A food composite packaging material based on collagen fiber and preparation method thereof

Abstract

The invention discloses a collagen fiber-based food composite packaging material and a preparation method thereof. The material comprises the following steps: heating and dissolving the collagen fiber and maintaining the dissolving temperature, adding glycerol, bacterial cellulose, nano-SiO2 and glutaraldehyde and stirring evenly, then adding starch thereto and mixing evenly to obtain a collagen fiber-based mixed material; wherein the mass ratio of collagen fiber: starch: bacterial cellulose is 25-35:5-15:1; glycerol is 20%-40% of the mass of the collagen fiber; nano-SiO2 is 3%-6% of the mass of the collagen fiber; glutaraldehyde is 1‰-5‰ of the mass of the collagen fiber; the collagen fiber-based mixed material is placed in a constant temperature and humidity chamber to balance the moisture content, then extruding to remove water and granulating to obtain collagen fiber-based mixed particles.

Description

Technical Field

[0001] The invention belongs to the technical field of food packaging film preparation, and in particular relates to a collagen fiber-based food composite packaging material and a preparation method thereof. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The purpose of food packaging is to avoid food contamination, reduce transportation damage, and extend the shelf life of food. With the country and people's attention to environmental awareness and food safety issues, petroleum-based plastic packaging has gradually been replaced by green and degradable bio-based materials. In terms of food applications, higher requirements are placed on the barrier and mechanical properties of packaging materials. In recent years, bio-based materials have been widely used in the field of food packaging. Among them, collagen fibers are composed of collagen, mainly found in animal dermis tissue, and have good film-forming properties, but the film is brittle and rigid. Plasticizers, as a commonly used additive, are mainly used to weaken the mutual forces between molecules, increase the mobility of molecular chains, reduce the crystallinity and thermal transition temperature of polymers, and then increase the plasticity of materials and improve the low-temperature heat sealing properties of polymers. In addition, plasticizers can promote the regular arrangement of molecular chains, improve the surface smoothness of some film materials, and improve the water and oxygen barrier properties. Usually, collagen fibers are used as the substrate, and some plasticizers are added to improve the processability of the film.

[0004] In the field of food packaging, heat sealing performance is very important for food transportation, packaging, and use. During heat sealing, the two films are heated and melted at a specific temperature and pressure, and the internal molecular chains move actively and entangle with each other. After cooling, the two polymer films are combined internally and recrystallized through hydrogen bonds and covalent bonds to produce a sealed joint. However, the sealing strength of bio-based materials is poor, and the heat sealing performance is difficult to meet the requirements of food packaging. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a collagen fiber-based food composite packaging material and a preparation method thereof. The packaging film prepared by the preparation method has the advantages of high heat sealing strength, good mechanical properties and excellent barrier properties.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a food composite packaging material based on collagen fibers, comprising the following steps:

[0008] The collagen fibers are heated and dissolved, and the dissolving temperature is maintained, glycerol, bacterial cellulose, nano-SiO2 and glutaraldehyde are added and stirred evenly, and then starch is added thereto, and the mixture is mixed evenly to obtain a collagen fiber-based mixed material, wherein the bacterial cellulose is treated with electron beam irradiation;

[0009] The mass ratio of collagen fiber: starch: bacterial cellulose is 25-35: 5-15: 1; glycerol is 20%-40% of the mass of collagen fiber; nano-SiO2 is 3%-6% of the mass of collagen fiber; glutaraldehyde is 1‰-5‰ of the mass of collagen fiber;

[0010] The collagen fiber-based mixed material is placed in a constant temperature and humidity chamber to balance the moisture, and then squeezed to remove water and granulated to obtain collagen fiber-based mixed particles.

[0011] Micro-nano materials have high specific surface area and more binding sites. Among them, bacterial cellulose is green, degradable, has good water retention, large specific surface area, and good physical properties and thermal stability, making it more suitable as a reinforcing agent for collagen fiber membranes. The bacterial cellulose suspension was irradiated with an electron beam (the adsorbent dosage was 55-65kGy, and the dose rate was 0.15-0.2kGy / s). By micro-nanoizing bacterial cellulose, more active sites are exposed, the crystallinity is reduced, and it is more conducive to heat sealing and improvement of mechanical properties.

