Use of a thermoplastic, biobased and biodegradable material having brittle fracture mechanics as the shell for an egg or egg-replacement product, and a vegan egg-replacement product encased by such a shell

Abstract

The present invention relates to the use of a material, produced by means of extrusion, composed of (A) one or more biodegradable, thermoplastically processable biolpolymer(s) and (B) one or more inorganic, organic or low-solubility salt(s) as the shell for an egg-replacement product, and to an egg-replacement product containing vegan-based egg white and egg yolk which are encased by such a shell.

Description

[0001] Use of a thermoplastic, bio-based and biodegradable material with brittle fracture mechanics as a shell for an egg or egg substitute, and a vegan egg substitute coated with such a shell

[0002] Area of ​​application

[0003] The invention relates to the use of a material based on bio-based and biodegradable polymers, which are suitably compounded with additives, for use as a shell for an egg or egg substitute product using thermoplastic manufacturing processes. The target application is therefore a novel packaging material for egg and egg substitute products.

[0004] State of the art

[0005] The germ cell of a chicken, consisting of yolk and egg white, is enclosed by two fibrillar membranes and a calcified, semi-crystalline shell. The structure of the eggshell serves to protect the egg from mechanical damage, microbial contamination, and desiccation, as well as to regulate gas and water exchange. The eggshell consists of 95–97% calcium carbonate crystals, stabilized by a protein matrix. This matrix also plays an important role in the mineralization process. The crystals grow upwards along it in a pallisade-like manner, forming a porous shell (see Fig. 1). This complex structure cannot be artificially reproduced. A chicken egg can measure between 40 mm and 50 mm in diameter, with the shell reaching a wall thickness of 340–410 pm. The maximum tensile stress of the shell of chicken eggs (measured along the longitudinal axis) is approximately 18.3–29.9 MPa.The strength of eggshells decreases with increasing egg size, meaning less force is required to break the egg. This is likely due to the proportional increase in the number and size of imperfections in the shell's microstructure [2]. The elastic modulus of eggshells is 18-27.5 GPa. Due to their porous structure and their associated function of not restricting the metabolism of a developing chick, eggshells do not have a significant gas barrier [3].

[0006] Naturally occurring organic-inorganic hybrid materials, such as eggshells, snail shells, mussel shells, corals, or bones, are characterized by high strength and hardness combined with a lightweight and material-economical construction. The outstanding mechanical properties result from a hierarchical structure of the individual components, such as inorganic constituents and organic matrix, which is difficult to copy and reproduce technically. However, in isolated cases, materials have already been developed on a laboratory scale that are astonishingly close to the natural model. For example, a nacre-like material was produced by alternately depositing bacterially produced CaCCh and bacterially produced polyglutamate (PGA) [4]. The hardness and fracture behavior were similar to those of natural nacre and thus superior to crystalline calcite.

[0007] However, most technologically mature manufacturing processes are in the area of ​​thermoplastic processing. A compounding step can be used to incorporate additives into the polymer or adjust the particle size distribution. Such a compounding step is often carried out on a twin-screw extruder [5] with the aim of processing, granulating, filling, or reinforcing the plastics. The resulting granules are suitable for subsequent thermoplastic processing into the final dosage form of the material, such as extrusion, injection molding, blow molding, etc. [6]

[0008] Various combinations of biopolymers and fillers, along with their expected properties, mostly mechanical properties, are described in the literature. The type of polymer, the filler, its concentration, and the temperature conditions during processing influence the final mechanical properties of the composite material.

[0009] Cinelli et al. [7] compounded polyhydroxyalkanoates (PHBV with 5% valerate content) with a bio-based and biodegradable plasticizer (acetyltributyl citrate, 10%), 5% CaCO3, and 10–30% lignocellulosic fibers (pea plant fibers, wood fibers) at 170°C, with the aim of using them as rigid, injection-molded food packaging. It was observed that with increasing fiber content, the Young's modulus increased, while tensile strength and elongation at break decreased. Chen et al. [8] investigated the crystallization kinetics in PHBV / clay nanocomposites. The crystallization rate of PHBV, as well as its tensile strength and Young's modulus, were improved when a small amount of organically modified montmorillonite (OMMT) was added, while the opposite occurred when an excessive amount of OMMT was used. A similar effect was observed by Duangphet et al. [9], where PHBV (3% valerate content) was compounded with 5-20% calcium carbonate and the crystallization behavior was investigated.The addition of small amounts (5%) of CaCO3 increased the crystallization rate of PHBV. An excess of CaCCh (20%), however, had the opposite effect, but with an associated increase in crystallite size and enhanced agglomeration of the CaCCh particles. Cabedo et al.

[0010] investigated the influence of processing conditions on the degradation of the PHBV / clay system. While kaolin was reported to have no effect on PHBV degradation, montmorillonite (MMT) induced degradation via the release of tightly bound water from the clay surface at high temperature, which was activated by the surface modifier in the MMT. Ding et al.

[0011] investigated P(3HB-4HB) compounds (5 mol% 4HB) with 0-80% CaCO2 of varying particle sizes. The thermal stability of P3 / 4HB decreased with increasing CaCO2 content. With increasing CaCO2 content, elongation at break, tensile strength, and impact toughness also decreased; however, the Young's modulus increased. The crystallization rate of P(3HB-4HB) was reduced by the addition of CaCO2; the highest crystallinity was achieved at a CaCO2 content of 40%. In addition to the mechanical properties of PHBV / CaCO2 compounds, Kirboga et al.

[0012] other packaging-relevant properties, such as oxygen and water vapor barrier properties, were also observed. PHBV was compounded with 0.1–1% CaCO3. An improvement in stiffness (storage modulus via DMA) as well as an improvement in oxygen and water vapor barrier properties was observed with just 0.1% CaCO3 addition. Xiong et al.

[0013] produced PBS with 10–30% CaCO3 and up to 3% (based on CaCO3) aluminate-, silane-, and titanate-based compatibilizers by compounding. The goal of adding CaCO3 was to reduce costs by reducing PBS usage. The addition of compatibilizers improved tensile strength and elongation at break. Blends of PLA / PBAT in a ratio of 3:1 with 2% talc and up to 20% ground mussel powder were prepared by Gigante et al.

[0014] described. The Young's modulus increased with increasing filler content, but the tensile strength decreased slightly. The compounds were suitable for injection molding applications.

[0010] Biodegradable polymers in combination with inorganic or organic fillers, as well as poorly soluble fillers, are also being researched and used for medical applications, such as bone tissue engineering, cartilage reconstruction, vascular transplants, and other implantable biomedical devices. An overview of materials based on naturally occurring and non-thermoplastic polymers, such as collagen, gelatin, chitosan, fibrin, cellulose, and alginate, which contain inorganic components such as hydroxyapatite, is provided in the review by Sathiyavimal et al.

[0015] Additional functions, such as drug delivery or antimicrobial effects, can also already be realized. Likewise, thermoplastic polymers such as polyhydroxyalkanoates, PCL, PLA, PVAc, PEO, and compounds thereof with inorganic and poorly soluble fillers, such as hydroxyapatite, calcium phosphate, bioactive glasses, or wollastonite, are already being used as biocompatible and biodegradable materials in implants.

[0016] , The review by Rodriguez-Contreras

[0017] describes the medical suitability of PHB, PHBV and P(3HB-4HB) as suture material and for valves, in tissue engineering as bone graft substitutes, as cartilage, stents for nerve repair and cardiovascular patches due to their biocompatibility, biodegradability and non-toxicity.

