Method for processing eggshell membrane in order to form a dimensionally stable homogenous body, and product produced using said method

Abstract

The invention relates to a method for processing eggshell membrane in order to form a dimensionally stable homogenous body. According to the method: for each gram of eggshell membrane, at least one gram of liquid is added in order to achieve an absorption of the liquid into the eggshell membrane, and the eggshell membrane mixed with the liquid is subjected to a pressure treatment, preferably a temperature and pressure treatment, wherein during the pressure treatment, a pressure of at least 5 bar, preferably at least 25 bar, more preferably at least 50 bar, is applied to the eggshell membrane mixed with the liquid in order to produce a dimensionally stable body therefrom, and the pressure treatment is carried out at least until more than 85%, preferably more than 90%, more preferably more than 95%, of the liquid mixed with the eggshell membrane is evaporated and / or discharged.

Description

[0001] Protegg GmbH DE - Munich

[0002] Process for processing eggshell membrane into a dimensionally stable, homogeneous body and product resulting from this process

[0003] The present invention relates to a method for processing eggshell membrane into a dimensionally stable body and the product obtained from this method.

[0004] The eggshell membrane is a thin, transparent layer located directly beneath the hard outer shell of an egg. It consists of two layers: the inner and outer eggshell membranes. The main function of the eggshell membrane is to protect the interior of the egg from bacterial infection while allowing gas exchange through the eggshell pores. The eggshell membrane is composed primarily of proteins, including collagen and other glycoproteins, which are responsible for its strength and elasticity.

[0005] During egg processing, particularly during the separation of egg white from yolk, the eggshell, including the eggshell membrane, remains as a waste product. In a penny-crunching business such as egg production and processing, the energy costs for the sanitization required for proper disposal of eggshell membrane, or the costly disposal via external companies, are a relevant economic factor. As a result, particularly in economically weaker areas, the leftover material is often not disposed of properly, leading to increasing problems with groundwater and soil quality. According to the Food and Agriculture Organization of the United Nations (FAO), daily global egg production currently stands at 3.8 billion, of which 328 million come from the EU.During this process, one gram of the precious eggshell membrane is lost per egg, and these amounts are expected to increase significantly in the future.

[0006] The present invention now provides access to the technological use of further processing the resulting eggshell membrane waste material to create a body of any shape yet dimensionally stable, which can be used, for example, as a plastic substitute. The advantage here is that such a plastic substitute does not fall under the EU Plastics Directive. This creates a recycling option for eggshell membrane, often considered only as a waste material, which can contribute to reducing the environmental impact caused by improper disposal of eggshell membrane and / or better exploiting the economic potential of the entire egg, including the eggshell membrane.

[0007] The partial or complete realization of the above advantages is achieved with a method according to claim 1, which is advantageously further developed by the dependent claims.

[0008] The invention accordingly proposes a method for processing eggshell membrane into a dimensionally stable body, wherein at least one gram of liquid is added per gram of eggshell membrane in order to achieve absorption of the liquid into the eggshell membrane. Furthermore, the eggshell membrane mixed with the liquid is subjected to a pressure treatment, preferably a temperature and pressure treatment, wherein a pressure of at least 5 bar, preferably at least 25 bar, and more preferably at least 50 bar acts on the eggshell membrane mixed with the liquid during the pressure treatment in order to create a dimensionally stable, homogeneous body. According to the method, the pressure treatment is to be carried out at least until more than 85%, preferably more than 90%, and more preferably more than 95% of the liquid added to the eggshell membrane has evaporated and / or drained away.

[0009] According to the invention, a dimensionally stable body can be produced from the eggshell membrane, which is considered a waste material, using the process according to the invention. This body can be used, for example, as a substitute for plastic, in particular for fossil-based / synthetic plastic, or the like. It is particularly noteworthy that the dimensionally stable body thus obtained requires no chemical additives, is not synthetically polymerized, and therefore does not fall under the EU Plastics Directive. The dimensionally stable body thus obtained is therefore 100% organic and contains no other artificial additives, which makes it particularly interesting as a packaging material for highly sensitive or consumable goods.