[0012] From an industrial perspective, starch can be extruded into granules due to its plasticity and then formed into films by hot pressing, replacing time-consuming casting.

[0013] Bacterial cellulose can improve the mechanical properties of the film; nano-SiO2 is used to improve the transparency, toughness and waterproof properties of the film; glycerol is used to weaken the forces between molecular chains to improve its flexibility and heat sealing properties; glutaraldehyde is mainly used for Schiff base reaction chemical cross-linking to improve the mechanical and barrier properties of the film.

[0014] After the collagen fibers are heated and dissolved, and the dissolving temperature is maintained before adding other components, the coagulation of the collagen fibers can be avoided and the mixing uniformity of the mixed materials can be improved.

[0015] In some embodiments, the temperature for heating and dissolving the collagen fibers is 45°C-65°C.

[0016] Preferably, the temperature for heating and dissolving the collagen fibers is 50-60°C.

[0017] In some embodiments, the mass ratio of collagen fiber:starch:bacterial cellulose is 27-32:7-12:1.

[0018] Preferably, the mass ratio of collagen fiber:starch:bacterial cellulose is 30:10:1.

[0019] Preferably, glycerol accounts for 25%-35% of the mass of the collagen fibers; nano-SiO2 accounts for 4%-6% of the mass of the collagen fibers; and glutaraldehyde accounts for 2‰-4‰ of the mass of the collagen fibers.

[0020] In some embodiments, the collagen fiber-based mixed material is equilibrated with moisture at a temperature of 22-30° C. and a humidity of 50-70% for 20-30 hours.

[0021] Preferably, the temperature of the collagen fiber-based mixed material to balance moisture is 22-27° C., and the humidity is 50-60%.

[0022] In some embodiments, the temperature of the extrusion dehydration is 110-130° C., and the starch is fully gelatinized.

[0023] Preferably, the extrusion dehydration is performed by a twin-screw extruder at a rotation speed of 100-300 rpm.

[0024] In some embodiments, the method further includes the step of flattening the prepared collagen fiber-based mixed particles and then hot pressing them into a film. Before hot pressing them into a film, the collagen fiber-based mixed particles are subjected to moisture balance.

[0025] Preferably, the temperature for moisture balancing the collagen fiber mixed particles is 22-30° C., the humidity is 20-50%, and the balancing time is 20-30 hours.

[0026] Preferably, the temperature of hot pressing film forming is 110-130° C., the pressure is 3-5 MPa, and the hot pressing time is 1-5 min.

[0027] Further preferably, the parameters of hot pressing film forming are:

[0028] The temperature is 110°C, the pressure is 5MPa, and the time is 2min;

[0029] Or, the temperature is 130°C, the pressure is 3MPa, and the time is 2min.

[0030] The collagen fiber heat-sealable high-barrier food composite packaging film is obtained.

[0031] In some embodiments, the starch is selected from one or a combination of corn starch, pea starch, native starch or cationic tapioca starch.

[0032] In some embodiments, the bacterial cellulose has a size of 50-100 μm.

[0033] In a second aspect, the present invention provides a collagen fiber-based food composite packaging material prepared by the preparation method.

[0034] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0035] The material is squeezed multiple times by a screw extruder and concentrated into granules, and then formed into a film by a convenient and fast hot pressing method. Finally, a food packaging film with excellent mechanical properties, high heat sealing strength and high barrier properties is obtained. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] The present invention will be further described below in conjunction with the embodiments.

[0038] Example 1

[0039] A method for preparing a food composite packaging material based on collagen fibers comprises the following steps:

[0040] 1) Take 30g collagen fibers and heat them in a 55℃ water bath to dissolve;

[0041] 2) irradiating the bacterial cellulose suspension with an electron beam (the adsorbent dosage was 60 kGy and the dose rate was 0.173 kGy / s);

[0042] 3) 1 g of the treated bacterial cellulose, 9 g of glycerol, 1.5 g of nano-SiO2, 0.18 g of glutaraldehyde (50%) and the dissolved collagen fibers were fully mixed, and then 10 g of cationic cassava starch was added and stirred to obtain a collagen fiber-based mixed material;

[0043] 4) The collagen fiber-based mixed material is placed in a field at a temperature of 25° C. and a humidity of 50% to equilibrate moisture for 24 hours.