[0011] In the field of biomedicine, there are complementary manufacturing processes for composites. For example, Chernozem et al.

[0018] PHB and PHBV (12% valerate content) were spun into fibers in chloroform using electrospinning. Subsequently, CaCCh was deposited on the fibers through a precipitation reaction of Na2CO3 and CaCh, and the inorganic filler was introduced into the fibers by ultrasonic treatment. The goal of this study was to produce bone tissue for regenerative medicine; therefore, bone-forming cells (osteoblasts) were immobilized on the surface and stimulated to grow, resulting in further biomineralization (formation of apatite). Jagoda

[0019] In their dissertation, they describe the production of a bone substitute material made of poly([R]-3-hydroxy-10-undecenoate) (PHUE), a representative of the medium-chain PHAs. This material was deposited as a monolayer on calcium phosphate. Due to its elastomeric properties, the polymer can form a flexible matrix for calcium phosphate crystals, similar to collagen in bone. Degli Esposti et al.

[0020] describe a process for producing porous material from PHB and hydroxyapatite that mimics natural bone material. PHB was dissolved in dioxane and mixed with up to 8% hydroxyapatite nanoparticles, or hydroxyapatite was produced in situ using a sol-gel process in the presence of dissolved PHB. A porous structure was created by temperature-dependent demixing.

[0012] US 2019 / 263557

[0021] describes a design of an egg shell composed of two rotationally symmetrical half-shells (the separation plane thus runs perpendicular to the longitudinal or rotational symmetry axis of the egg), which are sealed after being filled with the yolk. The lower half-shell has an opening through which the egg white is finally added, filling the entire egg and leaving the yolk floating in the egg white. Finally, the filling opening of the eggshell is also sealed. According to the statements in US 2019 / 263557, the shell, which is said to exhibit breakability, gas permeability, and an opaque visual appearance like a natural egg, can be made, for example, of "styrene maleic anhydride (SMA)." According to the statements, this material is said to be biodegradable, at least through the addition of "oxobiodegradable" additives. Subject of the application DE 103 01 984 A1

[0022] from 2003 is a flexible, breathable polymer film and a corresponding manufacturing process. The described film is flexible and breathable and features funnel-shaped pores in the surface area. Based on the model of a natural ostrich egg, a porous material that optimally converts photocatalysis is to be created, which is to be produced using a sol-gel process. However, a substitute eggshell with fracture behavior similar to that of a natural chicken egg is unlikely to be produced using the polymer film described in this document.

[0013] Application of the present invention

[0014] The objective of the present invention was to develop materials that exhibit similar properties to those of mineral composite materials found in living organisms, in terms of color, strength, fracture behavior, and biodegradability, and that retain their shape and impermeability in boiling water. Furthermore, the developed materials should provide a barrier against microorganisms, oxygen, water, and water vapor, as required for food packaging materials to achieve product protection. The materials should also be sterilizable (by heat or oxidizing agents such as H2O2) and therefore be used primarily for egg substitute products.

[0015] Description of the invention

[0016] This object is achieved by the features of patent claims 1 and 9. Advantageous embodiments emerge from the subclaims.

[0017] The material or material mixture, hereinafter also referred to as "compound", contains one or more biodegradable, thermoplastically processable biopolymers (A) in combination with one or more inorganic or organic and poorly soluble fillers or additives (B).

[0018] The biodegradability of the base material (A) used according to the invention is assessed according to different standards. It corresponds to a degradation rate of at least 90% within 180 days and an achieved disintegration level of less than 10% dry mass with particles larger than 2 mm after 12 weeks, passed ecotoxicity analysis with regard to plant growth and adherence to limits for heavy metals under

[0019] (semi-)industrial composting conditions (e.g. according to OK compost - EN13432),

[0020] - preferably under home composting conditions (e.g. according to OK compost home - TÜV Austria Belgium), particularly advantageous under limnic or marine degradation conditions (e.g. according to ISO 22403 or ASTM D6691-17).

[0021] The following are preferably suitable as biopolymer components (A):

[0022] One or more polyhydroxyalkanoate(s) and / or polyhydroxyalkanoate-

[0023] Copolymer(s), preferably poly(3-hydroxypropionate) PHP, poly(3-hydroxybutyrate) PHB / PH3B, poly(3-hydroxyvalerate) PHV, poly(3-hydroxyhexanoate)

[0024] PHHx, Poly(3-hydroxyheptanoate) PHH, Poly(3-hydroxyoctanoate) PHO, Poly(3-hydroxynonanoate) PHN, Poly(3-hydroxydecanoate) PHD, Poly(3-hydroxyundecanoate) PHIID, Poly(3-hydroxydodecanoate) PH DD, Poly(3-hydroxytetradecanoate) PHTD, Poly(3-hydroxypentadecanoate) PH PD, Poly(3-hydroxyhexadecanoate) PHHxD; Poly(3-hydroxypropionate-co-3-hydroxybutyrate)

[0025] (P3HP-3HB), poly(3-hydroxypropionate-co-4-hydroxybutyrate) (P3HP-4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-4HB)), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHB-HHx), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (PHBV-HHx), medium-chain PHAs (mcl-PHA) with side chain lengths of C3-C11, long-chain PHAs (Icl-PHA) with side chain lengths greater than C12, preferably PH3B, PHBV, PHB-HHx or (P(3HB-4HB).

[0026] Polylactic acid (polylactide): amorphous and crystalline variants of poly(L-lactide) PLLA, poly(D-lactide) PDLA, stereocomplex-(polylactide) sc-PLA, stereoblock-(polylactide) sb-PLA. One or more inorganic or organic salts can be used as filler or additive (B), preferably

[0027] Poorly soluble salts: carbonates, sulfates, hydrogen sulfates, sulfites, sulfides, phosphates, hydrogen phosphates, oxides, hydroxides, citrates, oxalates of an alkaline earth element, the transition metals or aluminum, preferably CaCO3, CaSO4, Ca3(PO4)2, MgCO3, BaSO4, Ca citrate, Ca oxalate, Fe2O3, AhO3.

[0028] - Stoichiometric and non-stoichiometric double salts and hydrates as well as silicates, preferably CaCO3*MgCO3 (dolomite), CaSO4*2 H2O (gypsum), CaSiO3 (wollastonite), clay minerals (e.g. montmorillonite, kaolinite, bentonite, talc), hydroxyapatite as well as SiO2 in various dosage forms (e.g. silicas, bioactive glasses, SiO2-based nanoparticles, etc.).

[0029] The mass fraction of filler(s) or additive (B) in the biopolymer matrix is ​​in the range of 1-50%, advantageously 5-45%, particularly advantageously 30-45%.

[0030] The powdered or granulated biopolymer component is preferably dewatered by pre-drying at temperatures between 50 and 80°C for 6-48 hours. The inorganic or organic fillers, as well as those with low solubility, are preferably dewatered by pre-drying at temperatures between 70 and 120°C for 6-48 hours.

[0031] The weight ratio of the components in the compounds is adjusted either by premixing the powdered components in the correct mixing ratio and preferably subsequent extrusion or application of another thermoplastic manufacturing process, or by separately feeding components of different bulk densities into the processing device, e.g. into the extruder.