[0010] To obtain a dimensionally stable body from the eggshell membrane residue, it is necessary to add liquid, especially water, preferably filtered water, such as reverse osmosis water, to the raw material of the eggshell membrane to be processed. The amount of liquid is selected so that at least one gram of liquid is added per gram of eggshell membrane.

[0011] The mixture of eggshell membrane and liquid is then subjected to a pressure treatment in which a pressure of at least 5 bar acts on the eggshell membrane mixed with the liquid. The duration of the pressure treatment is maintained until a large portion (more than 85%) of the liquid mixed with the eggshell membrane has evaporated and / or drained away. The application of pressure, combined with the evaporation or draining of the added liquid, results in the formation of a dimensionally stable, homogeneous body from the former eggshell membrane residue.

[0012] The dimensionally stable, homogeneous body formed by the process can be made of 100% biological components (but this does not have to be the case according to the invention, since, for example, the addition of plasticizers or the like can be advantageous, etc.) and, when water is used as the liquid to be mixed, does not contain any artificial additives, thus enabling the raw material eggshell membrane to enter a circular economy.

[0013] According to an optional development of the present invention, the duration of the pressure treatment can depend on the temperature acting on the eggshell membrane or the mixture of eggshell membrane and liquid during the treatment, and decreases with increasing ambient temperature, so that the duration of a pressure treatment with 5 bar at 20 °C lasts at least 360 minutes, at 50 °C at least 120 minutes, at 60 °C at least 60 minutes, at 70 °C at least 20 minutes, at 85 °C at least 10 minutes, at 100 °C at least 5 minutes, at 115 °C at least 2.5 minutes, at 130 °C at least 1 minute, at 145 °C at least 0.5 minutes, at 160 °C at least 0.2 minutes, at 180 °C at least 0.1 minute, and at 200 °C at least 0.05 minutes. In this case, it can preferably be assumed that the relative humidity is 50%.

[0014] Since the rate at which the added liquid evaporates depends on the temperature during the pressure treatment, the duration of the required pressure treatment varies accordingly. According to the invention, it is advantageously possible to deviate from the usual standard conditions (20 °C at a relative humidity of 50%) in order to accelerate the evaporation or removal of the added liquid during the pressure treatment. If, at room temperature of 20 °C (and a relative humidity of 50%, which is always used unless explicitly stated otherwise), it is still necessary to leave the eggshell membrane mixed with liquid under a pressure of at least 5 bar for at least 360 minutes in order to obtain a structurally homogeneous, dimensionally stable body, the required pressure treatment time is reduced as the temperature increases. For example,At a temperature of 50 °C, the duration of the pressure treatment is increased from at least 5 bar to 120 minutes, which is just under a third of the duration at 20 °C. At 60 °C, just 60 minutes are sufficient to produce the dimensionally stable body. As the temperature at which the pressure treatment is carried out or which acts on the combination of liquid and eggshell membrane during the pressure treatment continues to rise, the required duration decreases significantly, so that at 115 °C just 2.5 minutes, at 145 °C just 0.5 minutes, at 180 °C just 0.1 minutes and at 200 °C just 0.05 minutes are sufficient to form the dimensionally stable, homogeneous body from eggshell membrane.

[0015] It can be seen that a combined pressure and temperature treatment can significantly shorten the required process time, so that the manufacturing process of the dimensionally stable, homogeneous body made of eggshell membrane has a significantly improved throughput.

[0016] Accordingly, according to a preferred development of the present invention, it can be provided that during the pressure treatment a temperature treatment for the faster evaporation / flow-off of the liquid takes place in order to carry out a temperature and pressure treatment in which during the pressure treatment a temperature of at least 50° C, preferably at least 100° C and more preferably at least 150° C, at a pressure of at least 5 bar, preferably at least 25 bar and more preferably at least 50 bar acts on the eggshell membrane mixed with the liquid.

[0017] Furthermore, according to the present invention, it can be provided that the pressure treatment is carried out at a relative humidity of at least 30%, preferably at least 40% and more preferably at least 50%.