[0044] 5) preheating a twin-screw extruder at 110° C. for 30 min, and extruding the collagen fiber-based mixed material obtained in step 1 multiple times to remove moisture to obtain collagen fiber-based mixed particles.

[0045] 6) The obtained collagen fiber-based mixed particles were placed in a constant temperature and humidity chamber at a temperature of 25° C. and a humidity of 50% for 24 hours.

[0046] 7) The hot press was heated to 110° C. and preheated for 30 min. The collagen fiber-based particles laid flat on the hot press were hot pressed at a pressure of 5 MPa for 3 min to obtain a collagen fiber-based composite film.

[0047] Example 2

[0048] The amount of glycerol added in step 2) of Example 1 was replaced with 20% (Example 2-1) and 40% (Example 2-2) relative to the collagen fibers, corresponding to 6g and 12g respectively. Other conditions were consistent with Example 1 to obtain a collagen fiber composite film.

[0049] Example 3

[0050] The amount of starch added in step 2) of Example 1 was replaced with 5 g (Example 3-1) and 15 g (Example 3-2), respectively, and the other conditions were consistent with Example 1 to obtain a collagen fiber composite film.

[0051] Example 4

[0052] The amount of bacterial cellulose added in step 2) of Example 1 was replaced with 0.5 g (Example 4-1) and 1.5 g (Example 4-1), respectively, and the other conditions were consistent with Example 1 to obtain a collagen fiber composite film.

[0053] Example 5

[0054] The amount of nano-SiO2 added in step 2) of Example 1 was replaced with 3% (Example 5-1) and 5% (Example 5-2) relative to the collagen fibers, and the corresponding addition amounts were 0.9g and 1.5g respectively. Other conditions were consistent with Example 1 to obtain a collagen fiber-based composite film.

[0055] Example 6

[0056] The extrusion temperature in step 6) of Example 1 was adjusted to 100° C. (Example 6-1) and 140° C. (Example 6-2), and the other conditions were consistent with Example 1 to obtain a collagen fiber-based composite film.

[0057] Example 7

[0058] The hot pressing temperatures in step 6) of Example 1 were replaced with 100° C. (Example 7-1) and 130° C. (Example 7-2), respectively, and the other conditions were consistent with Example 1, to obtain a collagen fiber-based composite film.

[0059] Comparative Example 1

[0060] The starch in step 2) of Example 1 was omitted, and other conditions were consistent with those of Example 1 to obtain a collagen fiber-based composite film.

[0061] Comparative Example 2

[0062] The glycerol in step 2) of Example 1 was omitted, and other conditions were consistent with Example 1 to obtain a collagen fiber-based composite film.

[0063] Comparative Example 3

[0064] The bacterial cellulose in step 2) of Example 1 was omitted, and other conditions were consistent with Example 1 to obtain a collagen fiber-based composite film.

[0065] Comparative Example 4

[0066] The nano-SiO2 in step 2) of Example 1 was omitted, and other conditions were consistent with those of Example 1 to obtain a collagen fiber-based composite film.

[0067] The test data results of the collagen fiber-based composite films obtained in the above specific examples are listed in Table 1.

[0068] Table 1 Properties of composite films prepared in Examples and Comparative Examples

[0069]

[0070]

[0071]

[0072] in conclusion:

[0073] To obtain an ideal heat-sealable, high-barrier composite food packaging film based on collagen fibers, specific parameter requirements must be met: 20%-40% of glycerol relative to the mass of collagen fibers; 3%-6% of nano-SiO2 relative to collagen fibers; 1‰-5‰ of glutaraldehyde relative to collagen fibers; double-screw extrusion temperature of 110-130℃; 110℃, 5MPa or 130℃, 3MPa during hot pressing. The heat-sealable, high-barrier composite food packaging film based on collagen fibers obtained by the above parameters has a film thickness of about 0.18mm, a tensile strength of 45-60MPa, an elongation at break of 30-40%, a heat-seal strength of more than 2300N / m, and a water vapor permeability of no more than 2.5×10 -13 (g·m -1 ·s -1 ·Pa -1 ). In addition, by comparing with the comparative example, the lack of any one of the starch, glycerol, bacterial cellulose, and nano-SiO2 and the change of parameters cannot achieve the balance of various properties, and it is even more impossible to obtain an ideal heat-sealable, high-barrier food composite packaging film based on collagen fibers.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a food composite packaging material based on collagen fibers, characterized in that: The steps include: The collagen fibers are heated and dissolved, and the dissolving temperature is maintained, glycerol, bacterial cellulose, nano-SiO2 and glutaraldehyde are added and stirred evenly, and then starch is added thereto, and the mixture is mixed evenly to obtain a collagen fiber-based mixed material; the bacterial cellulose is treated with electron beam irradiation, the adsorbent dosage is 55-65 kGy, and the dose rate is 0.15-0.2 kGy / s; The mass ratio of collagen fiber: starch: bacterial cellulose is 25-35: 5-15: 1; glycerol is 20%-40% of the mass of collagen fiber; nano-SiO2 is 3%-6% of the mass of collagen fiber; glutaraldehyde is 1‰-5‰ of the mass of collagen fiber; The collagen fiber-based mixed material is placed in a constant temperature and humidity chamber to balance the moisture, and then squeezed to remove water and granulated to obtain collagen fiber-based mixed particles. The temperature of the extrusion dehydration is 110-130° C., and the starch is fully gelatinized.

2. The method for preparing the collagen fiber-based food composite packaging material according to claim 1, characterized in that: The temperature for heating and dissolving collagen fibers is 45°C-65°C.

3. The method for preparing the collagen fiber-based food composite packaging material according to claim 2, characterized in that: The temperature for heating and dissolving collagen fibers is 50-60°C.

4. The method for preparing the collagen fiber-based food composite packaging material according to claim 1, characterized in that: The mass ratio of collagen fiber:starch:bacterial cellulose is 27-32:7-12:

1.

5. The method for preparing the collagen fiber-based food composite packaging material according to claim 4, characterized in that: The mass ratio of collagen fiber:starch:bacterial cellulose is 30:10:

1.

6. The method for preparing the collagen fiber-based food composite packaging material according to claim 1, characterized in that: Glycerol accounts for 25%-35% of the mass of collagen fibers; Nano-SiO2 accounts for 4%-6% of the mass of collagen fibers; Glutaraldehyde accounts for 2‰-4‰ of the mass of collagen fibers.

7. The method for preparing the collagen fiber-based food composite packaging material according to claim 1, characterized in that: The collagen fiber-based mixed material is balanced in moisture at a temperature of 22-30°C and a humidity of 50-70% for 20-30 hours.

8. The method for preparing the collagen fiber-based food composite packaging material according to claim 7, characterized in that: The temperature of the collagen fiber-based mixed material to balance moisture is 22-27°C, and the humidity is 50-60%.

9. The method for preparing the collagen fiber-based food composite packaging material according to claim 1, characterized in that: The extrusion dehydration is carried out by a twin-screw extruder with a rotation speed of 100-300 rpm.

10. The method for preparing the collagen fiber-based food composite packaging material according to claim 1, characterized in that: The method also includes the step of flattening the prepared collagen fiber-based mixed particles and then hot pressing them into a film. Before hot pressing them into a film, the collagen fiber-based mixed particles are subjected to moisture balance.

11. The method for preparing the collagen fiber-based food composite packaging material according to claim 10, characterized in that: The temperature for moisture balancing the collagen fiber mixed particles is 22-30°C, the humidity is 20-50%, and the balancing time is 20-30h; The temperature of hot pressing film is 110-130°C, the pressure is 3-5MPa, and the hot pressing time is 1-5min.

12. The method for preparing the collagen fiber-based food composite packaging material according to claim 11, characterized in that: The parameters of hot pressing film formation are: temperature 110°C, pressure 5 MPa, and time 2 min.

13. The method for preparing the collagen fiber-based food composite packaging material according to claim 11, characterized in that: The parameters of hot pressing film formation are: temperature 130°C, pressure 3 MPa, and time 2 min.

14. The method for preparing a food composite packaging material based on collagen fiber according to claim 1, characterized in that: The starch is selected from one of corn starch, pea starch or cationic tapioca starch or a combination thereof.

15. The method for preparing a food composite packaging material based on collagen fiber according to claim 1, characterized in that: The size of the bacterial cellulose is 50-100 μm.

16. A food composite packaging material based on collagen fiber, characterized in that: Prepared by the preparation method described in any one of claims 1 to 15.

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