[0032] The extruder's temperature profile should be adjusted to prevent thermal degradation of the components. To achieve this, the processing temperature must be kept within the melting point of the polymer, typically 10–20°C below (to account for additional thermal contribution from the input of mechanical energy) or 10–20°C above (to reduce viscosity and improve homogeneous mixing). For PHBV as a matrix polymer (melting point 170–175°C depending on the type), this could, for example, be a temperature profile in the lower range of 40–50°C and in the upper range of 130–160°C, particularly 45–140–150–150–150°C. For PLA as a matrix polymer (melting point 150-200°C depending on the type), this could be, for example, a temperature profile in the lower range of 50-70°C and in the upper range of 140-200°C, in particular 60-160-190-190-145-145-145°C.

[0033] After leaving the extruder die, the compound is rapidly cooled. This can be done either using a water bath or dry ice. The finished compound can then be pelletized for further use.

[0034] Preferred combinations are

[0035] (A) Polyhydroxyalkanoates and polyhydroxyalkanoate copolymers, in particular

[0036] PH3B, PHBV, PHB-HHx or (P(3HB-4HB), or polylactides, especially PLLA or PLLA with low D-isomer content with

[0037] (B) Calcium salts, in particular CaCCh, CaSCL, Caa(PO4)2 or Ca citrate

[0038] Surprisingly, thin layers (< 1 mm) of such compounds exhibited fracture properties comparable to those of naturally occurring chicken egg shells. The brittleness or Young's modulus of the compounds ranged between 3 and 8 GPa, typically between 4 and 6 GPa, and can be adjusted by varying the concentration of the inorganic or organic filler, as well as the sparingly soluble filler. Despite the use of a thermoplastic, these compounds still exhibited sufficient strength when boiled in 100°C water. Furthermore, no dissolution behavior of the compound was observed in boiling water over a period of 20 minutes. No statistically significant dissolution behavior was observed in water at room temperature and at 4°C, in 1% aqueous sodium alginate solution at room temperature and at 4°C, or in other aqueous media at room temperature and at 4°C.

[0039] The compound is preferably formed into two rotationally symmetrical half-shells of equal height using an injection molding process (see Fig. 4). Before thermoplastic processing, the compound is dried at 50–80°C, preferably between 60 and 70°C, for 6–48 hours, preferably between 12 and 24 hours. Depending on the stability and viscosity of the melt, the temperature profile in the injection molding extruder corresponds to that of the preceding compounding process; however, it can be slightly higher if necessary. To ensure suitable material and heat distribution in the injection mold, the geometry of the injection point can be designed either centrally or equatorially. The volume of the egg-shaped hollow body resulting from the combination of the two half-shells corresponds to that of a large chicken egg and is between 50 and 70 ml, preferably 60–65 ml.The resulting shell thickness of the injection-molded half-shells is approximately equivalent to that of a chicken egg, between 0.5-1 mm, preferably 0.6-0.75 mm. The surface of the outer shell of the eggshell can be either smooth or rough – this is achieved by suitable mechanical processing of the inner surface of the mold (milling, eroding, etc.). The two half-shells have a plug-in mechanism along the equator, which allows them to be joined together precisely. In the area of ​​the plug-in connection, the shell thickness increases slightly, approximately by a factor of 2, to ensure greater mechanical stability. One of the two half-shells, ideally the upper one, which tapers slightly towards the tip, has an opening on the side in the upper third or centrally located on the axis of rotation, typically between 2 and 6 mm, optimally between 3 and 5 mm, which is formed during the injection molding process.This opening makes it possible to fill the resulting hollow body, which results from the solid connection of the two eggshell halves, with one or more flowable and conveyable components (egg white and egg yolk).

[0040] The following describes the coating of an egg substitute. An egg substitute is a vegan-based product that contains a separate egg white and yolk like a natural animal egg and is structured and can be used in the same way. Both egg white and yolk contain (a) plant protein from legumes, oilseeds, cereals, and / or algae, and (b) a combination of at least two hydrocolloids with different behaviors when exposed to temperature changes. Depending on whether it is an egg white or an egg yolk, additional components are added.

[0041] “Vegan-based” means that it does not contain any animal or animal-derived ingredients.

[0042] The percentages given in the following text are all percentages by weight.

[0043] In the following, the terms "egg white" and "protein" are used synonymously. For example, the vegan egg white substitute contains:

[0044] (a) Drinking water

[0045] (b) one or more proteins from pulses, oilseeds, cereals, microorganisms and / or algae,

[0046] (c) a combination of one or more thermogelling hydrocolloids with one or more reversibly gelling hydrocolloids,

[0047] (d) one or more salts, wherein the proportion of the combination of one or more reversibly thermogelling hydrocolloids with one or more reversibly gelling hydrocolloids is 0.25-5.00 wt%.

[0048] Suitable protein sources include plant-based raw materials from the group of pulses, cereals, oilseeds, microorganisms and (micro)algae, preferably plant proteins from peas (Pisum sativum), chickpeas (C. cer arientinum), garden beans (Phaseolus vulgaris), faba beans (also called "field beans"; Vicia faba), sweet lupins (Lupinus), lentils (Lens culinaris), maize (Zea mays), hemp (Cannabis sativa), sweet potatoes (Ipomoea batatas), cassava (Manihot esculenta), potatoes (Solanum tuberosum), pumpkin (Cucurbita), flax (Linum usitatissimum), rapeseed (Brassica napus), soy (Glycine max), oats (Avena sativa), bacteria (e.g. Lactobacillus spp., Streptococcus spp., and Bifidobacterium spp.), Yeasts (e.g. Saccharomyces cerevisiae), molds (e.g. Aspergillus spp., Mucor spp., and Rhizopus spp.), nori seaweed and / or wakame seaweed, particularly beneficial are proteins from peas, chickpeas, faba beans, lupin, hemp, pumpkin and mung beans.As a protein source, flours (raw and / or hydrolyzed and / or fermented), protein concentrates, protein isolates, and / or any combination thereof obtained from the plants and plant parts themselves, their seeds, tubers, and / or their fruits of the aforementioned raw materials can be used. The processing and nutritional suitability of the plants and respective plant parts is sufficiently known to the person skilled in the art of food technology.

[0049] According to the invention, a transparent white product is provided which is made from the aforementioned proteins from one or more plant protein sources. The solubility of the proteins is higher in saline solutions than in pure water. Therefore, to dissolve the proteins from drinking water and an inorganic salt suitable for consumption, a saline solution, preferably a sodium chloride (NaCl) solution, is prepared, and the protein source is dispersed therein. However, other salts are also suitable in principle, such as sodium dihydrogen phosphate (NaHPC), disodium hydrogen phosphate (NaHPC), trisodium phosphate (NaSPC), sodium pyrophosphate (NaP2O), and potassium chloride (KCl). It is of course also possible to disperse the protein source and the salt simultaneously in drinking water.In some embodiments, the salt concentration, preferably NaCl concentration, is greater than 0.05%, preferably greater than 0.10%, greater than 0.15%, greater than 0.20%, greater than 0.30%, greater than 0.40%, or more than 0.50%. In some embodiments, the salt concentration, preferably NaCl concentration, is 0.05%-0.80%, preferably 0.10%-0.70%, 0.20%-0.60%, or 0.4%-0.6%.

[0050] To create an egg-like flavor, either Kala Namak (black salt) or other salts and / or natural flavors containing sulfur compounds can be used. The sulfur-containing compounds, especially Kala Namak salt, can be used together with the salt in the brine, preferably NaCl, to achieve the same concentrations. However, it can also be used in smaller, larger, or equal amounts.

