at room temperature for 36 h, and then the straw was dried at 40° C. to a constant moisture content (7%).

[0047] Example 3

[0048] The enzyme-modified starch and malic acid-esterified modified bamboo powder were mixed at a ratio of 50:50, w / w, and a composite plasticizer (20%, based on the dry basis of the main ingredients) was stirred at a constant speed in a blender for 15 minutes, wherein the plasticizer was a mixture of water: glycerol: erythritol (5:3:2, w / w / w);

[0049] After the mixture is thoroughly mixed, it is placed in a ziplock bag and allowed to equilibrate at room temperature (25°C, RH = 53%) for 24 hours before extrusion. A three-screw extruder is used, and the extrusion temperature is divided into three temperature control zones from the extrusion outlet to the extrusion inlet: zone 1 temperature 90°C, zone 2 temperature 95°C, and zone 3 temperature 85°C;

[0050] The sample was extruded from the die and cooled at room temperature for 48 h, and then the straw was dried at 40° C. to a constant moisture content (7.0%).

[0051] Example 4

[0052] The enzyme-modified starch and malic acid-esterified modified bamboo powder were mixed at a ratio of (40:60, w / w) and a composite plasticizer (20%, based on the dry basis of the main ingredients) in a blender at a constant speed for 15 minutes, wherein the plasticizer was a mixture of water: glycerol: erythritol (4:2:4, w / w / w);

[0053] After the mixture is thoroughly mixed, it is placed in a ziplock bag and allowed to equilibrate at room temperature (25°C, RH = 53%) for 24 hours before extrusion. A three-screw extruder is used, and the extrusion temperature is divided into three temperature control zones from the extrusion outlet to the extrusion inlet: zone 1 temperature 95°C, zone 2 temperature 105°C, and zone 3 temperature 95°C;

[0054] The sample was extruded from the die and cooled at room temperature for 48 h, and then the straw was dried at 50° C. to a constant moisture content (7.0%).

[0055] Example 5

[0056] The enzyme-modified starch and malic acid-esterified modified bamboo powder were mixed at a ratio of (30:70, w / w) and a composite plasticizer (20%, based on the dry basis of the main ingredients) in a blender at a constant speed for 15 minutes, wherein the plasticizer was a mixture of water: glycerol: erythritol (4:3:3, w / w / w);

[0057] After the mixture is thoroughly mixed, it is placed in a ziplock bag and allowed to equilibrate at room temperature (25°C, RH = 53%) for 24 hours before extrusion. A three-screw extruder is used, and the extrusion temperature is divided into three temperature control zones from the extrusion outlet to the extrusion inlet: zone 1 temperature 80°C, zone 2 temperature 90°C, and zone 3 temperature 85°C;

[0058] The sample was extruded from the die and cooled at room temperature for 36 h, and then the straw was dried at 40° C. to a constant moisture content (7.0%).

[0059] Extract the straw samples prepared in Examples 1-5 ( Figure 2 (upper left picture) for performance testing:

[0060] Test 1

[0061] Soak the five groups of samples in 70℃ hot water for 30 minutes and record their appearance after soaking. Figure 2 As shown in the upper right image, straw C, prepared in Example 3, exhibits the least swelling upon water absorption. This indicates that the straw does not significantly expand upon contact with liquid and maintains its original structure and shape. This helps prevent deformation or loss of function during use, thereby providing a more stable user experience. Furthermore, the straw is less susceptible to deformation and deterioration during long-term use, thereby extending its service life and reducing the need for frequent replacement.

[0062] Test 2

[0063] The bending tests were carried out on five groups of samples respectively. The test results are as follows: Figure 2As shown in the following figure, the bending degree of the straw c is the largest, which indicates that the straw prepared in Example 3 is softer and can better adapt to different containers and use angles, providing greater use flexibility. In some cases, the greater bending degree can increase the comfort during use, especially for beverage containers that require a larger bending angle.

[0064] Test 3

[0065] X-ray diffraction experiments were performed on the five groups of samples respectively, and the test results are shown in Table 1. Figure 3 As can be seen from the diffraction intensity of the straw c is the largest, the sample with large diffraction intensity usually has high crystallinity, high crystallinity material usually has better compression and tensile strength, is more stable at high temperature, is not easy to deform, can resist chemical substances better, and helps the material to maintain stable shape and size during processing.

[0066] Test 4

[0067] X-ray diffraction experiments were performed on the five groups of samples respectively after being placed at room temperature for 30 days, and the test results are shown in Table 1. Figure 4 As can be seen from the diffraction intensity of the straw c is the smallest, which indicates that the straw prepared in Example 3 maintains structural stability during long-term storage, which is beneficial to the long-term storage of the straw and reduces failure or safety problems caused by material deterioration.

[0068] Test 5

[0069] The five groups of samples were placed in a room temperature environment, and the elastic index of 30% deformation in the diameter direction was recorded on different days, and the recording results are shown in Table 1.