[0018] However, the reduction of the relative humidity in the process room for the production of the dimensionally stable body has no significant impact on the required duration of the pressure treatment.

[0019] According to the invention, it can further be provided that the liquid to be added to the eggshell membrane comprises or consists of water, alcohol, acid, solvents, bases, oils and / or solutions.

[0020] For example, the addition of glycerin can act as a plasticizer for the dimensionally stable, homogeneous body.

[0021] The only essential aspect of the invention is the addition of a liquid so that the eggshell membrane can be transformed into a homogeneous, dimensionally stable body when the pressure treatment is applied.

[0022] According to a further development of the present invention, it can be provided that a ratio of the eggshell membrane to the liquid to be added is such that for each gram of eggshell membrane at least or exactly 1.5 grams of liquid is added, preferably at least or exactly 4 grams of liquid and more preferably at least or exactly 4.5 grams of liquid is added.

[0023] A particularly advantageous mixing ratio (based on weight) for easy processing of the eggshell membrane mixed with the liquid is at least 1.5 parts liquid for one part eggshell membrane. A ratio of at least or exactly 1:4 is particularly preferred. Preferably, the invention also provides for the eggshell membrane mixed with the liquid to be arranged in a compression mold during the pressure treatment in order to apply the pressure and to specify a desired three-dimensional shape for the resulting dimensionally stable, homogeneous body.

[0024] The simplest implementation of a compression molding tool can be provided with two plate-like elements which define a space in the surfaces facing each other in which the eggshell membrane mixed with the liquid is arranged and subjected to pressure by moving the plates towards each other.

[0025] The two plates thus define a negative space to define the shape of the rigid body. The compression molding tool can be used to produce anything from two-dimensional surfaces to more complex three-dimensional shapes, serving as a forming device.

[0026] In this case, it can advantageously be provided that the compression mold comprises, in addition to a pressure- and / or heat-resistant material, in particular aluminum, a hygroscopic material, in particular polyamide 6. The use of a hygroscopic material, i.e., a substance that can attract and absorb moisture from its surroundings, contributes to separating the admixed liquid from the eggshell membrane. This occurs, for example, through the process of adsorption, in which water molecules adhere to the surface of the hygroscopic material, and through absorption, in which the water penetrates into the interior of the material.

[0027] According to a further development, it can further be provided that the compression molding tool has at least one drainage channel with a diameter in the range of 0.1-0.5 mm, which is designed to drain off liquid escaping during the pressure treatment. By providing at least one drainage channel in the compression molding tool, the drainage of the liquid added to the eggshell membrane can be accelerated, which in turn can reduce the overall duration of the process. The mixture of eggshell membrane and liquid can be squeezed out using the compression molding tool, so that excess liquid can drain away via the at least one drainage channel with a diameter in the range of 0.1-0.5 mm.

[0028] According to a further development of the present invention, it can be provided that the pressure treatment provides for a continuous or step-by-step increase in pressure during the duration of the pressure treatment, wherein the pressure increase preferably takes place from a level which is less than 50 bar and is, for example, 10, 20, 25, 30 or 40 bar.

[0029] According to the invention, it can therefore be provided that during the pressure treatment, the pressure of at least 5 bar does not remain continuously at a certain pressure level, but rather varies. Thus, an increase in pressure and / or a decrease in pressure can be provided during the pressure treatment.

[0030] The same applies to the applied temperature, which can also rise and / or fall during the production of the dimensionally stable, homogeneous body.

[0031] Preferably, according to the invention, it can be provided that before adding liquid to the eggshell membrane, the eggshell membrane is brought into powder form, preferably with a grain size in the range of 10-500 pm, preferably 50-250 pm and more preferably 100-150 pm.

[0032] The powder form of the eggshell membrane facilitates subsequent processing and promotes the homogeneous distribution of the eggshell membrane in a potential compression mold, as well as its mixing with the liquid. The powder form supports flowability in the mold during the molding process, allowing the moist mass of eggshell membrane and liquid to penetrate all areas of the mold's negative space, even in more complex geometries. Furthermore, the powder form also prevents the formation of lumps when mixed with water, thus supporting the creation of a homogeneous, dimensionally stable body.