[0051] The amount of dissolved proteins is preferably more than 0.1%. In some embodiments, the amount of dissolved proteins is more than 1.0%, preferably more than 2.5%, more than 4.0%, more than 5.0%, more than 8.0%, more than 10.0%, or more than 12%. In some embodiments, the amount of dissolved proteins is 0.5%-15.0%, preferably 1.0%-12.0%, 1.5%-10.0%, or 2.0%-5.0% in the egg white substitute product according to the invention.

[0052] The egg white substitute contains hydrocolloids to achieve the desired viscosity and solidify upon heating. A combination of one or more thermogelling hydrocolloids with one or more reversibly gelling hydrocolloids has proven advantageous, although the two types differ in their behavior during temperature changes. Hydrocolloids that gel rapidly when the temperature is increased to > 40°C are called "thermogelling" or "thermoreversibly gelling" and are preferably modified celluloses, preferably methylcelluloses, hydroxyethylcelluloses, hydroxypropylmethylcelluloses (HPMC), and / or hydroxypropylcelluloses. However, the resulting gelation is only temporary: upon cooling to < 40°C, the gel reverts to its original viscous solution.To achieve thermogelation, a certain minimum concentration of the thermogelling hydrocolloids must be present; for methylcelluloses, this is approximately 1.5 g / l. The minimum concentration for other thermogelling hydrocolloids can be determined by a person skilled in the art without great experimental effort. Below this concentration, no gelling occurs when the aqueous solution is heated. Reversibly gelling hydrocolloids form gels at room temperature (approx. 20°C) which, in contrast to thermogelling hydrocolloids, melt when heated within a certain temperature range, i.e. they liquefy and form a viscous solution which, in turn, gels upon cooling to or below the gelling temperature. Hydrocolloids derived from algae, preferably carrageenan and / or agar, are used as reversibly gelling hydrocolloids.To achieve the desired consistency and support the permanent solidification of the vegan egg white, other hydrocolloids are additionally used, preferably gellan gum, locust bean gum, guar gum, alginate, and / or xanthan gum. According to the invention, the amount of hydrocolloids in the egg white is less than 5.00% (e.g., less than 4.75%, 4.50%, 4.25%, 4.00%, 3.75%, 3.50%, 3.25%, 3.00%, 2.75%, 2.50%, 2.25%, 2.00%, 1.75%, 1.50%, 1.00%, 0.75%, or equal to or less than 0.50%). In some embodiments, the amount of hydrocolloids in the egg yolk substitute is 0.10%-4.5% (e.g., 0.20%-4.00%, 0.25%-3.00%, 0.50%-2.50%, or 0.75%-2.00%). The ratio between thermogelling and reversibly gelling hydrocolloids is preferably 50:50, more preferably 25:75, 30:70, or 40:60, or 75:25, 70:30, or 60:40.A quantity of hydrocolloids of less than 5.00% allows the provision of a liquid raw egg substitute, but on the other hand ensures stability and texture, comparable to a chicken egg, when cooked.

[0053] In some embodiments, transglutaminases can optionally be added to improve the texture of the protein solutions or emulsions. The effect of the transglutaminases on the texture lies in their ability to promote protein cross-linking under certain temperatures and time conditions. The amount of transglutaminases is preferably between 0.001% and 3.00%, more preferably 0.01%-1.5%, and further preferably 0.1%-1.0%. The transglutaminases are activated while the protein solution or emulsion is heated to temperatures between 40°C-60°C for at least 15 minutes, preferably 30 minutes, 60 minutes, 90 minutes, or 120 minutes. The transglutaminase may, but need not, be microencapsulated and may preferably be inactivated during the manufacture of the egg replacer by pasteurization or UHT treatment (above 75°C or 120°C, respectively).

[0054] In some embodiments, vegetable oils can optionally be added to the mixture. The amount is preferably between 0.1% and 4%, more preferably between 0.5% and 2.0%. Suitable vegetable oils include olive oil, coconut oil, linseed oil, walnut oil, safflower oil, or peanut oil; however, neutral-tasting fats such as rapeseed oil, sunflower oil, coconut fat, and / or corn oil, as well as any combination thereof, are preferred.

[0055] In order to create browning of the product upon heating, for example when frying a “fried egg,” which occurs through a so-called Maillard reaction, a small amount of sugar is preferably added to the product. The sugars are preferably monosaccharides (e.g., dextrose, fructose, and / or galactose) and / or disaccharides (e.g., lactose and / or maltose). In some embodiments, the amount of sugar in the egg white is less than 1.00%, preferably less than 0.75%, less than 0.50%, less than 0.25%, or less than 0.10%. In some embodiments, the amount of sugar in the egg white is 0.10%-1.00%, preferably 0.25%-0.75%, 0.50%-0.50%, or 0.75%-0.25%.

[0056] The egg white substitute may also contain small amounts (less than 10.0%, preferably less than 5%, 3%, or 2%) of additional secondary components. These may include emulsifiers, flavorings (especially those containing sulfur compounds), spices, natural colors, preservatives, thickeners, or health-promoting additives. Examples include iodine, vitamins (e.g., vitamins B1, B2, B3, B5, B7, B9, B12, C, D3, or E), minerals (e.g., Ca or Mg), and / or plant lecithin (which also acts as an emulsifier).

[0057] The egg white substitute contains essentially no or no carotenoids.

[0058] The protein source and salt are dispersed in drinking water. The pH is adjusted between 6 and 9, preferably higher than 8.0, most preferably around 8.5, with pH food regulators such as sodium hydroxide (NaOH), potassium phosphate (K3PO4), or sodium citrate (NasCeH2O). The solution is preferably stirred for at least 1 minute, preferably 5-10 minutes, and even more preferably 15 minutes, to enhance the swelling of the proteins. It is preferred, but not necessary, to separate the proteins after swelling by suitable separation methods, preferably centrifugation, decantation, or membrane filtration. This separation results in a supernatant containing the soluble proteins and a pellet containing insoluble proteins. Depending on the salt concentration in the solutions used, the soluble proteins are mainly globulins and albumins. The supernatant solution (solution

[0059] (A)) is further used for egg white production, while the residue or pellet can be used to produce other products, e.g. a vegan egg yolk substitute.

[0060] According to the invention, the protein source is dispersed in water or an aqueous salt solution (solution (A)). Solution (A) can be divided into two parts ((A1) and (A2)). However, it is also possible to prepare two solutions (A1) and (A2) independently of each other: (A1) can be an aqueous protein or protein-salt solution, and (A2) that of another protein or just water. Optionally, 0.001% - 2.00% transglutaminase can be added to solution (A1). If unencapsulated transglutaminase is used, the solution should be kept at 50°C for less than 120 minutes. Solution (B) is prepared by heating solution (A1) to at least 40°C, preferably 50°C, but not more than 60°C, and adding one or more thermogelling hydrocolloids (e.g., modified cellulose, methylcellulose, and / or hydroxypropylcellulose). The heat treatment improves the dispersion of the hydrocolloids. Before or after the hydrocolloids are dispersed, oil (if necessary) is added.containing 0.01% - 50% emulsifiers), optionally a calcium ion source, natural colors, and optionally other additives are mixed into solution (B). Solution (C) is prepared by mixing solution (A2) with one or more reversibly gelling hydrocolloids at a temperature below 30°C, preferably less than 20°C, 15°C, or 10°C. Additionally, natural flavors, aroma formulations, oil, and (encapsulated) transglutaminase, or other additives, can be mixed into solution (C). Once all components of solutions (B) and (C) are fully dispersed, the solutions are stirred.