[0070]

[0071] According to the results shown in Table 1, the change range of the elastic index of the deformation of the straw c is the smallest, which indicates that the straw prepared in Example 3 can maintain relatively stable elastic performance after experiencing 30% deformation, indicating that the material has high stability and reliability.

[0072] According to the above test results, it can be seen that the biomass straw prepared in Example 3 has good performance, high toughness, is not easy to deform, has higher stability, and has the longest storage time.

[0073] The above tests all use existing test methods, and the test methods are not further improved in this application, so the detailed test process is not recorded.

[0074] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A multi-component composite modification preparation method for biomass straws, characterized in that: The following steps are involved: S1. Preparation of enzyme-modified starch: S101, mixing plant starch with phosphate buffer, gelatinizing in boiling water, and then adjusting to a suitable temperature; S102, performing enzymatic hydrolysis on the mixture; S103, after the enzymatic hydrolysis treatment, an enzyme inactivation operation is performed, followed by an aging and retrogradation treatment, washing with water, centrifugation, and drying to obtain enzyme-modified starch; S2, malic acid esterified modified bamboo powder: S201, mixing bamboo powder with sulfuric acid solution in a certain proportion, and after the reaction is completed, terminating the acid hydrolysis reaction with deionized water and removing the sulfuric acid; S202, dialyzing with deionized water to obtain a suspension with a neutral pH, and concentrating the suspension to adjust the pH of the concentrate; S203, mixing a certain proportion of malic acid into the concentrate, and performing a malic acid esterification reaction at a certain temperature; S204, drying at 45°C, grinding, and sieving to obtain malic acid esterified modified bamboo powder; S3. Preparation of biomass straws: S301, mixing enzyme-modified starch and malic acid esterified modified bamboo powder to obtain a mixture A, wherein the enzyme-modified starch accounts for 30%-70%, adding a composite plasticizer, and mixing, then placing the mixture in a ziplock bag, equilibrating at room temperature, and then extruding; S302: The balanced mixture is extruded using an extrusion device and cooled and dried.

2. The multi-component composite modification preparation method of biomass straws according to claim 1, characterized in that: In step S101, the plant starch is corn starch, the volume of the phosphate buffer is 100 mL, and the boiling water gelatinization time is 1 h.

3. The multi-component composite modification preparation method of biomass straws according to claim 2, characterized in that: In step S102, the specific steps are: The gelatinized mixture was placed in a 50°C water bath and stabilized for 10 minutes. 4U / g α-amylase was added and reacted for 30 minutes. The enzyme was inactivated in a boiling water bath for 20 minutes. After cooling to 65°C, 500U / g branching enzyme was added and reacted for 20 minutes. The enzyme was inactivated in a boiling water bath for 20 minutes. The mixture was placed in a 47°C water bath and 40U / g pullulanase was added and reacted for 24 hours.

4. The multi-component composite modification preparation method of biomass straws according to claim 3, characterized in that: In step S103, the specific steps are: inactivating the enzyme in the mixture by boiling water for 20 minutes, aging at 4°C for 24 hours, washing with water and centrifuging, washing the starch with anhydrous ethanol, centrifuging and drying to obtain enzyme-modified starch.

5. The multi-component composite modification preparation method of biomass straws according to claim 4, characterized in that: In step S201, the concentration of the sulfuric acid solution is 60%, the ratio of the bamboo powder to the sulfuric acid solution is 1:5, the unit is w / v, the reaction time is 50 minutes, the deionized water is 15 times the product, and a high-speed centrifuge is used to remove sulfuric acid through water exchange / centrifugal circulation.

6. The multi-component composite modification preparation method of biomass straws according to claim 5, characterized in that: In step S202, the specific steps are: dialyzing the suspension with deionized water to obtain a suspension with a neutral pH, concentrating the suspension to a concentration of 8% using a rotary evaporator, and then adjusting the pH of the concentrate to 3-4 using 0.1 mol / L hydrochloric acid.

7. The multi-component composite modification preparation method of biomass straws according to claim 6, characterized in that: In step S203, the ratio of the concentrate to malic acid is 3:1, in w / w units, the mixing time is 10 minutes, the reaction temperature is 140° C., and the reaction time is 1 hour.

8. The multi-component composite modification preparation method of biomass straws according to claim 7, characterized in that: In step S301, the composite plasticizer accounts for 20% of mixture A, and the composite plasticizer is a mixture of 5 parts of water, 3 parts of glycerol, and 2 parts of erythritol.

9. The multi-component composite modification preparation method of biomass straws according to claim 8, characterized in that: In step S302, the extrusion equipment is a three-screw extruder, and the extrusion temperature is divided into three temperature control zones from the extrusion outlet to the extrusion inlet: the temperature of zone 1 is 90°C, the temperature of zone 2 is 95°C, and the temperature of zone 3 is 85°C. The sample is extruded from the die head and cooled at room temperature for 48 hours, and then the straw is dried at 40°C to a moisture content of 7.0%.

10. A biomass straw, characterized in that: A biomass straw and a multi-component composite modification preparation method thereof according to any one of claims 1 to 9 are prepared.

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