[0033] In this case, it can advantageously be provided that the eggshell membrane is pulverized, for example, by grinding it in a mortar or using a cutting or ball mill. Preferably, liquid nitrogen can be added before the eggshell membrane is pulverized to simplify the pulverization process. This is particularly useful when pulverizing using a mortar. When using a cutting or ball mill, however, liquid nitrogen can be omitted.

[0034] By adding liquid nitrogen, the pulverization of the eggshell membrane is simplified, as the structure of the inherently flexible eggshell membrane solidifies and the subsequent pulverization process becomes much easier to handle.

[0035] Furthermore, according to the invention, a dehumidifying agent and / or a dry pressing powder can be added to the eggshell membrane mixed with the liquid before and / or during the pressure treatment in order to promote the removal of moisture during the pressure treatment.

[0036] Furthermore, according to an advantageous embodiment of the present invention, it can be provided that after the end of the temperature and / or pressure treatment, cooling is carried out while maintaining a pressure that is higher than the ambient pressure, preferably the pressure value last reached during the temperature and / or pressure treatment. The cooling is a reduction in the temperature that acts on the eggshell membrane mixed with liquid during the pressure treatment. If, for example, a temperature treatment is carried out during the pressure treatment that leads to an increase in temperature to 100 °C, the temperature can be maintained at a level higher than room temperature of 20 °C for a subsequent period even after the end of the pressure treatment, for example at a temperature value in the range of 30° to 40 °C.

[0037] According to the invention, the eggshell membrane can be the membrane of a chicken egg. It will be clear to those skilled in the art that the invention can, of course, be implemented not only with a single, but also with any multiple and / or fractional eggshell membrane.

[0038] According to the invention, it can further be provided that eggshell in powder form is added to the eggshell membrane after or before adding the liquid, wherein the eggshell makes up about 5-30 wt.% of the eggshell membrane, preferably 10-25 wt.% and more preferably 15-20 wt.% of the eggshell membrane.

[0039] According to an optional development of the invention, the added eggshell in powder form has a grain size in the range of 10-500 pm, preferably 50-250 pm and more preferably 100-150 pm.

[0040] The eggshell acts as a filler and can reduce the amount of eggshell membrane required.

[0041] The invention further relates to a dimensionally stable product obtained by the method according to one of the preceding claims, wherein the product is characterized in particular by being waterproof and / or having high UV stability with a UV transmission at a thickness of 1 mm of less than 30%, preferably less than 20%, and more preferably less than 15%. It is particularly advantageous to emphasize that the dimensionally stable body produced by the method according to the invention is waterproof, so that applications in the field of coatings for liquids are also conceivable. For example, a thin layer of the dimensionally stable body produced by the method according to the invention could be provided in a glass or cup shape, which is supported by a base layer of paper or the like for further stability. In this way, a drinking vessel made entirely of biological materials could be produced very easily.

[0042] Furthermore, it can be provided that the product is characterized by having a homogeneous transparent and / or translucent appearance.

[0043] The homogeneous appearance is particularly important for the visual impression made on the end consumer, since an irregular appearance of a product often leads to irritation, which (sometimes incorrectly) attributes inferior quality to the product.

[0044] Further features, details, and advantages of the invention will become apparent from the following description of the figures. These show:

[0045] Fig. 1 : a representation of the dimensionally stable, homogeneous body obtained by the method according to the invention, and

[0046] Fig. 2a-c: each shows a representation in which the pressure treatment was applied for too short a time or at too low a temperature, so that no homogeneous, dimensionally stable body was formed.

[0047] Fig. 1 shows a representation of the dimensionally stable, homogeneous body 1 obtained using the method according to the invention. In the figure, the dimensionally stable body 1 is held by a sample holder 2, which is not part of the dimensionally stable, homogeneous body 1. The regular structures visible are due to the compression molding tool / materials used. Furthermore, no irregularities are discernible in the body obtained by the method, so the formation of the homogeneous, dimensionally stable body can be considered successful.