[0061] (B) and (C) are mixed at a temperature preferably below 30°C, thereby producing the final egg white solution (solution (D)). The solutions and dispersions described above are prepared in standard mixing vessels using known dispersion techniques. In a second alternative embodiment, no division of solution (A) is carried out, but the reversibly gelling hydrocolloid(s) and optionally other ingredients, such as sugar and salt, are added to solution (A). The mixture is heated to at least 40°C, preferably 50°C, before the thermogelling hydrocolloid is added with stirring until it is completely dispersed. The mixture is cooled to room temperature to obtain the egg white substitute product according to the invention.

[0062] The second component of a vegan egg is the egg yolk, which contains:

[0063] (a) Drinking water

[0064] (b) one or more proteins from pulses, oilseeds, cereals, algae or microorganisms,

[0065] (c) vegetable oil, which optionally contains at least one emulsifier,

[0066] (d) a combination of one or more reversibly thermogelling hydrocolloids with one or more reversibly gelling hydrocolloids,

[0067] (e) at least one carotenoid-containing food and / or a natural colouring substance,

[0068] (f) optionally an at least partially pregelatinised starch, and

[0069] (g) salt, wherein the proportion of the combination of one or more reversibly thermogelling hydrocolloid(s) with one or more reversibly gelling hydrocolloid(s) is 0.5-5.0 wt%.

[0070] The product according to the invention preferably has a protein content between 1% and 35%, advantageously between 3% and 25% or 20%, very advantageously between 4% and 15% and particularly advantageously between 5% and 12%. Suitable protein sources include plant-based raw materials from the group of pulses, cereals, oilseeds, (micro)algae and microorganisms, preferably peas (Pisum sativum), chickpeas (Cicer arientinum), garden beans (Phaseolus vulgaris), faba beans (Vicia faba), sweet lupins (Lupinus), lentils (Lens culinaris), maize (Zea mays), hemp (Cannabis sativa), sweet potatoes (Ipomoea batatas), cassava (Manihot esculenta), potatoes (Solanum tuberosum), pumpkin (Cucurbita), flax (Linum usitatissimum), rapeseed (Brassica napus), soy (Glycine max), oats (Avena sativa), bacteria (e.g. Lactobacillus spp., Streptococcus spp., and Bifidobacterium spp.), yeasts (e.g. Saccharomyces cerevisiae), molds (e.g. Aspergillus spp., Mucor spp., and Rhizopus spp.), nori seaweed, and / or wakame seaweed; pea, lupin, potato, chickpea, and faba bean proteins are particularly advantageous. Protein sources that can be used include (raw and / or hydrolyzed and / or fermented) flours, protein concentrates, protein isolates, and / or any combination thereof obtained from the plants and plant parts themselves, their seeds, tubers, and / or their fruits of the aforementioned raw materials. The processing and nutritional suitability of the plants and respective plant parts is sufficiently known to those skilled in the art in the field of food technology.

[0071] In some embodiments, transglutaminases can optionally be added to improve the texture of the protein solutions or emulsions. The effect of the transglutaminases on the texture lies in their ability to promote protein cross-linking under certain temperatures and time conditions. The amount of transglutaminases is preferably between 0.001% and 3.00%, more preferably 0.01%-1.5%, and further preferably 0.1%-1.0%. The transglutaminases are activated while the protein solution or emulsion is heated to temperatures between 40°C-60°C for at least 15 minutes, preferably 30 minutes, 60 minutes, 90 minutes, or 120 minutes. The transglutaminase may, but need not, be microencapsulated and may preferably be inactivated during the manufacture of the egg replacer by pasteurization or UHT treatment (above 75°C or 120°C, respectively).

[0072] The fat content is preferably between 1% and 50%, advantageously between 5% and 30%, very advantageously between 10% and 25%, and particularly advantageously between 12% and 18%. Suitable fat components include vegetable oils, e.g., olive oil, coconut oil, linseed oil, walnut oil, safflower oil, or peanut oil; however, neutral-tasting fats such as rapeseed oil, sunflower oil, coconut fat, and / or corn germ oil, as well as any combination thereof, are preferred. Emulsifiers can advantageously be added to the fat component at a level of up to 50%, preferably 5-40%, and more preferably 10-30%, based on the fat component content. These include, for example, lecithin (or its components, such as phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine or phosphatidylinositol), ascorbyl palmitate, sodium phosphate, sodium pyrophosphate, potassium phosphate, propylene glycol alginate, polyoxyethyl stearate, ammonium phosphatides, acetic acid monoglycerides, lactic acid monoglycerides, citric acid monoglycerides, tartaric acid monoglycerides,

[0073] Stearyl tartrate or sorbitan monostearate.

[0074] To give the egg yolk substitute the appropriate color, at least one carotenoid-containing food and / or natural colorings are added as an additional ingredient. Preparations made from fruits, vegetables and tubers, advantageously from tuber and root vegetables, e.g. from carrots, apricots, tomatoes, peppers, pumpkin, fennel and / or sweet potatoes, are suitable for this purpose. These are preferably cooked and processed into a puree or finely chopped. In some embodiments, the amount of carotenoid-containing foods in the egg yolk is less than 15.0% (e.g. less than 12.0%, less than 8.00%, less than 4.00%, less than 2.00%, less than 1.50% or less than 0.50%). In some embodiments, the amount of carotenoid-containing foods in the egg yolk is 0.01%-10.0% (e.g., 0.50%-9.50%, 2.50%-7.50%, or 3.00%-5.50%).It has been discovered that the use of sweet potatoes as a carotenoid-containing food surprisingly results in a texture and color similar to that of a classic chicken egg yolk. The use of sweet potatoes also increases the protein and fiber content and adds a starch component to the mix, which has a beneficial effect on the texture. These are preferably cooked and mashed or finely chopped. The amount of sweet potatoes can be between 3% and 10%, advantageously between 5% and 8%. If sweet potatoes are included as a carotenoid-containing food, the further addition of at least partially pregelatinized starch is unnecessary (0%) or can be limited to a small amount of less than 0.5%. Otherwise, the addition of at least one (partially) pregelatinized starch is recommended, preferably in an amount of 0.5% - 4%, more preferably 1.0% - 3.0%.(Partially) pregelatinized starch is preferably obtained from corn starch, potato starch, or rice starch by mechanical processing in the presence of water, with or without the application of heat. This process causes some or all of the starch granules to burst. The powder is then dried. Pregelatinized starch is a white to yellowish-white powder and swells in cold water. It has good flow properties and is suitable as a binding agent.

[0075] Other suitable preparations from fruits, vegetables and tubers can be used to adjust texture, mouthfeel and color. For optimal color adjustment, the addition of preferably fat-soluble natural colors such as carotenoids (e.g. ß-carotene, lycopene, zeaxanthin), carrot extracts, curcumin and also colors that are poorly soluble in water such as riboflavin is also suitable. These are used individually or in combination to achieve the desired color. In some embodiments, the amount of natural colors in the egg yolk is less than 2.00% (e.g. less than 1.50%, less than 1.00%, less than 0.75% or less than 0.25%). In some embodiments, the amount of natural colors in the egg yolk is 0.01%-2.00% (e.g. 0.25%-1.75%, 1.00%-0.50% or 1.75%-0.25%). The egg yolk color can range from yellow to dark orange in the L*a*b* color space.The brightness (L*) can range from 70-85, advantageously from 75-80; the red-green (a*) can range from 15-30, advantageously from 19-25; the yellow-blue (b*) can be 60-95, advantageously 70-90, especially advantageously 75-88.

[0076] To create an egg-like flavor, salt is added. Preferably, NaCl, KCl, NaH2PO4, Na2HPO4, Na or K citrate, CaCl, NaaPO4, and / or kala namak (black salt) or a salt comparable to kala namak that contains a proportion of sulfur compounds. For this purpose, in some embodiments, the amount of salt, preferably kala namak salt, is less than 2.00%, e.g., less than 0.75%, less than 0.50%, less than 0.25%, or less than 0.10%.

[0077] The egg yolk substitute may also contain small amounts (less than 10.0%, preferably less than 5%, 3%, or 2%) of additional secondary components. These may include flavorings, spices, dried vegetables or fruits, sugar, preservatives, thickeners, or health-promoting additives. Examples include iodine, vitamins (e.g., vitamins B1, B2, B3, B5, B7, B9, B12, C, D3, or E), and / or minerals (e.g., calcium or magnesium).

[0078] The egg yolk substitute contains hydrocolloids to achieve the desired viscosity and solidify upon heating. A combination of one or more thermogelling hydrocolloids with one or more reversibly gelling hydrocolloids has proven advantageous, although the two types differ in their behavior during temperature changes. Hydrocolloids that gel rapidly when the temperature is increased to > 40°C are called "thermogelling" or "thermoreversibly gelling" and are preferably modified celluloses, preferably methylcelluloses, hydroxyethylcelluloses, hydroxypropylmethylcellulose (HPMC), and / or hydroxypropylcellulose. However, the resulting gelation is only temporary: upon cooling to < 40°C, the gel reverts to its original viscous solution.To achieve thermogelation, a certain minimum concentration of the thermogelling hydrocolloids must be present; for methylcelluloses, this is approximately 1.5 g / l. The minimum concentration for other thermogelling hydrocolloids can be determined by a person skilled in the art without great experimental effort. Below this concentration, no gelling occurs when the aqueous solution is heated. Reversibly gelling hydrocolloids form gels at room temperature (approx. 20°C) which, in contrast to thermogelling hydrocolloids, melt when heated within a certain temperature range, i.e. they liquefy and form a viscous solution which, in turn, gels upon cooling to or below the gelling temperature. Hydrocolloids derived from algae, preferably carrageenan and / or agar, are used as reversibly gelling hydrocolloids.To achieve the desired consistency and support the permanent solidification of the vegan egg yolk, other hydrocolloids are additionally used, preferably gellan gum, locust bean gum, guar gum, alginate, and / or xanthan gum. In some embodiments, the amount of hydrocolloids in the egg yolk substitute is less than 5.00% (e.g., less than 4.75%, 4.50%, 4.25%, 4.00%, 3.75%, 3.50%, 3.25%, 3.00%, 2.75%, 2.50%, 2.25%, 2.00%, 1.75%, 1.50%, 1.00%, 0.75%, or equal to or less than 0.50%). In some embodiments, the amount of hydrocolloids in the egg yolk substitute is 0.10%-4.5% (e.g., 0.20%-4.00%, 0.25%-3.00%, 0.50%-2.50%, or 0.75%-2.00%). The ratio between thermogelling and reversibly gelling hydrocolloids is preferably 50:50, more preferably 25:75, 30:70, or 40:60, or 75:25, 70:30, or 60:40.A quantity of hydrocolloids of less than 5.00% allows the provision of a liquid raw egg substitute, but on the other hand ensures stability and texture, comparable to a chicken egg, when cooked.

[0079] In a preferred embodiment, the egg yolk substitute mixture is surrounded by a shell of a highly cross-linked hydrocolloid or thermoreversibly gel-forming hydrocolloid, preferably calcium alginate or k-carrageenan.

[0080] According to the invention, the protein source is dispersed in water or an aqueous salt solution (solution (A)). Solution (A) can be divided into two parts ((A1) and (A2)). However, it is also possible to prepare two solutions (A1) and (A2) independently of each other: (A1) can be an aqueous protein or protein-salt solution, and (A2) that of another protein or just water. Optionally, 0.001% - 2.00% transglutaminase can be added to solution (A1). If unencapsulated transglutaminase is used, the solution should be kept at 50°C for less than 120 minutes. Solution (B) is prepared by heating solution (A1) to at least 40°C, preferably 50°C, but not more than 60°C, and adding one or more thermogelling hydrocolloids (e.g., modified cellulose, methylcellulose, and / or hydroxypropylcellulose). The heat treatment improves the dispersion of the hydrocolloids. Before or after the hydrocolloids are dispersed, oil (if necessary) is added.containing 0.01% - 50% emulsifiers), optionally a calcium ion source, carotenoid-containing foods or natural colors, and optionally other additives are mixed into solution (B). Solution (C) is prepared by mixing solution (A2) with one or more reversible gelling hydrocolloids at a temperature below 30°C, preferably less than 20°C, 15°C, or 10°C. Additionally, natural flavors, aroma formulations, oil, and (encapsulated) transglutaminase or other additives can be mixed into solution (C). Once all components of solutions (B) and (C) are fully dispersed, solutions (B) and (C) are mixed at a temperature preferably below 30°C, producing the final egg yolk solution (solution (D)). The solutions and dispersions described above are prepared in standard mixing vessels using known dispersion techniques.

[0081] The mixture (solution (D)) can be homogenized to achieve a complete and fine distribution of the oil particles. Surprisingly, this improved both the mouthfeel, eliminating any roughness on the tongue, and the brightness, reducing the need for coloring and resulting in a stronger product gloss. Pressures between 5 bar and 300 bar can be used for homogenization, but preferably between 25 bar and 225 bar, and especially between 50 bar and 250 bar. Homogenization can be performed in one or two stages.

[0082] The independent solutions and their mixing are preferably carried out under vacuum, but not necessarily. The vacuum can prevent the formation of air bubbles in the egg yolk.

[0083] According to the invention, each of the solutions ((A), (B), (C), and / or (D)) can be either pasteurized or sterilized. Pasteurization / sterilization can also be supplemented by other techniques, such as UV and / or high-pressure processing. These methods are standard techniques that are familiar to those skilled in the art and are adequately described in the literature.

[0084] The following four methods are preferably suitable for forming a ball of egg yolk. For the sphere formation (encapsulation) a soluble calcium salt (e.g.

[0085] Calcium lactate or calcium chloride) is added as part of the ingredients to solution (B) and / or (C), and solution (B) and / or (C) is further processed to solution (D) as described above. Solution (D) containing the calcium salt should be dosed, if possible in spherical form, into an aqueous solution of a highly cross-linking hydrocolloid, preferably sodium alginate, and should remain in contact with this solution for a maximum of 5 minutes, preferably less than 4 minutes, and even better less than 3 minutes, so that the filling (solution (D)) remains liquid. Solution (D) can be pre-frozen or frozen in spherical molds and then placed in a lukewarm bath of the highly cross-linking hydrocolloid to form the capsule. By diffusion of calcium ions from solution (D) into the solution of the highly cross-linking hydrocolloid, an outer shell is formed and encapsulates the egg yolk (= solution (D)) through a cross-linking reaction of the highly cross-linking hydrocolloid with the calcium ions.In other words, a surface layer forms around the solution (D), creating a shape very similar to a familiar animal egg yolk. The encapsulated egg yolk should be rinsed with water as soon as possible to stop the cross-linking reaction. The amount of hydrocolloid surrounding the solution (D) should not exceed 1% of the total weight of the encapsulated egg yolk.