[0048] The following Table 1 shows a selection of exemplary parameters for the method according to the invention, which lead to the result shown in Figure 1. Table 1:

[0049] From the table, it can be seen that for every 0.5 g of eggshell membrane, 2 g of liquid, namely water (H2O), was added. At a pressure of 5 bar, various combinations of pressure and temperature were determined to produce the dimensionally stable, homogeneous body. For the sake of completeness, it should be noted that liquids other than water also produce the desired result. The relative humidity during the various experiments was 50%.

[0050] Table 2 below also contains parameters that successfully produce dimensionally stable, homogeneous bodies made of eggshell membrane. The various tests were also conducted at a relative air frequency of 50%. The amount of eggshell membrane and the added liquid in the tests shown in Table 2 are 1:4.5, with water (H2O) again used as the liquid.

[0051] In contrast to the experiments in Table 1, variations in temperature (Experiment 15) and the pressure applied during the pressure treatment are evident. The temperature variation and the pressure variation are represented by an arrow, symbolizing the decrease / increase in pressure / temperature. The duration of the different pressure levels is also indicated, as the time specified in minutes contains a corresponding number of arrows. Thus, using the example of Experiment 2, it is clear that the pressure of 50 bar is applied for 60 minutes and the pressure of 100 bar is also applied for 60 minutes.

[0052] Table 2:

[0053] In experiments with a pressure of less than 5 bar, the production of the dimensionally stable body is not successful or only unsatisfactory, so that the eggshell membrane essentially retains its original properties and no dimensionally stable, homogeneous body is formed.

[0054] Figs. 2a-c each show an illustration in which the pressure treatment was applied for too short a time, so that no homogeneous, dimensionally stable body was formed.

[0055] The corresponding parameters used for production can be found in Table 3 below. It is also visually evident that not all or a large portion of the liquid previously added to the eggshell membrane has yet evaporated or drained away. This is evident from the not yet fully developed homogeneous structure, which is very clearly visible in Figure 2a, clearly visible in Figure 2b, and less clearly visible in Figure 2c. The areas in question are marked with corresponding arrows as examples.

[0056] Compared to the dimensionally stable, homogeneous body according to the invention, inclusions or irregularities in the structure of the body can be seen, indicating its unfinished state. In Figure 2a, some of these areas have been highlighted with arrows.

[0057] Table 3:

[0058] Comparing the first line entry from Table 3 with the sixth line entry from Table 1, it can be seen that at a pressure of 5 bar and a temperature of 70 °C, the time of 5 minutes was not sufficient for the complete transformation of the mixture of liquid and eggshell membrane into the dimensionally stable, homogeneous body.

[0059] In comparison, the third row entry from Table 3 will achieve a significantly better result (result shown in Figure 2c), since the temperature has been raised to 85 °C while maintaining a constant pressure of 5 bar.

[0060] Figure 2c shows that the untransformed components are significantly less extensive and appear only sporadically. To simplify the identification of these untransformed regions, arrows pointing to them have been inserted in Figure 2C.

[0061] Fig. 2b also uses the pressure of 5 bar at 70 °C, but - in deviation from the first experiment in Table 3 - for a duration of 10 instead of the previous 5 minutes.

[0062] The extent of the undesired non-homogeneous areas lies between those in Fig. 2a and Fig. 2c, but is still clearly visible. For simplicity, arrows have also been added here to visually mark the individual components of the non-homogeneous areas.

Claims

Protegg GmbH DE - Munich Process for processing eggshell membrane into a dimensionally stable, homogeneous body and product resulting from this process Claims 1. A method for processing eggshell membrane into a dimensionally stable, homogeneous body, wherein in the method: at least one gram of liquid is added per gram of eggshell membrane in order to achieve absorption of the liquid in the eggshell membrane, and the eggshell membrane mixed with the liquid is subjected to a pressure treatment, preferably a temperature and pressure treatment, wherein during the pressure treatment a pressure of at least 5 bar, preferably at least 25 bar and more preferably at least 50 bar acts on the eggshell membrane mixed with the liquid in order to create a dimensionally stable body therefrom, and the pressure treatment is carried out at least until more than 85%, preferably more than 90% and more preferably more than 95% of the liquid added to the eggshell membrane has evaporated and / or flowed away.