[0086] In a preferred embodiment of Method 1, the liquid "egg yolk" (solution (D)) is dosed into a hydrocolloid (preferably sodium alginate) solution as a spherical, coherent body (weight: between 5 and 20 g) using a nozzle and brought into contact with this solution for a period of less than 300 seconds, preferably less than 240 seconds, 120 seconds, or 60 seconds. The encapsulated egg yolk can then be rinsed in a demineralized water bath to remove excess alginate, preventing the "egg yolk" from hardening during storage and maintaining a liquid interior. Surprisingly, the liquid product remains so stable in its encapsulation that it can be transferred intact into a bowl / pan, where it remains curved and the liquid contents only flow out upon stirring / deliberate destruction of the shell.

[0087] METHOD 2: For sphere formation (encapsulation), a highly cross-linking

[0088] Hydrocolloid (e.g. sodium alginate) is added as part of the ingredients to solution (B and / or C) and solution (B and / or C) is further processed into solution (D) as described above. Solution (D) containing the highly cross-linking hydrocolloid should, if possible, be dosed in spherical form into an aqueous calcium salt (e.g. calcium lactate or calcium chloride) solution and remain in contact with this solution for a maximum of 5 minutes, preferably less than 4 minutes, and even better less than 3 minutes, so that the filling (solution (D)) remains liquid. Solution (D) can be pre-frozen or frozen in spherical molds and then placed in a lukewarm calcium salt bath to form the capsule. Through diffusion of calcium ions from the calcium salt solution, an outer shell is formed and encapsulates the egg yolk (= solution (D)) through a cross-linking reaction between the highly cross-linking hydrocolloid and the calcium ions.In other words, a surface layer forms around the solution (D), creating a shape very similar to a familiar animal egg yolk. The encapsulated egg yolk should be rinsed with water as soon as possible to stop the cross-linking reaction. Surprisingly, the liquid product remains so stable in its encapsulation that it can be transferred intact into a bowl / pan, where it remains curved, and the liquid contents only flow out upon stirring or deliberate disruption of the shell. The amount of calcium salt surrounding the solution (D) does not exceed 1% of the total weight of the encapsulated egg yolk.

[0089] METHOD 3 To form a spherical shape, the described egg yolk

[0090] Formulation (solution (D)) is deep-frozen in suitable molds made of silicone rubber, plastic, stainless steel, or similar materials at temperatures <0°C, typically -18°C and below. The resulting spheres or hemispheres of frozen solution D with diameters between 1 and 4 cm, ideally around 2-3 cm, are then further cooled using liquid nitrogen (boiling point -196°C) until no noticeable gas bubbles form on the surface of the spheres (thermodynamic equilibrium is reached). A previously prepared solution of a thermoreversibly gelling hydrocolloid, typically sodium alginate and / or k-carrageenan, is dissolved in water at temperatures above 35°C to obtain a 1-2% clear solution. This solution is then cooled to temperatures between 35°C and 50°C, ideally in the range of 45-50°C.The frozen spheres of solution D are then immersed in the hydrocolloid solution, so that a gel layer forms on the surface upon cooling. The thickness of the gel layer can be adjusted by immersion time, sphere size, and added amount of hydrocolloid solution, and is 1-5 mm, typically around 1-2 mm. In other words, a surface layer forms around the solidified solution (D), resulting in an overall shape very similar to a familiar animal egg yolk. Surprisingly, after thawing, the liquid product remains so stable in its encapsulation that it can be transferred intact into a bowl / pan, where it remains curved, and the liquid contents only flow out upon stirring or deliberate destruction of the shell. The amount of thermoreversibly gelling hydrocolloid surrounding solution (D) does not exceed 1% of the total weight of the encapsulated egg yolk.

[0091] METHOD 4 To form a spherical shape, the described egg yolk

[0092] Formulation (solution (D) without calcium ion source) in suitable forms from

[0093] Silicone rubber, plastic, stainless steel or similar at temperatures <0°C, typically at -

[0094] 18°C and below, deep-frozen. If necessary, the resulting spheres or hemispheres of frozen solution (D) with diameters between 1 and 4 cm, ideally around 2-3 cm, are then further cooled using liquid nitrogen (boiling point -196°C) until no noticeable gas bubbles develop on the surface of the spheres (thermodynamic equilibrium is reached). The spheres or hemispheres can be sprayed with calcium ions on their surfaces so that the ions adhere to the frozen surface. A previously prepared solution of a thermoreversibly gelling hydrocolloid, typically sodium alginate and / or k-carrageenan, is dissolved in water at temperatures above 35°C to obtain a 1-3% clear solution. This solution is then cooled to temperatures between 35 and 50°C, ideally in the range of 45-50°C.The deep-frozen spheres, which ideally have a homogeneous layer of calcium ions on their surface, are then immersed in the hydrocolloid solution, so that a gel layer forms on the surface upon cooling. The thickness of the gel layer can be adjusted by immersion time, sphere size, and added amount of hydrocolloid solution, and is 1-5 mm, typically around 1-2 mm. In other words, a surface layer forms around the solidified solution (D), resulting in an overall shape that is very similar to a well-known animal egg yolk. Surprisingly, after thawing, the liquid product remains so stable in its encapsulation that it can be transferred intact into a bowl / pan, where it remains curved and the liquid contents only seep through.

[0095] Stirring / deliberately disrupting the shell. The amount of thermoreversibly gelling hydrocolloid surrounding the solution (D) does not exceed 1% of the total weight of the encapsulated egg yolk. The encapsulated egg yolk can be stored in a preservative and / or buffer solution containing, for example, NaCl, calcium salt, benzoic acid, and / or ascorbic acid.

[0096] Further details on the structure and method of production of the egg white substitute and egg yolk substitute can be found in the applications with the application numbers 102021 130963.8 and 102021 130974.3, the disclosure of which is hereby incorporated by reference.

[0097] In order to fill the shell described above, preferably produced by injection molding, with the egg white and egg yolk substitute, two different methods are basically suitable: (I) filling variant using an externally formed yolk body and (II) filling variant using in-situ forming of the yolk body.

[0098] Filling variant (I) is characterized by the fact that it starts with an egg yolk mixture coated with cross-linked hydrocolloid, preferably calcium alginate. The mass of the formed yolk body is typically 20-30 g, ideally 25-29 g. The formed coating allows the yolk body to be positioned in the half-shell (see Example 3), which does not have an additional filling hole. The second half-shell is positioned on top of it using a plug-in connection to form a hollow body with the yolk body contained therein. In order to connect the half-shells together along the equator in a liquid- and gas-tight manner, suitable joining processes are used, which can be carried out a) by locally applying thermal energy (heat sealing, friction welding, laser pulse welding, etc.) or b) by chemically or physically setting a suitable sealing medium (food-compliant and optionally biodegradable sealing wax orSealing adhesive within the plug-in connection; external application of a food-safe and optionally biodegradable composite layer, e.g. sealing strip or spray paint). After both half-shells have been positively and irreversibly joined in this way, the second component (vegan egg white) is added via the additional filling hole using a dosing system. The maximum filling level of the egg white depends on the position of the filling hole and can be adjusted by changing the position of the egg body (e.g. tilting). The filling hole of the filled egg is sealed liquid- and gas-tight using suitable sealing materials, e.g. adhesive or sealing plates made of the same or a different material as the shell.