2. Method according to the preceding claim 1, wherein the duration of the pressure treatment depends on the ambient temperature and decreases with increasing ambient temperature, so that the duration of a pressure treatment with 5 bar at 20 °C is at least 360 minutes, at 50 °C at least 120 minutes, at 60 °C at least 60 minutes, at 70 °C at least 20 minutes, at 85 °C at least 10 minutes, at 100 °C at least 5 minutes, at 115 °C at least 2.5 minutes, at 130 °C at least 1 minute, at 145 °C at least 0.5 minutes, at 160 °C at least 0.2 minutes, at 180 °C at least 0.1 minute, and at 200 °C at least 0.05 minutes.

3. Method according to one of the preceding claims, wherein during the pressure treatment a temperature treatment is also carried out for the faster evaporation of the liquid in order to carry out a temperature and pressure treatment in which during the pressure treatment a temperature of at least 50°C, preferably at least 100°C and more preferably at least 150°C, at a pressure of at least 5 bar, preferably at least 25 bar and more preferably at least 50 bar acts on the eggshell membrane mixed with the liquid.

4. A method according to any one of the preceding claims, wherein the pressure treatment is carried out at a relative humidity of at least 30%, preferably at least 40% and more preferably at least 50%.

5. A method according to any one of the preceding claims, wherein the liquid to be added to the eggshell membrane comprises or consists of water, alcohol, acid, solvents, bases, oils and / or solutions.

6. Method according to one of the preceding claims, wherein a ratio of the eggshell membrane to the liquid to be added is such that for each gram of eggshell membrane at least or exactly 1.5 grams of liquid is added, preferably at least or exactly 4 grams of liquid and more preferably at least or exactly 4.5 grams of liquid is added.

7. A method according to any one of the preceding claims, wherein the eggshell membrane mixed with the liquid is arranged in a compression molding tool during the pressure treatment in order to apply the pressure and to specify a desired three-dimensional shape for the resulting dimensionally stable body.

8. Method according to the preceding claim 7, wherein the compression molding tool comprises, in addition to a pressure- and / or heat-resistant material, in particular aluminum and / or stainless steel, a hygroscopic material, in particular polyamide 6.

9. Method according to one of the preceding claims 7 or 8, wherein the compression molding tool has at least one drainage channel with a diameter in the range of 0.1 - 0.5 mm, which is designed to drain off liquid escaping during the pressure treatment.

10. Method according to one of the preceding claims, wherein the pressure treatment provides a continuous or stepwise increase in pressure during the duration of the pressure treatment, wherein the pressure increase preferably takes place from a level which is less than 50 bar and is, for example, 10, 20, 25, 30 or 40 bar.

11. Method according to one of the preceding claims, wherein before adding liquid to the eggshell membrane, the eggshell membrane is brought into powder form, preferably with a grain size in the range of 10-500 pm, preferably 50-250 pm and more preferably 100-150 pm.

12. The method according to the preceding claim 11, wherein, in order to bring the eggshell membrane into powder form, pulverization takes place, for example by grinding in a mortar or by using a cutting mill, preferably wherein liquid nitrogen is added to the eggshell membrane before pulverization.

13. A method according to any one of the preceding claims, wherein a dehumidifying agent and / or a dry press powder is added to the eggshell membrane mixed with the liquid before or during the pressure treatment to promote the removal of moisture during the pressure treatment.

14. A dimensionally stable product obtained by the process according to any one of the preceding claims, wherein the product is characterized in particular by being waterproof, preferably not water-soluble but hygroscopic, and / or having high UV stability with a UV transmission at a thickness of 1 mm of less than 30%, preferably less than 20%, and more preferably less than 15%.

15. A dimensionally stable product according to the preceding claim 14, wherein the product is characterized by having a homogeneous transparent and / or translucent appearance.

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