[0099] Filling variant (II) is characterized by the fact that it starts with a liquid egg yolk mixture and a liquid egg white mixture. The two half-shells (see example 3) are joined in an empty state along the equatorial plane using suitable joining processes as mentioned above, ensuring a liquid- and gas-tight seal. A highly cross-linked polysaccharide solution (e.g., alginate) not intended for final consumption is then metered into the hollow body through the filling hole. The required amount of egg yolk formulation is injected into this solution, resulting in the formation of a thin, edible, artificial yolk membrane at the interface between the egg yolk and the polysaccharide solution (in-situ formation). Once the desired membrane thickness has been achieved, the remaining polysaccharide solution is removed through the filling hole by pouring or suction, and optionally rinsed with deionized water.The further procedure (dosing the egg white, closing the filling hole) is carried out as described above for filling variant (I).

[0100] The invention is further explained with reference to the figures, which show:

[0101] Figure 1 : Microscopic structure of a chicken eggshell (taken from literature [1])

[0102] Figure 2: Water vapor and oxygen permeability of various polymers (adapted from reference

[0023] )

[0103] Figure 3: Tensile strength and stiffness (Young’s modulus) of various polymers (adapted from reference

[0023] )

[0104] Figure 4: Example of the finished eggshell

[0105] The following examples are to be understood as possible embodiments and do not represent a limitation to these exact embodiments.

[0106] Examples

[0107] Example 1 : Preparation of compound from PHBV and CaCOs

[0108] PHBV with a melting point of 175°C was dried overnight at 50°C and CaCO3 at 100°C, mixed in powder form in a ratio of 7:3, and compounded and granulated at a temperature profile of 45-140-150-150-150°C. A pressed film with a thickness of approximately 240 μm was produced from the light brown granules. The gas permeability measurement yielded a water vapor permeability (WVTR, 85 -> 0% relative humidity, 23°C) of 1.8 g m- 2 d' 1 (normalized to 100pm: 4.4 g rrr 2 d -1 ) and an oxygen permeability (OTR, 23°C / 50% rel. humidity) of 10.5 cm 3 rrr 2 d -1 (normalized to 100pm: 67.2 cm 3 rrr 2 d -1 ). The mechanical tensile test showed a tensile strength of 21.6 MPa, an elongation at break of 1.1% and a modulus of elasticity of 2.9 GPa.

[0109] Example 2: Production of compound from PLLA and CaCOs

[0110] PLLA with a low proportion of D-isomers (melting point 160°C) was dried overnight at 60°C and CaCO3 at 100°C, mixed in powder form in a ratio of 8:2, and compounded and granulated at a temperature profile of 60-160-190-190-145-145-145°C. A pressed film approximately 200 μm thick was produced from the whitish granules. Gas permeability measurements yielded a water vapor transmission rate (WVTR, 85 -> 0% relative humidity, 23°C) of 11 gm³. -2 d -1 (normalized to 100pm: 22 g rrr 2 d -1 ) and an oxygen permeability (OTR, 23°C / 50% rel. humidity) of 75 cm 3 rrr 2 d -1 (normalized to 100pm: 150 cm 3 rrr 2 d -1 ). The mechanical tensile test showed a tensile strength of 40 MPa, an elongation at break of 1.0% and a modulus of elasticity of 4 GPa.

[0111] Figures 2 and 3 show a comparison of the achieved permeation and mechanical properties of the compounds of Examples 1 and 2 with common polymers for food packaging.

[0112] Example 3: Texture and shape of the shell

[0113] The compound from Example 1 is injection molded into two rotationally symmetrical half-shells of equal height (see Fig. 4). Before thermoplastic processing, the compound is dried at 50–80°C for 6–48 hours. Depending on the stability and viscosity of the melt, the temperature profile in the injection molding extruder corresponds to that of the preceding compounding process; however, it can be slightly higher if necessary. To ensure suitable material and heat distribution in the injection mold, the geometry of the injection point can be designed either centrally or equatorially. The volume of the egg-shaped hollow body resulting from the combination of the two half-shells corresponds to that of a large chicken egg, ranging between 60–65 ml. The achieved shell thickness of the injected half-shells corresponds approximately to that of a chicken egg, i.e., approximately 0.6–0.75 mm.The two half-shells have a plug-in mechanism along the equator, which allows them to be joined precisely. In the area of ​​the plug-in connection, the shell thickness increases slightly, by a factor of 2, to ensure greater mechanical stability. One of the two half-shells, ideally the upper one, which tapers slightly towards the tip, has an opening between 3 and 5 mm in diameter on the side in the upper third or centrally located on the axis of rotation. This opening is formed during the injection molding process. This opening makes it possible to fill the resulting hollow body, which results from the firm connection of the two eggshell halves, with one or more flowable and conveyable components (egg white and optionally egg yolk).

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Claims

Patent claims 1) Use of a material from (A) one or more biodegradable, thermoplastic biopolymer(s), and (B) one or more inorganic, organic or sparingly soluble salt(s) as a shell for an egg substitute product. 2) Use according to claim 1, wherein the material is produced by extrusion from components (A) and (B). 3) Use according to claim 1 or 2, wherein the biopolymer (A) is characterized by a degradation rate of at least 90% within 180 days, a disintegration level of less than 10% dry mass with particles larger than 2 mm after 12 weeks and / or passing an ecotoxicity analysis with respect to plant growth. 4) Use according to any one of claims 1-3, wherein the biopolymer (A) is a polyhydroxyalkanoate, polyhydroxyalkanoate copolymer or polylactide. 5) Use according to any one of claims 1-4, wherein the salt (B) is a carbonate, sulfate, hydrogen sulfate, sulfite, sulfide, phosphate, hydrogen phosphate, oxide, hydroxide, citrate or oxalate of an alkaline earth element, a transition metal or of aluminium. ) Use according to any one of claims 1-5, wherein the salt (B) is CaCO3, CaSO4, Ca3(PO4)2, MgCO3, BaSO4, Ca citrate, Ca oxalate, Fe2O3 or AhO3.) Use according to any one of claims 4-6, wherein the polyhydroxyalkanoate and / or polyhydroxyalkanoate copolymer is poly(3-hydroxypropionate), poly(3-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3-hydroxyhexanoate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxynonanoate), poly(3-hydroxydecanoate), poly(3-hydroxyundecanoate), poly(3-hydroxydodecanoate), poly(3-hydroxytetradecanoate), poly(3-hydroxypentadecanoate), poly(3-hydroxyhexadecanoate); Poly(3-hydroxypropionate-co-3-hydroxybutyrate), Poly(3-hydroxypropionate-co-4-hydroxybutyrate), Poly(3-hydroxybutyrate-co-4-hydroxybutyrate), Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), Poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate), medium-chain PHAs with side chain lengths of C3-Cn or long-chain PHAs with side chain lengths greater than C12.) Use according to any one of claims 4-6, wherein the polylactide is an amorphous or crystalline variant of poly(L-lactide) PLLA, poly(D-lactide) PDLA, stereocomplex-(polylactide) sc-PLA, stereoblock-(polylactide) sb-PLA. ) Egg substitute product comprising a vegan-based egg white and egg yolk surrounded by a shell made of an extruded material consisting of (A) one or more biodegradable, thermoplastic biopolymer(s), and (B) one or more inorganic, organic, or sparingly soluble salt(s), wherein both the egg white and egg yolk contain (a) plant protein from pulses, oilseeds, cereals, and / or algae, and (b) a combination of at least two hydrocolloids exhibiting different temperature-change behavior.

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